Science.gov

Sample records for carbon abatement potential

  1. A Regionally-Specific Assessment of the Carbon Abatement Potential of Biochar

    NASA Astrophysics Data System (ADS)

    Birch, G.; Field, J.; Keske, C.; DeFoort, M.; Cotrufo, M.

    2012-12-01

    Biochar, the solid carbon-rich co-product of certain bioenergy conversion technologies, is receiving a great deal of attention as a strategy for sequestering carbon in soils and improving the performance of agricultural systems. Several studies have attempted to quantify the lifecycle carbon abatement potential of biochar systems, considering emissions associated with feedstock provisioning and processing, energy co-production, agronomic system impacts (yield increases and nitrous oxide emission suppression), and the recalcitrance of biochar in soil, as well as accounting for the carbon abatement value of using the char as a fuel that is foregone when it is used as a soil amendment instead. These assessments typically focus on biochar production in advanced, efficient slow pyrolysis systems, despite the fact that much biochar is currently produced through small-scale carbonization or gasification systems that lack energy recovery or even emission control capability. Here, a mechanistic biochar system assessment model is presented, capable of estimating system carbon abatement value and profitability for different feedstocks, conversion technologies and temperatures, and application into different agricultural soils. The variation of biochar recalcitrance in soil as a function of production temperature is considered, and agricultural impacts are assessed in the context of biochar's liming value, an effect that is straightforward to quantify and that has often been implicated in observed crop yield increases or nitrous oxide emission reductions. The analysis is rigorous in that tradeoffs between biochar production quantity and quality are endogenized, but conservative in that other potential agronomic benefits of biochar (e.g. improved soil water holding capacity) are not considered. This model is applied to a case study of bioenergy and biochar co-production in northern Colorado using beetle-killed pine wood and slash as a feedstock. Preliminary results suggest that

  2. Potential Cost-Effective Opportunities for Methane Emission Abatement

    SciTech Connect

    Warner, Ethan; Steinberg, Daniel; Hodson, Elke; Heath, Garvin

    2015-08-01

    The energy sector was responsible for approximately 84% of carbon dioxide equivalent (CO2e) greenhouse gas (GHG) emissions in the U.S. in 2012 (EPA 2014a). Methane is the second most important GHG, contributing 9% of total U.S. CO2e emissions. A large portion of those methane emissions result from energy production and use; the natural gas, coal, and oil industries produce approximately 39% of anthropogenic methane emissions in the U.S. As a result, fossil-fuel systems have been consistently identified as high priority sectors to contribute to U.S. GHG reduction goals (White House 2015). Only two studies have recently attempted to quantify the abatement potential and cost associated with the breadth of opportunities to reduce GHG emissions within natural gas, oil, and coal supply chains in the United States, namely the U.S. Environmental Protection Agency (EPA) (2013a) and ICF (2014). EPA, in its 2013 analysis, estimated the marginal cost of abatement for non-CO2 GHG emissions from the natural gas, oil, and coal supply chains for multiple regions globally, including the United States. Building on this work, ICF International (ICF) (2014) provided an update and re-analysis of the potential opportunities in U.S. natural gas and oil systems. In this report we synthesize these previously published estimates as well as incorporate additional data provided by ICF to provide a comprehensive national analysis of methane abatement opportunities and their associated costs across the natural gas, oil, and coal supply chains. Results are presented as a suite of marginal abatement cost curves (MACCs), which depict the total potential and cost of reducing emissions through different abatement measures. We report results by sector (natural gas, oil, and coal) and by supply chain segment - production, gathering and boosting, processing, transmission and storage, or distribution - to facilitate identification of which sectors and supply chain

  3. Save water to save carbon and money: developing abatement costs for expanded greenhouse gas reduction portfolios.

    PubMed

    Stokes, Jennifer R; Hendrickson, Thomas P; Horvath, Arpad

    2014-12-01

    The water-energy nexus is of growing interest for researchers and policy makers because the two critical resources are interdependent. Their provision and consumption contribute to climate change through the release of greenhouse gases (GHGs). This research considers the potential for conserving both energy and water resources by measuring the life-cycle economic efficiency of greenhouse gas reductions through the water loss control technologies of pressure management and leak management. These costs are compared to other GHG abatement technologies: lighting, building insulation, electricity generation, and passenger transportation. Each cost is calculated using a bottom-up approach where regional and temporal variations for three different California water utilities are applied to all alternatives. The costs and abatement potential for each technology are displayed on an environmental abatement cost curve. The results reveal that water loss control can reduce GHGs at lower cost than other technologies and well below California's expected carbon trading price floor. One utility with an energy-intensive water supply could abate 135,000 Mg of GHGs between 2014 and 2035 and save--rather than spend--more than $130/Mg using the water loss control strategies evaluated. Water loss control technologies therefore should be considered in GHG abatement portfolios for utilities and policy makers. PMID:25369123

  4. Essays on carbon abatement and electricity markets

    NASA Astrophysics Data System (ADS)

    Taber, John Timothy

    In the first chapter of this dissertation, I study the effects of a number of policies which affect the electric grid using the SuperOPF, a full AC optimization/simulation framework with optimal investment developed at Cornell University. A 36-node model of the Northeast Power Coordinating Council is used to test policies that aim to reduce CO2, other emissions, or otherwise impact the operation of the electric grid: a base case, with no new environmental legislation; enactment of the Kerry-Lieberman CO2 allowance proposal in 2012; following Fukishima, a retirement of all US nuclear plants by 2022 with and without Kerry-Lieberman; marginal damages from SO2 and NOX emissions charged to coal, gas and oil-fired generation; plug-in hybrid electric vehicle load filling; wind incentives in place; and two cases which combine these. The cases suggest that alternative policies may have very different outcomes in terms of electricity prices, emissions, and health outcomes. In all cases, however, the optimal strategy for future investment is investment in new natural gas combined cycle plants. Policies can change how much new generation is built, whether other plants are built, or what types of plants are retired. The second chapter of my dissertation utilizes the SuperOPF and the model of the Northeast Power Coordinating Council to analyze the issue of carbon leakage. I analyze the effects of a regionally-limited carbon cap and trade program, the Regional Greenhouse Initiative (RGGI), when additional generating assets in non-affected states are included in the analysis. In the face of different carbon prices on generating assets in covered and non-covered states, generation is expected to shift from states bound by RGGI to states outside of RGGI. This carbon leakage may undermine some or all of the benefits of RGGI while simultaneously increasing prices for customers in the area. Even though carbon prices under RGGI are very low, some leakage is occurring, and this leakage

  5. Perverse effects of carbon markets on HFC-23 and SF6 abatement projects in Russia

    NASA Astrophysics Data System (ADS)

    Schneider, Lambert; Kollmuss, Anja

    2015-12-01

    Carbon markets are considered a key policy tool to achieve cost-effective climate mitigation. Project-based carbon market mechanisms allow private sector entities to earn tradable emissions reduction credits from mitigation projects. The environmental integrity of project-based mechanisms has been subject to controversial debate and extensive research, in particular for projects abating industrial waste gases with a high global warming potential (GWP). For such projects, revenues from credits can significantly exceed abatement costs, creating perverse incentives to increase production or generation of waste gases as a means to increase credit revenues from waste gas abatement. Here we show that all projects abating HFC-23 and SF6 under the Kyoto Protocol’s Joint Implementation mechanism in Russia increased waste gas generation to unprecedented levels once they could generate credits from producing more waste gas. Our results suggest that perverse incentives can substantially undermine the environmental integrity of project-based mechanisms and that adequate regulatory oversight is crucial. Our findings are critical for mechanisms in both national jurisdictions and under international agreements.

  6. Achieving CO2 reductions in Colombia: Effects of carbon taxes and abatement targets

    SciTech Connect

    Calderón, Silvia; Alvarez, Andres Camilo; Loboguerrero, Ana Maria; Arango, Santiago; Calvin, Katherine; Kober, Tom; Daenzer, Kathryn; Fisher-Vanden, Karen

    2015-06-03

    In this paper we investigate CO2 emission scenarios for Colombia and the effects of implementing carbon taxes and abatement targets on the energy system. By comparing baseline and policy scenario results from two integrated assessment partial equilibrium models TIAM-ECN and GCAM and two general equilibrium models Phoenix and MEG4C, we provide an indication of future developments and dynamics in the Colombian energy system. Currently, the carbon intensity of the energy system in Colombia is low compared to other countries in Latin America. However, this trend may change given the projected rapid growth of the economy and the potential increase in the use of carbon-based technologies. Climate policy in Colombia is under development and has yet to consider economic instruments such as taxes and abatement targets. This paper shows how taxes or abatement targets can achieve significant CO2 reductions in Colombia. Though abatement may be achieved through different pathways, taxes and targets promote the entry of cleaner energy sources into the market and reduce final energy demand through energy efficiency improvements and other demand-side responses. The electric power sector plays an important role in achieving CO2 emission reductions in Colombia, through the increase of hydropower, the introduction of wind technologies, and the deployment of biomass, coal and natural gas with CO2 capture and storage (CCS). Uncertainty over the prevailing mitigation pathway reinforces the importance of climate policy to guide sectors toward low-carbon technologies. This paper also assesses the economy-wide implications of mitigation policies such as potential losses in GDP and consumption. As a result, an assessment of the legal, institutional, social and environmental barriers to economy-wide mitigation policies is critical yet beyond the scope of this paper.

  7. Achieving CO2 reductions in Colombia: Effects of carbon taxes and abatement targets

    DOE PAGESBeta

    Calderón, Silvia; Alvarez, Andres Camilo; Loboguerrero, Ana Maria; Arango, Santiago; Calvin, Katherine; Kober, Tom; Daenzer, Kathryn; Fisher-Vanden, Karen

    2015-06-03

    In this paper we investigate CO2 emission scenarios for Colombia and the effects of implementing carbon taxes and abatement targets on the energy system. By comparing baseline and policy scenario results from two integrated assessment partial equilibrium models TIAM-ECN and GCAM and two general equilibrium models Phoenix and MEG4C, we provide an indication of future developments and dynamics in the Colombian energy system. Currently, the carbon intensity of the energy system in Colombia is low compared to other countries in Latin America. However, this trend may change given the projected rapid growth of the economy and the potential increase inmore » the use of carbon-based technologies. Climate policy in Colombia is under development and has yet to consider economic instruments such as taxes and abatement targets. This paper shows how taxes or abatement targets can achieve significant CO2 reductions in Colombia. Though abatement may be achieved through different pathways, taxes and targets promote the entry of cleaner energy sources into the market and reduce final energy demand through energy efficiency improvements and other demand-side responses. The electric power sector plays an important role in achieving CO2 emission reductions in Colombia, through the increase of hydropower, the introduction of wind technologies, and the deployment of biomass, coal and natural gas with CO2 capture and storage (CCS). Uncertainty over the prevailing mitigation pathway reinforces the importance of climate policy to guide sectors toward low-carbon technologies. This paper also assesses the economy-wide implications of mitigation policies such as potential losses in GDP and consumption. As a result, an assessment of the legal, institutional, social and environmental barriers to economy-wide mitigation policies is critical yet beyond the scope of this paper.« less

  8. Microbial Sulfate Reduction and Its Potential Utility as an Acid Mine Water Pollution Abatement Procedure

    PubMed Central

    Tuttle, Jon H.; Dugan, Patrick R.; Randles, Chester I.

    1969-01-01

    The presence of high concentrations of sulfate, iron, and hydrogen (acid) ions in drainage from coal mines and other areas containing waste pyritic materials is a serious water pollution problem. Sulfate can be removed from solution by microbial reduction to sulfide and subsequent precipitation as FeS. A mixed culture of microorganisms degraded wood dust cellulose, and the degradation products served as carbon and energy sources for sulfate-reducing bacteria. Metabolism of carbon compounds resulted in a net pH increase in the system. Oxidation-reduction potential (Eh) and temperature and carbon supplements were studied in an effort to accelerate the sulfate reduction process, with the ultimate objective of utilizing the process as a pollution abatement procedure. PMID:5775914

  9. Irreversible membrane fouling abatement through pre-deposited layer of hierarchical porous carbons.

    PubMed

    Hamad, Juma Z; Dua, Rubal; Kurniasari, Novita; Kennedy, Maria D; Wang, Peng; Amy, Gary L

    2014-11-15

    In this work, dual-templated hierarchical porous carbons (HPCs), produced from a coupled ice-hard templating approach, are shown to be a highly effective solution to the commonly occurring problem of irreversible fouling of low-pressure membranes used for pre-treatment in wastewater reuse. For the first time, dual-templated HPCs, along with their respective counterparts - single-templated meso-porous carbon (MPCs) (without macropores) - are tested in terms of their fouling reduction capacity and ability to remove different effluent organic matter fractions present in wastewater and compared with a commercially available powdered activated carbon (PAC). The synthesized HPCs provided exceptional fouling abatement, a 4-fold higher fouling reduction as compared to the previously reported best performing commercial PAC and ∼2.5-fold better fouling reduction than their respective mesoporous counterpart. Thus, it is shown that not only mesoporosity, but macroporosity is also necessary to achieve high fouling reduction, thus emphasizing the need for dual templating. In the case of HPCs, the pre-deposition technique is also found to outperform the traditional sorbent-feed mixing approach, mainly in terms of removal of fouling components. Based on their superior performance, a high permeability (ultra-low-pressure) membrane consisting of the synthesized HPC pre-deposited on a large pore size membrane support (0.45 μm membrane), is shown to give excellent pre-treatment performance for wastewater reuse application. PMID:25128660

  10. Carbon Abatement and Emissions Associated with the Gasification of Walnut Shells for Bioenergy and Biochar Production

    PubMed Central

    Pujol Pereira, Engil Isadora; Suddick, Emma C.; Six, Johan

    2016-01-01

    By converting biomass residue to biochar, we could generate power cleanly and sequester carbon resulting in overall greenhouse gas emissions (GHG) savings when compared to typical fossil fuel usage and waste disposal. We estimated the carbon dioxide (CO2) abatements and emissions associated to the concurrent production of bioenergy and biochar through biomass gasification in an organic walnut farm and processing facility in California, USA. We accounted for (i) avoided-CO2 emissions from displaced grid electricity by bioenergy; (ii) CO2 emissions from farm machinery used for soil amendment of biochar; (iii) CO2 sequestered in the soil through stable biochar-C; and (iv) direct CO2 and nitrous oxide (N2O) emissions from soil. The objective of these assessments was to pinpoint where the largest C offsets can be expected in the bioenergy-biochar chain. We found that energy production from gasification resulted in 91.8% of total C offsets, followed by stable biochar-C (8.2% of total C sinks), offsetting a total of 107.7 kg CO2-C eq Mg-1 feedstock. At the field scale, we monitored gas fluxes from soils for 29 months (180 individual observations) following field management and precipitation events in addition to weekly measurements within three growing seasons and two tree dormancy periods. We compared four treatments: control, biochar, compost, and biochar combined with compost. Biochar alone or in combination with compost did not alter total N2O and CO2 emissions from soils, indicating that under the conditions of this study, biochar-prompted C offsets may not be expected from the mitigation of direct soil GHG emissions. However, this study revealed a case where a large environmental benefit was given by the waste-to-bioenergy treatment, addressing farm level challenges such as waste management, renewable energy generation, and C sequestration. PMID:26963623

  11. Carbon Abatement and Emissions Associated with the Gasification of Walnut Shells for Bioenergy and Biochar Production.

    PubMed

    Pujol Pereira, Engil Isadora; Suddick, Emma C; Six, Johan

    2016-01-01

    By converting biomass residue to biochar, we could generate power cleanly and sequester carbon resulting in overall greenhouse gas emissions (GHG) savings when compared to typical fossil fuel usage and waste disposal. We estimated the carbon dioxide (CO2) abatements and emissions associated to the concurrent production of bioenergy and biochar through biomass gasification in an organic walnut farm and processing facility in California, USA. We accounted for (i) avoided-CO2 emissions from displaced grid electricity by bioenergy; (ii) CO2 emissions from farm machinery used for soil amendment of biochar; (iii) CO2 sequestered in the soil through stable biochar-C; and (iv) direct CO2 and nitrous oxide (N2O) emissions from soil. The objective of these assessments was to pinpoint where the largest C offsets can be expected in the bioenergy-biochar chain. We found that energy production from gasification resulted in 91.8% of total C offsets, followed by stable biochar-C (8.2% of total C sinks), offsetting a total of 107.7 kg CO2-C eq Mg-1 feedstock. At the field scale, we monitored gas fluxes from soils for 29 months (180 individual observations) following field management and precipitation events in addition to weekly measurements within three growing seasons and two tree dormancy periods. We compared four treatments: control, biochar, compost, and biochar combined with compost. Biochar alone or in combination with compost did not alter total N2O and CO2 emissions from soils, indicating that under the conditions of this study, biochar-prompted C offsets may not be expected from the mitigation of direct soil GHG emissions. However, this study revealed a case where a large environmental benefit was given by the waste-to-bioenergy treatment, addressing farm level challenges such as waste management, renewable energy generation, and C sequestration. PMID:26963623

  12. THE CO2 ABATEMENT POTENTIAL OF CALIFORNIA'S MID-SIZED COMMERCIAL BUILDINGS

    SciTech Connect

    Stadler, Michael; Marnay, Chris; Cardoso, Goncalo; Lipman, Tim; Megel, Olivier; Ganguly, Srirupa; Siddiqui, Afzal; Lai, Judy

    2009-12-31

    stimulating CHP deployment, while the SGIP buy down is more powerful. The attractiveness of CHP varies widely by climate zone and service territory, but in general, hotter inlandareas and San Diego are the more attractive regions because high cooling loads achieve higher equipment utilization. Additionally, large office buildings are surprisingly good hosts for CHP, so large office buildings in San Diego and hotter urban centers emerge as promising target hosts. Overall the effect on CO2 emissions is limited, never exceeding 27 percent of the CARB target. Nonetheless, results suggest that the CO2 emissions abatement potential of CHP in mid-sized CA buildings is significant, and much more promising than is typically assumed.

  13. Coupled Climate-Economy-Biosphere (CoCEB) model - Part 1: Abatement share and investment in low-carbon technologies

    NASA Astrophysics Data System (ADS)

    Ogutu, K. B. Z.; D'Andrea, F.; Ghil, M.; Nyandwi, C.; Manene, M. M.; Muthama, J. N.

    2015-04-01

    The Coupled Climate-Economy-Biosphere (CoCEB) model described herein takes an integrated assessment approach to simulating global change. By using an endogenous economic growth module with physical and human capital accumulation, this paper considers the sustainability of economic growth, as economic activity intensifies greenhouse gas emissions that in turn cause economic damage due to climate change. Different types of fossil fuels and different technologies produce different volumes of carbon dioxide in combustion. The shares of different fuels and their future evolution are not known. We assume that the dynamics of hydrocarbon-based energy share and their replacement with renewable energy sources in the global energy balance can be modeled into the 21st century by use of logistic functions. Various climate change mitigation policy measures are considered. While many integrated assessment models treat abatement costs merely as an unproductive loss of income, we consider abatement activities also as an investment in overall energy efficiency of the economy and decrease of overall carbon intensity of the energy system. The paper shows that these efforts help to reduce the volume of industrial carbon dioxide emissions, lower temperature deviations, and lead to positive effects in economic growth.

  14. The cost effectiveness of a policy to store carbon in Australian agricultural soils to abate greenhouse gas emissions

    NASA Astrophysics Data System (ADS)

    White, Robert E.; Davidson, Brian

    2015-07-01

    Data for cropping and pastoral enterprises in south eastern Australia were used in a cost-effectiveness analysis to assess the feasibility of abating greenhouse gas (GHG) emissions through storing soil carbon (C) as soil organic matter under the Australian government's Carbon Farming Initiative. We used the C credit value for 2013-14 of 24.15 per tonne of CO2- equivalent (CO2-e) and a C storage rate of 0.5 tonne C/hectare/year for conversion of cropland to pasture. Given that a change of enterprise is driven primarily by farmer returns, we found that none of the changes were feasible at current prices, with the exception of wheat to cattle or sheep in an irrigated system, and dryland cotton to cattle or sheep. Given that our model scenario assumed the most favourable economic factors, it is unlikely that increased soil C storage through a change from cropping to pasture can make a significant contribution to abating Australia's CO2 emissions. However, of greater concern to society is the methane emissions from grazing cattle or sheep, which would negate any gain in soil C under pasture, except for a switch from dryland cropping to sheep.

  15. Exploring the potential of fungi for methane abatement: Performance evaluation of a fungal-bacterial biofilter.

    PubMed

    Lebrero, Raquel; López, Juan Carlos; Lehtinen, Iiro; Pérez, Rebeca; Quijano, Guillermo; Muñoz, Raúl

    2016-02-01

    Despite several fungal strains have been retrieved from methane-containing environments, the actual capacity and role of fungi on methane abatement is still unclear. The batch biodegradation tests here performed demonstrated the capacity of Graphium sp. to co-metabolically biodegrade methane and methanol. Moreover, the performance and microbiology of a fungal-bacterial compost biofilter treating methane at concentrations of ∼2% was evaluated at empty bed residence times of 40 and 20 min under different irrigation rates. The daily addition of 200 mL of mineral medium resulted in elimination capacities of 36.6 ± 0.7 g m(-3) h(-1) and removal efficiencies of ≈90% at the lowest residence time. The indigenous fungal community of the compost was predominant in the final microbial population and outcompeted the inoculated Graphium sp. during biofilter operation. PMID:26347931

  16. Simulation of the GHG Abatement Potentials in the U.S. Building Sector by 2050

    SciTech Connect

    Stadler, Michael; DeForest, Nicholas; Marnay, Chris; Bonnet, Florence; Lai, Judy; Phan, Trucy

    2010-10-01

    various USDOE research funding scenarios on the adoption of these and other building energy technologies. The results demonstrate that passive technologies contain significant potential for carbon reductions - exceeding 1165 Mt cumulative savings between 2005 and 2050 (with 50% likelihood) and outperforming similar R&D funding programs for distributed photovoltaics and high efficiency solid-state lighting.

  17. Noise Abatement

    NASA Technical Reports Server (NTRS)

    1983-01-01

    SMART, Sound Modification and Regulated Temperature compound, is a liquid plastic mixture with exceptional energy and sound absorbing qualities. It is derived from a very elastic plastic which was an effective noise abatement material in the Apollo Guidance System. Discovered by a NASA employee, it is marketed by Environmental Health Systems, Inc. (EHS). The product has been successfully employed by a diaper company with noisy dryers and a sugar company with noisy blowers. The company also manufactures an audiometric test booth and acoustical office partitions.

  18. POTENTIAL ABATEMENT PRODUCTION AND MARKETING OF BYPRODUCT SULFURIC ACID IN THE U.S

    EPA Science Inventory

    The report gives results of an evaluation of the market potential for sulfur and sulfuric acid byproducts of combustion in power plant boilers. (Air quality regulations require control of SOx emissions from power plant boilers. Recovery of sulfur in useful form would avoid waste ...

  19. Broadening the Appeal of Marginal Abatement Cost Curves: Capturing Both Carbon Mitigation and Development Benefits of Clean Energy Technologies; Preprint

    SciTech Connect

    Cowlin, S.; Cochran, J.; Cox, S.; Davison, C.; van der Gaast, Y.

    2012-08-01

    Low emission development strategies (LEDS) articulate policies and implementation plans that enable countries to advance sustainable, climate-resilient development and private sector growth while significantly reducing the greenhouse gas (GHG) emissions traditionally associated with economic growth. In creating a LEDS, policy makers often have access to information on abatement potential and costs for clean energy technologies, but there is a scarcity of economy-wide approaches for evaluating and presenting information on other dimensions of importance to development, such as human welfare, poverty alleviation, and energy security. To address this shortcoming, this paper proposes a new tool for communicating development benefits to policy makers as part of a LEDS process. The purpose of this tool is two-fold: 1. Communicate development benefits associated with each clean energy-related intervention; 2. Facilitate decision-making on which combination of interventions best contributes to development goals. To pilot this tool, the authors created a visual using data on developmental impacts identified through the Technology Needs Assessment (TNA) project in Montenegro. The visual will then be revised to reflect new data established through the TNA that provides information on cost, GHG mitigation, as well as the range and magnitude of developmental impacts.

  20. Nitrous oxide abatement potential from the wastewater sector and the monetary value of the emissions credits

    NASA Astrophysics Data System (ADS)

    Wang, J. S.; Hamburg, S. P.; Pryor, D.

    2009-12-01

    As an illustration of the monetary opportunities afforded by greenhouse gas emissions markets, we estimated the potential value of greenhouse gas credits generated in the wastewater sector by switching from secondary to tertiary treatment. Our methodology for estimating emissions is a modification of that used by the Environmental Protection Agency for the U.S. greenhouse gas inventories. Focusing on N2O, we found that tertiary treatment in some situations will result in a net decrease in emissions, though the full range of reported emission factors for treatment plants and effluent in receiving waters could result in a net increase as well. Implementation of tertiary treatment across the U.S. could reduce emissions by up to 800,000 tonnes of N2O per year, generating greenhouse gas emissions credits worth up to 10 billion per year (assuming a market price of 10-40/tonne CO2 equivalents). In practice, it will be important to account for potential increases in CO2 emissions associated with the additional power consumption and chemical use required by tertiary treatment that would reduce the net climatic benefit. The net credits would reduce the cost of operating and maintaining tertiary treatment plants and provide an incentive for managers to optimize operating conditions for N2O reductions, a critical benefit of raising awareness of the link between tertiary treatment and N2O emissions. We outline a strategy for minimizing the uncertainty in quantifying N2O reductions in the hopes of accelerating implementation of a N2O crediting system for tertiary wastewater treatment plants.

  1. Changes in the use and management of forests for abating carbon emissions: issues and challenges under the Kyoto Protocol.

    PubMed

    Brown, Sandra; Swingland, Ian R; Hanbury-Tenison, Robin; Prance, Ghillean T; Myers, Norman

    2002-08-15

    The global carbon cycle is significantly influenced by changes in the use and management of forests and agriculture. Humans have the potential through changes in land use and management to alter the magnitude of forest-carbon stocks and the direction of forest-carbon fluxes. However, controversy over the use of biological means to absorb or reduce emissions of CO(2) (often referred to as carbon 'sinks') has arisen in the context of the Kyoto Protocol. The controversy is based primarily on two arguments: sinks may allow developed nations to delay or avoid actions to reduce fossil fuel emissions, and the technical and operational difficulties are too threatening to the successful implementation of land use and forestry projects for providing carbon offsets. Here we discuss the importance of including carbon sinks in efforts to address global warming and the consequent additional social, environmental and economic benefits to host countries. Activities in tropical forest lands provide the lowest cost methods both of reducing emissions and reducing atmospheric concentrations of greenhouse gases. We conclude that the various objections raised as to the inclusion of carbon sinks to ameliorate climate change can be addressed by existing techniques and technology. Carbon sinks provide a practical available method of achieving meaningful reductions in atmospheric concentrations of carbon dioxide while at the same time contribute to national sustainable development goals. PMID:12460486

  2. [Carbon capture and storage (CCS) and its potential role to mitigate carbon emission in China].

    PubMed

    Chen, Wen-Ying; Wu, Zong-Xin; Wang, Wei-Zhong

    2007-06-01

    Carbon capture and storage (CCS) has been widely recognized as one of the options to mitigate carbon emission to eventually stabilize carbon dioxide concentration in the atmosphere. Three parts of CCS, which are carbon capture, transport, and storage are assessed in this paper, covering comparisons of techno-economic parameters for different carbon capture technologies, comparisons of storage mechanism, capacity and cost for various storage formations, and etc. In addition, the role of CCS to mitigate global carbon emission is introduced. Finally, China MARKAL model is updated to include various CCS technologies, especially indirect coal liquefaction and poly-generation technologies with CCS, in order to consider carbon emission reduction as well as energy security issue. The model is used to generate different scenarios to study potential role of CCS to mitigate carbon emissions by 2050 in China. It is concluded that application of CCS can decrease marginal abatement cost and the decrease rate can reach 45% for the emission reduction rate of 50%, and it can lessen the dependence on nuclear power development for stringent carbon constrains. Moreover, coal resources can be cleanly used for longer time with CCS, e.g., for the scenario C70, coal share in the primary energy consumption by 2050 will increase from 10% when without CCS to 30% when with CCS. Therefore, China should pay attention to CCS R&D activities and to developing demonstration projects. PMID:17674718

  3. Insect abatement system

    NASA Technical Reports Server (NTRS)

    Spiro, Clifford Lawrence (Inventor); Burnell, Timothy Brydon (Inventor); Wengrovius, Jeffrey Hayward (Inventor)

    1997-01-01

    An insect abatement system prevents adhesion of insect debris to surfaces which must be kept substantially free of insect debris. An article is coated with an insect abatement coating comprising polyorganosiloxane with a Shore A hardness of less than 50 and a tensile strength of less than 4 MPa. A method for preventing the adhesion of insect debris to surfaces includes the step of applying an insect abatement coating to a surface which must be kept substantially free of insect debris.

  4. Photochemical roles of rapid economic growth and potential abatement strategies on tropospheric ozone over South and East Asia in 2030

    NASA Astrophysics Data System (ADS)

    Chatani, S.; Amann, M.; Goel, A.; Hao, J.; Klimont, Z.; Kumar, A.; Mishra, A.; Sharma, S.; Wang, S. X.; Wang, Y. X.; Zhao, B.

    2014-04-01

    A regional air quality simulation framework including the Weather Research and Forecasting modelling system (WRF), the Community Multi-scale Air Quality modeling system (CMAQ), and precursor emissions to simulate tropospheric ozone over South and East Asia is introduced. Concentrations of tropospheric ozone and related species simulated by the framework are validated by comparing with observation data of surface monitorings, ozone zondes, and satellites obtained in 2010. The simulation demonstrates acceptable performance on tropospheric ozone over South and East Asia at regional scale. Future energy consumption, carbon dioxide (CO2), nitrogen oxides (NOx), and volatile organic compound (VOC) emissions in 2030 under three future scenarios are estimated. One of the scenarios assumes a business-as-usual (BAU) pathway, and other two scenarios consider implementation of additional energy and environmental strategies to reduce energy consumption, CO2, NOx, and VOC emissions in China and India. Future surface ozone under these three scenarios is predicted by the simulation. The simulation indicates future surface ozone significantly increases around India for a whole year and around north eastern China in summer. NOx is a main driver on significant seasonal increase of surface ozone, whereas VOC as well as increasing background ozone and methane is also an important factor on annual average of surface ozone in East Asia. Warmer weather around India is also preferable for significant increase of surface ozone. Additional energy and environmental strategies assumed in future scenarios are expected to be effective to reduce future surface ozone over South and East Asia.

  5. Photochemical roles of rapid economic growth and potential abatement strategies on tropospheric ozone over South and East Asia in 2030

    NASA Astrophysics Data System (ADS)

    Chatani, S.; Amann, M.; Goel, A.; Hao, J.; Klimont, Z.; Kumar, A.; Mishra, A.; Sharma, S.; Wang, S. X.; Wang, Y. X.; Zhao, B.

    2014-09-01

    A regional air quality simulation framework including the Weather Research and Forecasting modeling system (WRF), the Community Multi-scale Air Quality modeling system (CMAQ), and precursor emissions to simulate tropospheric ozone over South and East Asia is introduced. Concentrations of tropospheric ozone and related species simulated by the framework are validated by comparing with observation data of surface monitoring, ozonesondes, and satellites obtained in 2010. The simulation demonstrates acceptable performance on tropospheric ozone over South and East Asia at regional scale. Future energy consumption, carbon dioxide (CO2), nitrogen oxides (NOx), and volatile organic compound (VOC) emissions in 2030 under three future scenarios are estimated. One of the scenarios assumes a business-as-usual (BAU) pathway, and other two scenarios consider implementation of additional energy and environmental strategies to reduce energy consumption, CO2, NOx, and VOC emissions in China and India. Future surface ozone under these three scenarios is predicted by the simulation. The simulation indicates future surface ozone significantly increases around India for a whole year and around northeastern China in summer. NOx is a main driver on significant seasonal increase of surface ozone, whereas VOC as well as increasing background ozone and methane is also an important factor on annual average of surface ozone in East Asia. Warmer weather around India is also preferable for significant increase of surface ozone. Additional energy and environmental strategies assumed in future scenarios are expected to be effective to reduce future surface ozone over South and East Asia.

  6. Shifts in the recent distribution of energy intake among U.S. children aged 2-18 years reflect potential abatement of earlier declining trends.

    PubMed

    Mendez, Michelle A; Sotres-Alvarez, Daniela; Miles, Donna R; Slining, Meghan M; Popkin, Barry M

    2014-08-01

    Recent national surveys suggest that child obesity in the United States may have reached a plateau, but corresponding trends in energy intake have not been examined in depth. This article evaluates medium-term trends in children's reported energy intake by using 4 waves of national dietary surveillance from 2003-2004 to 2009-2010. The analysis uses up to 2 24-h dietary recalls, incorporating methods that address challenges in estimating usual intake, accounting for intraindividual variance and covariates such as the presence of atypical consumption days. Quantile regression was used to assess disparities in intake among sociodemographic subgroups at extremes of the distribution as well as at the median, and the potential influence of misreporting was evaluated. Results indicated that after an initial decline in intakes across all age groups through 2007-2008, there were significant increases of ∼90 kcal/d at the median among adolescents in 2009-2010, whereas intakes in younger children remained steady. Among adolescent boys, the recent increase was larger at the 90th percentile than at the median. Intake trends did not vary by race/ethnic group, among whom intakes were similar at the upper end of the distribution. Misreporting did not influence trends over time, but intakes were lower in younger children and higher in older children after excluding misreporters. Overall, findings suggest that declines in children's energy intake from 2003-2004 through 2007-2008 were consistent with the obesity plateau observed in most age and gender subgroups through 2009-2010. However, there is evidence of increased intakes among adolescents in 2009-2010, which may threaten the earlier abatement in overweight in this older age group. PMID:24919689

  7. Comparing primary energy attributed to renewable energy with primary energy equivalent to determine carbon abatement in a national context.

    PubMed

    Gallachóir, Brian P O; O'Leary, Fergal; Bazilian, Morgan; Howley, Martin; McKeogh, Eamon J

    2006-01-01

    The current conventional approach to determining the primary energy associated with non-combustible renewable energy (RE) sources such as wind energy and hydro power is to equate the electricity generated from these sources with the primary energy supply. This paper compares this with an approach that was formerly used by the IEA, in which the primary energy equivalent attributed to renewable energy was equated with the fossil fuel energy it displaces. Difficulties with implementing this approach in a meaningful way for international comparisons lead to most international organisations abandoning the primary energy equivalent methodology. It has recently re-emerged in prominence however, as efforts grow to develop baseline procedures for quantifying the greenhouse gas (GHG) emissions avoided by renewable energy within the context of the Kyoto Protocol credit trading mechanisms. This paper discusses the primary energy equivalent approach and in particular the distinctions between displacing fossil fuel energy in existing plant or in new plant. The approach is then extended provide insight into future primary energy displacement by renewable energy and to quantify the amount of CO2 emissions avoided by renewable energy. The usefulness of this approach in quantifying the benefits of renewable energy is also discussed in an energy policy context, with regard to increasing security of energy supply as well as reducing energy-related GHG (and other) emissions. The approach is applied in a national context and Ireland is case study country selected for this research. The choice of Ireland is interesting in two respects. The first relates to the high proportion of electricity only fossil fuel plants in Ireland resulting in a significant variation between primary energy and primary energy equivalent. The second concerns Ireland's poor performance to date in limiting GHG emissions in line with its Kyoto target and points to the need for techniques to quantify the potential

  8. The Cost of Conserved Carbon: Weighing the Monetary, Social, and Climactic Implications of Regional-, National-, and Global-Scale Carbon Abatement Strategies

    NASA Astrophysics Data System (ADS)

    Kantner, J. W.; Hoffman, I.; Johnston, J. L.; Kammen, D. M.; Levin, J. E.; Komiyama, R.; Motschenbacher, A.; Gimon, E.

    2008-05-01

    Previous schema for analyzing carbon mitigation methods often have lacked realistic costs, comprehensive accounting of trade-offs, and methodological transparency. We offer a dynamic model for evaluating diverse carbon mitigation scenarios based on economics, policy traction, and interplay with climate, society and ecosystems. The model will test the impacts of policy changes across more than two dozen strategies for conserving or avoiding carbon emissions. Users will be able to access the model at rael-c3.berkeley.edu and change underlying assumptions as desired.

  9. Fly Ash Characteristics and Carbon Sequestration Potential

    SciTech Connect

    Palumbo, Anthony V.; Amonette, James E.; Tarver, Jana R.; Fagan, Lisa A.; McNeilly, Meghan S.; Daniels, William L.

    2007-07-20

    Concerns for the effects of global warming have lead to an interest in the potential for inexpensive methods to sequester carbon dioxide (CO2). One of the proposed methods is the sequestration of carbon in soil though the growth of crops or forests.4,6 If there is an economic value placed on sequestration of carbon dioxide in soil there may be an an opportunity and funding to utilize fly ash in the reclamation of mine soils and other degraded lands. However, concerns associated with the use of fly ash must be addressed before this practice can be widely adopted. There is a vast extent of degraded lands across the world that has some degree of potential for use in carbon sequestration. Degraded lands comprise nearly 2 X 109 ha of land throughout the world.7 Although the potential is obviously smaller in the United States, there are still approximately 4 X 106 ha of degraded lands that previously resulted from mining operations14 and an additional 1.4 X 108 ha of poorly managed lands. Thus, according to Lal and others the potential is to sequester approximately 11 Pg of carbon over the next 50 years.1,10 The realization of this potential will likely be dependent on economic incentives and the use of soil amendments such as fly ash. There are many potential benefits documented for the use of fly ash as a soil amendment. For example, fly ash has been shown to increase porosity, water-holding capacity, pH, conductivity, and dissolved SO42-, CO32-, HCO3-, Cl- and basic cations, although some effects are notably decreased in high-clay soils.8,13,9 The potential is that these effects will promote increased growth of plants (either trees or grasses) and result in greater carbon accumulation in the soil than in untreated degraded soils. This paper addresses the potential for carbon sequestration in soils amended with fly ash and examines some of the issues that should be considered in planning this option. We describe retrospective studies of soil carbon accumulation on

  10. Impacts of Geological Variability on Carbon Storage Potential

    NASA Astrophysics Data System (ADS)

    Eccles, Jordan Kaelin

    The changes to the environment caused by anthropogenic climate change pose major challenges for energy production in the next century. Carbon Capture and Storage (CCS) is a group of technologies that would permit the continued use of carbon-intense fuels such as coal for energy production while avoiding further impact on the global climate system. The mechanism most often proposed for storage is injection of CO2 below the surface of the Earth in geological media, with the most promising option for CO2 reservoirs being deep saline aquifers (DSA's). Unlike oil and gas reservoirs, deep saline aquifers are poorly characterized and the variability in their properties is large enough to have a high impact on the overall physical and economic viability of CCS. Storage in saline aquifers is likely to be a very high-capacity resource, but its economic viability is almost unknown. We consider the impact of geological variability on the total viability of the CO 2 storage system from several perspectives. First, we examine the theoretical range of costs of storage by coupling a physical and economic model of CO 2 storage with a range of possible geological settings. With the relevant properties of rock extending over several orders of magnitude, it is not surprising that we find costs and storage potential ranging over several orders of magnitude. Second, we use georeferenced data to evaluate the spatial distribution of cost and capacity. When paired together to build a marginal abatement cost curve (MACC), this cost and capacity data indicates that low cost and high capacity are collocated; storage in these promising areas is likely to be quite viable but may not be available to all CO2 sources. However, when we continue to explore the impact of geological variability on realistic, commercial-scale site sizes by invoking capacity and pressure management constraints, we find that the distribution costs and footprints of these sites may be prohibitively high. The combination

  11. Noise Abatement Materials

    NASA Technical Reports Server (NTRS)

    1986-01-01

    A former NASA employee who discovered a kind of plastic that soaked up energy, dampened vibrations, and was a good noise abatement material, founded a company to market noise deadening adhesives, sheets, panels and enclosures. Known as SMART products, they are 75-80% lighter than ordinary soundproofing material and have demonstrated a high degree of effectiveness. The company, Varian Associates, makes enclosures for high voltage terminals and other electronic system components, and easily transportable audiometric test booths.

  12. Functionalized carbon nanotubes for potential medicinal applications

    PubMed Central

    Zhang, Yi; Bai, Yuhong; Yan, Bing

    2016-01-01

    Functionalized carbon nanotubes display unique properties that enable a variety of medicinal applications, including the diagnosis and treatment of cancer, infectious diseases and central nervous system disorders, and applications in tissue engineering. These potential applications are particularly encouraged by their ability to penetrate biological membranes and relatively low toxicity. PMID:20451656

  13. Hanford Site Asbestos Abatement Plan. Revision 1

    SciTech Connect

    Mewes, B.S.

    1993-09-01

    The Hanford Site Asbestos Abatement Plan (Plan) lists priorities for asbestos abatement activities to be conducted in Hanford Site facilities. The Plan is based on asbestos assessment information gathered in fiscal year 1989 that evaluated all Hanford Site facilities for the presence and condition of asbestos. Of those facilities evaluated, 414 contain asbestos-containing materials and are classified according to the potential risk of asbestos exposure to building personnel. The Plan requires that asbestos condition update reports be prepared for all affected facilities. The reporting is completed by the asbestos coordinator for each of the 414 affected facilities and transmitted to the Plan manager annually. The Plan manager uses this information to reprioritize future project lists. Currently, five facilities are determined to be Class Al, indicating a high potential for asbestos exposure. Class Al and B1 facilities are the highest priority for asbestos abatement. Abatement of the Class A1 and Bl facilities is scheduled through fiscal year 1997. Removal of asbestos in B1 facilities will reduce the risk for further Class ``A`` conditions to arise.

  14. Global forestry emission projections and abatement costs

    NASA Astrophysics Data System (ADS)

    Böttcher, H.; Gusti, M.; Mosnier, A.; Havlik, P.; Obersteiner, M.

    2012-04-01

    In this paper we present forestry emission projections and associated Marginal Abatement Cost Curves (MACCs) for individual countries, based on economic, social and policy drivers. The activities cover deforestation, afforestation, and forestry management. The global model tools G4M and GLOBIOM, developed at IIASA, are applied. GLOBIOM uses global scenarios of population, diet, GDP and energy demand to inform G4M about future land and commodity prices and demand for bioenergy and timber. G4M projects emissions from afforestation, deforestation and management of existing forests. Mitigation measures are simulated by introducing a carbon tax. Mitigation activities like reducing deforestation or enhancing afforestation are not independent of each other. In contrast to existing forestry mitigation cost curves the presented MACCs are not developed for individual activities but total forest land management which makes the estimated potentials more realistic. In the assumed baseline gross deforestation drops globally from about 12 Mha in 2005 to below 10 Mha after 2015 and reach 0.5 Mha in 2050. Afforestation rates remain fairly constant at about 7 Mha annually. Although we observe a net area increase of global forest area after 2015 net emissions from deforestation and afforestation are positive until 2045 as the newly afforested areas accumulate carbon rather slowly. About 200 Mt CO2 per year in 2030 in Annex1 countries could be mitigated at a carbon price of 50 USD. The potential for forest management improvement is very similar. Above 200 USD the potential is clearly constrained for both options. In Non-Annex1 countries avoided deforestation can achieve about 1200 Mt CO2 per year at a price of 50 USD. The potential is less constrained compared to the potential in Annex1 countries, achieving a potential of 1800 Mt CO2 annually in 2030 at a price of 1000 USD. The potential from additional afforestation is rather limited due to high baseline afforestation rates assumed

  15. Emission Abatement System

    DOEpatents

    Bromberg, Leslie; Cohn, Daniel R.; Rabinovich, Alexander

    2003-05-13

    Emission abatement system. The system includes a source of emissions and a catalyst for receiving the emissions. Suitable catalysts are absorber catalysts and selective catalytic reduction catalysts. A plasma fuel converter generates a reducing gas from a fuel source and is connected to deliver the reducing gas into contact with the absorber catalyst for regenerating the catalyst. A preferred reducing gas is a hydrogen rich gas and a preferred plasma fuel converter is a plasmatron. It is also preferred that the absorber catalyst be adapted for absorbing NO.sub.x.

  16. Biological abatement of cellulase inhibitors

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Bio-abatement uses a fungus to metabolize and remove fermentation inhibitors. To determine whether bio-abatement could alleviate enzyme inhibitor effects observed in biomass liquors after pretreatment, corn stover at 10% (w/v) solids was pretreated with either dilute acid or liquid hot water. The ...

  17. Everglades restoration could decrease carbon sink potential

    NASA Astrophysics Data System (ADS)

    Schultz, Colin

    2013-01-01

    Starting more than a century ago and ramping up to a massive scale in the 1950s, canal building and drainage projects in the Florida Everglades steadily degraded the sprawling wetland ecosystem. In the coming years, a massive 30-year multibillion-dollar restoration program is set to naturalize the Florida Everglades, returning the drained land to a closer approximation of its original structure. Restoring the Everglades, however, will have consequent effects on wetland dynamics, as plants and soil processes adjust to the changing water levels. Using eddy covariance measurements of surface-atmosphere gas exchange, Jimenez et al. tracked the roles of two different types of Everglades wetlands in the regional carbon cycle. Based on their findings, the authors suggest that, contrary to previous research, restoring the Everglades will likely diminish the potential of the region to serve as a carbon sink.

  18. Estimating the financial risks of Andropogon gayanus to greenhouse gas abatement projects in northern Australia

    NASA Astrophysics Data System (ADS)

    Adams, Vanessa M.; Setterfield, Samantha A.

    2013-06-01

    Financial mechanisms such as offsets are one strategy to abate greenhouse gas emissions, and the carbon market is expanding with a growing demand for offset products. However, in the case of carbon offsets, if the carbon is released due to intentional or unintentional reversal through environmental events such as fire, the financial liability to replace lost offsets will likely fall on the provider. This liability may have implications for future participation in programmes, but common strategies such as buffer pool and insurance products can be used to minimize this liability. In order for these strategies to be effective, an understanding of the spatial and temporal distributions of expected reversals is needed. We use the case study of savanna burning, an approved greenhouse gas abatement methodology under the Carbon Farming Initiative in Australia, to examine potential risks to carbon markets in northern Australia and quantify the financial risks. We focus our analysis on the threat of Andropogon gayanus (gamba grass) to savanna burning due to its documented impacts of increased fuel loads and altered fire regimes. We assess the spatial and financial extent to which gamba grass poses a risk to savanna burning programmes in northern Australia. We find that 75% of the eligible area for savanna burning is spatially coincident with the high suitability range for gamba grass. Our analysis demonstrates that the presence of gamba grass seriously impacts the financial viability of savanna burning projects. For example, in order to recuperate the annual costs of controlling 1 ha of gamba grass infestation, 290 ha of land must be enrolled in annual carbon abatement credits. Our results show an immediate need to contain gamba grass to its current extent to avoid future spread into large expanses of land, which are currently profitable for savanna burning.

  19. Carbon Sequestration Potential of Agricultural Systems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Through proper management, agricultural systems (cropland, pasture, and forest) have the ability to remove carbon dioxide from the atmosphere and sequester it in soils and wood products. The carbon thus sequestered can help slow the increase in atmospheric carbon dioxide currently occurring as a res...

  20. Model curriculum for asbestos abatement workers

    SciTech Connect

    1993-12-31

    These slides are part of a 4-day-course intended for those persons seeking accreditation as asbestos abatement workers. The course presents a straight forward, easy-to-read approach to learning the basics of asbestos abatement.

  1. ASSESSMENT OF HOUSEHOLD CARBON FOOTPRINT REDUCTION POTENTIALS

    SciTech Connect

    Kramer, Klaas Jan; Homan, Greg; Brown, Rich; Worrell, Ernst; Masanet, Eric

    2009-04-15

    The term ?household carbon footprint? refers to the total annual carbon emissions associated with household consumption of energy, goods, and services. In this project, Lawrence Berkeley National Laboratory developed a carbon footprint modeling framework that characterizes the key underlying technologies and processes that contribute to household carbon footprints in California and the United States. The approach breaks down the carbon footprint by 35 different household fuel end uses and 32 different supply chain fuel end uses. This level of end use detail allows energy and policy analysts to better understand the underlying technologies and processes contributing to the carbon footprint of California households. The modeling framework was applied to estimate the annual home energy and supply chain carbon footprints of a prototypical California household. A preliminary assessment of parameter uncertainty associated with key model input data was also conducted. To illustrate the policy-relevance of this modeling framework, a case study was conducted that analyzed the achievable carbon footprint reductions associated with the adoption of energy efficient household and supply chain technologies.

  2. 23 CFR 772.11 - Noise abatement.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... OF HIGHWAY TRAFFIC NOISE AND CONSTRUCTION NOISE § 772.11 Noise abatement. (a) In determining and abating traffic noise impacts, primary consideration is to be given to exterior areas. Abatement will usually be necessary only where frequent human use occurs and a lowered noise level would be of...

  3. 23 CFR 772.11 - Noise abatement.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... OF HIGHWAY TRAFFIC NOISE AND CONSTRUCTION NOISE § 772.11 Noise abatement. (a) In determining and abating traffic noise impacts, primary consideration is to be given to exterior areas. Abatement will usually be necessary only where frequent human use occurs and a lowered noise level would be of...

  4. Biological abatement of enzyme inhibitors

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Lignocellulose pretreatments release phenolic compounds that cause enzyme inhibition and deactivation. Bio-abatement, the biological removal of furfurals, acetic acid and phenolics, may utilize fungal fermentation to metabolize these compounds to CO2, water, cell mass, and heat. Our work with Coni...

  5. Lead Abatement Worker Skill Standards.

    ERIC Educational Resources Information Center

    Laborers-AGC Education and Training Fund, Pomfret Center, CT.

    This document identifies skill standards for lead abatement in a manner that is easy to understand, useful, and meaningful to workers, educators, trainers, labor leaders, contractors, and project owners. To meet the needs of the various users of this document who will have a different application of the standards and seek different information,…

  6. Asbestos Abatement--Practical Considerations.

    ERIC Educational Resources Information Center

    Sedrel, Roy A.

    Illinois Senate Bill 1644, the recently passed "Asbestos Abatement Act," requires all schools in the state, public and private alike, to remove friable asbestos by whichever comes first: July 1, 1989, or 3 years following the establishment of a system for state funding for corrective action. This document addresses practical considerations in…

  7. Asbestos Abatement: Start to Finish.

    ERIC Educational Resources Information Center

    Makruski, Edward D.

    1984-01-01

    An EPA survey of the largest school districts in the nation revealed that over 50 percent have not inspected for asbestos and two-thirds have failed to notify parents adequately. Seven steps are therefore provided for successful asbestos abatement, in anticipation of tougher regulations now under consideration. (TE)

  8. An analytical bond-order potential for carbon

    DOE PAGESBeta

    Zhou, Xiaowang; Ward, Donald K.; Foster, Michael E.

    2015-05-27

    Carbon is the most widely studied material today because it exhibits special properties not seen in any other materials when in nano dimensions such as nanotube and graphene. Reduction of material defects created during synthesis has become critical to realize the full potential of carbon structures. Molecular dynamics (MD) simulations, in principle, allow defect formation mechanisms to be studied with high fidelity, and can, therefore, help guide experiments for defect reduction. Such MD simulations must satisfy a set of stringent requirements. First, they must employ an interatomic potential formalism that is transferable to a variety of carbon structures. Second, themore » potential needs to be appropriately parameterized to capture the property trends of important carbon structures, in particular, diamond, graphite, graphene, and nanotubes. The potential must predict the crystalline growth of the correct phases during direct MD simulations of synthesis to achieve a predictive simulation of defect formation. An unlimited number of structures not included in the potential parameterization are encountered, thus the literature carbon potentials are often not sufficient for growth simulations. We have developed an analytical bond order potential for carbon, and have made it available through the public MD simulation package LAMMPS. We also demonstrate that our potential reasonably captures the property trends of important carbon phases. As a result, stringent MD simulations convincingly show that our potential accounts not only for the crystalline growth of graphene, graphite, and carbon nanotubes but also for the transformation of graphite to diamond at high pressure.« less

  9. An analytical bond-order potential for carbon

    SciTech Connect

    Zhou, Xiaowang; Ward, Donald K.; Foster, Michael E.

    2015-05-27

    Carbon is the most widely studied material today because it exhibits special properties not seen in any other materials when in nano dimensions such as nanotube and graphene. Reduction of material defects created during synthesis has become critical to realize the full potential of carbon structures. Molecular dynamics (MD) simulations, in principle, allow defect formation mechanisms to be studied with high fidelity, and can, therefore, help guide experiments for defect reduction. Such MD simulations must satisfy a set of stringent requirements. First, they must employ an interatomic potential formalism that is transferable to a variety of carbon structures. Second, the potential needs to be appropriately parameterized to capture the property trends of important carbon structures, in particular, diamond, graphite, graphene, and nanotubes. The potential must predict the crystalline growth of the correct phases during direct MD simulations of synthesis to achieve a predictive simulation of defect formation. An unlimited number of structures not included in the potential parameterization are encountered, thus the literature carbon potentials are often not sufficient for growth simulations. We have developed an analytical bond order potential for carbon, and have made it available through the public MD simulation package LAMMPS. We also demonstrate that our potential reasonably captures the property trends of important carbon phases. As a result, stringent MD simulations convincingly show that our potential accounts not only for the crystalline growth of graphene, graphite, and carbon nanotubes but also for the transformation of graphite to diamond at high pressure.

  10. An analytical bond-order potential for carbon.

    PubMed

    Zhou, X W; Ward, D K; Foster, M E

    2015-09-01

    Carbon is the most widely studied material today because it exhibits special properties not seen in any other materials when in nano dimensions such as nanotube and graphene. Reduction of material defects created during synthesis has become critical to realize the full potential of carbon structures. Molecular dynamics (MD) simulations, in principle, allow defect formation mechanisms to be studied with high fidelity, and can, therefore, help guide experiments for defect reduction. Such MD simulations must satisfy a set of stringent requirements. First, they must employ an interatomic potential formalism that is transferable to a variety of carbon structures. Second, the potential needs to be appropriately parameterized to capture the property trends of important carbon structures, in particular, diamond, graphite, graphene, and nanotubes. Most importantly, the potential must predict the crystalline growth of the correct phases during direct MD simulations of synthesis to achieve a predictive simulation of defect formation. Because an unlimited number of structures not included in the potential parameterization are encountered, the literature carbon potentials are often not sufficient for growth simulations. We have developed an analytical bond order potential for carbon, and have made it available through the public MD simulation package LAMMPS. We demonstrate that our potential reasonably captures the property trends of important carbon phases. Stringent MD simulations convincingly show that our potential accounts not only for the crystalline growth of graphene, graphite, and carbon nanotubes but also for the transformation of graphite to diamond at high pressure. PMID:26018402

  11. Impact of Various Biochars on Greenhouse Gas Production Potentials

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A potential abatement strategy to increasing atmospheric levels of carbon dioxide (CO2) is to sequester atmospheric CO2 into a more stable form through the use of pyrolysis. The biomass feed stock generates energy and a more stable carbon form (biochar) that then can be returned to the soil sequeste...

  12. Managing lead-based paint abatement wastes

    SciTech Connect

    Steele, N.L.C.

    1994-12-31

    Renovation, remodeling, demolition, and surface preparation for painting, in addition to specified lead abatement, are all activities that have the potential to produce hazardous wastes if a property was painted with lead-based paint. Lead-based paint was used on residential structures until 1978, when most residential uses were banned by the Consumer Products Safety Council. Prior to the 1950s, paints for residential uses may have contained up to 50% lead by weight. Today, commercial and military paints may still contain lead and can be used on non-residential structures. The lead content of residential paints is limited to 0.06% lead (by weight) in the dried film. This paper provides an overview of some of the information needed to properly manage lead-based paint abatement wastes. The issues covered in this paper include waste classification, generator status, treatment, and land disposal restrictions. The author assumes that the reader is familiar with the provision of the Health and Safety Code and the California Code of Regulations that pertain to generation and management of hazardous wastes. Citations provided herein do not constitute an exhaustive list of all the regulations with which a generator of hazardous waste must comply.

  13. Glovebags handle asbestos abatement

    SciTech Connect

    Ross, K.

    1997-12-01

    Regulations from OSHA mean that industry can use glovebags to perform many asbestos maintenance operations in less time, at less cost, and with less chance of personnel being exposed. The regulations became effective July 10, 1995, with some clarifications issued since that date. The standards allow glovebags to be used in maintenance operations or removal of asbestos from straight runs of pipe without any size limitations. They can also be used on elbows and other connections if the glovebags are designed for a particular configuration. The paper discusses potential savings, construction activities, procedures that must be followed when using glovebags, and training.

  14. Novel forms of carbon as potential anodes for lithium batteries

    SciTech Connect

    Winans, R.E.; Carrado, K.A.

    1994-06-01

    The objective of this study is to design and synthesize novel carbons as potential electrode materials for lithium rechargeable batteries. A synthetic approach which utilizes inorganic templates is described and initial characterization results are discussed. The templates also act as a catalyst enabling carbon formation at low temperatures. This synthetic approach should make it easier to control the surface and bulk characteristics of these carbons.

  15. New Potential Sources for Black Onaping Carbon

    NASA Technical Reports Server (NTRS)

    Bunch, T. E.; Becker, L.; Schultz, P. H.; Wolbach, W. S.

    1997-01-01

    One intriguing and important issue of the Sudbury Structure concerns the source of the relatively large amount of C in the Onaping Formation Black member. This dilemma was recently addressed, and the conclusion was reached that an impactor could not have delivered all of the requisite C. Becker et al. have suggested that much of the C came from the impactor and reported the presence of interstellar He "caged" inside some fullerenes that may have survived the impact. So, conceivably, the C inventory in the Sudbury Structure comes from both target and impactor materials, although the known target rocks have little C. We discuss here the possibility of two terrestrial sources for at least some of the C: (1) impact evaporation/dissociation of C from carbonate target rocks and (2) the presence of heretofore-unrecognized C-rich (up to 26 wt%) siliceous "shale," fragments, which are found in the upper, reworked Black member. Experimental: Hypervelocity impact of a 0.635-diameter Al projectile into dolomite at 5.03 km/s (performed at the Ames Research Center vertical gun range) produced a thin, black layer (= 0.05 mm thick) that partially lined the crater and coated impactor remnants. Scanning electronic microscope (SEM) imagery shows this layer to be spongelike on a submicron scale and Auger spectroscopic analyses yield: 33% C, 22% Mg, 19% 0, and 9% Al (from the projectile). Elemental mapping shows that all of the available 0 is combined with Ca and Mg, Al is not oxidized, and C is in elemental form. Dissociation efficiency of C from CO2 is estimated to be <10% of crater volume. Raman spectroscopy indicates that the C is highly disorganized graphite. Another impact experiment [4] also produced highly disordered graphite from a limestone target (reducing collector), in addition to small amounts of diamond/lonsdaleite/chaoite (oxidizing collector). These experiments confirm the reduction of C from carbonates in impact vapor plumes. Observational: SEM observations and

  16. Assessing carbon dynamics in semiarid ecosystems : Balancing potential gains with potential large rapid losses

    SciTech Connect

    Breshears, D. D.; Ebinger, M. H.; Unkefer, P. J.

    2001-01-01

    Photosynthesis and respiration are the largest fluxes into and out of the biosphere (Molles 1999). Consequently, small changes in these fluxes can potentially produce large changes in the storage of carbon in the biosphere. Terrestrial carbon fluxes account for more than half of the carbon transferred between the atmosphere and the earth's surface (about 120 GigaTons/year), and current stores of carbon in terrestrial ecosystem are estimated at 2060 GigaTons. Increasing attention is being focused on the role of managing and sequestering carbon in the terrestrial biosphere as a means for addressing global climate change (IGBP, 1998; U.S. Department of Energy, 1999). Terrestrial ecosystems are widely recognized as a major biological scrubber for atmosphereic CO{sub 2} and their ability to finction as such can be increased significantly over the next 25 years through careful manipulation. The potential for terrestrial carbon gains has been the subject of much attention (Dixon et al., 1994; Masera et al. 1997; Cao and Woodward, 1998; DeLucia et al. 1999). In contrast to other strategies for reducing net carbon emissions, terrestrial sequestration has the potential for rapid implementation. Strategies that focus on soil carbon are likely to be effective because in addition to being a storage pool of carbon, soil carbon also improves site productivity through improving soil quality (e.g., water retention and nutrient availability). The carbon pool in soils is immense and highly dynamic. The flux of carbon into and out of soils is one of the largest uncertainties in the total mass balance of global carbon (NRC, 1999; La1 et al., 1998; Cambardella, 1998). Reducing these uncertainties is key to developing carbon sequestration strategies. Soil carbon pools have been greatly depleted over recent centuries, and there is potential to increase storage of carbon in these soils through effective land management. Whereas carbon in vegetation can be managed directly through land use

  17. Carbon Sequestration Potential of a Switchgrass Bioenergy Crop

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Switchgrass is an important bioenergy crop with the potential to provide a reliable supply of renewable energy while also removing carbon dioxide from the atmosphere and sequestering it in the soil. We conducted a four-year study to quantify carbon dioxide sequestration during the establishment and ...

  18. Zeta Potential in Intact Natural Carbonates at Elevated Temperatures

    NASA Astrophysics Data System (ADS)

    Al-Mahrouqi, D.; Vinogradov, J.; Jackson, M.

    2015-12-01

    Measurements of zeta potential have been used to monitor subsurface flows in many natural brine systems. Numerous studies report zeta potentials in carbonates using crushed samples at low ionic strength and laboratory temperatures. However, natural brines have much higher salinity; moreover, temperatures are considerably higher in many subsurface settings. The variation of zeta potentials with temperature has not been examined in natural carbonates. We report zeta potential values interpreted from streaming potential measurements in two intact carbonate rock samples, saturated with artificial brines at elevated temperatures. We measure streaming potential using an experimental set-up that incorporates in-situ measurements of saturated rock conductivity, brine temperature, brine pH, brine electrical conductivity, pressure difference and voltage at temperatures up to 120oC. The streaming potential measurements are complemented with brine effluent studies. We find that the interpreted zeta potential is negative and decreases in magnitude with increasing temperature at low ionic strength (0.01M) and independent of temperature at high ionic strength (0.5M); consistent with published zeta potential in intact natural sandstones. The concentration of Ca2+ (main potential determining ion) also decreases with temperature at low ionic strength, but remains constant at high ionic strength. The temperature dependence of the zeta potential is consistent between two different natural carbonate samples and can be explained by the temperature dependence of pCa2+. We suggest that zeta potential of carbonate is independent of temperature or pH when pCa2+ remains constant. A linear variation of pH vs. pCa2+ is exhibited, at ambient and elevated temperatures, when pCa2+ is allowed to change with pH. This linear variation explains the numerous published data that shows apparent relationship between zeta potential of carbonates and pH.

  19. New Potential Sources for Black Onaping Carbon

    NASA Technical Reports Server (NTRS)

    Bunch, T. E.; Becker, L.; Schultz, P. H.; Wolbach, W. S.

    1997-01-01

    One intriguing and important issue of the Sudbury Structure concerns the source of the relatively large amount of C in the Onaping Formation Black member. This dilemma was recently addressed, and the conclusion was reached that an impactor could not have delivered all of the requisite C. Becker et al. have suggested that much of the C came from the impactor and reported the presence of interstellar He "caged" inside some fullerenes that may have survived the impact. So, conceivably, the C inventory in the Sudbury Structure comes from both target and impactor materials, although the known target rocks have little C. We discuss here the possibility of two terrestrial sources for at least some of the C: (1) impact evaporation/dissociation of C from carbonate target rocks and (2) the presence of heretofore-unrecognized C-rich (up to 26 wt%) siliceous "shale," fragments, which are found in the upper, reworked Black member. Experimental: Hypervelocity impact of a 0.635-diameter Al projectile into dolomite at 5.03 km/s (performed at the Ames Research Center vertical gun range) produced a thin, black layer (= 0.05 mm thick) that partially lined the crater and coated impactor remnants. Scanning electronic microscope (SEM) imagery shows this layer to be spongelike on a submicron scale and Auger spectroscopic analyses yield: 33% C, 22% Mg, 19% 0, and 9% Al (from the projectile). Elemental mapping shows that all of the available 0 is combined with Ca and Mg, Al is not oxidized, and C is in elemental form. Dissociation efficiency of C from CO2 is estimated to be <10% of crater volume. Raman spectroscopy indicates that the C is highly disorganized graphite. Another impact experiment [4] also produced highly disordered graphite from a limestone target (reducing collector), in addition to small amounts of diamond/lonsdaleite/chaoite (oxidizing collector). These experiments confirm the reduction of C from carbonates in impact vapor plumes. Observational: SEM observations and

  20. 76 FR 39368 - Migratory Bird Permits; Abatement Regulations

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-07-06

    ... abatement permit holder may use captive-bred raptors held under his or her migratory bird master falconry permit for abatement activities without transferring them to his or her abatement permit, provided the... used under his or her abatement permit. Raptors used under a Federal abatement permit must be...

  1. [Legal aspects of noise abatement].

    PubMed

    Kierski, W S

    1976-12-01

    Noise abatement is a problem of technology, medicine, law, and education. In the technical field, the problem of avoiding hazards is the primary one. In respect of encroachment upon neighbours mutual regard should be the foremost consideration. From the legal angle, a distinction is made between protection of the individial-above all under the provisions of the German Civil Code (Bürgerliches Gesetzbuch)-and of the community-under the provisions of criminal law and administrative law. Future legislation will have to concentrate increasingly upon governmental control measures especially with a view to prevention, instead of the issue of protection of the individual. PMID:1002088

  2. PFC Abatement in Capacitevely-Coupled Plasma Reactor

    NASA Astrophysics Data System (ADS)

    Porshnev, P. I.; Alaoui, M.; Diamant, Stela; Francis, Terry; Raoux, Sebastien; Woolston, Mike

    2001-10-01

    A low-pressure plasma reactor, was developed to reduce PFC emissions of dielectric etch tools, is a point-of-use environmentally and economically sound solution. Generally, local electric fields in capacitively-coupled (CC) plasmas are higher than in inductively-coupled (IC) plasmas. As a result, electron energy distributions in CC plasmas have more pronounced high-energy part compared to the ones in IC plasmas. This is particularly important for effective breaking of the strong C-F bonds, which dissociation potentials are observably higher than the average electron energy. CC plasma in the Pegasys (Plasma Exhaust Gas Abatement SYStem) reactor was found to be in so-called g-regime, in which ionization is provided with secondary emission electrons. Though in these plasmas, the majority of electrons still reside in plasma bulk, the most important discharge characteristics, in particular, the abatement efficiency, are determined by highly-energetic electrons from sheath zones. With water being added to the incoming gas mixture, better than 95% destruction removal efficiency of the PFCs has been achieved for all dielectric etch applications. CC plasma-based abatement significantly differs from existing abatement methods, especially combustion and catalytic oxidation, which are much less environmentally friendly and economically viable.

  3. Induced Potential in Porous Carbon Films through Water Vapor Absorption.

    PubMed

    Liu, Kang; Yang, Peihua; Li, Song; Li, Jia; Ding, Tianpeng; Xue, Guobin; Chen, Qian; Feng, Guang; Zhou, Jun

    2016-07-01

    Sustainable electrical potential of tens of millivolts can be induced by water vapor adsorption on a piece of porous carbon film that has two sides with different functional group contents. Integrated experiments, and Monte Carlo and ab initio molecular dynamics simulations reveal that the induced potential originates from the nonhomogeneous distribution of functional groups along the film, especially carboxy groups. Sufficient adsorbed water molecules in porous carbon facilitate the release of protons from the carboxy groups, resulting in a potential drop across the carbon film because of the concentration difference of the released free protons on the two sides. The potential utilization of such a phenomenon is also demonstrated by a self-powered humidity sensor. PMID:27159427

  4. The potential for carbon storage in UK peatlands

    NASA Astrophysics Data System (ADS)

    Rowson, J.; Worrall, F.; Evans, M.; Bonn, A.; Reed, M.; Chapman, D.; Holden, J.

    2008-12-01

    Upland peat soils represent a large terrestrial carbon store and as such have the potential to be either an ongoing net sink of carbon or a significant net source of carbon. In the UK many upland peats are managed for a range of purposes but these purposes have rarely included carbon stewardship. However, there is now an opportunity to consider whether management practices could be altered to enhance storage of carbon in upland peats. Further, there are now voluntary and regulated carbon trading schemes operational throughout Europe that mean stored carbon, if verified, could have an economic and tradeable value. This means that new income streams could become available for upland management. The 'Sustainable Uplands' RELU project has developed a model for calculating carbon fluxes from peat soils that covers all carbon uptake and release pathways (e.g. fluvial and gaseous pathways). The model has been developed so that the impact of common management options within UK upland peats can be considered. The model was run for a decade from 1997-2006 and applied to an area of 550 km2 of upland peat soils in the Peak District. The study estimates that the region is presently a net sink of -62 Ktonnes CO2 equivalent at an average export of - 136 tonnes CO2 equivalent/km2/yr. If management interventions were targeted across the area the total sink could increase to -160 Ktonnes CO2/yr at an average export of- 219 tonnes CO2 equivalent/km2/yr. The model suggests which management interventions would be most effective and given present costs of peatland restoration and value of carbon offsets the study suggests that 51% of those areas, where a carbon benefit was estimated by modelling for targeted action of management interventions, would show a profit from carbon offsetting within 30 years.

  5. AHERA CLEARANCE AT TWENTY ABATEMENT SITES

    EPA Science Inventory

    A study was conducted during the summer of 1988 to document Asbestos Hazard Emergency Response Act (AHERA) clearance air sampling practices and clearance concentrations of airborne asbestos at 20 asbestos-abatement sites in New Jersey. ach abatement took place in a school buildin...

  6. AHERA CLEARANCE AT TWENTY ABATEMENT SITES

    EPA Science Inventory

    A study was conducted during the summer of 1988 to document Asbestos Hazard Emergency Response Act (AHERA) clearance air-sampling practices and clearance concentrations of airborne asbestos at 20 asbestos-abatement sites in New Jersey. Each abatement took place in a school buildi...

  7. An Overview of Geologic Carbon Sequestration Potential in California

    SciTech Connect

    Cameron Downey; John Clinkenbeard

    2005-10-01

    As part of the West Coast Regional Carbon Sequestration Partnership (WESTCARB), the California Geological Survey (CGS) conducted an assessment of geologic carbon sequestration potential in California. An inventory of sedimentary basins was screened for preliminary suitability for carbon sequestration. Criteria included porous and permeable strata, seals, and depth sufficient for critical state carbon dioxide (CO{sub 2}) injection. Of 104 basins inventoried, 27 met the criteria for further assessment. Petrophysical and fluid data from oil and gas reservoirs was used to characterize both saline aquifers and hydrocarbon reservoirs. Where available, well log or geophysical information was used to prepare basin-wide maps showing depth-to-basement and gross sand distribution. California's Cenozoic marine basins were determined to possess the most potential for geologic sequestration. These basins contain thick sedimentary sections, multiple saline aquifers and oil and gas reservoirs, widespread shale seals, and significant petrophysical data from oil and gas operations. Potential sequestration areas include the San Joaquin, Sacramento, Ventura, Los Angeles, and Eel River basins, followed by the smaller Salinas, La Honda, Cuyama, Livermore, Orinda, and Sonoma marine basins. California's terrestrial basins are generally too shallow for carbon sequestration. However, the Salton Trough and several smaller basins may offer opportunities for localized carbon sequestration.

  8. Impact of field exposure on greenhouse gas production potentials from biochar additions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A potential abatement strategy to increasing atmospheric levels of carbon dioxide (CO2) is to sequester atmospheric CO2 into a more stable form through the pyrolysis of biomass. Biomass feed stocks are used to generate a more stable carbon form (biochar) that when added to soils can act place atmosp...

  9. Potential release of fibers from burning carbon composites. [aircraft fires

    NASA Technical Reports Server (NTRS)

    Bell, V. L.

    1980-01-01

    A comprehensive experimental carbon fiber source program was conducted to determine the potential for the release of conductive carbon fibers from burning composites. Laboratory testing determined the relative importance of several parameters influencing the amounts of single fibers released, while large-scale aviation jet fuel pool fires provided realistic confirmation of the laboratory data. The dimensions and size distributions of fire-released carbon fibers were determined, not only for those of concern in an electrical sense, but also for those of potential interest from a health and environmental standpoint. Fire plume and chemistry studies were performed with large pool fires to provide an experimental input into an analytical modelling of simulated aircraft crash fires. A study of a high voltage spark system resulted in a promising device for the detection, counting, and sizing of electrically conductive fibers, for both active and passive modes of operation.

  10. Potential Influence of Perchlorate on Organic Carbon in Martian Regolith

    NASA Astrophysics Data System (ADS)

    Oze, C.; Vithanage, M. S.; Kumarathilaka, P. R.; Indraratne, S.; Horton, T. W.

    2014-12-01

    Perchlorate is a strong oxidizer present at elevated concentrations in surface martian regolith. Chemical and isotopic modification of potential organic carbon with perchlorate in martian regolith during H2O(l) interactions is unknown. Here we assess the relationship between martian levels of perchlorate and organic carbon present in life harbouring geologic material from Earth. These materials represent chemical (i.e., processed serpentine soils from Sri Lanka) and temperature (i.e., hydrothermal jarosite/goethite deposit from White Island, New Zealand) extremes to where life exists on Earth. Preliminary evidence demonstrates that organic carbon decreases and δ13C values are modified for ultramafic sediment in both perchlorate kinetic and incubation experiments. In hydrothermal jarosite/goethite with microbial communities present, total and organic carbon is maintained and little modification in δ13C values is apparent. These preliminary results suggest that surface hydrothermal deposits with mineralogically 'protected' organic carbon are preferable sites to assess the potential of life on Mars.

  11. How Sensitive Is the Carbon Budget Approach to Potential Carbon Cycle Changes?

    NASA Astrophysics Data System (ADS)

    Matthews, D.

    2014-12-01

    The recent development of global Earth-system models, which include dynamic representations of both physical climate and carbon cycle processes, has led to new insights about how the climate responds to human carbon dioxide emissions. Notably, several model analyses have now shown that global temperature responds linearly to cumulative CO2 emissions across a wide range of emissions scenarios. This implies that the timing of CO2 emissions does not affect the overall climate response, and allows a finite global carbon carbon budget to be defined for a given global temperature target. This linear climate response, however, emerges from the interaction of several non-linear processes and feedbacks involving how carbon sinks respond to changes in atmospheric CO2 and climate. In this presentation, I will give an overview of how carbon sinks and carbon cycle feedbacks contribute to the overall linearity of the climate response to cumulative emissions, and will assess how robust this relationship is to a range of possible changes in the carbon cycle, including (a) potential positive carbon cycle feedbacks that are not well represented in the current generation of Earth-system models and (b) negative emission scenarios resulting from possible technological strategies to remove CO2 from the atmosphere.

  12. Comparing carbon sequestration potential of pyrogenic carbon from natural and anthropogenic sources

    NASA Astrophysics Data System (ADS)

    Santin, Cristina; Doerr, Stefan; Merino, Augustin

    2014-05-01

    The enhanced resistance to environmental degradation of Pyrogenic Carbon (PyC), both produced in wildfires (charcoal), and man-made (biochar), gives it the potential to sequester carbon by preventing it to be released into the atmosphere. Sustainable addition of biochar to soils is seen as a viable global approach for carbon sequestration and climate change mitigation. Also the role of its 'natural counterpart', i.e. wildfire charcoal, as a long-term carbon sink in soils is widely recognized. However, in spite of their fundamental similarities, research on the potential of 'man-made' biochar and wildfire charcoal for carbon sequestration has been carried out essentially in isolation as analogous materials for accurate comparison are not easily available. Here we assess the carbon sequestration potential of man-made biochar and wildfire charcoal generated from the same material under known production conditions: (i) charcoal from forest floor and down wood produced during an experimental boreal forest fire (FireSmart, June 2012, NWT- Canada) and (ii) biochar produced from the same feedstock by slow pyrolysis [three treatments: 2 h at 350, 500 and 650°C, respectively]. The carbon sequestration potential of these PyC materials is given by the recalcitrance index, R50, proposed by Harvey et al. (2012). R50 is based on the relative thermal stability of a given PyC material to that of graphite and is calculated using thermogravimetric analyses. Our results show highest R50 for PyC materials produced from down wood than from forest floor, which points to the importance of feedstock chemical composition in determining the C sequestration potential of PyC both from natural (charcoal) and anthropogenic (biochar) sources. Moreover, production temperature is also a major factor affecting the carbon sequestration potential of the studied PyC materials, with higher R50 for PyC produced at higher temperatures. Further investigation on the similarities and differences between man

  13. Properties and potential applications of brominated P-100 carbon fibers

    NASA Technical Reports Server (NTRS)

    Jaworske, D. A.; Gaier, J. R.; Hung, C. C.; Banks, B. A.

    1986-01-01

    A review of the properties and potential applications of bromine-intercalated pitch-based carbon fibers is presented. The dynamics of the intercalation reaction are summarized, and characteristics, such as resistivity, density, and stability, are discussed. In addition, the mechanical and electrical properties of bromine-intercalated fiber-epoxy conposites will be addressed. With conductivities comparable to stainless steel, these brominated carbon fibers may be used in a number of composite applications, such as electromagnetic interference shielding containers, large conductive space structures, lightning strike-tolerant aircraft surfaces, and aircraft deicing applications.

  14. Interaction of pollution abatement with world dynamics

    NASA Technical Reports Server (NTRS)

    Smith, G. L.

    1973-01-01

    The world dynamics model of Jay W. Forrester was modified to account for pollution abatement. In the modified model, it is assumed that as pollution increases, efforts are made to control pollution. There is a competition between food supply, material standard of living, and pollution abatement for capital, and time is required for diversion of capital toward pollution abatement. Inclusion of pollution abatement in the model drastically alters the response of the world system for the case in which depletion of natural resources is not considered. Instead of undergoing a pollution catastrophe, all system levels move more or less smoothly toward an equilibrium. A FORTRAN program listing of the modified world dynamics model is included.

  15. 24 CFR 35.1325 - Abatement.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... authorized by EPA, or by EPA at 40 CFR 745.227(e), and shall be completed by achieving clearance in... accordance with § 35.1355. Abatement of an intact, factory-applied prime coating on metal surfaces is...

  16. 24 CFR 35.1325 - Abatement.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... authorized by EPA, or by EPA at 40 CFR 745.227(e), and shall be completed by achieving clearance in... accordance with § 35.1355. Abatement of an intact, factory-applied prime coating on metal surfaces is...

  17. 24 CFR 35.1325 - Abatement.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... authorized by EPA, or by EPA at 40 CFR 745.227(e), and shall be completed by achieving clearance in accordance with § 35.1340. If encapsulation or enclosure is used as a method of abatement, ongoing...

  18. 24 CFR 35.1325 - Abatement.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... authorized by EPA, or by EPA at 40 CFR 745.227(e), and shall be completed by achieving clearance in accordance with § 35.1340. If encapsulation or enclosure is used as a method of abatement, ongoing...

  19. 24 CFR 35.1325 - Abatement.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... authorized by EPA, or by EPA at 40 CFR 745.227(e), and shall be completed by achieving clearance in accordance with § 35.1340. If encapsulation or enclosure is used as a method of abatement, ongoing...

  20. Low-Potential Stable NADH Detection at Carbon-Nanotube-Modified Glassy Carbon Electrodes

    SciTech Connect

    Musameh, Mustafa; Wang, Joseph; Merkoci, Arben; Lin, Yuehe )

    2002-11-22

    Carbon-nanotube (CNT) modified glassy-carbon electrodes exhibiting strong and stable electrocatalytic response toward NADH are described. A substantial (490 mV) decrease in the overvoltage of the NADH oxidation reaction (compared to ordinary carbon electrodes) is observed using single-wall and multi-wall carbon-nanotube coatings, with oxidation starting at ca.?0.05V (vs. Ag/AgCl; pH 7.4). Furthermore, the NADH amperometric response of the coated electrodes is extremely stable, with 96 and 90% of the initial activity remaining after 60min stirring of 2x10-4M and 5x10-3M NADH solutions, respectively (compared to 20 and 14% at the bare surface). The CNT-coated electrodes thus allow highly-sensitive, low-potential, stable amperometric sensing. Such ability of carbon-nanotubes to promote the NADH electron-transfer reaction suggests great promise for dehydrogenase-based amperometric biosensors.

  1. Carbon stewardship: land management decisions and the potential for carbon sequestration in Colorado, USA

    NASA Astrophysics Data System (ADS)

    Failey, Elisabeth L.; Dilling, Lisa

    2010-04-01

    Land use and its role in reducing greenhouse gases is a key element of policy negotiations to address climate change. Calculations of the potential for enhanced terrestrial sequestration have largely focused on the technical characteristics of carbon stocks, such as vegetation type and management regime, and to some degree, on economic incentives. However, the actual potential for carbon sequestration critically depends on who owns the land and additional land management decision drivers. US land ownership patterns are complex, and consequently land use decision making is driven by a variety of economic, social and policy incentives. These patterns and incentives make up the 'carbon stewardship landscape'—that is, the decision making context for carbon sequestration. We examine the carbon stewardship landscape in the US state of Colorado across several public and private ownership categories. Achieving the full potential for land use management to help mitigate carbon emissions requires not only technical feasibility and financial incentives, but also effective implementing mechanisms within a suite of often conflicting and hard to quantify factors such as multiple-use mandates, historical precedents, and non-monetary decision drivers.

  2. Formation Buffering Potential Pertaining to Geological Storage of Carbon Dioxide

    NASA Astrophysics Data System (ADS)

    Ellis, B. R.; Peters, C. A.; Buschkuehle, M.

    2007-12-01

    One promising strategy for decreasing CO2 emissions to the atmosphere is carbon capture and storage in deep saline formations. Modeling efforts and the experimental measurements that support these efforts are critical to determining the fate of injected CO2. The focus of this work is CO2-water-rock interactions as they pertain to formation buffering potential. PHREEQC was used to model pH evolution in siliciclastic and carbonate rocks after simulated injection of CO2. The initial mineral and formation water compositions were determined from analysis of core samples and brines from several formations in the Alberta sedimentary basin in western Canada. Simulation parameters correspond to injection conditions of 50°C, CO2 pressure of 100 bar and high ionic strength. Results indicate that the carbonate formations have a higher buffering potential relative to siliciclastic formations. Considerable variability of acid-catalyzed reactions among formations with similar mineralogical compositions was also observed. To assess the effect of grain coating by clay minerals, a comparative simulation was performed with kaolinite as the dominant mineral in contact with the pore fluids. Results from this simulation showed a pronounced retardation in pH buffering reaction kinetics. This emphasizes the importance for differentiating between mineral abundance and accessibility in model calculations when clay coatings may obscure contact between pore fluids and potentially reactive minerals.

  3. Historical forest baselines reveal potential for continued carbon sequestration.

    PubMed

    Rhemtulla, Jeanine M; Mladenoff, David J; Clayton, Murray K

    2009-04-14

    One-third of net CO(2) emissions to the atmosphere since 1850 are the result of land-use change, primarily from the clearing of forests for timber and agriculture, but quantifying these changes is complicated by the lack of historical data on both former ecosystem conditions and the extent and spatial configuration of subsequent land use. Using fine-resolution historical survey records, we reconstruct pre-EuroAmerican settlement (1850s) forest carbon in the state of Wisconsin, examine changes in carbon after logging and agricultural conversion, and assess the potential for future sequestration through forest recovery. Results suggest that total above-ground live forest carbon (AGC) fell from 434 TgC before settlement to 120 TgC at the peak of agricultural clearing in the 1930s and has since recovered to approximately 276 TgC. The spatial distribution of AGC, however, has shifted significantly. Former savanna ecosystems in the south now store more AGC because of fire suppression and forest ingrowth, despite the fact that most of the region remains in agriculture, whereas northern forests still store much less carbon than before settlement. Across the state, continued sequestration in existing forests has the potential to contribute an additional 69 TgC. Reforestation of agricultural lands, in particular, the formerly high C-density forests in the north-central region that are now agricultural lands less optimal than those in the south, could contribute 150 TgC. Restoring historical carbon stocks across the landscape will therefore require reassessing overall land-use choices, but a range of options can be ranked and considered under changing needs for ecosystem services. PMID:19369213

  4. Historical forest baselines reveal potential for continued carbon sequestration

    PubMed Central

    Rhemtulla, Jeanine M.; Mladenoff, David J.; Clayton, Murray K.

    2009-01-01

    One-third of net CO2 emissions to the atmosphere since 1850 are the result of land-use change, primarily from the clearing of forests for timber and agriculture, but quantifying these changes is complicated by the lack of historical data on both former ecosystem conditions and the extent and spatial configuration of subsequent land use. Using fine-resolution historical survey records, we reconstruct pre-EuroAmerican settlement (1850s) forest carbon in the state of Wisconsin, examine changes in carbon after logging and agricultural conversion, and assess the potential for future sequestration through forest recovery. Results suggest that total above-ground live forest carbon (AGC) fell from 434 TgC before settlement to 120 TgC at the peak of agricultural clearing in the 1930s and has since recovered to approximately 276 TgC. The spatial distribution of AGC, however, has shifted significantly. Former savanna ecosystems in the south now store more AGC because of fire suppression and forest ingrowth, despite the fact that most of the region remains in agriculture, whereas northern forests still store much less carbon than before settlement. Across the state, continued sequestration in existing forests has the potential to contribute an additional 69 TgC. Reforestation of agricultural lands, in particular, the formerly high C-density forests in the north-central region that are now agricultural lands less optimal than those in the south, could contribute 150 TgC. Restoring historical carbon stocks across the landscape will therefore require reassessing overall land-use choices, but a range of options can be ranked and considered under changing needs for ecosystem services. PMID:19369213

  5. The economic potential of carbon sequestration in Californian agricultural land

    NASA Astrophysics Data System (ADS)

    Catala-Luque, Rosa

    This dissertation studies the potential success of a carbon sequestration policy based on payments to farmers for adoption of alternative, less intensive, management practices in California. Since this is a first approach from a Californian perspective, we focus on Yolo County, an important agricultural county of the State. We focus on the six more important crops of the region: wheat, tomato, corn, rice, safflower, and sunflower. In Chapter 1, we characterize the role of carbon sequestration in Climate Change policy. We also give evidence on which alternative management practices have greenhouse gas mitigation potential (reduced tillage, cover-cropping, and organic systems) based on a study of experimental sites. Chapter 2 advances recognizing the need for information at the field level, and describes the survey designed used to obtain data at the field level, something required to perform a complete integrated assessment of the issue. The survey design is complex in the sense that we use auxiliary information to obtain a control (subpopulation of conventional farmers)-case (subpopulation of innovative farmers) design with stratification for land use. We present estimates for population quantities of interest such as total variable costs, profits, managerial experience in different alternatives, etc. This information efficiently gives field level information for innovative farmers, a missing piece of information so far, since our sampling strategy required the inclusion with probability one of farmers identified as innovative. Using an agronomic process model (DayCent) for the sample and population units, we construct carbon mitigation cost curves for each crop and management observed. Chapter 3 builds different econometric models for cross-sectional data taking into account the survey design, and expanding the sample size constructing productivity potential under each alternative. Based on the yield productivity potential modeled for each unit, we conclude that a

  6. Coarse-grained potentials of single-walled carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Zhao, Junhua; Jiang, Jin-Wu; Wang, Lifeng; Guo, Wanlin; Rabczuk, Timon

    2014-11-01

    We develop the coarse-grained (CG) potentials of single-walled carbon nanotubes (SWCNTs) in CNT bundles and buckypaper for the study of the static and dynamic behaviors. The explicit expressions of the CG stretching, bending and torsion potentials for the nanotubes are obtained by the stick-spiral and the beam models, respectively. The non-bonded CG potentials between two different CG beads are derived from analytical results based on the cohesive energy between two parallel and crossing SWCNTs from the van der Waals interactions. We show that the CG model is applicable to large deformations of complex CNT systems by combining the bonded potentials with non-bonded potentials. Checking against full atom molecular dynamics calculations and our analytical results shows that the present CG potentials have high accuracy. The established CG potentials are used to study the mechanical properties of the CNT bundles and buckypaper efficiently at minor computational cost, which shows great potential for the design of micro- and nanomechanical devices and systems.

  7. Hydrocarbon potential of Middle Eocene carbonates, Sirt Basin, Libya

    NASA Astrophysics Data System (ADS)

    Swei, Giuma H.; Tucker, Maurice E.

    2015-11-01

    Deposition of Middle Eocene carbonates in the Sirt Basin in Libya has been the subject of considerable study in recent years because of the importance of sediments of this age as hydrocarbon reservoirs. The Gialo Formation is an important gas-producing reservoir in the Assumood, Sahl and other nearby fields. The gas which is generated from the gas-prone Sirt Shale source rock of the northern Ajdabiya Trough probably migrated in to the Assumood Ridge from the northeast through late Cretaceous, Paleocene and early Eocene carbonates, before being trapped beneath the Augila Shale (Upper Eocene) which is the principal regional seal in the area. This integrated study has enhanced our understanding of reservoir heterogeneity and hydrocarbon potential of the Gialo carbonates and should lead to improved exploration in the future. Reservoir quality in the Gialo Formation is a function of grain types, pore types, grain size, sorting, cementation and compaction, and predicting areas of high reservoir quality has proved difficult; exploration should be oriented to positioning wells into the main trend of the mid-ramp, nummulite accumulation. Different nummulite facies can be reservoirs depending on their diagenetic history. A diagenetic reduction in porosity must be distinguished from a lack of porosity resulting from an unfavourable depositional environment, so that exploration alternatives can be assessed. This integrated study has demonstrated the presence of suitable reservoir rocks, hydrocarbon traps and the close proximity of potential source rocks. These features should encourage further hydrocarbon exploration in the area.

  8. Abatement of CF4 by atmospheric-pressure microwave plasma torch

    NASA Astrophysics Data System (ADS)

    Hong, Yong C.; Uhm, Han S.

    2003-08-01

    An atmospheric microwave plasma torch is presented for post-pump destruction of perfluorocompound gases (PFCs), which are used widely in the semiconductor industry and are emitted with nitrogen gas for vacuum pump purges. Discharges of the microwave plasma torch are well suited for abatement of PFC contaminants discharged at a typical flow rate. The abatement was carried out using oxygen or air as additive gases. Analytical results are systematically compared to quadrupole mass spectroscopy and Fourier transform infrared (FTIR) data in the laboratory. Destruction and removal efficiency of more than 99% in FTIR data was achieved for carbon tetrafluoride.

  9. Impacts of Woodchip Biochar Additions on Soil Carbon Net, CH4 Oxidation and Sorption/Degradation of Two Herbicides in a Minnesota Soil

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A potential abatement to increasing levels of carbon dioxide (CO2) in the atmosphere is the use of pyrolysis to convert vegetative biomass into a more stable form of carbon (biochar) that could then be applied to the soil. However, the impacts of pyrolysis biochar on the soil system need to be asses...

  10. Cost of abating greenhouse gas emissions with cellulosic ethanol.

    PubMed

    Dwivedi, Puneet; Wang, Weiwei; Hudiburg, Tara; Jaiswal, Deepak; Parton, William; Long, Stephen; DeLucia, Evan; Khanna, Madhu

    2015-02-17

    We develop an integrated framework to determine and compare greenhouse gas (GHG) intensities and production costs of cellulosic ethanol derived from corn stover, switchgrass, and miscanthus grown on high and low quality soils for three representative counties in the Eastern United States. This information is critical for assessing the cost-effectiveness of utilizing cellulosic ethanol for mitigating GHG emissions and designing appropriate policy incentives to support cellulosic ethanol production nationwide. We find considerable variations in the GHG intensities and production costs of ethanol across feedstocks and locations mostly due to differences in yields and soil characteristics. As compared to gasoline, the GHG savings from miscanthus-based ethanol ranged between 130% and 156% whereas that from switchgrass ranged between 97% and 135%. The corresponding range for GHG savings with corn stover was 57% to 95% and marginally below the threshold of at least 60% for biofuels classified as cellulosic biofuels under the Renewable Fuels Standard. Estimates of the costs of producing ethanol relative to gasoline imply an abatement cost of at least $48 Mg(-1) of GHG emissions (carbon dioxide equivalent) abated and can be used to infer the minimum carbon tax rate needed to induce consumption of cellulosic ethanol. PMID:25588032

  11. Potential climate impact of black carbon emitted by rockets

    NASA Astrophysics Data System (ADS)

    Ross, Martin; Mills, Michael; Toohey, Darin

    2010-12-01

    A new type of hydrocarbon rocket engine is expected to power a fleet of suborbital rockets for commercial and scientific purposes in coming decades. A global climate model predicts that emissions from a fleet of 1000 launches per year of suborbital rockets would create a persistent layer of black carbon particles in the northern stratosphere that could cause potentially significant changes in the global atmospheric circulation and distributions of ozone and temperature. Tropical stratospheric ozone abundances are predicted to change as much as 1%, while polar ozone changes by up to 6%. Polar surface temperatures change as much as one degree K regionally with significant impacts on polar sea ice fractions. After one decade of continuous launches, globally averaged radiative forcing from the black carbon would exceed the forcing from the emitted CO2 by a factor of about 105 and would be comparable to the radiative forcing estimated from current subsonic aviation.

  12. Anesthesia-Related Carbon Monoxide Exposure: Toxicity and Potential Therapy.

    PubMed

    Levy, Richard J

    2016-09-01

    Exposure to carbon monoxide (CO) during general anesthesia can result from volatile anesthetic degradation by carbon dioxide absorbents and rebreathing of endogenously produced CO. Although adherence to the Anesthesia Patient Safety Foundation guidelines reduces the risk of CO poisoning, patients may still experience subtoxic CO exposure during low-flow anesthesia. The consequences of such exposures are relatively unknown. In contrast to the widely recognized toxicity of high CO concentrations, the biologic activity of low concentration CO has recently been shown to be cytoprotective. As such, low-dose CO is being explored as a novel treatment for a variety of different diseases. Here, we review the concept of anesthesia-related CO exposure, identify the sources of production, detail the mechanisms of overt CO toxicity, highlight the cellular effects of low-dose CO, and discuss the potential therapeutic role for CO as part of routine anesthetic management. PMID:27537758

  13. Potential for Carbon Dioxide Sequestration in Flood Basalts

    SciTech Connect

    McGrail, B. PETER; Schaef, Herbert T.; Ho, Anita M.; Chien, Yi-Ju; Dooley, James J.; Davidson, Casie L.

    2006-12-01

    Flood basalts are a potentially important host medium for geologic sequestration of anthropogenic CO2. Most lava flows have flow tops that are porous, permeable, and have enormous capacity for storage of CO2. Interbedded sediment layers and dense low-permeability basalt rock overlying sequential flows may act as effective seals allowing time for mineralization reactions to occur. Laboratory experiments confirm relatively rapid chemical reaction of CO2-saturated pore water with basalts to form stable carbonate minerals. Calculations suggest a sufficiently short time frame for onset of carbonate precipitation after CO2 injection that verification of in situ mineralization rates appears feasible in field pilot studies. If proven viable, major flood basalts in the U.S. and India would provide significant additional CO2 storage capacity and additional geologic sequestration options in certain regions where more conventional storage options are limited.

  14. Tobacco litter costs and public policy: a framework and methodology for considering the use of fees to offset abatement costs

    PubMed Central

    Peterson, N Andrew; Kiss, Noemi; Ebeid, Omar; Doyle, Alexis S

    2011-01-01

    Objectives Growing concern over the costs, environmental impact and safety of tobacco product litter (TPL) has prompted states and cities to undertake a variety of policy initiatives, of which litter abatement fees are part. The present work describes a framework and methodology for calculating TPL costs and abatement fees. Methods Abatement is associated with four categories of costs: (1) mechanical and manual abatement from streets, sidewalks and public places, (2) mechanical and manual abatement from storm water and sewer treatment systems, (3) the costs associated with harm to the ecosystem and harm to industries dependent on clean and healthy ecosystems, and (4) the costs associated with direct harm to human health. The experiences of the City of San Francisco's recently proposed tobacco litter abatement fee serve as a case study. Results City and municipal TPL costs are incurred through manual and mechanical clean-up of surfaces and catchment areas. According to some studies, public litter abatement costs to US cities range from US$3 million to US$16 million. TPL typically comprises between 22% and 36% of all visible litter, implying that total public TPL direct abatement costs range from about US$0.5 million to US$6 million for a city the size of San Francisco. The costs of mitigating the negative externalities of TPL in a city the size of San Francisco can be offset by implementing a fee of approximately US$0.20 per pack. Conclusions Tobacco litter abatement costs to cities can be substantial, even when the costs of potential environmental pollution and tourism effects are excluded. One public policy option to address tobacco litter is levying of fees on cigarettes sold. The methodology described here for calculating TPL costs and abatement fees may be useful to state and local authorities who are considering adoption of this policy initiative. PMID:21504923

  15. Experimental Study of Potential Wellbore Cement Carbonation by Various Phases of Carbon Dioxide during Geologic Carbon Sequestration

    NASA Astrophysics Data System (ADS)

    Jung, H.; Um, W.

    2012-12-01

    Hydrated Portland cement was reacted with three different carbon dioxide (CO2) phases (supercritical, gaseous, and aqueous) to understand potential cement alteration processes along the length of a wellbore, extending from the deep CO2 storage reservoir to the shallow subsurface. Three-dimensional X-ray microtomography (XMT) images showed that cement alteration was significantly more extensive in CO2-saturated water experiments than in dry or wet supercritical CO2 experiments at high P (10 MPa)-T (50°C) conditions. XMT imaging was capable of visualizing the degradation front with lower density and higher porosity as well as the carbonated zone with higher density and lower porosity in the cement matrix altered by CO2-saturated water. Scanning electron microscopy with energy dispersive spectroscopy (SEM-EDS) analysis showed a systematic change in Ca and C atom % in the cement matrix after reaction with CO2-saturated water for 1-5 months due to Ca depletion and C enrichment as a result of progressive carbonation. Integrated XMT and SEM-EDS analyses revealed that cement carbonation by CO2-saturated water formed three alteration zones; the degradation front, the carbonated zone, and the outermost porous zone. Cement pores in the carbonated zone were filled with CaCO3(s), resulting in a decrease in the porosity and permeability of the cement columns by an order of magnitude. In contrast, cement carbonation by dry or wet supercritical CO2 was slow and minor, and only a thin single carbonation zone was formed after exposure to dry supercritical CO2 for 15 months. Extensive calcite coating was formed on the outside surface of a cement sample after exposure to wet gaseous CO2 for 1-3 months, which reduced the pore volume of the cement by a factor of 3-6. The chemical-physical characterization of hydrated Portland cement after exposure to various phases of carbon dioxide indicates that the extent of cement carbonation can be significantly heterogeneous depending on CO2

  16. FEASIBILITY OF ELK CREEK ACID MINE DRAINAGE ABATEMENT PROJECT

    EPA Science Inventory

    A study was conducted within the Elk Creek Watershed, West Virginia to determine the technical and economic feasibility of three acid mine drainage abatement techniques. Alkaline regarding and slurry trench construction were established as technically and economically viable abat...

  17. Soil Organic Carbon Loss: An Overlooked Factor in the Carbon Sequestration Potential of Enhanced Mineral Weathering

    NASA Astrophysics Data System (ADS)

    Dietzen, Christiana; Harrison, Robert

    2016-04-01

    Weathering of silicate minerals regulates the global carbon cycle on geologic timescales. Several authors have proposed that applying finely ground silicate minerals to soils, where organic acids would enhance the rate of weathering, could increase carbon uptake and mitigate anthropogenic CO2 emissions. Silicate minerals such as olivine could replace lime, which is commonly used to remediate soil acidification, thereby sequestering CO2 while achieving the same increase in soil pH. However, the effect of adding this material on soil organic matter, the largest terrestrial pool of carbon, has yet to be considered. Microbial biomass and respiration have been observed to increase with decreasing acidity, but it is unclear how long the effect lasts. If the addition of silicate minerals promotes the loss of soil organic carbon through decomposition, it could significantly reduce the efficiency of this process or even create a net carbon source. However, it is possible that this initial flush of microbial activity may be compensated for by additional organic matter inputs to soil pools due to increases in plant productivity under less acidic conditions. This study aimed to examine the effects of olivine amendments on soil CO2 flux. A liming treatment representative of typical agricultural practices was also included for comparison. Samples from two highly acidic soils were split into groups amended with olivine or lime and a control group. These samples were incubated at 22°C and constant soil moisture in jars with airtight septa lids. Gas samples were extracted periodically over the course of 2 months and change in headspace CO2 concentration was determined. The effects of enhanced mineral weathering on soil organic matter have yet to be addressed by those promoting this method of carbon sequestration. This project provides the first data on the potential effects of enhanced mineral weathering in the soil environment on soil organic carbon pools.

  18. Continuous nitrous oxide abatement in a novel denitrifying off-gas bioscrubber.

    PubMed

    Frutos, Osvaldo D; Arvelo, Ilan A; Pérez, Rebeca; Quijano, Guillermo; Muñoz, Raúl

    2015-04-01

    The potential of a bioscrubber composed of a packed bed absorption column coupled to a stirred tank denitrification bioreactor (STR) was assessed for 95 days for the continuous abatement of a diluted air emission of N2O at different liquid recycling velocities. N2O removal efficiencies of up to 40 ± 1 % were achieved at the highest recirculation velocity (8 m h(-1)) at an empty bed residence time of 3 min using a synthetic air emission containing N2O at 104 ± 12 ppmv. N2O was absorbed in the packed bed column and further reduced in the STR at efficiencies >80 % using methanol as electron donor. The long-term operation of the bioscrubber suggested that the specialized N2O degrading community established was not able to use N2O as nitrogen source. Additional nitrification assays showed that the activated sludge used as inoculum was not capable of aerobically oxidizing N2O to nitrate or nitrite, regardless of the inorganic carbon concentration tested. Denitrification assays confirmed the ability of non-acclimated activated sludge to readily denitrify N2O at a specific rate of 3.9 mg N2O g VSS h(-1) using methanol as electron donor. This study constitutes, to the best of our knowledge, the first systematic assessment of the continuous abatement of N2O in air emission. A characterization of the structure of the microbial population in the absorption column by DGGE-sequencing revealed a high microbial diversity and the presence of heterotrophic denitrifying methylotrophs. PMID:25547842

  19. OPTIONS FOR ABATING GREENHOUSE GASES FROM EXHAUST STREAMS.

    SciTech Connect

    FTHENAKIS,V.

    2001-12-01

    This report examines different alternatives for replacing, treating, and recycling greenhouse gases. It is concluded that treatment (abatement) is the only viable short-term option. Three options for abatement that were tested for use in semiconductor facilities are reviewed, and their performance and costs compared. This study shows that effective abatement options are available to the photovoltaic (PV) industry, at reasonable cost.

  20. 23 CFR 772.13 - Analysis of noise abatement.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... standard and in conformance with the provisions of 40 CFR 1506.5(c) and 23 CFR 636.109. (j) Third party... PROCEDURES FOR ABATEMENT OF HIGHWAY TRAFFIC NOISE AND CONSTRUCTION NOISE § 772.13 Analysis of noise abatement. (a) When traffic noise impacts are identified, noise abatement shall be considered and evaluated...

  1. 23 CFR 772.13 - Analysis of noise abatement.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 23 Highways 1 2012-04-01 2012-04-01 false Analysis of noise abatement. 772.13 Section 772.13 Highways FEDERAL HIGHWAY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION RIGHT-OF-WAY AND ENVIRONMENT PROCEDURES FOR ABATEMENT OF HIGHWAY TRAFFIC NOISE AND CONSTRUCTION NOISE § 772.13 Analysis of noise abatement. (a) When traffic noise impacts are...

  2. 23 CFR 772.13 - Analysis of noise abatement.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 23 Highways 1 2013-04-01 2013-04-01 false Analysis of noise abatement. 772.13 Section 772.13 Highways FEDERAL HIGHWAY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION RIGHT-OF-WAY AND ENVIRONMENT PROCEDURES FOR ABATEMENT OF HIGHWAY TRAFFIC NOISE AND CONSTRUCTION NOISE § 772.13 Analysis of noise abatement. (a) When traffic noise impacts are...

  3. 10 CFR 851.22 - Hazard prevention and abatement.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 10 Energy 4 2010-01-01 2010-01-01 false Hazard prevention and abatement. 851.22 Section 851.22 Energy DEPARTMENT OF ENERGY WORKER SAFETY AND HEALTH PROGRAM Specific Program Requirements § 851.22 Hazard prevention and abatement. (a) Contractors must establish and implement a hazard prevention and abatement process to ensure that all identified...

  4. POLLUTION ABATEMENT COSTS AND EXPENDITURES SURVEY

    EPA Science Inventory

    The Pollution Abatement Costs and Expenditures (PACE) Survey is a Census Bureau product funded via a cooperative agreement with EPA. PACE data was collected by Census from 1974-1996 (except 1987) and 1999. The survey consists of approximately 20,000 manufacturing facilities in ...

  5. 29 CFR 4207.3 - Abatement.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... section, as appropriate. If a bond or escrow has been provided to the plan under § 4207.4, the plan sponsor shall send a copy of the notice to the bonding or escrow agent. (c) Effects of abatement. If the... applicable; (3) Any bonds furnished under § 4207.4 shall be cancelled and any amounts held in escrow...

  6. 29 CFR 4207.3 - Abatement.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... section, as appropriate. If a bond or escrow has been provided to the plan under § 4207.4, the plan sponsor shall send a copy of the notice to the bonding or escrow agent. (c) Effects of abatement. If the... applicable; (3) Any bonds furnished under § 4207.4 shall be cancelled and any amounts held in escrow...

  7. The potential of clear-sky carbon dioxide satellite retrievals

    NASA Astrophysics Data System (ADS)

    Nelson, Robert R.; O'Dell, Christopher W.; Taylor, Thomas E.; Mandrake, Lukas; Smyth, Mike

    2016-04-01

    Since the launch of the Greenhouse Gases Observing Satellite (GOSAT) in 2009, retrieval algorithms designed to infer the column-averaged dry-air mole fraction of carbon dioxide (XCO2) from hyperspectral near-infrared observations of reflected sunlight have been greatly improved. They now generally include the scattering effects of clouds and aerosols, as early work found that absorption-only retrievals, which neglected these effects, often incurred unacceptably large errors, even for scenes with optically thin cloud or aerosol layers. However, these "full-physics" retrievals tend to be computationally expensive and may incur biases from trying to deduce the properties of clouds and aerosols when there are none present. Additionally, algorithms are now available that can quickly and effectively identify and remove most scenes in which cloud or aerosol scattering plays a significant role. In this work, we test the hypothesis that non-scattering, or "clear-sky", retrievals may perform as well as full-physics retrievals for sufficiently clear scenes. Clear-sky retrievals could potentially avoid errors and biases brought about by trying to infer properties of clouds and aerosols when none are present. Clear-sky retrievals are also desirable because they are orders of magnitude faster than full-physics retrievals. Here we use a simplified version of the Atmospheric Carbon Observations from Space (ACOS) XCO2 retrieval algorithm that does not include the scattering and absorption effects of clouds or aerosols. It was found that for simulated Orbiting Carbon Observatory-2 (OCO-2) measurements, the clear-sky retrieval had errors comparable to those of the full-physics retrieval. For real GOSAT data, the clear-sky retrieval had errors 0-20 % larger than the full-physics retrieval over land and errors roughly 20-35 % larger over ocean, depending on filtration level. In general, the clear-sky retrieval had XCOAbatement of methane emissions from landfills -- the German way

    SciTech Connect

    Angerer, G.; Kalb, H.

    1996-12-31

    Landfills are a major source of methane. Methane is generated by biological degradation of native organic matter under anaerobic conditions. In Germany one quarter to one third of the total methane emissions into the air originate from landfills for municipal wastes. These emissions amounts to 1.2--1.9 million metric tons annually. Landfills represent the second most important methane source. For stock farming the technical opportunities to reduce methane emissions are limited. Therefore, environmental policy aiming to abate methane emissions focuses on waste management. In Germany the most effective policy instrument for this task is the Third Administrative Provision to the waste framework law. This provision came into operation in 1993 and requires that waste disposed in landfills must be inert. Beginning in the year 2005 the total organic carbon (TOC) content of the waste will be limited to 1--3%. This limit requires a pretreatment of municipal waste, and among the currently available technology options only an incineration is able to fulfill the stipulated criteria. Methane abatement will be further regulated by the new waste law, Cycle Economy and Waste Law.

  8. Carbon dynamics of Oregon and Northern California forests and potential land-based carbon storage.

    PubMed

    Hudiburg, Tara; Law, Beverly; Turner, David P; Campbell, John; Donato, Dan; Duane, Maureen

    2009-01-01

    Net uptake of carbon from the atmosphere (net ecosystem production, NEP) is dependent on climate, disturbance history, management practices, forest age, and forest type. To improve understanding of the influence of these factors on forest carbon stocks and flux in the western United States, federal inventory data and supplemental field measurements at additional plots were used to estimate several important components of the carbon balance in forests in Oregon and Northern California during the 1990s. Species- and ecoregion-specific allometric equations were used to estimate live and dead biomass stores, net primary productivity (NPP), and mortality. In the semiarid East Cascades and mesic Coast Range, mean total biomass was 8 and 24 kg C/m2, and mean NPP was 0.30 and 0.78 kg C.m(-2).yr(-1), respectively. Maximum NPP and dead biomass stores were most influenced by climate, whereas maximum live biomass stores and mortality were most influenced by forest type. Within ecoregions, mean live and dead biomass were usually higher on public lands, primarily because of the younger age class distribution on private lands. Decrease in NPP with age was not general across ecoregions, with no marked decline in old stands (>200 years old) in some ecoregions. In the absence of stand-replacing disturbance, total landscape carbon stocks could theoretically increase from 3.2 +/- 0.34 Pg C to 5.9 +/- 1.34 Pg C (a 46% increase) if forests were managed for maximum carbon storage. Although the theoretical limit is probably unattainable, given the timber-based economy and fire regimes in some ecoregions, there is still potential to significantly increase the land-based carbon storage by increasing rotation age and reducing harvest rates. PMID:19323181

  9. Experimental study of potential wellbore cement carbonation by various phases of carbon dioxide during geologic carbon sequestration

    SciTech Connect

    Jung, Hun Bok; Um, Wooyong

    2013-08-16

    Hydrated Portland cement was reacted with carbon dioxide (CO2) in supercritical, gaseous, and aqueous phases to understand the potential cement alteration processes along the length of a wellbore, extending from deep CO2 storage reservoir to the shallow subsurface during geologic carbon sequestration. The 3-D X-ray microtomography (XMT) images displayed that the cement alteration was significantly more extensive by CO2-saturated synthetic groundwater than dry or wet supercritical CO2 at high P (10 MPa)-T (50°C) conditions. Scanning electron microscopy with energy dispersive spectroscopy (SEM-EDS) analysis also exhibited a systematic Ca depletion and C enrichment in cement matrix exposed to CO2-saturated groundwater. Integrated XMT, XRD, and SEM-EDS analyses identified the formation of extensive carbonated zone filled with CaCO3(s), as well as the porous degradation front and the outermost silica-rich zone in cement after exposure to CO2-saturated groundwater. The cement alteration by CO2-saturated groundwater for 2-8 months overall decreased the porosity from 31% to 22% and the permeability by an order of magnitude. Cement alteration by dry or wet supercritical CO2 was slow and minor compared to CO2-saturated groundwater. A thin single carbonation zone was formed in cement after exposure to wet supercritical CO2 for 8 months or dry supercritical CO2 for 15 months. Extensive calcite coating was formed on the outside surface of a cement sample after exposure to wet gaseous CO2 for 1-3 months. The chemical-physical characterization of hydrated Portland cement after exposure to various phases of carbon dioxide indicates that the extent of cement carbonation can be significantly heterogeneous depending on CO2 phase present in the wellbore environment. Both experimental and geochemical modeling results suggest that wellbore cement exposure to supercritical, gaseous, and aqueous phases of CO2 during geologic carbon sequestration is unlikely to damage the wellbore

  10. The potential of clear-sky carbon dioxide satellite retrievals

    NASA Astrophysics Data System (ADS)

    Nelson, R. R.; O'Dell, C. W.; Taylor, T. E.; Mandrake, L.; Smyth, M.

    2015-12-01

    Since the launch of the Greenhouse Gases Observing Satellite (GOSAT) in 2009, retrieval algorithms designed to infer the column-averaged dry-air mole fraction of carbon dioxide (XCO2) from hyperspectral near-infrared observations of reflected sunlight have been greatly improved. They now generally include the scattering effects of clouds and aerosols, as early work found that absorption-only retrievals, which neglected these effects, often incurred unacceptably large errors, even for scenes with optically thin cloud or aerosol layers. However, these "full-physics" retrievals tend to be computationally expensive and may incur biases from trying to deduce the properties of clouds and aerosols when there are none present. Additionally, algorithms are now available that can quickly and effectively identify and remove most scenes in which cloud or aerosol scattering plays a significant role. In this work, we test the hypothesis that non-scattering, or "clear-sky", retrievals may perform as well as full-physics retrievals for sufficiently clear scenes. Clear-sky retrievals could potentially avoid errors and biases brought about by trying to infer properties of clouds and aerosols when none are present. Clear-sky retrievals are also desirable because they are orders of magnitude faster than full-physics retrievals. Here we use a simplified version of the Atmospheric Carbon Observations from Space (ACOS) XCO2 retrieval algorithm that does not include the scattering and absorption effects of clouds or aerosols. It was found that for simulated Orbiting Carbon Observatory-2 (OCO-2) measurements, the clear-sky retrieval had errors comparable to those of the full-physics retrieval. For real GOSAT data, the clear-sky retrieval had nearly indistinguishable error characteristics over land, but roughly 30-60 % larger errors over ocean, depending on filtration level, compared to the full-physics retrieval. In general, the clear-sky retrieval had XCO2 root-mean-square (RMS) errors of

  11. Genotoxicity of carbon nanofibers: are they potentially more or less dangerous than carbon nanotubes or asbestos?

    PubMed Central

    Kisin, E. R.; Murray, A.R.; Sargent, L.; Lowry, D.; Chirila, M.; Siegrist, K.J.; Schwegler-Berry, D.; Leonard, S.; Castranova, V.; Fadeel, B.; Kagan, V.E.; Shvedova, A.A.

    2011-01-01

    The production of carbon nanofibers and nanotubes (CNF/CNT) and their composite products is increasing globally. CNF are generating great interest in industrial sectors such as energy production and electronics, where alternative materials may have limited performance or are produced at a much higher cost. However, despite the increasing industrial use of carbon nanofibers, information on their potential adverse health effects is limited. In the current study, we examine the cytotoxic and genotoxic potential of carbon-based nanofibers (Pyrograf®-III) and compare this material with the effects of asbestos fibers (crocidolite) or single-walled carbon nanotubes (SWCNT). The genotoxic effects in the lung fibroblast (V79) cell line were examined using two complementary assays: the comet assay and micronucleus (MN) test. In addition, we utilized fluorescence in situ hybridization to detect the chromatin pan-centromeric signals within the MN indicating their origin by aneugenic (chromosomal malsegregation) or clastogenic (chromosome breakage) mechanisms. Cytotoxicity tests revealed a concentration- and time-dependent loss of V79 cell viability after exposure to all tested materials in the following sequence: asbestos>CNF>SWCNT. Additionally, cellular uptake and generation of oxygen radicals was seen in the murine RAW264.7 macrophages following exposure to CNF or asbestos but not after administration of SWCNT. DNA damage and MN induction were found after exposure to all tested materials with the strongest effect seen for CNF. Finally, we demonstrated that CNF induced predominately centromere-positive MN in primary human small airway epithelial cells (SAEC) indicating aneugenic events. Further investigations are warranted to elucidate the possible mechanisms involved in CNF-induced genotoxicity. PMID:21310169

  12. Genotoxicity of carbon nanofibers: Are they potentially more or less dangerous than carbon nanotubes or asbestos?

    SciTech Connect

    Kisin, E.R.; Murray, A.R.; Sargent, L.; Lowry, D.; Chirila, M.; Siegrist, K.J.; Schwegler-Berry, D.; Leonard, S.; Castranova, V.; Fadeel, B.; Kagan, V.E.; Shvedova, A.A.

    2011-04-01

    The production of carbon nanofibers and nanotubes (CNF/CNT) and their composite products is increasing globally. CNF are generating great interest in industrial sectors such as energy production and electronics, where alternative materials may have limited performance or are produced at a much higher cost. However, despite the increasing industrial use of carbon nanofibers, information on their potential adverse health effects is limited. In the current study, we examine the cytotoxic and genotoxic potential of carbon-based nanofibers (Pyrograf (registered) -III) and compare this material with the effects of asbestos fibers (crocidolite) or single-walled carbon nanotubes (SWCNT). The genotoxic effects in the lung fibroblast (V79) cell line were examined using two complementary assays: the comet assay and micronucleus (MN) test. In addition, we utilized fluorescence in situ hybridization to detect the chromatin pan-centromeric signals within the MN indicating their origin by aneugenic (chromosomal malsegregation) or clastogenic (chromosome breakage) mechanisms. Cytotoxicity tests revealed a concentration- and time-dependent loss of V79 cell viability after exposure to all tested materials in the following sequence: asbestos > CNF > SWCNT. Additionally, cellular uptake and generation of oxygen radicals was seen in the murine RAW264.7 macrophages following exposure to CNF or asbestos but not after administration of SWCNT. DNA damage and MN induction were found after exposure to all tested materials with the strongest effect seen for CNF. Finally, we demonstrated that CNF induced predominately centromere-positive MN in primary human small airway epithelial cells (SAEC) indicating aneugenic events. Further investigations are warranted to elucidate the possible mechanisms involved in CNF-induced genotoxicity.

  13. Soil organic carbon of an intensively reclaimed region in China: Current status and carbon sequestration potential.

    PubMed

    Deng, Xunfei; Zhan, Yu; Wang, Fei; Ma, Wanzhu; Ren, Zhouqiao; Chen, Xiaojia; Qin, Fangjin; Long, Wenli; Zhu, Zhenling; Lv, Xiaonan

    2016-09-15

    Land reclamation has been highly intensive in China, resulting in a large amount of soil organic carbon (SOC) loss to the atmosphere. Evaluating the factors which drive SOC dynamics and carbon sequestration potential in reclaimed land is critical for improving soil fertility and mitigating global warming. This study aims to determine the current status and factors important to the SOC density in a typical reclaimed land located in Eastern China, where land reclamation has been undergoing for centuries. A total of 4746 topsoil samples were collected from 2007 to 2010. The SOC density of the reclaimed land (3.18±0.05kgCm(-2); mean±standard error) is significantly lower than that of the adjacent non-reclaimed land (5.71±0.04kgCm(-2)) (p<0.05). A Random Forest model is developed and it captures the relationships between the SOC density and the environmental/anthropogenic factors (R(2)=0.59). The soil pH, land use, and elevation are the most important factors for determining SOC dynamics. In contrast, the effect of the reclamation age on the SOC density is negligible, where SOC content in the land reclaimed during years 1047-1724 is as low as that reclaimed during years 1945-2004. The scenario analysis results indicate that the carbon sequestration potential of the reclaimed lands may achieve a maximum of 5.80±1.81kgCO2m(-2) (mean±SD) when dryland is converted to flooded land with vegetable-rice cropping system and soil pH of ~5.9. Note that in some scenarios the methane emission substantially offsets the carbon sequestration potential, especially for continuous rice cropping system. With the optimal setting for carbon sequestration, it is estimated that the dryland reclaimed in the last 50years in China is able to sequester 0.12milliontons CO2 equivalent per year. PMID:27196991

  14. Abating environmentally harmful waste gases

    NASA Astrophysics Data System (ADS)

    Sridhar, S.; Sichen, Du; Pal, U. B.; Seetharaman, S.

    2002-05-01

    A gas-purification method, based on the condensation of nitrogen, sulfur, and carbon-containing environmentally hazardous gases produced from industrial processes, is proposed in this article. The method, which utilizes the cooling capacity of waste nitrogen in the oxygen plant to condense the hazardous gases, is capable of removing hazardous impurities up to 99.98%. Theoretical calculations underlying the condensation process are presented employing gases produced in a blast furnace and coke oven in an integrated steel plant. The cooling power required for the condensation process is calculated using the waste nitrogen generated from an oxygen plant that generates captive oxygen for the steel plant. Design modifications that need to be made to the oxygen plant in order to utilize the cooling power of the waste nitrogen gas are also presented. As a case study, the advantages of the method are illustrated with purification of coke-oven gas. The economic impact and the investment aspects are also discussed.

  15. The streaming potential of liquid carbon dioxide in Berea sandstone

    NASA Astrophysics Data System (ADS)

    Moore, Jeffrey R.; Glaser, Steven D.; Morrison, H. Frank; Hoversten, G. Michael

    2004-09-01

    We report here, for the first time, evolution of the streaming potential coupling coefficient as liquid carbon dioxide infiltrates Berea sandstone. Using 125 Ω-m tap water, the coupling coefficient determined before and after each CO2 flood of five samples averaged approximately -30 mV/0.1 MPa. After liquid CO2 passed through the specimens displacing all mobile pore water, trapped water remained and the coupling coefficient was approximately -3 mV/0.1 MPa. A bound water limit of the coupling coefficient for liquid CO2 flow was found using an air-dried sample to be -0.02 mV/0.1 MPa. For initially water-saturated samples, bulk resistivity varied during CO2 invasion from 330 Ω-m, to 150 Ω-m during CO2/water mixing, to a final value of 380 Ω-m. Results suggest that trapped and bound water control electrical conduction and the electrokinetic response. Applications include monitoring CO2 injectate in subsurface reservoirs using the self potential method.

  16. Potential release scenarios for carbon nanotubes used in composites.

    PubMed

    Nowack, Bernd; David, Raymond M; Fissan, Heinz; Morris, Howard; Shatkin, Jo Anne; Stintz, Michael; Zepp, Richard; Brouwer, Derk

    2013-09-01

    The expected widespread use of carbon nanotube (CNT)-composites in consumer products calls for an assessment of the possible release and exposure to workers, consumers and the environment. Release of CNTs may occur at all steps in the life cycle of products, but to date only limited information is available about release of CNTs from actual products and articles. As a starting point for exposure assessment, exploring sources and pathways of release helps to identify relevant applications and situations where the environment and especially humans may encounter releases of CNTs. It is the aim of this review to identify various potential release scenarios for CNTs used in polymers and identify the greatest likelihood of release at the various stages throughout the life-cycle of the product. The available information on release of CNTs from products and articles is reviewed in a first part. In a second part nine relevant release scenarios are described in detail: injection molding, manufacturing, sports equipment, electronics, windmill blades, fuel system components, tires, textiles, incineration, and landfills. Release from products can potentially occur by two pathways; (a) where free CNTs are released directly, or more frequently (b) where the initial release is a particle with CNTs embedded in the matrix, potentially followed by the subsequent release of CNTs from the matrix. The potential for release during manufacturing exists for all scenarios, however, this is also the situation when exposure can be best controlled. For most of the other life cycle stages and their corresponding release scenarios, potential release of CNTs can be considered to be low, but it cannot be excluded totally. Direct release to the environment is also considered to be very low for most scenarios except for the use of CNTs in tires where significant abrasion during use and release into the environment would occur. Also the possible future use of CNTs in textiles could result in consumer

  17. MICROBIAL ECOLOGY OF POLLUTION ABATEMENT

    EPA Science Inventory

    My career started with Cliff Dahm at the University of New Mexico. The western United States had been experiencing a new “gold rush” using cyanide to mine previously unextractable, low-grade ore and we studied the potential to stimulate native cyanide-degrading micro...

  18. New insights into the nation's carbon storage potential

    USGS Publications Warehouse

    Warwick, Peter D.; Zhu, Zhi-Liang

    2012-01-01

    Carbon sequestration is a method of securing carbon dioxide (CO2) to prevent its release into the atmosphere, where it contributes to global warming as a greenhouse gas. Geologic storage of CO2 in porous and permeable rocks involves injecting high-pressure CO2 into a subsurface rock unit that has available pore space. Biologic carbon sequestration refers to both natural and anthropogenic processes by which CO2 is removed from the atmosphere and stored as carbon in vegetation, soils, and sediments.

  19. Abating exhaust noises in jet engines

    NASA Technical Reports Server (NTRS)

    Schwartz, I. R. (Inventor)

    1974-01-01

    A noise abating improvement for jet engines including turbojets, turbofans, turboprops, ramjets, scramjets, and hybrid jets is introduced. A provision is made for an apparatus in the primary and/or secondary flow streams of the engines; the apparatus imparts to the exhaust gases a component rotation or swirl about the engine's longitudinal axis. The rotary component in the exhaust gases causes a substantial suppression of sound energy build up normally produced by an axial flow exhaust system.

  1. Carbon Sequestration Potential in Mangrove Wetlands of Southern of India

    NASA Astrophysics Data System (ADS)

    Chokkalingam, L.; Ponnambalam, K.; Ponnaiah, J. M.; Roy, P.; Sankar, S.

    2012-12-01

    Mangrove forest and the soil on which it grows are major sinks of atmospheric carbon. We present the results of a study on the carbon sequestration in the ground biomass of Avicennia marina including the organic carbon deposition, degradation and preservation in wetland sediments of Muthupet mangrove forest (southeast coast of India) in order to evaluate the influence of forests in the global carbon cycle. The inventory for estimating the ground biomass of Avicennia marina was carried out using random sampling technique (10 m × 10 m plot) with allometric regression equation. The carbon content in different vegetal parts (leaves, stem and root) of mangrove species and associated marshy vegetations was estimated using the combustion method. We observe that the organic carbon was higher (ca. 54.8%) recorded in the stems of Aegiceras corniculatum and Salicornia brachiata and lower (ca. 30.3%) in the Sesuvium portulacastrum leaves. The ground biomass and carbon sequestration of Avicennia marina are 58.56±12.65 t/ ha and 27.52±5.95 mg C/ha, respectively. The depth integrated organic carbon model profiles indicate an average accumulation rate of 149.75gC/m2.yr and an average remineralization rate of 32.89gC/m2.yr. We estimate an oxidation of ca. 21.85% of organic carbon and preservation of ca. 78.15% of organic carbon in the wetland sediments. Keywords: Above ground biomass, organic carbon, sequestration, mangrove, wetland sediments, Muthupet.

  2. Potential Carbon Negative Commercial Aviation through Land Management

    NASA Technical Reports Server (NTRS)

    Hendricks, Robert C.

    2008-01-01

    Brazilian terra preta soil and char-enhanced soil agricultural systems have demonstrated both enhanced plant biomass and crop yield and functions as a carbon sink. Similar carbon sinking has been demonstrated for both glycophyte and halophyte plants and plant roots. Within the assumption of 3.7 t-C/ha/yr soils and plant root carbon sinking, it is possible to provide carbon neutral U.S. commercial aviation using about 8.5% of U.S. arable lands. The total airline CO2 release would be offset by carbon credits for properly managed soils and plant rooting, becoming carbon neutral for carbon sequestered synjet processing. If these lands were also used to produce biomass fuel crops such as soybeans at an increased yield of 60 bu/acre (225gal/ha), they would provide over 3.15 10(exp 9) gallons biodiesel fuel. If all this fuel were refined into biojet it would provide a 16% biojet-84% synjet blend. This allows the U.S. aviation industry to become carbon negative (carbon negative commercial aviation through carbon credits). Arid land recovery could yield even greater benefits.

  3. Carbon nanotubes buckypapers for potential transdermal drug delivery.

    PubMed

    Schwengber, Alex; Prado, Héctor J; Zilli, Darío A; Bonelli, Pablo R; Cukierman, Ana L

    2015-12-01

    Drug loaded buckypapers based on different types of carbon nanotubes (CNTs) were prepared and characterized in order to evaluate their potentialities for the design of novel transdermal drug delivery systems. Lab-synthesized CNTs as well as commercial samples were employed. Clonidine hydrochloride was used as model drug, and the influence of composition of the drug loaded buckypapers and processing variables on in vitro release profiles was investigated. To examine the influence of the drug nature the evaluation was further extended to buckypapers prepared with flurbiprofen and one type of CNTs, their selection being based on the results obtained with the former drug. Scanning electronic microscopy images indicated that the model drugs were finely dispersed on the CNTs. Differential scanning calorimetry, and X-ray diffraction pointed to an amorphous state of both drugs in the buckypapers. A higher degree of CNT-drug superficial interactions resulted in a slower release of the drug. These interactions were in turn affected by the type of CNTs employed (single wall or multiwall CNTs), their functionalization with hydroxyl or carboxyl groups, the chemical structure of the drug, and the CNT:drug mass ratio. Furthermore, the application of a second layer of drug free CNTs on the loaded buckypaper, led to decelerate the drug release and to reduce the burst effect. PMID:26354234

  4. Land use efficiency: anticipating future demand for land-sector greenhouse gas emissions abatement and managing trade-offs with agriculture, water, and biodiversity.

    PubMed

    Bryan, Brett A; Crossman, Neville D; Nolan, Martin; Li, Jing; Navarro, Javier; Connor, Jeffery D

    2015-11-01

    Competition for land is increasing, and policy needs to ensure the efficient supply of multiple ecosystem services from land systems. We modelled the spatially explicit potential future supply of ecosystem services in Australia's intensive agricultural land in response to carbon markets under four global outlooks from 2013 to 2050. We assessed the productive efficiency of greenhouse gas emissions abatement, agricultural production, water resources, and biodiversity services and compared these to production possibility frontiers (PPFs). While interacting commodity markets and carbon markets produced efficient outcomes for agricultural production and emissions abatement, more efficient outcomes were possible for water resources and biodiversity services due to weak price signals. However, when only two objectives were considered as per typical efficiency assessments, efficiency improvements involved significant unintended trade-offs for the other objectives and incurred substantial opportunity costs. Considering multiple objectives simultaneously enabled the identification of land use arrangements that were efficient over multiple ecosystem services. Efficient land use arrangements could be selected that meet society's preferences for ecosystem service provision from land by adjusting the metric used to combine multiple services. To effectively manage competition for land via land use efficiency, market incentives are needed that effectively price multiple ecosystem services. PMID:26147156

  5. Potential for Carbon Sequestration in Transplanted Salt Marshes

    NASA Astrophysics Data System (ADS)

    O'Brien, C.; Davis, J.; Currin, C.

    2014-12-01

    The photosynthetic uptake of atmospheric carbon dioxide (CO2) by tidal salt marshes results in the long-term storage of carbon in the sediment. In recent decades, pressures such as land-use change and sea level rise have significantly reduced the global extent of salt marshes and increased the need for restoration projects. Restored salt marshes have been shown to provide many of the same ecological and economic benefits as natural marshes, including fish habitat, pollution filtration, and shoreline stabilization. Given the high carbon sequestration capacity of tidal marshes, carbon storage is likely an additional benefit of restoration; however, the degree to which restored marshes achieve equivalency with natural marshes in terms of carbon burial has not been well-defined. In this study, annual carbon sequestration rates in transplanted marshes were estimated and belowground carbon stocks were compared in transplanted versus natural marshes. Sediment cores were collected from five transplanted Spartina alterniflora marshes of known age (12-38 years old) in the Newport River Estuary, NC and from two natural marshes of unknown age. Organic matter content was estimated using the loss on ignition method and carbon content was estimated based on previously established relationships. In transplanted marshes, the rate of carbon sequestration in the top 30 cm decreased with marsh age and ranged from 76.70 g C/m2/yr (38 year old marsh) to 212.83 g C/m2/yr (12 year old marsh). The natural marshes contained significantly larger carbon stocks in the top 30 cm (4534.61 - 7790.18 g C m-2) than the transplanted marshes (1822.97 - 3798.62 g C m-2). However, the annual sequestration rates in the transplanted marshes are similar to those observed by others in natural marshes, and therefore it is likely that over time restored marshes are capable of accreting belowground carbon stocks equivalent to those found in natural marshes.

  6. CARBON STORAGE POTENTIAL OF SHORT ROTATION TROPICAL TREE PLANTATIONS

    EPA Science Inventory

    Forests are a major sin or car on an play an important role in the global carbon cycle. ot only do forests contain hugh amounts of carbon, they exchange it very actively with the atmosphere. xpanding the world's forests, therefore, may present an opportunity to increase the terre...

  7. Carbon sequestration potential for forage and pasture systems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Grassland soils represent a large reservoir of organic and inorganic carbon. Regionally, grasslands are annual CO2 sources or sinks depending on crop and soil management, current soil organic carbon (SOC) concentration and climate. Land management changes (LMC) impact SOC sequestration rate, the du...

  8. Global potential of biospheric carbon management for climate mitigation.

    PubMed

    Canadell, Josep G; Schulze, E Detlef

    2014-01-01

    Elevated concentrations of atmospheric greenhouse gases (GHGs), particularly carbon dioxide (CO2), have affected the global climate. Land-based biological carbon mitigation strategies are considered an important and viable pathway towards climate stabilization. However, to satisfy the growing demands for food, wood products, energy, climate mitigation and biodiversity conservation-all of which compete for increasingly limited quantities of biomass and land-the deployment of mitigation strategies must be driven by sustainable and integrated land management. If executed accordingly, through avoided emissions and carbon sequestration, biological carbon and bioenergy mitigation could save up to 38 billion tonnes of carbon and 3-8% of estimated energy consumption, respectively, by 2050. PMID:25407959

  9. Assessment of the potential of urban organic carbon dynamics to off-set urban anthropogenic emissions

    NASA Astrophysics Data System (ADS)

    Gottschalk, P.; Churkina, G.; Wattenbach, M.; Cubasch, U.

    2010-12-01

    The impact of urban systems on current and future global carbon emissions has been a focus of several studies. Many mitigation options in terms of increasing energy efficiency are discussed. However, apart from technical mitigation potential urban systems also have a considerable biogenic potential to mitigate carbon through an optimized management of organic carbon pools of vegetation and soil. Berlin city area comprises almost 50% of areas covered with vegetation or largely covered with vegetation. This potentially offers various areas for carbon mitigation actions. To assess the mitigation potentials our first objective is to estimate how large current vegetation and soil carbon stocks of Berlin are. We use publicly available forest and soil inventories to calculate soil organic carbon of non-pervious areas and forest standing biomass carbon. This research highlights data-gaps and assigns uncertainty ranges to estimated carbon resources. The second objective is to assess the carbon mitigation potential of Berlin’s vegetation and soils using a biogeochemical simulation model. BIOME-BGC simulates carbon-, nitrogen- and water-fluxes of ecosystems mechanistically. First, its applicability for Berlin forests is tested at selected sites. A spatial application gives an estimate of current net carbon fluxes. The application of such a model allows determining the sensitivity of key ecosystem processes (e.g. carbon gains through photosynthesis, carbon losses through decomposition) towards external drivers. This information can then be used to optimise forest management in terms of carbon mitigation. Initial results of Berlin’s current carbon stocks and its spatial distribution and preliminary simulations results will be presented.

  10. Emission abatement system utilizing particulate traps

    DOEpatents

    Bromberg, Leslie; Cohn, Daniel R.; Rabinovich, Alexander

    2004-04-13

    Emission abatement system. The system includes a source of emissions and a catalyst for receiving the emissions. Suitable catalysts are absorber catalysts and selective catalytic reduction catalysts. A plasma fuel converter generates a reducing gas from a fuel source and is connected to deliver the reducing gas into contact with the absorber catalyst for regenerating the catalyst. A preferred reducing gas is a hydrogen rich gas and a preferred plasma fuel converter is a plasmatron. It is also preferred that the absorber catalyst be adapted for absorbing NO.sub.x.

  11. [Research on carbon reduction potential of electric vehicles for low-carbon transportation and its influencing factors].

    PubMed

    Shi, Xiao-Qing; Li, Xiao-Nuo; Yang, Jian-Xin

    2013-01-01

    Transportation is the key industry of urban energy consumption and carbon emissions. The transformation of conventional gasoline vehicles to new energy vehicles is an important initiative to realize the goal of developing low-carbon city through energy saving and emissions reduction, while electric vehicles (EV) will play an important role in this transition due to their advantage in energy saving and lower carbon emissions. After reviewing the existing researches on energy saving and emissions reduction of electric vehicles, this paper analyzed the factors affecting carbon emissions reduction. Combining with electric vehicles promotion program in Beijing, the paper analyzed carbon emissions and reduction potential of electric vehicles in six scenarios using the optimized energy consumption related carbon emissions model from the perspective of fuel life cycle. The scenarios included power energy structure, fuel type (energy consumption per 100 km), car type (CO2 emission factor of fuel), urban traffic conditions (speed), coal-power technologies and battery type (weight, energy efficiency). The results showed that the optimized model was able to estimate carbon emissions caused by fuel consumption more reasonably; electric vehicles had an obvious restrictive carbon reduction potential with the fluctuation of 57%-81.2% in the analysis of six influencing factors, while power energy structure and coal-power technologies play decisive roles in life-cycle carbon emissions of electric vehicles with the reduction potential of 78.1% and 81.2%, respectively. Finally, some optimized measures were proposed to reduce transport energy consumption and carbon emissions during electric vehicles promotion including improving energy structure and coal technology, popularizing energy saving technologies and electric vehicles, accelerating the battery R&D and so on. The research provides scientific basis and methods for the policy development for the transition of new energy vehicles

  12. Evaluation of Equipment Vulnerability and Potential Shock Hazards. [carbon fibers

    NASA Technical Reports Server (NTRS)

    Taback, I.

    1980-01-01

    The vulnerability of electric equipment to carbon fibers released from aircraft accidents is investigated and the parameters affecting vulnerability are discussed. The shock hazard for a hypothetical set of accidents is computed.

  13. Potential for Carbon Sequestration using Organic Amendments on Rangeland Soils

    NASA Astrophysics Data System (ADS)

    Ryals, R.; Silver, W. L.

    2009-12-01

    Managed rangelands represent a geographically large land-use footprint and thus have considerable potential to sequester carbon (C) in soil through changes in management practices. Organic amendments are frequently added to agricultural and rangeland soils in an effort to improve fertility and yield, yet little is known about their impact on greenhouse gas dynamics and soil biogeochemical dynamics, especially in rangeland soils. This research aims to explore the effects of organic amendments on soil chemical and physical properties, plant inputs, and soil C and N dynamics in managed rangeland ecosystems. Our research uses field manipulations at two Mediterranean grassland ecosystems replicated within and across bioclimatic zones: the Sierra Foothills Research and Extension Center (SFREC) in Browns Valley, CA and the Nicasio Native Grass Ranch in Nicasio, CA. Both sites are dominated by annual grasses and are moderately grazed by cattle. Three replicate blocks at each site contain 60m x 25m treatment plots (organic amendments and control) with 5m buffer strips. Organic amendments were applied at a level of 14 MgC/ha (equivalent to a 1.27cm surface dressing) at the beginning of the wet season (December 2008). During the wet season (October through June), carbon dioxide (CO2) flux was measured weekly using a LI-8100, while fluxes of methane (CH4) and nitrous oxide (N2O) were measured biweekly using static flux chambers. During the dry season (June through September), fluxes were measured biweekly and monthly, respectively. Soil organic C (SOC) and nitrogen (N) were measured prior to treatment and seven months following treatment at 0-10, 10-30, 30-50, and 50-100 cm depths. Soil moisture and temperature were measured continuously. Changes in oxidative and hydrolytic extracellular enzyme activities are also being explored. After the first year of management, both sites responded similarly to treatments in both trend and magnitude. For example, at SFREC, total soil

  14. The microbial carbon pump concept: Potential biogeochemical significance in the globally changing ocean

    NASA Astrophysics Data System (ADS)

    Legendre, Louis; Rivkin, Richard B.; Weinbauer, Markus G.; Guidi, Lionel; Uitz, Julia

    2015-05-01

    Three vertical ocean carbon pumps have been known for almost three decades to sequester atmospheric carbon in the deep-water and sediment reservoirs, i.e. the solubility pump, the carbonate pump, and the soft-tissue (also known as organic, or biological) carbon pump (BCP). These three pumps maintain the vertical gradient in total dissolved inorganic carbon between the surface and deep waters. The more recently proposed microbial carbon pump (MCP) would maintain a gradient between short- and long-lived dissolved organic carbon (DOC; average lifetimes of <100 and >100 years, respectively). Long-lived DOC is an additional proposed reservoir of sequestered carbon in the ocean. This review: examines critically aspects of the vertical ocean carbon pumps and the MCP, in particular their physical dimensions and their potential roles in carbon sequestration; normalises the dimensions of the MCP to allow direct comparisons with the three vertical ocean carbon pumps; compares the MCP and vertical ocean carbon pumps; organises in a coherent framework the information available in the literature on refractory DOC; explores the potential effects of the globally changing ocean on the MCP; and identifies the assumptions that generally underlie the MCP studies, as bases for future research. The study: proposes definitions of terms, expressions and concepts related to the four ocean carbon pumps (i.e. three vertical pumps and MCP); defines the magnitude for the MCP as the rate of production of DOC with an average lifetime of >100 years and provides its first estimate for the World Ocean, i.e. 0.2 Pg C year-1; and introduces an operational "first-time-sequestration" criterion that prevents organic carbon fluxes from being assigned to both the BCP and the MCP. In our review of the potential effects of predicted climate-related changes in the ocean environment on the MCP, we found that three of the seven predicted changes could potentially enhance carbon sequestration by the MCP, and

  15. Topographic variability influences the carbon sequestration potential of arable soils

    NASA Astrophysics Data System (ADS)

    Chirinda, N.; Elsgaard, L.; Thomsen, I. K.; Lægdsmand, M.; Heckrath, G.; Petersen, B. M.; Olesen, JE

    2012-04-01

    There is presently limited knowledge on the influence of field spatial variability on the carbon (C) sink-source relationships in arable landscapes. This is accompanied by the fact that our understanding of soil profile C dynamics is also limited. This study aimed at investigating how spatial variability along a short catena influences C sink-source relationships and temporal dynamics of CO2 concentrations in soils. In spring 2011, soil samples were collected from topsoil (2-5.5 cm) and subsoil (38-41.5 cm) horizons at upslope and footslope positions in a Danish winter wheat field on a sandy loam soil developed on glacial till. Bulk densities and C concentrations of the soils were characterized. From June 2011, gas samples were collected at least bimonthly from the same slope positions in four spatial replicates using stainless steel needles that were permanently installed at 5, 10, 20 and 30 cm soil depths. Concurrently, gas was sampled from 40, 50, and 80 cm depths using steel rods connected to a sampling port. Concentrations of CO2 in the gas samples were analyzed by gas chromatography. The results show that at the upslope position, soils from the topsoil horizon clearly had higher C pools (5.2 Mg C ha-1) compared to those from the subsoil horizon (1.0 Mg C ha-1). At the footslope position, however, C pools in topsoil (6.9 Mg C ha-1) and subsoil (7.0 C Mg ha-1) horizons were similar but higher than those at the upslope position. The gas monitoring study is still ongoing, but preliminary results show that CO2 concentrations generally increased with depth. At the upslope position, CO2 concentrations ranged between 800 and 24000 ppm and were generally lower than the concentrations observed at the footslope position (3000-42000 ppm) for similar soil depths. The upslope position has been subject to soil erosion while the footslope position has been a depositional site; thus the subsoil at the footslope position was to a large extent a buried topsoil horizon. The

  16. Determination of the atherogenic potential of inhaled carbon monoxide

    SciTech Connect

    Penn, A. )

    1993-05-01

    he effects of chronic exposure to moderate levels of carbon monoxide upon the augmentation of arteriosclerotic plaque development were investigated in a series of in vivo studies in the cockerel (young rooster). This animal model has been well characterized, especially regarding the role of environmental agents in exacerbating early stages of plaque development. Cockerels injected with subtumorigenic doses of carcinogens exhibit markedly accelerated development of aortic arteriosclerotic plaques. Inhalation of mainstream smoke from two packs of cigarettes (100 minutes/day for 16 weeks) causes small but statistically significant increases in plaque size. As is the case with many animal models of plaque development, raised fat-proliferative plaques also appear in these animals following cholesterol feeding. Carbon monoxide is a ubiquitous pollutant in urban environments, where it is derived largely from mobile sources and cigarette smoke. Exposure to chronically elevated carbon monoxide levels has been implicated in a number of health-related problems. Whether such exposure plays a role in the development of arteriosclerosis has not been determined conclusively. In the present study, three questions were posed: 1. Will inhaled carbon monoxide at levels of 50 to 200 parts per million (ppm)* (two hours/day for 16 weeks) be sufficient to augment arteriosclerotic plaque development in cockerels, in the absence of other plaque-promoting agents 2. Will the inhalation of 100 ppm carbon monoxide (two hours/day for 16 weeks), concomitant with the feeding of low levels (0.1%) of cholesterol, yield larger plaques than those obtained with either of these agents administered alone 3. Will inhalation of 100 ppm carbon monoxide (two hours/day for 11 or 22 weeks), by cockerels in whom plaques have already appeared, further augment plaque development Cockerels were exposed to carefully regulated levels of carbon monoxide in stainless-steel and Plexiglas dynamic exposure chambers.

  17. An index-based approach to assessing recalcitrance and soil carbon sequestration potential of engineered black carbons (biochars).

    PubMed

    Harvey, Omar R; Kuo, Li-Jung; Zimmerman, Andrew R; Louchouarn, Patrick; Amonette, James E; Herbert, Bruce E

    2012-02-01

    The ability of engineered black carbons (or biochars) to resist abiotic and, or biotic degradation (herein referred to as recalcitrance) is crucial to their successful deployment as a soil carbon sequestration strategy. A new recalcitrance index, the R(50), for assessing biochar quality for carbon sequestration is proposed. The R(50) is based on the relative thermal stability of a given biochar to that of graphite and was developed and evaluated with a variety of biochars (n = 59), and soot-like black carbons. Comparison of R(50), with biochar physicochemical properties and biochar-C mineralization revealed the existence of a quantifiable relationship between R(50) and biochar recalcitrance. As presented here, the R(50) is immediately applicable to pre-land application screening of biochars into Class A (R(50) ≥ 0.70), Class B (0.50 ≤ R(50) < 0.70) or Class C (R(50) < 0.50) recalcitrance/carbon sequestration classes. Class A and Class C biochars would have carbon sequestration potential comparable to soot/graphite and uncharred plant biomass, respectively, whereas Class B biochars would have intermediate carbon sequestration potential. We believe that the coupling of the R(50), to an index-based degradation, and an economic model could provide a suitable framework in which to comprehensively assess soil carbon sequestration in biochars. PMID:22242866

  18. An Index-Based Approach to Assessing Recalcitrance and Soil Carbon Sequestration Potential of Engineered Black Carbons (Biochars)

    SciTech Connect

    Harvey, Omar R.; Kuo, Li-Jung; Zimmerman, Andrew R.; Louchouarn, Patrick; Amonette, James E.; Herbert, Bruce

    2012-01-10

    The ability of engineered black carbons (or biochars) to resist abiotic and, or biotic degradation (herein referred to as recalcitrance) is crucial to their successful deployment as a soil carbon sequestration strategy. A new recalcitrance index, the R{sub 50}, for assessing biochar quality for carbon sequestration is proposed. The R{sub 50} is based on the relative thermal stability of a given biochar to that of graphite and was developed and evaluated with a variety of biochars (n = 59), and soot-like black carbons. Comparison of R{sub 50}, with biochar physicochemical properties and biochar-C mineralization revealed the existence of a quantifiable relationship between R{sub 50} and biochar recalcitrance. As presented here, the R{sub 50} is immediately applicable to pre-land application screening of biochars into Class A (R{sub 50} {>=} 0.70), Class B (0.50 {<=} R{sub 50} < 0.70) or Class C (R{sub 50} < 0.50) recalcitrance/carbon sequestration classes. Class A and Class C biochars would have carbon sequestration potential comparable to soot/graphite and uncharred plant biomass, respectively, while Class B biochars would have intermediate carbon sequestration potential. We believe that the coupling of the R{sub 50}, to an index-based degradation, and an economic model could provide a suitable framework in which to comprehensively assess soil carbon sequestration in biochars.

  19. Nitrogen oxide abatement by distributed fuel addition

    SciTech Connect

    Wendt, J.O.L.; Meraab, J.

    1988-03-25

    The purpose of this project is to develop techniques for nitrogen oxides abatement by distributed fuel addition. The major nitrogen oxide of interest is Nitric Oxide (NO), a precursor to premature forest damage and to acid rain. Recently interest has also been evoked with respect to an additional oxide of nitrogen, namely Nitrous Oxide (N{sub 2}O). Therefore, abatement measures for NO{sub x} are being investigated to determine their influence on N{sub 2}O as well. This report briefly describes the significance of N{sub 2}O emissions to the environment and the urgent need to develop techniques that can reduce emissions of both NO and N{sub 2}O. Reburning through distributed fuel addition may be an effective technique for NO{sub x} (mainly NO) emission control as described in the previous quarterly report. Reburning may also be effective in reducing N{sub 2}O levels. A technique for N{sub 2}O measurement by gas chromatography/electron capture detection was developed during this quarter, and is described in this report. This analysis technique will be used in the proposed experimental study to investigate the effectiveness of reburning on N{sub 2}O control.

  20. 30 CFR 722.13 - Failure to abate.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 3 2011-07-01 2011-07-01 false Failure to abate. 722.13 Section 722.13 Mineral Resources OFFICE OF SURFACE MINING RECLAMATION AND ENFORCEMENT, DEPARTMENT OF THE INTERIOR INITIAL PROGRAM REGULATIONS ENFORCEMENT PROCEDURES § 722.13 Failure to abate. An authorized representative of the...

  1. 30 CFR 722.13 - Failure to abate.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 3 2010-07-01 2010-07-01 false Failure to abate. 722.13 Section 722.13 Mineral Resources OFFICE OF SURFACE MINING RECLAMATION AND ENFORCEMENT, DEPARTMENT OF THE INTERIOR INITIAL PROGRAM REGULATIONS ENFORCEMENT PROCEDURES § 722.13 Failure to abate. An authorized representative of the...

  2. 30 CFR 722.13 - Failure to abate.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 3 2013-07-01 2013-07-01 false Failure to abate. 722.13 Section 722.13 Mineral Resources OFFICE OF SURFACE MINING RECLAMATION AND ENFORCEMENT, DEPARTMENT OF THE INTERIOR INITIAL PROGRAM REGULATIONS ENFORCEMENT PROCEDURES § 722.13 Failure to abate. An authorized representative of the...

  3. 30 CFR 722.13 - Failure to abate.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 3 2014-07-01 2014-07-01 false Failure to abate. 722.13 Section 722.13 Mineral Resources OFFICE OF SURFACE MINING RECLAMATION AND ENFORCEMENT, DEPARTMENT OF THE INTERIOR INITIAL PROGRAM REGULATIONS ENFORCEMENT PROCEDURES § 722.13 Failure to abate. An authorized representative of the...

  4. 76 FR 67650 - Migratory Bird Permits; Abatement Regulations

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-11-02

    ... for a specific permit authorizing the use of raptors in abatement activities (76 FR 39368). The... the advance notice of proposed rulemaking, please refer to that document at 76 FR 39368 (July 6, 2011... Fish and Wildlife Service 50 CFR Part 21 RIN 1018-AW75 Migratory Bird Permits; Abatement...

  5. 30 CFR 722.13 - Failure to abate.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 3 2012-07-01 2012-07-01 false Failure to abate. 722.13 Section 722.13 Mineral Resources OFFICE OF SURFACE MINING RECLAMATION AND ENFORCEMENT, DEPARTMENT OF THE INTERIOR INITIAL PROGRAM REGULATIONS ENFORCEMENT PROCEDURES § 722.13 Failure to abate. An authorized representative of the...

  6. 29 CFR 4207.10 - Plan rules for abatement.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 29 Labor 9 2013-07-01 2013-07-01 false Plan rules for abatement. 4207.10 Section 4207.10 Labor Regulations Relating to Labor (Continued) PENSION BENEFIT GUARANTY CORPORATION WITHDRAWAL LIABILITY FOR MULTIEMPLOYER PLANS REDUCTION OR WAIVER OF COMPLETE WITHDRAWAL LIABILITY § 4207.10 Plan rules for abatement. (a) General rule. Subject to...

  7. 47 CFR 22.971 - Obligation to abate unacceptable interference.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 47 Telecommunication 2 2014-10-01 2014-10-01 false Obligation to abate unacceptable interference. 22.971 Section 22.971 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES PUBLIC MOBILE SERVICES Cellular Radiotelephone Service § 22.971 Obligation to abate unacceptable interference. (a) Strict...

  8. 47 CFR 22.878 - Obligation to abate unacceptable interference.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 47 Telecommunication 2 2014-10-01 2014-10-01 false Obligation to abate unacceptable interference. 22.878 Section 22.878 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES PUBLIC MOBILE SERVICES Air-Ground Radiotelephone Service Commercial Aviation Air-Ground Systems § 22.878 Obligation to abate...

  9. ASBESTOS CONCENTRATIONS TWO YEARS AFTER ABATEMENT IN SEVENTEEN SCHOOLS

    EPA Science Inventory

    Airborne asbestos concentrations were measured at 17 schools that underwent an asbestos abatement 2 years before in 1988. These 17 schools, which involved 20 abatement sites, were part of a study conducted by the U.S. Environmental Protection Agency (EPA) and the New Jersey Depar...

  10. ASBESTOS CONCENTRATIONS IN TWO YEARS AFTER ABATEMENT IN SEVENTEEN SCHOOLS

    EPA Science Inventory

    Airborne asbestos concentrations were measured at 17 schools that underwent an asbestos abatement 2 years before in 1988. hese 17 schools, which involved 20 abatement sites, were part of a study conducted by the U.S Environmental Protection Agency (EPA) and the New Jersey Departm...

  11. VISUAL INSPECTION AND AHERA CLEARANCE AT ASBESTOS ABATEMENT SITES

    EPA Science Inventory

    Asbestos abatement carried out in schools is subject to regulations under the Asbestos Hazard Emergency Response Act (AHERA) of 1986. The AHERA rule (40 CFR Part 763) specifies a bifactorial process for determining when an asbestos abatement site is clean enough for the primary ...

  12. VISUAL INSPECTION AND AHERA CLEARANCE AT ASBESTOS-ABATEMENT SITES

    EPA Science Inventory

    Asbestos abatement carried out in schools is subject to regulations under the Asbestos Hazard Emergency Response Act (AHERA) of 1986. he AHERA rule (40 CFR Part 763) specifies a bifactorial process for determining when an asbestos abatement site is clean enough for the primary co...

  13. Carbonate Precipitation through Microbial Activities in Natural Environment, and Their Potential in Biotechnology: A Review

    PubMed Central

    Zhu, Tingting; Dittrich, Maria

    2016-01-01

    Calcium carbonate represents a large portion of carbon reservoir and is used commercially for a variety of applications. Microbial carbonate precipitation, a by-product of microbial activities, plays an important metal coprecipitation and cementation role in natural systems. This natural process occurring in various geological settings can be mimicked and used for a number of biotechnologies, such as metal remediation, carbon sequestration, enhanced oil recovery, and construction restoration. In this study, different metabolic activities leading to calcium carbonate precipitation, their native environment, and potential applications and challenges are reviewed. PMID:26835451

  14. Carbonate Precipitation through Microbial Activities in Natural Environment, and Their Potential in Biotechnology: A Review.

    PubMed

    Zhu, Tingting; Dittrich, Maria

    2016-01-01

    Calcium carbonate represents a large portion of carbon reservoir and is used commercially for a variety of applications. Microbial carbonate precipitation, a by-product of microbial activities, plays an important metal coprecipitation and cementation role in natural systems. This natural process occurring in various geological settings can be mimicked and used for a number of biotechnologies, such as metal remediation, carbon sequestration, enhanced oil recovery, and construction restoration. In this study, different metabolic activities leading to calcium carbonate precipitation, their native environment, and potential applications and challenges are reviewed. PMID:26835451

  15. Coal reserves and resources as well as potentials for underground coal gasification in connection with carbon capture and storage (CCS)

    NASA Astrophysics Data System (ADS)

    Ilse, Jürgen

    2010-05-01

    . However, these otherwise unprofitable coal deposits can be mined economically by means of underground coal gasification, during which coal is converted into a gaseous product in the deposit. The synthesis gas can be used for electricity generation, as chemical base material or for the production of petrol. This increases the usability of coal resources tremendously. At present the CCS technologies (carbon capture and storage) are a much discussed alternative to other CO2 abatement techniques like efficiency impovements. The capture and subsequent storage of CO2 in the deposits created by the actual underground gasification process seem to be technically feasible.

  16. Preliminary Feasibility Assessment of Geologic Carbon Sequestration Potential for TVA's John Sevier and Kingston Power Plants

    SciTech Connect

    Smith, Ellen D; Saulsbury, Bo

    2008-03-01

    This is a preliminary assessment of the potential for geologic carbon sequestration for the Tennessee Valley Authority's (TVA) John Sevier and Kingston power plants. The purpose of this assessment is to make a 'first cut' determination of whether there is sufficient potential for geologic carbon sequestration within 200 miles of the plants for TVA and Oak Ridge National Laboratory (ORNL) to proceed with a joint proposal for a larger project with a strong carbon management element. This assessment does not consider alternative technologies for carbon capture, but assumes the existence of a segregated CO{sub 2} stream suitable for sequestration.

  17. Potential carbon dioxide fixation by industrially important microalgae.

    PubMed

    Sydney, Eduardo Bittencourt; Sturm, Wilerson; de Carvalho, Julio Cesar; Thomaz-Soccol, Vanete; Larroche, Christian; Pandey, Ashok; Soccol, Carlos Ricardo

    2010-08-01

    The present study aimed at investigating the carbon metabolism in terms of carbon dioxide fixation and its destination in microalgae cultivations. To this purpose, analysis of growth parameters, media of cultivation, biomass composition and productivity and nutrients balance were performed. Four microalgae suitable for mass cultivation were evaluated: Dunaliella tertiolecta SAD-13.86, Chlorella vulgaris LEB-104, Spirulina platensis LEB-52 and Botryococcus braunii SAG-30.81. Global rates of carbon dioxide and oxygen were determinated by a system developed in our laboratory. B. braunii presented the highest CO(2) fixation rate, followed by S. platensis,D. tertiolecta and C. vulgaris (496.98, 318.61, 272.4 and 251.64 mg L(-1)day(-1), respectively). Carbon dioxide fixated was mainly used for microalgal biomass production. Nitrogen, phosphorus (calcium for D. tertiolecta), potassium and magnesium consumption rates (mg gX(-1)) were evaluated for the four microalgae. Biomass composition presented a predominance of proteins but also a high amount of lipids, especially in D. tertiolecta and B. braunii. PMID:20350804

  18. Potential for Soil Carbon Sequestration in Central Kazakhstan

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The World Bank Kazakhstan Drylands Management Project has the goal of restoring degraded soils associated with abandoned croplands in Kazakhstan. Global markets for carbon sequestration are likely to grow with continued implementation of international agreements such as Kyoto as well as those expec...

  19. Potential release scenarios for carbon nanotubes used in composites

    EPA Science Inventory

    The expected widespread use of carbon nanotube (CNT)-composites in consumer products calls for an assessment of the possible release and exposure to workers, consumers and the environment. Release of CNTs may occur at all steps in the life cycle of products, but to date only limi...

  20. Modeling carbon sequestration potential in Mollisols under climate change scenarios

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Carbon sequestration in agricultural soils, besides its importance in mitigating global climate change, impacts and will be impacted by provisioning, regulating and supporting agroecosystem services. The objectives of this study were to (1) provide an improved understanding of the role of projected ...

  1. Carbon stocks and potential carbon storage in the mangrove forests of China.

    PubMed

    Liu, Hongxiao; Ren, Hai; Hui, Dafeng; Wang, Wenqing; Liao, Baowen; Cao, Qingxian

    2014-01-15

    Mangrove forests provide important ecosystem services, and play important roles in terrestrial and oceanic carbon (C) cycling. Although the C stocks or storage in terrestrial ecosystems in China have been frequently assessed, the C stocks in mangrove forests have often been overlooked. In this study, we estimated the C stocks and the potential C stocks in China's mangrove forests by combining our own field data with data from the National Mangrove Resource Inventory Report and from other published literature. The results indicate that mangrove forests in China store about 6.91 ± 0.57 Tg C, of which 81.74% is in the top 1 m soil, 18.12% in the biomass of mangrove trees, and 0.08% in the ground layer (i.e. mangrove litter and seedlings). The potential C stocks are as high as 28.81 ± 4.16 Tg C. On average, mangrove forests in China contain 355.25 ± 82.19 Mg C ha(-1), which is consistent with the global average of mangrove C density at similar latitudes, but higher than the average C density in terrestrial forests in China. Our results suggest that C storage in mangroves can be increased by selecting high C-density species for afforestation and stand improvement, and even more by increasing the mangrove area. The information gained in this study will facilitate policy decisions concerning the restoration of mangrove forests in China. PMID:24374165

  2. Estimating organic micro-pollutant removal potential of activated carbons using UV absorption and carbon characteristics.

    PubMed

    Zietzschmann, Frederik; Altmann, Johannes; Ruhl, Aki Sebastian; Dünnbier, Uwe; Dommisch, Ingvild; Sperlich, Alexander; Meinel, Felix; Jekel, Martin

    2014-06-01

    Eight commercially available powdered activated carbons (PAC) were examined regarding organic micro-pollutant (OMP) removal efficiencies in wastewater treatment plant (WWTP) effluent. PAC characteristic numbers such as B.E.T. surface, iodine number and nitrobenzene number were checked for their potential to predict the OMP removal of the PAC products. Furthermore, the PAC-induced removal of UV254 nm absorption (UVA254) in WWTP effluent was determined and also correlated with OMP removal. None of the PAC characteristic numbers can satisfactorily describe OMP removal and accordingly, these characteristics have little informative value on the reduction of OMP concentrations in WWTP effluent. In contrast, UVA254 removal and OMP removal correlate well for carbamazepine, diclofenac, and several iodinated x-ray contrast media. Also, UVA254 removal can roughly describe the average OMP removal of all measured OMP, and can accordingly predict PAC performance in OMP removal. We therefore suggest UVA254 as a handy indicator for the approximation of OMP removal in practical applications where direct OMP concentration quantification is not always available. In continuous operation of large-scale plants, this approach allows for the efficient adjustment of PAC dosing to UVA254, in order to ensure reliable OMP removal whilst minimizing PAC consumption. PMID:24651017

  3. [Estimation of soil carbon sequestration potential in typical steppe of Inner Mongolia and associated uncertainty].

    PubMed

    Wang, Wei; Wu, Jian-Guo; Han, Xing-Guo

    2012-01-01

    Based on the measurements in the enclosure and uncontrolled grazing plots in the typical steppe of Xilinguole, Inner Mongolia, this paper studied the soil carbon storage and carbon sequestration in the grasslands dominated by Leymus chinensis, Stipa grandis, and Stipa krylovii, respectively, and estimated the regional scale soil carbon sequestration potential in the heavily degraded grassland after restoration. At local scale, the annual soil carbon sequestration in the three grasslands all decreased with increasing year of enclosure. The soil organic carbon storage was significantly higher in the grasslands dominated by L. chinensis and Stipa grandis than in that dominated by Stipa krylovii, but the latter had much higher soil carbon sequestration potential, because of the greater loss of soil organic carbon during the degradation process due to overgrazing. At regional scale, the soil carbon sequestration potential at the depth of 0-20 cm varied from -0.03 x 10(4) to 3.71 x 10(4) kg C x a(-1), and the total carbon sequestration potential was 12.1 x 10(8) kg C x a(-1). Uncertainty analysis indicated that soil gravel content had less effect on the estimated carbon sequestration potential, but the estimation errors resulted from the spatial interpolation of climate data could be about +/- 4.7 x 10(9) kg C x a(-1). In the future, if the growth season precipitation in this region had an average variation of -3.2 mm x (10 a)(-1), the soil carbon sequestration potential would be de- creased by 1.07 x 10(8) kg C x (10 a)(-1). PMID:22489476

  4. CO2 abatement costs of greenhouse gas (GHG) mitigation by different biogas conversion pathways.

    PubMed

    Rehl, T; Müller, J

    2013-01-15

    Biogas will be of increasing importance in the future as a factor in reducing greenhouse gas emissions cost-efficiently by the optimal use of available resources and technologies. The goal of this study was to identify the most ecological and economical use of a given resource (organic waste from residential, commercial and industry sectors) using one specific treatment technology (anaerobic digestion) but applying different energy conversion technologies. Average and marginal abatement costs were calculated based on Life Cycle Cost (LCC) and Life Cycle Assessment (LCA) methodologies. Eight new biogas systems producing electricity, heat, gas or automotive fuel were analyzed in order to identify the most cost-efficient way of reducing GHG emissions. A system using a combined heat and power station (which is connected to waste treatment and digestion operation facilities and located nearby potential residential, commercial or industrial heat users) was found to be the most cost-efficient biogas technology for reducing GHG emissions. Up to € 198 per tonne of CO(2) equivalents can be saved by replacing the "business as usual" systems based on fossil resources with ones based on biogas. Limited gas injection (desulfurized and dried biogas, without compression and upgrading) into the gas grid can also be a viable option with an abatement cost saving of € 72 per tonne of CO(2) equivalents, while a heating plant with a district heating grid or a system based on biogas results in higher abatement costs (€ 267 and € 270 per tonne CO(2) eq). Results from all systems are significantly influenced by whether average or marginal data are used as a reference. Beside that energy efficiency, the reference system that was replaced and the by-products as well as feedstock and investment costs were identified to be parameters with major impacts on abatement costs. The quantitative analysis was completed by a discussion of the role that abatement cost methodology can play in

  5. Carbon budgets and potential blue carbon stores in Scotland's coastal and marine environment

    NASA Astrophysics Data System (ADS)

    Howe, John; austin, william

    2016-04-01

    The role of marine ecosystems in storing blue carbon has increasingly become a topic of interest to both scientists and politicians. This is the first multidisciplinary study to assess Scotland's marine blue carbon stores, using GIS to collate habitat information based on existing data. Relevant scientific information on primary habitats for carbon uptake and storage has been reviewed, and quantitative rates of production and storage were obtained. Habitats reviewed include kelp, phytoplankton, saltmarshes, biogenic reefs (including maerl), marine sediments (coastal and shelf), and postglacial geological sediments. Each habitat has been individually assessed for any specific threats to its carbon sequestration ability. Here we present an ecosystem-scale inventory of the key rates and ultimate sequestration capacity of each habitat. Coastal and offshore sediments are the main repositories for carbon in Scotland's marine environment. Habitat-forming species on the coast (seagrasses, saltmarsh, bivalve beds, coralline algae), are highly productive but their contribution to the overall carbon budget is very small because of the limited extent of each habitat. This study highlights the importance of marine carbon stores in global carbon cycles, and the implications of climate change on the ability of marine ecosystems to sequester carbon.

  6. Interleaved Carbon Minibeams: An Experimental Radiosurgery Method With Clinical Potential

    SciTech Connect

    Dilmanian, F. Avraham; Rusek, Adam; Fois, Giovanna R.; Olschowka, John; Desnoyers, Nicolle R.; Park, Jane Y.; Dioszegi, Istvan; Dane, Bari; Wang Ruiliang; Tomasi, Dardo; Lee, Hedok; Hurley, Sean D.; Coyle, Patricia K.; Meek, Allen G.; O'Banion, M. Kerry

    2012-10-01

    Purpose: To evaluate the efficacy of 'interleaved carbon minibeams' for ablating a 6.5-mm target in a rabbit brain with little damage to the surrounding brain. The method is based on the well-established tissue-sparing effect of arrays of thin planes of radiation. Methods and Materials: Broad carbon beams from the National Aeronautics and Space Agency Space Radiation Facility at Brookhaven National Laboratory were segmented into arrays of parallel, horizontal, 0.3-mm-thick planar beams (minibeams). The minibeams' gradual broadening in tissues resulted in 0.525-mm beam thickness at the target's proximal side in the spread-out Bragg peak. Interleaving was therefore implemented by choosing a 1.05 mm beam spacing on-center. The anesthetized rabbit, positioned vertically on a stage capable of rotating about a vertical axis, was exposed to arrays from four 90 Degree-Sign angles, with the stage moving up by 0.525 mm in between. This produced a solid radiation field at the target while exposing the nontargeted tissues to single minibeam arrays. The target 'physical' absorbed dose was 40.2 Gy. Results: The rabbit behaved normally during the 6-month observation period. Contrast magnetic resonance imaging and hematoxylin and eosin histology at 6 months showed substantial focal target damage with little damage to the surrounding brain. Conclusion: We plan to evaluate the method's therapeutic efficacy by comparing it with broad-beam carbon therapy in animal models. The method's merits would combine those of carbon therapy (i.e., tight target dose because of the carbon's Bragg-peak, sharp dose falloff, and high relative biological effectiveness at the target), together with the method's low impact on the nontargeted tissues. The method's smaller impact on the nontargeted brain might allow carbon therapy at higher target doses and/or lower normal tissue impact, thus leading to a more effective treatment of radioresistant tumors. It should also make the method more amenable to

  7. Carbon carry capacity and carbon sequestration potential in China based on an integrated analysis of mature forest biomass.

    PubMed

    Liu, YingChun; Yu, GuiRui; Wang, QiuFeng; Zhang, YangJian; Xu, ZeHong

    2014-12-01

    Forests play an important role in acting as a carbon sink of terrestrial ecosystem. Although global forests have huge carbon carrying capacity (CCC) and carbon sequestration potential (CSP), there were few quantification reports on Chinese forests. We collected and compiled a forest biomass dataset of China, a total of 5841 sites, based on forest inventory and literature search results. From the dataset we extracted 338 sites with forests aged over 80 years, a threshold for defining mature forest, to establish the mature forest biomass dataset. After analyzing the spatial pattern of the carbon density of Chinese mature forests and its controlling factors, we used carbon density of mature forests as the reference level, and conservatively estimated the CCC of the forests in China by interpolation methods of Regression Kriging, Inverse Distance Weighted and Partial Thin Plate Smoothing Spline. Combining with the sixth National Forest Resources Inventory, we also estimated the forest CSP. The results revealed positive relationships between carbon density of mature forests and temperature, precipitation and stand age, and the horizontal and elevational patterns of carbon density of mature forests can be well predicted by temperature and precipitation. The total CCC and CSP of the existing forests are 19.87 and 13.86 Pg C, respectively. Subtropical forests would have more CCC and CSP than other biomes. Consequently, relying on forests to uptake carbon by decreasing disturbance on forests would be an alternative approach for mitigating greenhouse gas concentration effects besides afforestation and reforestation. PMID:25424432

  8. Hydrology affects carbon storage potential of prairie potholes

    NASA Astrophysics Data System (ADS)

    Balcerak, Ernie

    2013-06-01

    Prairie potholes, the small, dynamic, unconnected ponds that dot central Canada as well as parts of the north central United States, can store significant amounts of soil nutrients that can be transformed to carbon dioxide and other greenhouse gases. Scientists would like to better understand how these regions could contribute to climate warming, but there are challenges, given the large heterogeneity in greenhouse gas emissions over the prairie pothole landscape.

  9. The Lifestyle Carbon Dividend: Assessment of the Carbon Sequestration Potential of Grasslands and Pasturelands Reverted to Native Forests

    NASA Astrophysics Data System (ADS)

    Rao, S.; Jain, A. K.; Shu, S.

    2015-12-01

    What is the potential of a global transition to a vegan lifestyle to sequester carbon and mitigate climate change? To answer this question, we use an Earth System Model (ESM), the Integrated Science Assessment Model (ISAM). ISAM is a fully coupled biogeochemistry (carbon and nitrogen cycles) and biogeophysics (hydrology and thermal energy) ESM, which calculates carbon sources and sinks due to land cover and land use change activities, such as reforestation and afforestation. We calculate the carbon sequestration potential of grasslands and pasturelands that can be reverted to native forests as 265 GtC on 1.96E+7 km2 of land area, just 41% of the total area of such lands on Earth. The grasslands and pasturelands are assumed to revert back to native forests which existed prior to any human intervention and these include tropical, temperate and boreal forests. The results are validated with above ground regrowth measurements. Since this carbon sequestration potential is greater than the 240 GtC of that has been added to the atmosphere since the industrial era began, it shows that such global lifestyle transitions have tremendous potential to mitigate and even reverse climate change.

  10. Lead paint abatement -- A technological review

    SciTech Connect

    Draper, A.C. III; Kapuscik, D.

    1994-12-31

    Abatement of lead from various surfaces proves to be a rapidly developing industry. Removal techniques and effectiveness varies greatly with varying substrates (wood, concrete, steel, etc.) and surface configurations including interior/exterior considerations, habitability and anticipated retrofit. Numerous technologies advances, and/or adaptations of long accepted removal techniques have recently emerged. Some of the more commonly used removal procedures including vacuum blasting, chemical stripping, scarifiers, grinders, sanders, etc. will be reviewed. Specific emphasis will be placed upon mode of application, positive and negative environmental aspects, and varying emissions generated. Personnel sampling data will be discussed with respect to associated personal protective equipment impact to derive the most cost productive environmentally conscious alternatives.

  11. Properties and potential environmental applications of carbon adsorbents from waste tire rubber

    USGS Publications Warehouse

    Lehmann, C.M.B.; Rameriz, D.; Rood, M.J.; Rostam-Abadi, M.

    2000-01-01

    The properties of tire-derived carbon adsorbents (TDCA) produced from select tire chars were compared with those derived from an Illinois coal and pistachio nut shells. Chemical analyses of the TDCA indicated that these materials contain metallic elements not present in coal-and nut shell-derived carbons. These metals, introduced during the production of tire rubber, potentially catalyze steam gasification reactions of tire char. TDCA carbons contained larger meso-and macopore volumes than their counterparts derived from coal and nut shell (on the moisture-and ash-free-basis). Adsorptive properties of the tire-derived adsorbent carbons for air separation, gas storage, and gas clean up were also evaluated and compared with those of the coal-and nut shell derived carbons as well as a commercial activated carbon. The results revealed that TDCA carbons are suitable adsorbents for removing vapor-phase mercury from combustion flue gases and hazardous organic compounds from industrial gas streams.

  12. Use of glassy carbon as a working electrode in controlled potential coulometry.

    PubMed

    Plock, C E; Vasquez, J

    1969-11-01

    Glassy carbon has been used as the working electrode in controlled potential coulometry. The results of coulometric investigations of chromium, copper, iron, uranium and neptunium are compared with results obtained with platinum or mercury working electrodes. The accuracy of results with the glassy carbon electrode compares favourably with the results obtainable with the other electrodes, but the precision is poorer. PMID:18960665

  13. CONSERVATION AND SEQUESTRATION OF CARBON: THE POTENTIAL OF FOREST AND AGROFOREST MANAGEMENT PRACTICES

    EPA Science Inventory

    Forests play a major role in the Earth's carbon cycle through assimilation, storage, and emission of CO2. stablishment and management of boreal, temperate, and tropical forest and agroforest systems could potentially enhance sequestration of carbon in the terrestrial biosphere. i...

  14. Dissolved organic carbon and its potential predictors in eutrophic lakes.

    PubMed

    Toming, Kaire; Kutser, Tiit; Tuvikene, Lea; Viik, Malle; Nõges, Tiina

    2016-10-01

    Understanding of the true role of lakes in the global carbon cycle requires reliable estimates of dissolved organic carbon (DOC) and there is a strong need to develop remote sensing methods for mapping lake carbon content at larger regional and global scales. Part of DOC is optically inactive. Therefore, lake DOC content cannot be mapped directly. The objectives of the current study were to estimate the relationships of DOC and other water and environmental variables in order to find the best proxy for remote sensing mapping of lake DOC. The Boosted Regression Trees approach was used to clarify in which relative proportions different water and environmental variables determine DOC. In a studied large and shallow eutrophic lake the concentrations of DOC and coloured dissolved organic matter (CDOM) were rather high while the seasonal and interannual variability of DOC concentrations was small. The relationships between DOC and other water and environmental variables varied seasonally and interannually and it was challenging to find proxies for describing seasonal cycle of DOC. Chlorophyll a (Chl a), total suspended matter and Secchi depth were correlated with DOC and therefore are possible proxies for remote sensing of seasonal changes of DOC in ice free period, while for long term interannual changes transparency-related variables are relevant as DOC proxies. CDOM did not appear to be a good predictor of the seasonality of DOC concentration in Lake Võrtsjärv since the CDOM-DOC coupling varied seasonally. However, combining the data from Võrtsjärv with the published data from six other eutrophic lakes in the world showed that CDOM was the most powerful predictor of DOC and can be used in remote sensing of DOC concentrations in eutrophic lakes. PMID:27318445

  15. Carbon-enriched calcium carbide and its potential use

    SciTech Connect

    Ivakhnyuk, G.K.; Samonin, V.V.; Fedorov, N.F.; Vladimirov, V.A.; Stepanova, L.V.; Kas'yanova, O.M.

    1987-10-10

    The authors comparatively assess the feasibility of a variety of carbonaceous materials--lean coal, specialty coke, coal coke, semicoke, and coke residue from shale production--as raw materials for the production and carburization of calcium carbide and subsequently assess the value of the calcium carbide produced as a raw material in the production of graphite. They determine that calcium carbide enriched by their process is characterized by a high carbon content having the graphite structure and that the use of carburized calcium carbide allows for a significant increase in the output of graphite during low-temperature reaction of the carbide with magnesium chloride.

  16. Carbon sequestration potential of coastal wetland soils of Veracruz, Mexico

    NASA Astrophysics Data System (ADS)

    Fuentes-Romero, Elisabeth; García-Calderón, Norma Eugenia; Ikkonen, Elena; García-Varela, Kl

    2014-05-01

    Tropical coastal wetlands, including rainforests and mangrove ecosystems play an increasingly important ecological and economic role in the tropical coastal area of the State of Veracruz /Mexico. However, soil processes in these environments, especially C-turnover rates are largely unknown until today. Therefore, we investigated CO2 and CH4 emissions together with gains and losses of organic C in the soils of two different coastal ecosystems in the "Natural Protected Area Cienaga del Fuerte (NPACF)" near Tecolutla, in the State of Veracruz. The research areas were an artificially introduced grassland (IG) and a wetland rainforest (WRF). The gas emissions from the soil surfaces were measured by a static chamber array, the soil organic C was analysed in soil profiles distributed in the two areas, humic substances were characterized and C budget was calculated. The soils in both areas acted as carbon sinks, but the soils of the WRF sequestered more C than those of the IG, which showed a higher gas emission rate and produced more dissolved organic carbon. The gas emission measurements during the dry and the rainy seasons allowed for estimating the possible influence of global warming on gas fluxes from the soils of the two different ecological systems, which show in the WRF a quite complex spatial emission pattern during the rainy season in contrast to a more continuous emission pattern in the IG plots

  17. Carbon sequestration potential of second-growth forest regeneration in the Latin American tropics.

    PubMed

    Chazdon, Robin L; Broadbent, Eben N; Rozendaal, Danaë M A; Bongers, Frans; Zambrano, Angélica María Almeyda; Aide, T Mitchell; Balvanera, Patricia; Becknell, Justin M; Boukili, Vanessa; Brancalion, Pedro H S; Craven, Dylan; Almeida-Cortez, Jarcilene S; Cabral, George A L; de Jong, Ben; Denslow, Julie S; Dent, Daisy H; DeWalt, Saara J; Dupuy, Juan M; Durán, Sandra M; Espírito-Santo, Mario M; Fandino, María C; César, Ricardo G; Hall, Jefferson S; Hernández-Stefanoni, José Luis; Jakovac, Catarina C; Junqueira, André B; Kennard, Deborah; Letcher, Susan G; Lohbeck, Madelon; Martínez-Ramos, Miguel; Massoca, Paulo; Meave, Jorge A; Mesquita, Rita; Mora, Francisco; Muñoz, Rodrigo; Muscarella, Robert; Nunes, Yule R F; Ochoa-Gaona, Susana; Orihuela-Belmonte, Edith; Peña-Claros, Marielos; Pérez-García, Eduardo A; Piotto, Daniel; Powers, Jennifer S; Rodríguez-Velazquez, Jorge; Romero-Pérez, Isabel Eunice; Ruíz, Jorge; Saldarriaga, Juan G; Sanchez-Azofeifa, Arturo; Schwartz, Naomi B; Steininger, Marc K; Swenson, Nathan G; Uriarte, Maria; van Breugel, Michiel; van der Wal, Hans; Veloso, Maria D M; Vester, Hans; Vieira, Ima Celia G; Bentos, Tony Vizcarra; Williamson, G Bruce; Poorter, Lourens

    2016-05-01

    Regrowth of tropical secondary forests following complete or nearly complete removal of forest vegetation actively stores carbon in aboveground biomass, partially counterbalancing carbon emissions from deforestation, forest degradation, burning of fossil fuels, and other anthropogenic sources. We estimate the age and spatial extent of lowland second-growth forests in the Latin American tropics and model their potential aboveground carbon accumulation over four decades. Our model shows that, in 2008, second-growth forests (1 to 60 years old) covered 2.4 million km(2) of land (28.1% of the total study area). Over 40 years, these lands can potentially accumulate a total aboveground carbon stock of 8.48 Pg C (petagrams of carbon) in aboveground biomass via low-cost natural regeneration or assisted regeneration, corresponding to a total CO2 sequestration of 31.09 Pg CO2. This total is equivalent to carbon emissions from fossil fuel use and industrial processes in all of Latin America and the Caribbean from 1993 to 2014. Ten countries account for 95% of this carbon storage potential, led by Brazil, Colombia, Mexico, and Venezuela. We model future land-use scenarios to guide national carbon mitigation policies. Permitting natural regeneration on 40% of lowland pastures potentially stores an additional 2.0 Pg C over 40 years. Our study provides information and maps to guide national-level forest-based carbon mitigation plans on the basis of estimated rates of natural regeneration and pasture abandonment. Coupled with avoided deforestation and sustainable forest management, natural regeneration of second-growth forests provides a low-cost mechanism that yields a high carbon sequestration potential with multiple benefits for biodiversity and ecosystem services. PMID:27386528

  18. Carbon sequestration potential of second-growth forest regeneration in the Latin American tropics

    PubMed Central

    Chazdon, Robin L.; Broadbent, Eben N.; Rozendaal, Danaë M. A.; Bongers, Frans; Zambrano, Angélica María Almeyda; Aide, T. Mitchell; Balvanera, Patricia; Becknell, Justin M.; Boukili, Vanessa; Brancalion, Pedro H. S.; Craven, Dylan; Almeida-Cortez, Jarcilene S.; Cabral, George A. L.; de Jong, Ben; Denslow, Julie S.; Dent, Daisy H.; DeWalt, Saara J.; Dupuy, Juan M.; Durán, Sandra M.; Espírito-Santo, Mario M.; Fandino, María C.; César, Ricardo G.; Hall, Jefferson S.; Hernández-Stefanoni, José Luis; Jakovac, Catarina C.; Junqueira, André B.; Kennard, Deborah; Letcher, Susan G.; Lohbeck, Madelon; Martínez-Ramos, Miguel; Massoca, Paulo; Meave, Jorge A.; Mesquita, Rita; Mora, Francisco; Muñoz, Rodrigo; Muscarella, Robert; Nunes, Yule R. F.; Ochoa-Gaona, Susana; Orihuela-Belmonte, Edith; Peña-Claros, Marielos; Pérez-García, Eduardo A.; Piotto, Daniel; Powers, Jennifer S.; Rodríguez-Velazquez, Jorge; Romero-Pérez, Isabel Eunice; Ruíz, Jorge; Saldarriaga, Juan G.; Sanchez-Azofeifa, Arturo; Schwartz, Naomi B.; Steininger, Marc K.; Swenson, Nathan G.; Uriarte, Maria; van Breugel, Michiel; van der Wal, Hans; Veloso, Maria D. M.; Vester, Hans; Vieira, Ima Celia G.; Bentos, Tony Vizcarra; Williamson, G. Bruce; Poorter, Lourens

    2016-01-01

    Regrowth of tropical secondary forests following complete or nearly complete removal of forest vegetation actively stores carbon in aboveground biomass, partially counterbalancing carbon emissions from deforestation, forest degradation, burning of fossil fuels, and other anthropogenic sources. We estimate the age and spatial extent of lowland second-growth forests in the Latin American tropics and model their potential aboveground carbon accumulation over four decades. Our model shows that, in 2008, second-growth forests (1 to 60 years old) covered 2.4 million km2 of land (28.1% of the total study area). Over 40 years, these lands can potentially accumulate a total aboveground carbon stock of 8.48 Pg C (petagrams of carbon) in aboveground biomass via low-cost natural regeneration or assisted regeneration, corresponding to a total CO2 sequestration of 31.09 Pg CO2. This total is equivalent to carbon emissions from fossil fuel use and industrial processes in all of Latin America and the Caribbean from 1993 to 2014. Ten countries account for 95% of this carbon storage potential, led by Brazil, Colombia, Mexico, and Venezuela. We model future land-use scenarios to guide national carbon mitigation policies. Permitting natural regeneration on 40% of lowland pastures potentially stores an additional 2.0 Pg C over 40 years. Our study provides information and maps to guide national-level forest-based carbon mitigation plans on the basis of estimated rates of natural regeneration and pasture abandonment. Coupled with avoided deforestation and sustainable forest management, natural regeneration of second-growth forests provides a low-cost mechanism that yields a high carbon sequestration potential with multiple benefits for biodiversity and ecosystem services. PMID:27386528

  19. Investigation of Microbial Respirometry for Monitoring Natural Sulfide Abatement in Geothermal Cooling Tower Basins

    SciTech Connect

    Peter A. Pryfogle

    2005-09-01

    Geothermal plant operators are interested in investigating the ability of micro-organisms found in the cooling tower basin to metabolize and cycle sulfide to less toxic sulfur compounds. If the growth or activity of the organisms participating in sulfur-oxidation could be selectively enhanced, then hydrogen sulfide could be naturally abated in the cooling basin, substantially reducing the costs associated with the chemicals used for abatement. The use of respirometry has been proposed as a technique for monitoring the response of the microbial populations found in geothermal cooling towers to various conditions, including the addition of nutrients such as nitrogen and phosphorus. Respiro-metry is a manometric measurement of dissolved gases that are in equilibrium in a con-fined sample volume. Since microbes expire varying amounts of carbon dioxide or oxygen as they metabolize nutrients, this technique can be used to evaluate their activities in process streams. This report describes a series of experiments designed to determine the suitability of respirometry for tracking microbial activity for evaluating and enhancing natural abatement processes in geothermal cooling basins.

  20. Bragg gratings in carbon coated optical fibers and their potential sensor applications in harsh environment

    NASA Astrophysics Data System (ADS)

    Li, Yaowen; Kudelko, David J.; Hokansson, Adam S.; Simoff, Debra A.; Stolov, Andrei A.; Ng, Joanna; Mann, Joel

    2014-05-01

    We have demonstrated that fiber Bragg gratings can be written through the carbon layer of carbon-coated optical fibers having different coating thicknesses. Specifically, grating index modulation amplitudes of ~2.5x10-5 and 0.52x10-5 were obtained in optical fibers having carbon layers 29 nm and 56 nm thick, respectively, without any extra photosensitization of the fibers. Subsequent experimental results showed that the carbon coatings in the grating areas didn't change their hermetic properties. Finally, we describe the advantages of these gratings and their potential applications in fiber optic sensing.

  1. Conservation and sequestration of carbon: The potential of forest and agroforest management practices

    SciTech Connect

    Dixon, R.K.; Winjum, J.K.; Schroeder, P.E.

    1993-01-01

    Forests play a major role in the Earth's carbon cycle through assimilation, storage, and emission of CO2. Establishment and management of boreal, temperate, and tropical forest and agroforest systems could potentially enhance sequestration of carbon in the terrestrial biosphere. A biologic and economic analysis of forest establishment and management options from 94 nations revealed that forestation, agroforestry, and silviculture could be employed to conserve and sequester one gigaton (Gt) of carbon annually over a 50 year period. The marginal cost of implementing these options to sequester 55 Gt of carbon would be approximately $10/ton.

  2. Soil carbon sequestration in degraded semiarid agro-ecosystems--perils and potentials.

    PubMed

    Olsson, Lennart; Ardö, Jonas

    2002-09-01

    The Kyoto Protocol opens new possibilities for using the biosphere as a carbon sink. Using agro-ecosystems as carbon sinks may be the most appropriate practice from both environmental and socioeconomic points of view. Degraded agro-ecosystems in Africa might benefit significantly from the improved land management that would be part of a carbon sequestration program. There are vast areas of these agro-ecosystems in Africa and their rehabilitation is an urgent matter. We agree with UNEP that there are potentially important synergies to be made between the Convention on Climate Change, the UN Convention to Combat Desertification and the UN Convention on Biodiversity. In this paper, we have investigated the potential for increasing soil carbon content in semiarid agro-ecosystems in the Sudan and found that increasing fallow periods will result in increased soil carbon content and converting marginal agricultural areas to rangeland will restore the carbon levels to 80% of the natural savannah carbon levels in 100 years. The economic gain from a future carbon sequestration program has the potential of a significant contribution to the household economy in these agro-ecosystems. PMID:12436845

  3. NO{sub x} Emission Abatement Technologies

    SciTech Connect

    Goles, R

    1991-10-01

    The Hanford Waste Vitrification Plant (HWVP) will convert Hanford Site high-level liquid defense waste to a solid vitrified (glass) form suitable for final disposal in a geological repository. Future process flow sheet developments may establish a need for a NO, scrubber in the melter off-gas system. Consequently, a technology review has been conducted to identify and compare applicable off-gas processing alternatives should NO, emission abatement be required. Denitrification processes can be separated into two distinct categories, wet or dry, depending upon whether or not NO{sub x} is absorbed into an aqueous solution. The dry methods of removal are generally more efficient (>90%) than wet scrubbing approaches (>60%); however, most dry approaches are applicable only to NO,. Of the dry removal methods, selective catalytic reduction (SCR) using NH3 reductant and a hydrogen zeolite catalyst appears to be the most suitable technology for reducing HWVP NO{sub x} emissions should emission abatement be required. SCR is a relatively simple, well established technology that produces no secondary waste stream and is applicable to a wide range of NO{sub x} concentrations (500 to 30,000 ppm). This technology has been successfully applied to uranium dissolver exhaust streams and has, more recently, been tested and evaluated as the best available control technology for reducing NO, emissions at the Idaho National Engineering Laboratory's waste calciner facility, and at DOE's West Valley Demonstration Project. Unlike dry NO, scrubbing methods, the wet techniques are not specific to NO{sub x}, so they may support the process in more than one way. This is the only major advantage associated with wet technologies. Their disadvantages are that they are not highly efficient at low NO{sub x} concentrations, they produce a secondary waste stream, and they may require complex chemical support to reduce equipment size. Wet scrubbing of HWVP process NO{sub x} emissions is an option that

  4. A METHOD FOR COMPARING MULTICOMPONENT, MULTIMEDIA POLLUTION ABATEMENT PROCESSES

    EPA Science Inventory

    The paper describes a comparison of the cost-effectiveness of four multicomponent, multimedia pollution abatement options: coal cleaning, limestone, limestone plus adipic acid, and coal cleaning plus limestone plus adipic acid. The comparison makes cost-effectiveness evaluations ...

  5. 47 CFR 22.971 - Obligation to abate unacceptable interference.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... SERVICES PUBLIC MOBILE SERVICES Cellular Radiotelephone Service § 22.971 Obligation to abate unacceptable... licensee that can show that its signal does not directly or indirectly, cause or contribute to...

  6. Potential Occupational Risks Associated with Pulmonary Toxicity of Carbon Nanotubes

    PubMed Central

    Manke, Amruta; Luanpitpong, Sudjit; Rojanasakul, Yon

    2014-01-01

    Given their remarkable properties, carbon nanotubes (CNTs) have made their way through various industrial and medicinal applications and the overall production of CNTs is expected to grow rapidly in the next few years, thus requiring an additional recruitment of workers. However, their unique applications and desirable properties are fraught with concerns regarding occupational exposure. The concern about worker exposure to CNTs arises from the results of recent animal studies. Short-term and sub-chronic exposure studies in rodents have shown consistent adverse health effects such as pulmonary inflammation, granulomas, fibrosis, genotoxicity and mesothelioma after inhalation or instillation of several types of CNTs. Furthermore, physicochemical properties of CNTs such as dispersion, functionalization and particle size can significantly affect their pulmonary toxicity. Risk estimates from animal studies necessitate implementation of protective measures to limit worker exposure to CNTs. Information on workplace exposure is very limited, however, studies have reported that CNTs can be aerosolized and attain respirable airborne levels during synthesis and processing activities in the workplace. Quantitative risk assessments from sub-chronic animal studies recommend the health-based need to reduce exposures below the recommended exposure limit of 1 µg/m3. Practice of prevention measures including the use of engineering controls, personal protective equipment, health surveillance program, safe handling and use, as well as worker training can significantly minimize worker exposure and improve worker health and safety. PMID:25621290

  7. Soil carbon storage and respiration potential across a landscape age and climate gradient in western Greenland

    NASA Astrophysics Data System (ADS)

    Bradley-Cook, J. I.; Virginia, R. A.; Hammond Wagner, C.; Racine, P. E.

    2013-12-01

    The soil formation state factors proposed by Hans Jenny (climate, organisms, relief, parent material, time) explain many soil characteristics, yet geological controls on biological carbon cycling are not well represented in regional carbon models. Landscape age, for instance, can directly affect the quantity and quality of soil organic carbon, which are key determinants of the temperature sensitivity of soil organic matter (SOM) to decomposition. Temperature control of SOM decomposition is of particular importance in Arctic soils, which contain nearly half of global belowground organic carbon and have a permafrost thermal regime that straddles the freeze-thaw threshold. We investigated soil carbon storage and respiration potential across a west Greenland transect, and related the landscape carbon patterns to regional variation in climate and landscape age. The four study sites capture a range in: landscape age from 180 years on the inland Little Ice Age moraine near Kangerlussuaq to ~10,000 years at the coastal sites near Sisimiut and Nuuk, mean annual air temperatures from -5.7 to -1.4 °C, and mean annual precipitation from 149 to 752 mm. At each site, we collected surface and mineral samples from nine soil pits within similar vegetation cover and relief classes. We measured total organic carbon and nitrogen though elemental analysis, and incubated soils at 4 °C and field capacity moisture for 175 day to measure carbon dioxide production from which we derived soil respiration potential. We hypothesized that soil carbon storage and respiration potential would be greatest at the sites with the oldest landscape age. Soil carbon content was more than four times greater at the 10,000 year sites (Nuuk = 24.03%, Sisimiut = 17.34%) than the inland sites (Ørkendalen = 3.49%, LIA = 0.05%). Carbon quality decreased across the age gradient, as measured by a nearly two-fold increase in C:N ratio from the youngest and driest to the oldest and wettest soils (LIA = 12.2, Nuuk

  8. A Comparison of Lead Abatement Technologies at Lewis Research Center

    NASA Technical Reports Server (NTRS)

    Jeziorowski, Luz Y.; Calla, Joanne

    1997-01-01

    In 1995, Lewis participated in a pilot test of Lead Specifications. The Specifications were sponsored by the Center to Protect Worker's Rights (CPWR). Entitled "Model Specifications for the Protection of Worker's from Lead on Steel Structures", one aspect of this endeavor was to test and compare several lead abatement technologies. The project overview, objectives, team, and requirements as well as abatement methods and materials are outlined.

  9. Post-Soviet farmland abandonment, forest recovery, and carbon storage potential in Ukraine

    NASA Astrophysics Data System (ADS)

    Olofsson, P.; Kuemmerle, T.; Baumann, M.; Radeloff, V. C.; Woodcock, C. E.; Hostert, P.

    2010-12-01

    Land use is a critical factor in the global carbon cycle, but land use effects on carbon fluxes are poorly understood in many regions. One such region is the former Eastern Bloc, where land use intensity decreased substantially after the collapse of the Soviet Union, resulting in widespread farmland abandonment and forest regrowth. The aim of this study was to examine how land use trends altered net carbon fluxes in Western Ukraine (57,000 km2) for the communist (1945-1991) and the post-communist period (1991-2007), and to assess the regions’ future carbon sequestration potential. Forest disturbance and farmland abandonment between 1988 to 2007 was estimated from Landsat imagery in former study. Historical land use change rates were obtained from forest inventories to reconstruct forest trends back to the mid-1800s. Using a carbon book-keeping model, we quantified net carbon fluxes from land use change and assessed potential future carbon fluxes for a range of reforestation and logging scenarios. Our results suggest that the low-point in forest cover occurred in the 1920s. Forest expansion in the second half of the 20th century turned the region from a carbon source to a sink, despite heavy logging during Soviet times. The current land-use related sink strength is about 1.5 Tg of carbon per year. Sequestration potential on abandoned farmland is enormous, even when assuming that only a minor fraction of the currently abandoned land will revert to forests. Beyond our study area, farmland abandonment has been widespread throughout Eastern Europe and the former Soviet Union, suggesting that a substantial proportion of the regions’ industrial carbon emissions may be offset by reforesting farmland.

  10. Nitrogen oxide abatement by distributed fuel addition

    SciTech Connect

    Wendt, J.O.L.; Meraab, J.

    1988-06-27

    This research is directed towards the development of engineering guidelines that define the application of distributed fuel addition as a technique for NOx abatement. It is expected that multiple fuel and air addition in the post-flame of a combustion process will increase free radical concentrations which destroy nitrogenous species and thus help them decay toward their equilibrium concentrations, which can be very low in that region of the combustor. Screening experiments were conducted on a laboratory scale downfired combustor. The objective was to compare NOx emissions arising from various combustion configurations, including fuel and/or air staging. Although the primary focus of this research is on NO control, a secondary effort was directed towards the measurement of N2O emissions from various coal combustion processes. N2O has been identified as a trace gas responsible for stratospheric ozone depletion, and has been hypothesized to arise from combustion processes, in amounts roughly proportional to NO emissions. Results presented in this report showed that the ratio N2O/NO was far from constant. The introduction of secondary air into a combustion process was accompanied an increase in N2O emissions. The measured N2O was always less than 10 ppm even under the most favorable combustion conditions. Reburning with premixed fuel and air mixtures was not effective in reducing NO emissions.

  11. The Veterans Administration's Asbestos Abatement Program

    SciTech Connect

    Schepers, G.W. )

    1991-12-31

    The Veterans Administration has developed a program of asbestos abatement for its more than 1000 buildings, where health care personnel from 173 hospitals and 238 ambulatory care clinics are likely to encounter respirable asbestos. This is a costly program, which has averaged about $25 million annually for the past ten years. The VA has banned the use of new asbestos products containing more than 1% of asbestos in building construction or renovation projects. Industrial hygiene engineering programs have been ordered instituted at all VA medical centers to monitor dust levels in compliance with OSHA and EPA requirements. Health surveillance programs, managed by an environmental health physician at each medical center, have been instituted for all personnel who have been identified to have breathed asbestos fibers in excess of OSHA-EPA threshold limit values. The health care program focuses on the identification of asbestosis and asbestos-related cancer through periodic X-ray films, lung function tests, and electrocardiographic and physical examination screening. The program also stresses cessation of smoking.

  12. Geologic Carbon Sequestration: Leakage Potential and Policy Implications

    NASA Astrophysics Data System (ADS)

    Bielicki, J. M.; Peters, C. A.; Fitts, J. P.; Wilson, E. J.

    2014-12-01

    The geologic reservoirs that could be used for long-term sequestration of carbon dioxide (CO2) may have natural or manmade pathways that allow injected CO2, or the brine it displaces, to leak into overlying formations. Using a basin-scale leakage estimation model, we investigated the geophysical parameters that govern this leakage, and the resulting accumulations of leaked fluids in overlying formations. The results are discussed in the context of two polices aimed at governing long-term sequestration and protecting groundwater: the U.S. DOE guideline for storage permanence and the U.S. EPA UIC Program Class VI Rule. For a case study of CO2 injection into the Mt. Simon sandstone in the Michigan sedimentary basin, we showed that (1) the U.S. DOE guideline would allow for more leakage from larger injection projects than for smaller ones; (2) leakage amounts are determined mostly by well leakage permeability rather than by variation in formation permeabilities; (3) numerous leaking wells with anomalously high leakage permeabilities are necessary in order to achieve substantial leakage rates; (4) leakage can reach potable groundwater but intervening stratigraphic traps reduce the amount to be multiple orders of magnitude less than the leakage out of the reservoir, and (5) this leakage can reduce the Area of Review that is defined by the U.S. EPA as the area within which leakage can threaten groundwater. In summary, leakage that exceeds the U.S. DOE storage permanence goal would occur only under extreme conditions, the amount that reaches shallow potable groundwater may be inconsequential from a pollution standpoint, and leakage may be beneficial. Future federal policies should be harmonized to achieve the dual goals of protecting groundwater while allowing for adaptive management that incorporates uncertainties and imperfections inherent in geologic reservoirs.

  13. The GABA transaminase, ABAT, is essential for mitochondrial nucleoside metabolism

    PubMed Central

    Besse, Arnaud; Wu, Ping; Bruni, Francesco; Donti, Taraka; Graham, Brett H.; Craigen, William J.; McFarland, Robert; Moretti, Paolo; Lalani, Seema; Scott, Kenneth L.; Taylor, Robert W.; Bonnen, Penelope E.

    2015-01-01

    Summary ABAT is a key enzyme responsible for catabolism of principal inhibitory neurotransmitter gamma-aminobutyric acid (GABA). We report an essential role for ABAT in a seemingly unrelated pathway, mitochondrial nucleoside salvage, and demonstrate that mutations in this enzyme cause an autosomal recessive neurometabolic disorder and mtDNA depletion syndrome (MDS). We describe a family with encephalomyopathic MDS caused by a homozygous missense mutation in ABAT that results in elevated GABA in subjects’ brains as well as decreased mtDNA levels in subjects’ fibroblasts. Nucleoside rescue and co-IP experiments pinpoint that ABAT functions in the mitochondrial nucleoside salvage pathway to facilitate conversion of dNDPs to dNTPs. Pharmacological inhibition of ABAT through the irreversible inhibitor Vigabatrin caused depletion of mtDNA in photoreceptor cells that was prevented through addition of dNTPs in cell culture media. This work reveals ABAT as a connection between GABA metabolism and nucleoside metabolism and defines a neurometabolic disorder that includes MDS. PMID:25738457

  14. Physically Based Simulation of Potential Effects of Carbon Dioxide Altered Climates on Groundwater Recharge

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Increased concentrations of atmospheric carbon-dioxide (CO2) will alter regional rainfall and potential evapotranspiration regimes that drive groundwater recharge. Improved methods are needed for assessing the potential sensitivities of the soil-water-vegetation system to climate change. This study ...

  15. Spatial optimization of carbon-stocking projects across Africa integrating stocking potential with co-benefits and feasibility

    NASA Astrophysics Data System (ADS)

    Greve, Michelle; Reyers, Belinda; Mette Lykke, Anne; Svenning, Jens-Christian

    2013-12-01

    Carbon offset projects through forestation are employed within the emissions trading framework to store carbon. Yet, information about the potential of landscapes to stock carbon, essential to the design of offset projects, is often lacking. Here, based on data on vegetation carbon, climate and soil, we quantify the potential for carbon storage in woody vegetation across tropical Africa. The ability of offset projects to produce co-benefits for ecosystems and people is then quantified. When co-benefits such as biodiversity conservation are considered, the top-ranked sites are sometimes different to sites selected purely for their carbon-stocking potential, although they still possess up to 92% of the latter carbon-stocking potential. This work provides the first continental-scale assessment of which areas may provide the greatest direct and indirect benefits from carbon storage reforestation projects at the smallest costs and risks, providing crucial information for prioritization of investments in carbon storage projects.

  16. Spatial optimization of carbon-stocking projects across Africa integrating stocking potential with co-benefits and feasibility.

    PubMed

    Greve, Michelle; Reyers, Belinda; Mette Lykke, Anne; Svenning, Jens-Christian

    2013-01-01

    Carbon offset projects through forestation are employed within the emissions trading framework to store carbon. Yet, information about the potential of landscapes to stock carbon, essential to the design of offset projects, is often lacking. Here, based on data on vegetation carbon, climate and soil, we quantify the potential for carbon storage in woody vegetation across tropical Africa. The ability of offset projects to produce co-benefits for ecosystems and people is then quantified. When co-benefits such as biodiversity conservation are considered, the top-ranked sites are sometimes different to sites selected purely for their carbon-stocking potential, although they still possess up to 92% of the latter carbon-stocking potential. This work provides the first continental-scale assessment of which areas may provide the greatest direct and indirect benefits from carbon storage reforestation projects at the smallest costs and risks, providing crucial information for prioritization of investments in carbon storage projects. PMID:24352139

  17. Potential climate change effects on rice: Carbon dioxide and temperature

    SciTech Connect

    Baker, J.T.; Boote, K.J.; Allen, L.H. Jr. |

    1995-12-31

    The projected doubling of current levels of atmospheric CO{sub 2} concentration [CO{sub 2}] during the next century, along with increases in other radiatively active gases, has led to predictions of increases in global air temperature and shifts in precipitation patterns. Since 1987, several [CO{sub 2}] and temperature experiments have been conducted on rice (Oryza sativa L., cv. IR-30) in outdoor, naturally-sunlit, environmentally-controlled, plant growth chambers. The objectives of this chapter are to summarize some of the major findings of these experiments. In these experiments, season-long [CO{sub 2}] treatments ranged from 160 to 900 {micro}mol CO{sub 2} mol{sup {minus}1} air, while temperature treatments ranged from 25/18/21 to 40/33/37 C (daytime dry bulb air temperature/nighttime dry bulb air temperature/constant paddy water temperature). Total growth duration was shortened by 10 to 12 d as [CO{sub 2}] increased across a [CO{sub 2}] range from 160 to 500 {micro}mol mol{sup {minus}1}, due mainly to a shortened vegetative phase of development and a reduction in the number of mainstem leaves formed prior to panicle initiation. Photosynthesis, growth, and final grain yield increased with [CO{sub 2}] from 160 to 500 {micro}mol mol{sup {minus}1}, but were very similar from 500 to 900 {micro}mol mol{sup {minus}1}. Carbon dioxide enrichment from 330 to 660 {micro}mol mol{sup {minus}1} increased grain yield mainly by increasing the number of panicles per plant, and increasing temperature treatment above 28/21/25 C resulted in decreased grain yield, due largely to a decline in the number of filled grain per panicle. Evapotranspiration decreased and water-use efficiency increased with increasing [CO{sub 2}] treatment, while the reverse trends were found with increasing temperature treatment. 60 refs., 7 figs., 2 tabs.

  18. Development of an assessment methodology for hydrocarbon recovery potential using carbon dioxide and associated carbon sequestration-Workshop findings

    USGS Publications Warehouse

    Verma, Mahendra K.; Warwick, Peter D.

    2011-01-01

    The Energy Independence and Security Act of 2007 (Public Law 110-140) authorized the U.S. Geological Survey (USGS) to conduct a national assessment of geologic storage resources for carbon dioxide (CO2) and requested that the USGS estimate the "potential volumes of oil and gas recoverable by injection and sequestration of industrial carbon dioxide in potential sequestration formations" (121 Stat. 1711). The USGS developed a noneconomic, probability-based methodology to assess the Nation's technically assessable geologic storage resources available for sequestration of CO2 (Brennan and others, 2010) and is currently using the methodology to assess the Nation's CO2 geologic storage resources. Because the USGS has not developed a methodology to assess the potential volumes of technically recoverable hydrocarbons that could be produced by injection and sequestration of CO2, the Geologic Carbon Sequestration project initiated an effort in 2010 to develop a methodology for the assessment of the technically recoverable hydrocarbon potential in the sedimentary basins of the United States using enhanced oil recovery (EOR) techniques with CO2 (CO2-EOR). In collaboration with Stanford University, the USGS hosted a 2-day CO2-EOR workshop in May 2011, attended by 28 experts from academia, natural resource agencies and laboratories of the Federal Government, State and international geologic surveys, and representatives from the oil and gas industry. The geologic and the reservoir engineering and operations working groups formed during the workshop discussed various aspects of geology, reservoir engineering, and operations to make recommendations for the methodology.

  19. Use of multi-transition-metal-ion-exchanged zeolite 13X catalysts in methane emissions abatement

    SciTech Connect

    Hui, K.S.; Chao, C.Y.H.; Kwong, C.W.; Wan, M.P.

    2008-04-15

    Methane is a potent greenhouse gas. It has a global warming potential (GWP) 23 times greater than carbon dioxide. Reducing methane emissions would lead to substantial economic and environmental benefits. This study investigated the performance of multi-transition-metal-(Cu, Cr, Ni, and Co)-ion-exchanged zeolite 13X catalysts in methane emissions abatement. The catalytic activity in methane combustion using multi-ion-exchanged catalysts was studied with different parameters including the molar percentage of metal loading, the space velocity, and the inlet methane concentration under atmospheric pressure and at a relatively low reaction temperature of 500 C. The performance of the catalysts was determined in terms of the apparent activation energy, the number of active sites of the catalyst, and the BET surface area of the catalyst. This study showed that multi-ion-exchanged catalysts outperformed single-ion-exchanged and acidified 13X catalysts and that lengthening the residence time led to a higher methane conversion percentage. The enhanced catalytic activity in the multi-ion-exchanged catalysts was attributed to the presence of exchanged transition ions instead of acid sites in the catalyst. The catalytic activity of the catalysts was influenced by the metal loading amount, which played an important role in affecting the apparent activation energy for methane combustion, the active sites, and the BET surface area of the catalyst. Increasing the amount of metal loading in the catalyst decreased the apparent activation energy for methane combustion and also the BET surface area of the catalyst. An optimized metal loading amount at which the highest catalytic activity was observed due to the combined effects of the various factors was determined. (author)

  20. Loess Plateau check dams can potentially sequester eroded soil organic carbon

    NASA Astrophysics Data System (ADS)

    Zhang, Haicheng; Liu, Shuguang; Yuan, Wenping; Dong, Wenjie; Xia, Jiangzhou; Cao, Yaojun; Jia, Yanwei

    2016-06-01

    Check dams are special soil and water conservation structures in the Loess Plateau, China. They play an important role in intercepting sediments and soil organic carbon (SOC). However, the decomposition of intercepted SOC and the environmental regulations at check dams have not been investigated. We conducted several paired field experiments at both check dams and slope lands in the Yanhe Watershed of the Loess Plateau to examine the characteristics of SOC decomposition at check dams. On average, the SOC mineralization rate in slope lands was approximately three times higher than in check dams. Increased soil moisture and compaction in check dams can constrain carbon mineralization by limiting the oxygen availability of SOC and can isolate substrate carbon from heterotrophic microorganisms. Our results indicate that check dams display a considerable potential for eroded SOC sequestration via reducing the soil respiration rate and highlight the important implications of lateral carbon redistribution and human engineering projects when estimating regional or global ecosystem carbon cycles.

  1. The potential for damage from the accidental release of conductive carbon fibers from aircraft composites

    NASA Technical Reports Server (NTRS)

    Bell, V. L.

    1980-01-01

    Carbon and graphite fibers are known to be electrically conductive. The rapidly accelerating use of carbon fibers as the reinforcement in filamentary composite materials brought up the possibility of accidental release of carbon fibers from the burning of crashed commercial airliners with carbon composite parts. Such release could conceivably cause widespread damage to electrical and electronic equipment. The experimental and analytical results of a comprehensive investigation of the various elements necessary to assess the extent of such potential damage in terms of annual expected costs and maximum losses at low probabilities of occurrence are presented. A review of NASA materials research program to provide alternate or modified composite materials to overcome any electrical hazards from the use of carbon composites in aircraft structures is described.

  2. Direct Carbon Conversion: Review of Production and Electrochemical Conversion of Reactive Carbons, Economics and Potential Impact on the Carbon Cycle

    SciTech Connect

    Cooper, J F; Cherepy, N; Upadhye, R; Pasternak, A; Steinberg, M

    2000-12-12

    Concerns over global warning have motivated the search for more efficient technologies for electric power generation from fossil fuels. Today, 90% of electric power is produced from coal, petroleum or natural gas. Higher efficiency reduces the carbon dioxide emissions per unit of electric energy. Exercising an option of deep geologic or ocean sequestration for the CO{sub 2} byproduct would reduce emissions further and partially forestall global warming. We introduce an innovative concept for conversion of fossil fuels to electricity at efficiencies in the range of 70-85% (based on standard enthalpy of the combustion reaction). These levels exceed the performance of common utility plants by up to a factor of two. These levels are also in excess of the efficiencies of combined cycle plants and of advanced fuel cells now operated on the pilot scale. The core of the concept is direct carbon conversion a process that is similar to that a fuel cell but differs in that synthesized forms of carbon, not hydrogen, are used as fuel. The cell sustains the reaction, C + O{sub 2} = CO{sub 2} (E {approx} 1.0 V, T = 800 C). The fuel is in the form of fine particulates ({approx}100 nm) distributed by entrainment in a flow of CO{sub 2} to the cells to form a slurry of carbon in the melt. The byproduct stream of CO{sub 2} is pure. It affords the option of sequestration without additional separation costs, or can be reused in secondary oil or gas recovery. Our experimental program has discovered carbon materials with orders of magnitude spreads in anode reactivity reflected in cell power density. One class of materials yields energy at about 1 kW/m{sup 2} sufficiently high to make practical the use of the cell in electric utility applications. The carbons used in such cells are highly disordered on the nanometer scale (2-30 nm), relative to graphite. Such disordered or turbostratic carbons can be produced by controlled pyrolysis (thermal decomposition) of hydrocarbons extracted from

  3. Black carbon from the Mississippi River: quantities, sources, and potential implications for the global carbon cycle.

    PubMed

    Mitra, Siddhartha; Bianchi, Thomas S; McKee, Brent A; Sutula, Martha

    2002-06-01

    Black carbon (BC) may be a major component of riverine carbon exported to the ocean, but its flux from large rivers is unknown. Furthermore, the global distribution of BC between natural and anthropogenic sources remains uncertain. We have determined BC concentrations in suspended sediments of the Mississippi River, the 7th largest river in the world in terms of sediment and water discharge, during high flow and low flow in 1999. The 1999 annual flux of BC from the Mississippi River was 5 x 10(-4) petagrams (1 Pg = 10(15) g = 1 gigaton). We also applied a principal components analysis to particulate-phase high molecular weight polycyclic aromatic hydrocarbon isomer ratios in Mississippi River suspended sediments. In doing so, we determined that approximately 27% of the BC discharged from the Mississippi River in 1999 originated from fossil fuel combustion (coal and smelter-derived combustion), implicating fluvial BC as an important source of anthropogenic BC contamination into the ocean. Using our value for BC flux and the annual estimate for BC burial in ocean sediments, we calculate that, in 1999, the Mississippi River discharged approximately 5% of the BC buried annually in the ocean. These results have important implications, not only for the global carbon cycle but also for the fluvial discharge of particulate organic contaminants into the world's oceans. PMID:12075780

  4. Integrated geologic and engineering determination of oil-reserve-growth potential in carbonate reservoirs

    SciTech Connect

    Holtz, M.H.; Rupel, S.C.; Hocott, C.R. )

    1992-11-01

    Leonardian restricted-platform carbonate reservoirs in the Permian Basin in West Texas and southeastern New Mexico exhibit abnormally low recovery efficiencies. Cumulative production form these mature reservoirs is only 18% of the original oil in place (OOIP), or about one-half the average recovery efficiency of Permian Basin carbonate reservoirs. Low recovery efficiency is directly related to high degrees of vertical and lateral facies heterogeneity caused by high-frequency, cyclic sedimentation in low-energy, carbonate platform environments and by equally complex postdepositional diagenesis. This paper reports that because of their geologic complexity, these reservoirs have high reserve-growth potential.

  5. Potential biodiversity benefits from international programs to reduce carbon emissions from deforestation.

    PubMed

    Siikamäki, Juha; Newbold, Stephen C

    2012-01-01

    Deforestation is the second largest anthropogenic source of carbon dioxide emissions and options for its reduction are integral to climate policy. In addition to providing potentially low cost and near-term options for reducing global carbon emissions, reducing deforestation also could support biodiversity conservation. However, current understanding of the potential benefits to biodiversity from forest carbon offset programs is limited. We compile spatial data on global forest carbon, biodiversity, deforestation rates, and the opportunity cost of land to examine biodiversity conservation benefits from an international program to reduce carbon emissions from deforestation. Our results indicate limited geographic overlap between the least-cost areas for retaining forest carbon and protecting biodiversity. Therefore, carbon-focused policies will likely generate substantially lower benefits to biodiversity than a more biodiversity-focused policy could achieve. These results highlight the need to systematically consider co-benefits, such as biodiversity in the design and implementation of forest conservation programs to support international climate policy. PMID:22307280

  6. Oak Ridge Gaseous Diffusion Plant Biological Monitoring and Abatement Program for Mitchell Branch

    SciTech Connect

    Loar, J.M.; Adams, S.M.; Kszos, L.A.; Ryon, M.G.; Smith, J.G.; Southworth, G.R.; Stewart, A.J.

    1992-01-01

    A proposed Biological Monitoring and Abatement Program (BMAP) for the Oak Ridge Gaseous Diffusion Plant (ORGDP; currently the Oak Ridge K-25 Site) was prepared in December 1986, as required by the modified National Pollutant Discharge Elimination System (NPDES) permit that was issued on September 11, 1986. The effluent discharges to Mitchell Branch are complex, consisting of trace elements, organic chemicals, and radionuclides in addition to various conventional pollutants. Moreover, the composition of these effluent streams will be changing over time as various pollution abatement measures are implemented over the next several years. Although contaminant inputs to the stream originate primarily as point sources from existing plant operations, area sources, such as the classified burial grounds and the K-1407-C holding pond, can not be eliminated as potential sources of contaminants. The proposed BMAP consists of four tasks. These tasks include (1) ambient toxicity testing, (2) bioaccumulation studies, (3) biological indicator studies, and (4) ecological surveys of the benthic invertebrate and fish communities. BMAP will determine whether the effluent limits established for ORGDP protect the designated use of the receiving stream (Mitchell Branch) for growth and propagation of fish and aquatic life. Another objective of the program is to document the ecological effects resulting from various pollution abatement projects, such as the Central Neutralization Facility.

  7. Identification of root cause and abatement of vibration of monochromator.

    SciTech Connect

    Jendrzejczyk, J. A.

    1998-01-13

    Silicon crystal mirrors are used to reflect high-intensity X-ray beams. A large amount of heat is generated in each mirror. To minimize the effect of thermal expansion on the crystal mirrors, heat is removed by pumping liquid gallium (with a boiling point of 29.8 C) through passages in the crystal mirrors. During system operation, mirror motion should be kept to an acceptable level to avoid performance degradation. There are many potential sources of excitation to the crystal assembly; one such source is the flowing gallium. Two series of tests were performed earlier for a near-prototypical gallium cooling system (1-2). This paper describes a series of tests to measure the general vibration response characteristics of critical components in the monochromator system that contains the mirrors. The main objective of this work is to identify the root cause of vibration and to recommend general guidelines for abatement of vibration. This is achieved by performing many tests to understand the response characteristics under various conditions, by analysis of the response data, and by use of some theoretical considerations.

  8. Abatement of an aircraft exhaust plume using aerodynamic baffles.

    PubMed

    Bennett, Michael; Christie, Simon M; Graham, Angus; Garry, Kevin P; Velikov, Stefan; Poll, D Ian; Smith, Malcolm G; Mead, M Iqbal; Popoola, Olalekan A M; Stewart, Gregor B; Jones, Roderic L

    2013-03-01

    The exhaust jet from a departing commercial aircraft will eventually rise buoyantly away from the ground; given the high thrust/power (i.e., momentum/buoyancy) ratio of modern aero-engines, however, this is a slow process, perhaps requiring ∼ 1 min or more. Supported by theoretical and wind tunnel modeling, we have experimented with an array of aerodynamic baffles on the surface behind a set of turbofan engines of 124 kN thrust. Lidar and point sampler measurements show that, as long as the intervention takes place within the zone where the Coanda effect holds the jet to the surface (i.e., within about 70 m in this case), then quite modest surface-mounted baffles can rapidly lift the jet away from the ground. This is of potential benefit in abating both surface concentrations and jet blast downstream. There is also some modest acoustic benefit. By distributing the aerodynamic lift and drag across an array of baffles, each need only be a fraction of the height of a single blast fence. PMID:23343109

  9. Sinking Jelly-Carbon Unveils Potential Environmental Variability along a Continental Margin

    PubMed Central

    Lebrato, Mario; Molinero, Juan-Carlos; Cartes, Joan E.; Lloris, Domingo; Mélin, Frédéric; Beni-Casadella, Laia

    2013-01-01

    Particulate matter export fuels benthic ecosystems in continental margins and the deep sea, removing carbon from the upper ocean. Gelatinous zooplankton biomass provides a fast carbon vector that has been poorly studied. Observational data of a large-scale benthic trawling survey from 1994 to 2005 provided a unique opportunity to quantify jelly-carbon along an entire continental margin in the Mediterranean Sea and to assess potential links with biological and physical variables. Biomass depositions were sampled in shelves, slopes and canyons with peaks above 1000 carcasses per trawl, translating to standing stock values between 0.3 and 1.4 mg C m2 after trawling and integrating between 30,000 and 175,000 m2 of seabed. The benthopelagic jelly-carbon spatial distribution from the shelf to the canyons may be explained by atmospheric forcing related with NAO events and dense shelf water cascading, which are both known from the open Mediterranean. Over the decadal scale, we show that the jelly-carbon depositions temporal variability paralleled hydroclimate modifications, and that the enhanced jelly-carbon deposits are connected to a temperature-driven system where chlorophyll plays a minor role. Our results highlight the importance of gelatinous groups as indicators of large-scale ecosystem change, where jelly-carbon depositions play an important role in carbon and energy transport to benthic systems. PMID:24367499

  10. Sinking jelly-carbon unveils potential environmental variability along a continental margin.

    PubMed

    Lebrato, Mario; Molinero, Juan-Carlos; Cartes, Joan E; Lloris, Domingo; Mélin, Frédéric; Beni-Casadella, Laia

    2013-01-01

    Particulate matter export fuels benthic ecosystems in continental margins and the deep sea, removing carbon from the upper ocean. Gelatinous zooplankton biomass provides a fast carbon vector that has been poorly studied. Observational data of a large-scale benthic trawling survey from 1994 to 2005 provided a unique opportunity to quantify jelly-carbon along an entire continental margin in the Mediterranean Sea and to assess potential links with biological and physical variables. Biomass depositions were sampled in shelves, slopes and canyons with peaks above 1000 carcasses per trawl, translating to standing stock values between 0.3 and 1.4 mg C m(2) after trawling and integrating between 30,000 and 175,000 m(2) of seabed. The benthopelagic jelly-carbon spatial distribution from the shelf to the canyons may be explained by atmospheric forcing related with NAO events and dense shelf water cascading, which are both known from the open Mediterranean. Over the decadal scale, we show that the jelly-carbon depositions temporal variability paralleled hydroclimate modifications, and that the enhanced jelly-carbon deposits are connected to a temperature-driven system where chlorophyll plays a minor role. Our results highlight the importance of gelatinous groups as indicators of large-scale ecosystem change, where jelly-carbon depositions play an important role in carbon and energy transport to benthic systems. PMID:24367499

  11. Chemical abatement of acid mine drainage formation

    SciTech Connect

    Steven, J.

    1987-01-01

    Chemical and thermodynamic data were used to develop a unified model of hydroxo-, sulfato-, and bisulfato-iron complexes and their stability constants in iron-sulfate solutions. Free energy of formation for each ligand series species was hypothesized to be linear in ligand number because of supporting evidence from the literature. Laboratory tests on the inhibition of acid mine drainage bacteria were conducted. Benzoic acid, sorbic acid, and sodium lauryl sulfate at low concentrations (5 to 10 mg/liter) each effectively inhibited oxidation of ferrous iron in batch cultures of Thiobacillus ferrooxidans. The rate of chemical oxidation of ferrous iron in low-pH, sterile batch reactors was not substantially affected at the tested concentrations (5 to 50 mg/liter) of any of the compounds. Low-pH cultures of Thiobacillus thioxidans significantly increased zinc sulfide dissolution rates relative to sterile controls. Sodium lauryl sulfate, benzoic acid, and sorbic acid at concentrations of 10, 25, and 50 mg/liter, respectively, in identical low-pH, batch cultures of Thiobacillus thiooxidans, were sufficient for complete inhibition of bacterial zinc sulfide dissolution. Pilot-scale experiments on the abatement of acid mine drainage formation in both fresh and weathered pyritic coal refuse were also conducted. At doses of 0.5 g/kg and 5.0 g/kg in fresh and weathered refuse, respectively, sodium benzoate, potassium sorbate, and most significantly, sodium lauryl surface, reduced the rate of iron, sulfate, and acidity production in water-leached barrels of coal refuse material.

  12. Potential threshold of anode materials for foldable lithium-ion batteries featuring carbon nanotube current collectors

    NASA Astrophysics Data System (ADS)

    Wang, Qing Hui; Zhong, Sheng Wen; Hu, Jing Wei; Liu, Ting; Zhu, Xian Yan; Chen, Jing; Hong, Yin Yan; Wu, Zi Ping

    2016-04-01

    Flexible carbon nanotube macro-films (CMFs) are perfect current collectors for preparing foldable lithium-ion batteries (LIBs). However, selecting appropriate anodes for electrode is difficult because of the different potentials (vs. Li/Li+) of carbon nanotubes and traditional metallic current collector. This study demonstrated an additional reaction at potential below 0.9 V (vs. Li/Li+) caused by CMF, And Li+ will be constrained, which decreased capacity of anode/CMF electrode. Conversely, results changed when the anode potential exceeded 0.9 V (vs. Li/Li+) because Li+ passed the potential threshold, and the CMF retained its electrochemical inactivity. Consequently, the CMF-based foldable LIBs performed well. The potential threshold mechanism of anode is expected to provide new impetus to both academia and industry for exploring flexible or foldable LIBs.

  13. Evaluation of Fibrogenic Potential of Industrial Multi-Walled Carbon Nanotubes in Acute Aspiration Experiment

    PubMed Central

    Khaliullin, T. O.; Shvedova, A. A.; Kisin, E. R.; Zalyalov, R. R.; Fatkhutdinova, L. M.

    2015-01-01

    Local inflammatory response in the lungs and fibrogenic potential of multi-walled carbon nanotubes were studied in an acute aspiration experiment in mice. The doses were chosen based on the concentration of nanotubes in the air at a workplace of the company-producer. ELISA, flow cytometry, enhanced darkfield microscopy, and histological examination showed that multi-walled carbon nanotubes induced local inflammation, oxidative stress, and connective tissue growth (fibrosis). Serum levels of TGF-β1 and osteopontin proteins can serve as potential exposure biomarkers. PMID:25778660

  14. Mechanisms controlling soil carbon turnover and their potential application for enhancing carbon sequestration

    SciTech Connect

    Jastrow, Julie D.; Amonette, James E.; Bailey, Vanessa L.

    2007-01-01

    Two major mechanisms, (bio)chemical alteration and physicochemical protection, stabilize soil organic carbon (SOC) and thereby control soil carbon turnover. With (bio)chemical alteration, SOC is transformed by biotic and abiotic processes to chemical forms that are more resistant to decomposition and, in some cases, more easily retained by sorption to soil solids. With physicochemical protection, biochemical attack of SOC is inhibited by organomineral interactions at molecular to millimeter scales. Stabilization of otherwise decomposable SOM can occur via sorption to soil surfaces, complexation with soil minerals, occlusion within aggregates, and deposition in pores inaccessible to decomposers and extracellular enzymes. Soil structure (i.e., the arrangement of solids and pores in the soil) is a master integrating variable that both controls and indicates the SOC stabilization status of a soil. To enhance SOC sequestration, the best option is to modify the soil physicochemical environment to favor the activities of fungi. Specific practices that accomplish this include minimizing tillage, maintaining a near-neutral soil pH and an adequate base cation exchange capacity (particularly Ca), ensuring adequate drainage, and minimizing erosion by water and wind. In some soils, amendments with various high-specific-surface micro- and mesoporous sorbents such as fly ash or charcoal can be beneficial.

  15. Global economic potential for reducing carbon dioxide emissions from mangrove loss.

    PubMed

    Siikamäki, Juha; Sanchirico, James N; Jardine, Sunny L

    2012-09-01

    Mangroves are among the most threatened and rapidly disappearing natural environments worldwide. In addition to supporting a wide range of other ecological and economic functions, mangroves store considerable carbon. Here, we consider the global economic potential for protecting mangroves based exclusively on their carbon. We develop unique high-resolution global estimates (5' grid, about 9 × 9 km) of the projected carbon emissions from mangrove loss and the cost of avoiding the emissions. Using these spatial estimates, we derive global and regional supply curves (marginal cost curves) for avoided emissions. Under a broad range of assumptions, we find that the majority of potential emissions from mangroves could be avoided at less than $10 per ton of CO(2). Given the recent range of market price for carbon offsets and the cost of reducing emissions from other sources, this finding suggests that protecting mangroves for their carbon is an economically viable proposition. Political-economy considerations related to the ability of doing business in developing countries, however, can severely limit the supply of offsets and increases their price per ton. We also find that although a carbon-focused conservation strategy does not automatically target areas most valuable for biodiversity, implementing a biodiversity-focused strategy would only slightly increase the costs. PMID:22847435

  16. Development of a carbonate platform with potential for large discoveries - an example from Vietnam

    SciTech Connect

    Mayall, M.; Bent, A.; Dale, B. )

    1996-01-01

    In offshore central and southern Vietnam a number of carbonate accumulations can be recognized. Platform carbonates form basin-wide units of carbonate characterized by strong, continuous parallel seismic reflectors. Facies are dominated by bioclastic wackestones with poor-moderate reservoir quality. On the more isolated highs, large buildups developed. These are typically 5-10 km across and 300 m thick. They unconformably overlie the platform carbonate facies which are extensively karstified. In places these are pinnacles, typically 2-5 km across, 300 m+ thick with chaotic or mounded internal seismic facies. The large carbonate buildups are characterized by steep sided slopes with talus cones, reef-margin rims usually developed around only part of the buildup, and a prominent back-stepping geometry. Buildup interior facies form the main potential reservoirs They are dominated by fine to coarse grained coralgal packstones. Fine grained carbonates are associated with deeper water events and multiple karst surfaces can also be identified. Reservoir quality is excellent, largely controlled by extensive dissolution and dolomitization believed to be related to the exposure events. Gas has been found in a number of reservoirs. Heterogeneities can be recognized which could potentially effect production. These include the extensive finer grained facies, cementation or open fissures associated with the karst surfaces, a more cemented reef rim, shallowing upwards facies cycles and faults.

  17. Development of a carbonate platform with potential for large discoveries - an example from Vietnam

    SciTech Connect

    Mayall, M.; Bent, A.; Dale, B.

    1996-12-31

    In offshore central and southern Vietnam a number of carbonate accumulations can be recognized. Platform carbonates form basin-wide units of carbonate characterized by strong, continuous parallel seismic reflectors. Facies are dominated by bioclastic wackestones with poor-moderate reservoir quality. On the more isolated highs, large buildups developed. These are typically 5-10 km across and 300 m thick. They unconformably overlie the platform carbonate facies which are extensively karstified. In places these are pinnacles, typically 2-5 km across, 300 m+ thick with chaotic or mounded internal seismic facies. The large carbonate buildups are characterized by steep sided slopes with talus cones, reef-margin rims usually developed around only part of the buildup, and a prominent back-stepping geometry. Buildup interior facies form the main potential reservoirs They are dominated by fine to coarse grained coralgal packstones. Fine grained carbonates are associated with deeper water events and multiple karst surfaces can also be identified. Reservoir quality is excellent, largely controlled by extensive dissolution and dolomitization believed to be related to the exposure events. Gas has been found in a number of reservoirs. Heterogeneities can be recognized which could potentially effect production. These include the extensive finer grained facies, cementation or open fissures associated with the karst surfaces, a more cemented reef rim, shallowing upwards facies cycles and faults.

  18. Evaluation of the potential for operating carbon neutral WWTPs in China.

    PubMed

    Hao, Xiaodi; Liu, Ranbin; Huang, Xin

    2015-12-15

    Carbon neutrality is starting to become a hot topic for wastewater treatment plants (WWTPs) all over the world, and carbon neutral operations have emerged in some WWTPs. Although China is still struggling to control its water pollution, carbon neutrality will definitely become a top priority for WWTPs in the near future. In this review, the potential for operating carbon neutral WWTPs in China is technically evaluated. Based on the A(2)/O process of a typical municipal WWTP, an evaluation model is first configured, which couples the COD/nutrient removals (mass balance) with the energy consumption/recovery (energy balance). This model is then applied to evaluate the potential of the organic (COD) energy with regards to carbon neutrality. The model's calculations reveal that anaerobic digestion of excess sludge can only provide some 50% of the total amount of energy consumption. Water source heat pumps (WSHP) can effectively convert the thermal energy contained in wastewater to heat WWTPs and neighbourhood buildings, which can supply a net electrical equivalency of 0.26 kWh when 1 m(3) of the effluent is cooled down by 1 °C. Photovoltaic (PV) technology can generate a limited amount of electricity, barely 10% of the total energy consumption. Moreover, the complexity of installing solar panels on top of tanks makes PV technology almost not worth the effort. Overall, therefore, organic and thermal energy sources can effectively supply enough electrical equivalency for China to approach to its target with regards to carbon neutral operations. PMID:26072280

  19. Global economic potential for reducing carbon dioxide emissions from mangrove loss

    PubMed Central

    Siikamäki, Juha; Sanchirico, James N.; Jardine, Sunny L.

    2012-01-01

    Mangroves are among the most threatened and rapidly disappearing natural environments worldwide. In addition to supporting a wide range of other ecological and economic functions, mangroves store considerable carbon. Here, we consider the global economic potential for protecting mangroves based exclusively on their carbon. We develop unique high-resolution global estimates (5′ grid, about 9 × 9 km) of the projected carbon emissions from mangrove loss and the cost of avoiding the emissions. Using these spatial estimates, we derive global and regional supply curves (marginal cost curves) for avoided emissions. Under a broad range of assumptions, we find that the majority of potential emissions from mangroves could be avoided at less than $10 per ton of CO2. Given the recent range of market price for carbon offsets and the cost of reducing emissions from other sources, this finding suggests that protecting mangroves for their carbon is an economically viable proposition. Political-economy considerations related to the ability of doing business in developing countries, however, can severely limit the supply of offsets and increases their price per ton. We also find that although a carbon-focused conservation strategy does not automatically target areas most valuable for biodiversity, implementing a biodiversity-focused strategy would only slightly increase the costs. PMID:22847435

  20. Mineral Carbonation Potential of CO2 from Natural and Industrial-based Alkalinity Sources

    NASA Astrophysics Data System (ADS)

    Wilcox, J.; Kirchofer, A.

    2014-12-01

    Mineral carbonation is a Carbon Capture and Storage (CSS) technology where gaseous CO2 is reacted with alkaline materials (such as silicate minerals and alkaline industrial wastes) and converted into stable and environmentally benign carbonate minerals (Metz et al., 2005). Here, we present a holistic, transparent life cycle assessment model of aqueous mineral carbonation built using a hybrid process model and economic input-output life cycle assessment approach. We compared the energy efficiency and the net CO2 storage potential of various mineral carbonation processes based on different feedstock material and process schemes on a consistent basis by determining the energy and material balance of each implementation (Kirchofer et al., 2011). In particular, we evaluated the net CO2 storage potential of aqueous mineral carbonation for serpentine, olivine, cement kiln dust, fly ash, and steel slag across a range of reaction conditions and process parameters. A preliminary systematic investigation of the tradeoffs inherent in mineral carbonation processes was conducted and guidelines for the optimization of the life-cycle energy efficiency are provided. The life-cycle assessment of aqueous mineral carbonation suggests that a variety of alkalinity sources and process configurations are capable of net CO2 reductions. The maximum carbonation efficiency, defined as mass percent of CO2 mitigated per CO2 input, was 83% for CKD at ambient temperature and pressure conditions. In order of decreasing efficiency, the maximum carbonation efficiencies for the other alkalinity sources investigated were: olivine, 66%; SS, 64%; FA, 36%; and serpentine, 13%. For natural alkalinity sources, availability is estimated based on U.S. production rates of a) lime (18 Mt/yr) or b) sand and gravel (760 Mt/yr) (USGS, 2011). The low estimate assumes the maximum sequestration efficiency of the alkalinity source obtained in the current work and the high estimate assumes a sequestration efficiency

  1. Carbon storage potential by four macrophytes as affected by planting diversity in a created wetland.

    PubMed

    Means, Mary M; Ahn, Changwoo; Korol, Alicia R; Williams, Lisa D

    2016-01-01

    Wetland creation has become a commonplace method for mitigating the loss of natural wetlands. Often mitigation projects fail to restore ecosystem services of the impacted natural wetlands. One of the key ecosystem services of newly created wetlands is carbon accumulation/sequestration, but little is known about how planting diversity (PD) affects the ability of herbaceous wetland plants to store carbon in newly created wetlands. Most mitigation projects involve a planting regime, but PD, which may be critical in establishing biologically diverse and ecologically functioning wetlands, is seldom required. Using a set of 34 mesocosms (∼1 m(2) each), we investigated the effects of planting diversity on carbon storage potential of four native wetland plant species that are commonly planted in created mitigation wetlands in Virginia - Carex vulpinoidea, Eleocharis obtusa, Juncus effusus, and Mimulus ringens. The plants were grown under the four distinctive PD treatments [i.e., monoculture (PD 1) through four different species mixture (PD 4)]. Plant biomass was harvested after two growing seasons and analyzed for tissue carbon content. Competition values (CV) were calculated to understand how the PD treatment affected the competitive ability of plants relative to their biomass production and thus carbon storage potentials. Aboveground biomass ranged from 988 g/m(2) - 1515 g/m(2), being greatest in monocultures, but only when compared to the most diverse mixture (p = 0.021). However, carbon storage potential estimates per mesocosm ranged between 344 g C/m(2) in the most diverse mesocosms (PD 4) to 610 g C/m(2) in monoculture ones with no significant difference (p = 0.089). CV of E. obtusa and C. vulpinoidea showed a declining trend when grown in the most diverse mixtures but J. effusus and M. ringens displayed no difference across the PD gradient (p = 0.910). In monocultures, both M. ringens, and J. effusus appeared to store carbon as biomass more

  2. Assessing the potential of native tree species for carbon sequestration forestry in Northeast China.

    PubMed

    Thomas, S C; Malczewski, G; Saprunoff, M

    2007-11-01

    Although the native forests of China are exceptionally diverse, only a small number of tree species have been widely utilized in forest plantations and reforestation efforts. We used dendrochronological sampling methods to assess the potential growth and carbon sequestration of native tree species in Jilin Province, Northeast China. Trees were sampled in and near the Changbaishan Biosphere Reserve, with samples encompassing old-growth, disturbed forest, and plantations. To approximate conditions for planted trees, sampling focused on trees with exposed crowns (dominant and co-dominant individuals). A log-linear relationship was found between diameter increment and tree diameter, with a linear decrease in increment with increasing local basal area; no significant differences in these patterns between plantations and natural stands were detected for two commonly planted species (Pinus koraiensis and Larix olgensis). A growth model that incorporates observed feedbacks with individual tree size and local basal area (in conjunction with allometric models for tree biomass), was used to project stand-level biomass increment. Predicted growth trajectories were then linked to the carbon process model InTEC to provide estimates of carbon sequestration potential. Results indicate substantial differences among species, and suggest that certain native hardwoods (in particular Fraxinus mandshurica and Phellodendron amurense), have high potential for use in carbon forestry applications. Increased use of native hardwoods in carbon forestry in China is likely to have additional benefits in terms of economic diversification and enhanced provision of "ecosystem services", including biodiversity protection. PMID:17188419

  3. The potential storage of carbon caused by eutrophication of the biosphere

    NASA Technical Reports Server (NTRS)

    Peterson, B. J.; Melillo, J. M.

    1985-01-01

    The hypothesis that the rate of atmospheric CO2 increase has been reduced due to increased net storage of carbon in forests, coastal oceans, and the open sea, caused by eutrophication of the biosphere with nitrogen and phosphorus, is examined. The potential for carbon storage, the balance of C, N, and P, and man's influence on the forests, rivers, coastal oceans, and the open sea is studied and discussed. It is concluded that biotic carbon sinks are small relative to the rate of CO2 release from fossil fuel; therefore, storage is limited. Man has reduced the stocks of carbon held in forests and soils and there is a redistribution of C, N, and P from the land to the oceans.

  4. Potential climate engineering effectiveness and side effects during a high carbon dioxide-emission scenario.

    PubMed

    Keller, David P; Feng, Ellias Y; Oschlies, Andreas

    2014-01-01

    The realization that mitigation efforts to reduce carbon dioxide emissions have, until now, been relatively ineffective has led to an increasing interest in climate engineering as a possible means of preventing the potentially catastrophic consequences of climate change. While many studies have addressed the potential effectiveness of individual methods there have been few attempts to compare them. Here we use an Earth system model to compare the effectiveness and side effects of afforestation, artificial ocean upwelling, ocean iron fertilization, ocean alkalinization and solar radiation management during a high carbon dioxide-emission scenario. We find that even when applied continuously and at scales as large as currently deemed possible, all methods are, individually, either relatively ineffective with limited (<8%) warming reductions, or they have potentially severe side effects and cannot be stopped without causing rapid climate change. Our simulations suggest that the potential for these types of climate engineering to make up for failed mitigation may be very limited. PMID:24569320

  5. Potential climate engineering effectiveness and side effects during a high carbon dioxide-emission scenario

    PubMed Central

    Keller, David P.; Feng, Ellias Y.; Oschlies, Andreas

    2014-01-01

    The realization that mitigation efforts to reduce carbon dioxide emissions have, until now, been relatively ineffective has led to an increasing interest in climate engineering as a possible means of preventing the potentially catastrophic consequences of climate change. While many studies have addressed the potential effectiveness of individual methods there have been few attempts to compare them. Here we use an Earth system model to compare the effectiveness and side effects of afforestation, artificial ocean upwelling, ocean iron fertilization, ocean alkalinization and solar radiation management during a high carbon dioxide-emission scenario. We find that even when applied continuously and at scales as large as currently deemed possible, all methods are, individually, either relatively ineffective with limited (<8%) warming reductions, or they have potentially severe side effects and cannot be stopped without causing rapid climate change. Our simulations suggest that the potential for these types of climate engineering to make up for failed mitigation may be very limited. PMID:24569320

  6. THE POTENTIAL OF RECLAIMED LANDS TO SEQUESTER CARBON AND MITIGATE THE GREENHOUSE EFFECT

    SciTech Connect

    Terry Brown; Song Jin

    2006-05-01

    Reclaimed mine lands have the potential to sequester carbon. The use of amendments to increase fertility and overall soil quality is encouraging. Waste amendments such as sewage sludge and clarifier sludge, as well as commercial compost were tested to determine their effects on carbon sequestration and humic acid formation in reclaimed mine lands. Sewage sludge and clarifier sludge have the potential to work as reclaimed mine lands amendments. C:N ratios need to be understood to determine probability of nutrient leaching and water contamination. Microbial activity on the humic acid fraction of sludge is directed toward the readily degradable constituents containing single chain functional groups. This finding indicate that amendments with lower molecular constituents such as aliphatic compounds are more amenable to microbial degradation, therefore serves as better nutrient sources to enhance the formation of vegetation in mine lands and leads to more efficient carbon sequestration.

  7. The potential of carbon fiber induced shock hazards in household toasters

    NASA Technical Reports Server (NTRS)

    Meyers, J. A.

    1979-01-01

    The average exposure to carbon fibers which produced a short and potential shock hazard in a household toaster was determined. Toasters are normally in the off state. They are used for brief periods during the day and have timed cycles during which power is applied. The possibility of a short occurring from the heating element to the case was investigated to find the exposure levels at which a potential shock hazard could appear. The short produced was tested to determine its importance.

  8. High biomass removal limits carbon sequestration potential of mature temperate pastures

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Decades of plowing have depleted organic carbon stocks in many agricultural soils. Conversion of plowed fields to pasture has the potential to reverse this process, recapturing organic matter that was lost under more intensive cropping systems. Temperate pastures in the northeast USA are highly prod...

  9. SEQUESTERING CARBON IN SOIL: A WORKSHOP TO EXPLORE THE POTENTIAL FOR MITIGATING GLOBAL CLIMATE CHANGE

    EPA Science Inventory

    This workshop was an excellent forum for a scientific debate on the potential of soils to sequester additional carbon from the atmosphere. wo primary conclusions can be drawn from the workshop. irst, that steps should be taken to protect and preserve the size and integrity of the...

  10. The potential for damage from the accidental release of conductive carbon fibers from burning composites

    NASA Technical Reports Server (NTRS)

    Bell, V. L.

    1980-01-01

    The potential damage to electrical equipment caused by the release of carbon fibers from burning commercial airliners is assessed in terms of annual expected costs and maximum losses at low probabilities of occurrence. A materials research program to provide alternate or modified composite materials for aircraft structures is reviewed.

  11. Using semi-analytic solutions to approximate the area of potential impact for carbon dioxide injection

    EPA Science Inventory

    This study examines using the threshold critical pressure increase and the extent of the carbon dioxide (CO2) plume to delineate the area of potential impact (AoPI) for geologic CO2 storage projects. The combined area covering both the CO2 plume and the region where the pressure ...

  12. Evaluating Renewable Cornstarch/biochar Fillers as Potential Substitutes for Carbon Black in SBR Composites

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The continually growing demand for fossil fuels coupled with the potential risk of relying on foreign sources for these fuels strengthens the need to find renewable substitutes for petroleum products. Carbon black is a petroleum product that dominates the rubber composite filler market. Agricultur...

  13. Realistic costs of carbon capture

    SciTech Connect

    Al Juaied, Mohammed . Belfer Center for Science and International Affiaris); Whitmore, Adam )

    2009-07-01

    transport and storage costs appears to be US$100-150/tCO2 for first-of-a-kind plants and perhaps US$30-50/tCO2 for nth-of-a-kind plants.The estimates for FOAK and NOAK costs appear to be broadly consistent in the light of estimates of the potential for cost reductions with increased experience. Cost reductions are expected from increasing scale, learning on individual components, and technological innovation including improved plant integration. Innovation and integration can both lower costs and increase net output with a given cost base. These factors are expected to reduce abatement costs by approximately 65% by 2030. The range of estimated costs for NOAK plants is within the range of plausible future carbon prices, implying that mature technology would be competitive with conventional fossil fuel plants at prevailing carbon prices.

  14. Environmental projects. Volume 1: Polychlorinated biphenyl (PCB) abatement program

    NASA Technical Reports Server (NTRS)

    Kushner, L.

    1987-01-01

    Six large parabolic dish antennas are located at the Goldstone Deep Space Communications Complex north of Barstow, California. Some of the ancillary electrical equipment of thes Deep Space Stations, particularly transformers and power capicitors, were filled with stable, fire-retardant, dielectric fluids containing substances called polychlorobiphenyls (PCBs). Because the Environmental Protection Agency has determined that PCBs are environmental pollutants toxic to humans, all NASA centers have been asked to participate in a PCB-abatement program. Under the supervision of JPL's Office of Telecommunications and Data Acquisition, a two-year long PCB-abatement program has eliminated PCBs from the Goldstone Complex.

  15. Carbon financing of household water treatment: background, operation and recommendations to improve potential for health gains.

    PubMed

    Hodge, James M; Clasen, Thomas F

    2014-11-01

    Household water treatment (HWT) provides a means for vulnerable populations to take charge of their own drinking water quality as they patiently wait for the pipe to finally reach them. In many low-income countries, however, promoters have not succeeded in scaling up the intervention among the target population or securing its consistent and sustained use. Carbon financing can provide the funding for reaching targeted populations with effective HWT solutions and the incentives to ensure their long-term uptake. Nevertheless, programs have been criticized because they do not actually reduce carbon emissions. We summarize the background and operation of carbon financing of HWT interventions, including the controversial construct of "suppressed demand". We agree that these programs have limited potential to reduce greenhouse gas emissions and that their characterization of trading "carbon for water" is misleading. Nevertheless, we show that the Kyoto Protocol expressly encouraged the use of suppressed demand as a means of allowing low-income countries to benefit from carbon financing provided it is used to advance development priorities such as health. We conclude by recommending changes to existing criteria for eligible HWT programs that will help ensure that they meet the conditions of microbiological effectiveness and actual use that will improve their potential for health gains. PMID:25314642

  16. Evaluation of the sediment remediation potential of magnetite impregnated activated carbons and biochars

    NASA Astrophysics Data System (ADS)

    Werner, David; Han, Zhantao; Karapanagioti, Hrissi

    2014-05-01

    We evaluated the sediment remediation potential of magnetic composite materials synthesized by precipitating magnetite minerals onto activated carbons and biochars. Magnetite impregnation did not reduce the phenanthrene sorption capacity of the activated carbon or biochar component of the composite materials. The phenanthrene sorption capacity of the composite materials correlated with the surface areas of the pristine carbonaceous sorbents. XRD data and mass magnetic susceptibility data indicate that the mineral component of the composites is indeed nearly 100% magnetite. Addition of magnetic activated carbon to River Tyne sediment slurries reduced polycyclic aromatic hydrocarbon availability by more than 90%. After 3 months of mixing, 77% of the added magnetic activated carbon could be recovered with a magnetic rod. Continued monitoring showed that polycyclic aromatic hydrocarbon availability remained low following the magnetic recovery of most of the added sorbent mass. XRD analysis confirmed the presence of magnetite in the recovered sorbent material, with some other mineral phases such as calcite and quartz also being identifiable. Magnetic activated carbon has potential as a recoverable sorbent amendment for the treatment of sediment polluted with hydrophobic organic compounds. Further work will include an evaluation of the long-term magnetic sorbent effectiveness and stability in unmixed sediments under aerobic and anaerobic conditions and regeneration and re-use options for the recovered sorbent materials.

  17. Potential responses of soil organic carbon to global environmental change

    PubMed Central

    Trumbore, Susan E.

    1997-01-01

    Recent improvements in our understanding of the dynamics of soil carbon have shown that 20–40% of the approximately 1,500 Pg of C stored as organic matter in the upper meter of soils has turnover times of centuries or less. This fast-cycling organic matter is largely comprised of undecomposed plant material and hydrolyzable components associated with mineral surfaces. Turnover times of fast-cycling carbon vary with climate and vegetation, and range from <20 years at low latitudes to >60 years at high latitudes. The amount and turnover time of C in passive soil carbon pools (organic matter strongly stabilized on mineral surfaces with turnover times of millennia and longer) depend on factors like soil maturity and mineralogy, which, in turn, reflect long-term climate conditions. Transient sources or sinks in terrestrial carbon pools result from the time lag between photosynthetic uptake of CO2 by plants and the subsequent return of C to the atmosphere through plant, heterotrophic, and microbial respiration. Differential responses of primary production and respiration to climate change or ecosystem fertilization have the potential to cause significant interrannual to decadal imbalances in terrestrial C storage and release. Rates of carbon storage and release in recently disturbed ecosystems can be much larger than rates in more mature ecosystems. Changes in disturbance frequency and regime resulting from future climate change may be more important than equilibrium responses in determining the carbon balance of terrestrial ecosystems. PMID:11607735

  18. Reforestation as a novel abatement and compliance measure for ground-level ozone.

    PubMed

    Kroeger, Timm; Escobedo, Francisco J; Hernandez, José L; Varela, Sebastián; Delphin, Sonia; Fisher, Jonathan R B; Waldron, Janice

    2014-10-01

    High ambient ozone (O3) concentrations are a widespread and persistent problem globally. Although studies have documented the role of forests in removing O3 and one of its precursors, nitrogen dioxide (NO2), the cost effectiveness of using peri-urban reforestation for O3 abatement purposes has not been examined. We develop a methodology that uses available air quality and meteorological data and simplified forest structure growth-mortality and dry deposition models to assess the performance of reforestation for O3 precursor abatement. We apply this methodology to identify the cost-effective design for a hypothetical 405-ha, peri-urban reforestation project in the Houston-Galveston-Brazoria O3 nonattainment area in Texas. The project would remove an estimated 310 tons of (t) O3 and 58 t NO2 total over 30 y. Given its location in a nitrogen oxide (NOx)-limited area, and using the range of Houston area O3 production efficiencies to convert forest O3 removal to its NOx equivalent, this is equivalent to 127-209 t of the regulated NOx. The cost of reforestation per ton of NOx abated compares favorably to that of additional conventional controls if no land costs are incurred, especially if carbon offsets are generated. Purchasing agricultural lands for reforestation removes this cost advantage, but this problem could be overcome through cost-share opportunities that exist due to the public and conservation benefits of reforestation. Our findings suggest that peri-urban reforestation should be considered in O3 control efforts in Houston, other US nonattainment areas, and areas with O3 pollution problems in other countries, wherever O3 formation is predominantly NOx limited. PMID:25201970

  19. Reforestation as a novel abatement and compliance measure for ground-level ozone

    PubMed Central

    Kroeger, Timm; Escobedo, Francisco J.; Hernandez, José L.; Varela, Sebastián; Delphin, Sonia; Fisher, Jonathan R. B.; Waldron, Janice

    2014-01-01

    High ambient ozone (O3) concentrations are a widespread and persistent problem globally. Although studies have documented the role of forests in removing O3 and one of its precursors, nitrogen dioxide (NO2), the cost effectiveness of using peri-urban reforestation for O3 abatement purposes has not been examined. We develop a methodology that uses available air quality and meteorological data and simplified forest structure growth-mortality and dry deposition models to assess the performance of reforestation for O3 precursor abatement. We apply this methodology to identify the cost-effective design for a hypothetical 405-ha, peri-urban reforestation project in the Houston–Galveston–Brazoria O3 nonattainment area in Texas. The project would remove an estimated 310 tons of (t) O3 and 58 t NO2 total over 30 y. Given its location in a nitrogen oxide (NOx)-limited area, and using the range of Houston area O3 production efficiencies to convert forest O3 removal to its NOx equivalent, this is equivalent to 127–209 t of the regulated NOx. The cost of reforestation per ton of NOx abated compares favorably to that of additional conventional controls if no land costs are incurred, especially if carbon offsets are generated. Purchasing agricultural lands for reforestation removes this cost advantage, but this problem could be overcome through cost-share opportunities that exist due to the public and conservation benefits of reforestation. Our findings suggest that peri-urban reforestation should be considered in O3 control efforts in Houston, other US nonattainment areas, and areas with O3 pollution problems in other countries, wherever O3 formation is predominantly NOx limited. PMID:25201970

  20. Assessing potential diagenetic alteration of primary iodine-to-calcium ratios in carbonate rocks

    NASA Astrophysics Data System (ADS)

    Hardisty, D. S.; Lu, Z.; Swart, P. K.; Planavsky, N.; Gill, B. C.; Loyd, S. J.; Lyons, T. W.

    2015-12-01

    We have evaluated iodine-to-calcium (I/Ca) ratios from a series of carbonate samples with well-constrained histories of diagenetic alteration to assess the likelihood of overprints on primary water column-derived signals. Because only the oxidized iodine species, iodate, is incorporated during carbonate precipitation, I/Ca ratios have strong potential as proxies for both marine redox and carbon cycling. This utility lies with the combination of iodate's redox sensitivity as well as the close association between iodine and marine organic matter. However, despite the possibility of large pore water iodine enrichments relative to overlying seawater, carbonate alteration under reducing diagenetic conditions, and iodate-to-iodide reduction, no study has assessed the prospect of diagenetic alteration of primary I/Ca ratios. Here, we evaluated aragonite-to-calcite transformations and dolomitization within the Key Largo Limestone of South Florida and the Clino and Unda drill cores of the Bahamas Bank. Also, early burial diagenesis was studied through analysis of I/Ca ratios in short cores from a variety of shallow settings within the Exuma Bay, Bahamas. Further, we evaluated authigenic carbonates through analysis of iodine in concretions constrained to have formed during varying stages of evolving pore fluid chemistry. In all cases, I/Ca ratios show the potential for diagenetic iodine loss relative to water-column derived values, consistent with observations of quantitative reduction of dissolved iodate to iodide in pore waters before or synchronous with carbonate alteration. In no case, however, did we observe an increase in I/Ca during diagenetic transformation. Our results suggest both that primary I/Ca values and trends can be preserved but that maximum I/Ca ratios should be considered a minimum estimate of seawater iodate. We recommend that ancient carbonates with distinct I/Ca trends not indicative of diagenetic iodine loss reflect preservation of or very early

  1. Current and potential carbon stocks in Moso bamboo forests in China.

    PubMed

    Li, Pingheng; Zhou, Guomo; Du, Huaqiang; Lu, Dengsheng; Mo, Lufeng; Xu, Xiaojun; Shi, Yongjun; Zhou, Yufeng

    2015-06-01

    Bamboo forests provide important ecosystem services and play an important role in terrestrial carbon cycling. Of the approximately 500 bamboo species in China, Moso bamboo (Phyllostachys pubescens) is the most important one in terms of distribution, timber value, and other economic values. In this study, we estimated current and potential carbon stocks in China's Moso bamboo forests and in their products. The results showed that Moso bamboo forests in China stored about 611.15 ± 142.31 Tg C, 75% of which was in the top 60 cm soil, 22% in the biomass of Moso bamboos, and 3% in the ground layer (i.e., bamboo litter, shrub, and herb layers). Moso bamboo products store 10.19 ± 2.54 Tg C per year. The potential carbon stocks reach 1331.4 ± 325.1 Tg C, while the potential C stored in products is 29.22 ± 7.31 Tg C a(-1). Our results indicate that Moso bamboo forests and products play a critical role in C sequestration. The information gained in this study will facilitate policy decisions concerning carbon sequestration and management of Moso bamboo forests in China. PMID:25836664

  2. Effects of climate extremes on the terrestrial carbon cycle: concepts, processes and potential future impacts.

    PubMed

    Frank, Dorothea; Reichstein, Markus; Bahn, Michael; Thonicke, Kirsten; Frank, David; Mahecha, Miguel D; Smith, Pete; van der Velde, Marijn; Vicca, Sara; Babst, Flurin; Beer, Christian; Buchmann, Nina; Canadell, Josep G; Ciais, Philippe; Cramer, Wolfgang; Ibrom, Andreas; Miglietta, Franco; Poulter, Ben; Rammig, Anja; Seneviratne, Sonia I; Walz, Ariane; Wattenbach, Martin; Zavala, Miguel A; Zscheischler, Jakob

    2015-08-01

    Extreme droughts, heat waves, frosts, precipitation, wind storms and other climate extremes may impact the structure, composition and functioning of terrestrial ecosystems, and thus carbon cycling and its feedbacks to the climate system. Yet, the interconnected avenues through which climate extremes drive ecological and physiological processes and alter the carbon balance are poorly understood. Here, we review the literature on carbon cycle relevant responses of ecosystems to extreme climatic events. Given that impacts of climate extremes are considered disturbances, we assume the respective general disturbance-induced mechanisms and processes to also operate in an extreme context. The paucity of well-defined studies currently renders a quantitative meta-analysis impossible, but permits us to develop a deductive framework for identifying the main mechanisms (and coupling thereof) through which climate extremes may act on the carbon cycle. We find that ecosystem responses can exceed the duration of the climate impacts via lagged effects on the carbon cycle. The expected regional impacts of future climate extremes will depend on changes in the probability and severity of their occurrence, on the compound effects and timing of different climate extremes, and on the vulnerability of each land-cover type modulated by management. Although processes and sensitivities differ among biomes, based on expert opinion, we expect forests to exhibit the largest net effect of extremes due to their large carbon pools and fluxes, potentially large indirect and lagged impacts, and long recovery time to regain previous stocks. At the global scale, we presume that droughts have the strongest and most widespread effects on terrestrial carbon cycling. Comparing impacts of climate extremes identified via remote sensing vs. ground-based observational case studies reveals that many regions in the (sub-)tropics are understudied. Hence, regional investigations are needed to allow a global

  3. Soil organic carbon sequestration potential and gap of the sub-tropical region

    NASA Astrophysics Data System (ADS)

    Chiti, T.; Santini, M.; Valentini, R.

    2012-04-01

    A database of soil organic carbon (SOC) stocks was created for the sub-tropical belt using existing global SOC databases (WISE3; various SOTER) and new data from an ongoing project (ERC Africa-GHG) specific for the tropical forests of the African continent. The intent of this database is to evaluate the sequestration potential of a critical area of the world where most of the primary rainforests are located, and actually show undoubtedly high SOC losses associated with deforestation. About 4100 profiles, quite well distributed over the entire sub-tropical belt, were used to calculate the actual SOC stock for the 0-30 cm and 30-100 cm depths of mineral soil. First, this actual SOC stock has been related to the current Land Use Systems; successively, it has been interpolated taking into account Homogeneous Land Units (HLUs) in terms of soil type, climate zone and land use. Then, relying on consistent projections, of both climate and land use changes, for the years 2050 and 2100 under extremes IPCC-SRES emission scenarios such as the B1 and the A2, potential SOC stocks for these time frames has been calculated. Soil carbon sequestration gap is calculated by the difference of the actual SOC stock and the future projections. When subtracting potential from the actual SOC stocks, negative values represent a gap in terms of possible SOC losses and so reduced carbon sequestration. The soil carbon gap indicates locations where there will be low soil-carbon levels associated with medium-to-high actual SOC stocks, and medium soil-carbon levels associated with high actual SOC stocks, depending on soil type, climate and land use conditions. On the long term, 2076-2100, a SOC gap is observed under all scenarios in South America, just below the Amazonia basin, where are located open and fragmented forests. However, in the Amazonia basin deforestation decrease since no sensible SOC losses were observed. An important gap is observed also in the Congo basin and West Africa, but the

  4. Biomass Carbon in the South Mexican Pacific Coast: Exploring Mangrove Potential to REDD+ Mechanisms

    NASA Astrophysics Data System (ADS)

    Bejarano, M.; Amezcua-Torrijos, I.

    2014-12-01

    Mangroves have the highest carbon stocks amongst tropical forests. In Mexico, however, little is known about their potential to mitigate climate change. In this work, we estimated biomass carbon stocks in the Southern Mexican Pacific Coast (~69,000 ha). We quantified above and belowground biomass carbon stocks at (1) the regional scale along two environmental strata (i.e. dry and wet), and (2) at the local scale along three geomorphological types of mangroves (i.e. fringe, estuarine and basin). Regional strata were defined using intensity and influence of rivers and, the mean annual precipitation and evapotranspiration ratio (i.e., wet < 1 > dry). By lowering the stressing environmental conditions (e.g., low salinity and high sediment accumulation), we expected the highest stocks in mangroves growing in wet and estuarine strata at the regional scale and local scale, respectively. Quantifications were carried out in sixty-six sites chosen through stratified randomized design in which six strata were obtained by a full combination of regional and local strata. In all strata, aboveground carbon represents 64-67% of total carbon. Total biomass carbon was higher in wet than dry stratum (W: 87.3 ± 6.9, D: 47.0 ± 5.0, p<0.001). While at local scale, total biomass carbon was high in estuarine mangroves of both wet and dry regions (W: 91.6 ± 7.8, D: 77.6 ± 14.8, p<0.001), and these were statistically similar to fringe wet mangroves (110.9 ± 24.2, p<0.001), the stratum with the highest total carbon. Following a conservative approach, the Mexican Southern Pacific Coast is storing near 20,344 Gg CO2e. If the historical annual deforestation rate of 0.54% continues, this region could emit between 0.03 and 14.4 Gg of CO2e ha/year, out of which wet estuarine mangroves would have the highest emission values. Evidence suggests that these mangroves are the most important strata in which REDD+ mechanisms could be implemented due to (1) their carbon stocks, and (2) their highest

  5. Assessing global potential and implications of Carbon Dioxide Removal: how much, for how long, and where might it take us?

    NASA Astrophysics Data System (ADS)

    Scott, V.

    2014-12-01

    Aiming to keep cumulative anthropogenic carbon release within the 2 degrees C warming budget, useful energy services and value of fossil carbon might be retained if its extraction is balanced by carbon dioxide capture and carbon storage creation. Here, we examine this proposition: assessing the global resource available for carbon storage, the reliable duration of storage, and exploring the resulting hierarchy of different storage types. The balance between fossil carbon supply, and the sufficiency (size) and capability (technology, security) of candidate carbon stores is assessed. The timescale of carbon retention by the variety of proposed stores has potentially important consequences for future climates. A distinction between 'permanent' and 'temporary' carbon storage is considered, and the results and implications for the usage of 'temporary' stores discussed.

  6. [Calculus removal efficiency and injury potential of vertically oscillating metallic and carbon ultrasonic tips].

    PubMed

    Naef, Felix H F; Sener, Beatrice; Bürgi-Tiedemann, Christine; Schmidlin, Patrick R

    2004-01-01

    This laboratory study investigated the efficiency and aggressiveness of metallic and carbonic inserts of a vertically oscillating ultrasonic device (Vector-system) at different power settings. The following parameters concerning periodontal treatment were assessed under standardized conditions: calculus and tooth substance removal, mean surface roughness and micro morphological appearance of the treated roots. Concerning the calculus removal potential, no significant differences were found between the types of insert used. The carbon fibre inserts, however, showed significantly more tooth substance loss than the metallic inserts. These findings were confirmed by micromorphological SEM analysis. In view of these results, the repeated use of these carbon fiber inserts during periodonatal sustaining therapy cannot be recommended. PMID:15587598

  7. A guide to potential soil carbon sequestration; land-use management for mitigation of greenhouse gas emissions

    USGS Publications Warehouse

    Markewich, H.W.; Buell, G.R.

    2001-01-01

    Terrestrial carbon sequestration has a potential role in reducing the recent increase in atmospheric carbon dioxide (CO2) that is, in part, contributing to global warming. Because the most stable long-term surface reservoir for carbon is the soil, changes in agriculture and forestry can potentially reduce atmospheric CO2 through increased soil-carbon storage. If local governments and regional planning agencies are to effect changes in land-use management that could mitigate the impacts of increased greenhouse gas (GHG) emissions, it is essential to know how carbon is cycled and distributed on the landscape. Only then can a cost/benefit analysis be applied to carbon sequestration as a potential land-use management tool for mitigation of GHG emissions. For the past several years, the U.S. Geological Survey (USGS) has been researching the role of terrestrial carbon in the global carbon cycle. Data from these investigations now allow the USGS to begin to (1) 'map' carbon at national, regional, and local scales; (2) calculate present carbon storage at land surface; and (3) identify those areas having the greatest potential to sequester carbon.

  8. Marginal abatement cost curve for NOx incorporating controls, renewable electricity, energy efficiency and fuel switching

    EPA Science Inventory

    A marginal abatement cost curve (MACC) traces out the relationship between the quantity of pollution abated and the marginal cost of abating each additional unit. In the context of air quality management, MACCs typically are developed by sorting end-of-pipe controls by their resp...

  9. Marginal abatement cost curves for NOx incorporating both controls and alternative measures

    EPA Science Inventory

    A marginal abatement cost curve (MACC) traces out the efficient marginal abatement cost level for any aggregate emissions target when a least cost approach is implemented. In order for it to represent the efficient MAC level, all abatement opportunities across all sectors and loc...

  10. 23 CFR 772.9 - Analysis of traffic noise impacts and abatement measures.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 23 Highways 1 2011-04-01 2011-04-01 false Analysis of traffic noise impacts and abatement measures... AND ENVIRONMENT PROCEDURES FOR ABATEMENT OF HIGHWAY TRAFFIC NOISE AND CONSTRUCTION NOISE § 772.9 Analysis of traffic noise impacts and abatement measures. (a) The highway agency shall determine...