WorldWideScience

Sample records for carbon black particles

  1. CCN activation of pure and coated carbon black particles.

    Science.gov (United States)

    Dusek, U; Reischl, G P; Hitzenberger, R

    2006-02-15

    The CCN (cloud condensation nucleus) activation of pure and coated carbon black particles was investigated using the University of Vienna cloud condensation nuclei counter (Giebl, H.; Berner, A.; Reischl, G.; Puxbaum, H.; Kasper-Giebl, A.; Hitzenberger, R. J. Aerosol Sci. 2002, 33, 1623-1634). The particles were produced by nebulizing an aqueous suspension of carbon black in a Collison atomizer. The activation of pure carbon black particles was found to require higher supersaturations than predicted by calculations representing the particles as insoluble, wettable spheres with mobility equivalent diameter. To test whether this effect is an artifact due to heating of the light-absorbing carbon black particles in the laser beam, experiments at different laser powers were conducted. No systematic dependence of the activation of pure carbon black particles on laser power was observed. The observations could be modeled using spherical particles and an effective contact angle of 4-6 degrees of water at their surface. The addition of a small amount of NaCl to the carbon black particles (by adding 5% by mass NaCl to the carbon black suspension) greatly enhanced their CCN efficiency. The measured CCN efficiencies were consistent with Kohler theory for particles consisting of insoluble and hygroscopic material. However, coating the carbon black particles with hexadecanol (a typical film-forming compound with one hydrophobic and one hydrophilic end) efficiently suppressed the CCN activation of the carbon black particles.

  2. Worker exposure to ultrafine particles during carbon black treatment

    Directory of Open Access Journals (Sweden)

    Urszula Mikołajczyk

    2015-07-01

    Full Text Available Background: The aim of the project was to assess the exposure of workers to ultrafine particles released during handling and packing of carbon black. The assessment included the results of the measurements performed in a carbon black handling plant before, during, and after work shift. Material and Methods: The number concentration of particles within the dimension range 10–1000 nm and 10–100 nm was assayed by a condensation particle counter (CPC. The mass concentration of particles was determined by a DustTrak II DRX aerosol concentration monitor. The surface area concentration of the particles potentially deposited in the alveolar (A and tracheo-bronchial (TB regions was estimated by an AeroTrak 9000 nanoparticle monitor. Results: An average mass concentration of particles during the process was 6-fold higher than that before its start, while a 3-fold increase in the average number concentration of particles within the dimension range 10–1000 nm and 10–100 nm was observed during the process. At the same time a 4-fold increase was found in the surface area concentration of the particles potentially deposited in the A and TB regions. Conclusions: During the process of carbon black handling and packing a significantly higher values of each of the analysed parameters, characterizing the exposure to ultrafine particles, were noted. Med Pr 2015;66(3:317–326

  3. Probing Black Carbon-containing Particle Microphysics with the Single-Particle Soot Photometer (SP2)

    Science.gov (United States)

    Sedlacek, A. J.; Lewis, E. R.; Onasch, T. B.; Lambe, A. T.; Davidovits, P.; Kleinman, L. I.

    2012-12-01

    Knowledge of the structure and mixing state of black-carbon containing particles is important for calculating their radiative forcing and provides insight into their source and life cycle. Recently analysis of black carbon-containing particles has demonstrated that for a fraction of such particles, the black carbon may reside on or near the surface of the particle as opposed to the traditional core-shell configuration typically assumed in which the black carbon core is surrounded by a shell of non-refractory material. During the DOE-sponsored Aerosol Lifecycle field campaign held in summer, 2011 at Brookhaven National Laboratory on Long Island, NY, episodes were encountered in which a high fraction of particles containing black carbon had such configurations, and these episodes corresponded to air masses that contained biomass burning plumes (Sedlacek et al., 2012). Subsequent analysis found other episodes in field campaigns in Colorado and California in which high fractions this configuration corresponded to biomass burning plumes. In an effort to evaluate this interpretation and explore formation mechanisms, a series of laboratory-based experiments examining the coagulation of regal black (surrogate for collapsed soot) with model non-refractory coatings [dioctyl sebacate (surrogate for organic aerosols with liquid-like character) and deliquesced ammonium sulfate (solid)] were carried out. The results of these experiments and their potential implications on black carbon radiative forcing will be discussed. Sedlacek, III, Arthur, E. R. Lewis, L. I. Kleinman, J. Xu and Q. Zhang (2012), Determination of and Evidence for Non-core-shell structure of particles containing black carbon using the single particle soot photometer (SP2). Geophys. Res. Lett., 39 L06802, doi:10.1029/2012GL050905

  4. Black-carbon absorption enhancement in the atmosphere determined by particle mixing state

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    Liu, Dantong; Whitehead, James; Alfarra, M. Rami; Reyes-Villegas, Ernesto; Spracklen, Dominick V.; Reddington, Carly L.; Kong, Shaofei; Williams, Paul I.; Ting, Yu-Chieh; Haslett, Sophie; Taylor, Jonathan W.; Flynn, Michael J.; Morgan, William T.; McFiggans, Gordon; Coe, Hugh; Allan, James D.

    2017-02-01

    Atmospheric black carbon makes an important but poorly quantified contribution to the warming of the global atmosphere. Laboratory and modelling studies have shown that the addition of non-black-carbon materials to black-carbon particles may enhance the particles’ light absorption by 50 to 60% by refracting and reflecting light. Real-world experimental evidence for this `lensing’ effect is scant and conflicting, showing that absorption enhancements can be less than 5% or as large as 140%. Here we present simultaneous quantifications of the composition and optical properties of individual atmospheric black-carbon particles. We show that particles with a mass ratio of non-black carbon to black carbon of less than 1.5, which is typical of fresh traffic sources, are best represented as having no absorption enhancement. In contrast, black-carbon particles with a ratio greater than 3, which is typical of biomass-burning emissions, are best described assuming optical lensing leading to an absorption enhancement. We introduce a generalized hybrid model approach for estimating scattering and absorption enhancements based on laboratory and atmospheric observations. We conclude that the occurrence of the absorption enhancement of black-carbon particles is determined by the particles’ mass ratio of non-black carbon to black carbon.

  5. Influence of carbon black and indium tin oxide absorber particles on laser transmission welding

    Science.gov (United States)

    Aden, Mirko; Mamuschkin, Viktor; Olowinsky, Alexander

    2015-06-01

    For laser transmission welding of polypropylene carbon black and indium tin oxide (ITO) are used as absorber particles. Additionally, the colorant titanium dioxide is mixed to the absorbing part, while the transparent part is kept in natural state. The absorption coefficients of ITO and carbon black particles are obtained, as well as the scattering properties of polypropylene loaded with titanium dioxide (TiO2). At similar concentrations the absorption coefficient of ITO is an order of magnitude smaller than that of carbon black. Simulations of radiation propagation show that the penetration depth of laser light is smaller for carbon black. Therefore, the density of the released heat is higher. Adding TiO2 changes the distribution of heat in case of ITO, whereas for carbon black the effect is negligible. Thermal simulations reveal the influence of the two absorbers and TiO2 on the heat affected zone. The results of the thermal simulations are compared to tensile test results.

  6. Morphology and Optical Properties of Black-Carbon Particles Relevant to Engine Emissions

    Science.gov (United States)

    Michelsen, H. A.; Bambha, R.; Dansson, M. A.; Schrader, P. E.

    2013-12-01

    Black-carbon particles are believed to have a large influence on climate through direct radiative forcing, reduction of surface albedo of snow and ice in the cryosphere, and interaction with clouds. The optical properties and morphology of atmospheric particles containing black carbon are uncertain, and characterization of black carbon resulting from engines emissions is needed. Refractory black-carbon particles found in the atmosphere are often coated with unburned fuel, sulfuric acid, water, ash, and other combustion by-products and atmospheric constituents. Coatings can alter the optical and physical properties of the particles and therefore change their optical properties and cloud interactions. Details of particle morphology and coating state can also have important effects on the interpretation of optical diagnostics. A more complete understanding of how coatings affect extinction, absorption, and incandescence measurements is needed before these techniques can be applied reliably to a wide range of particles. We have investigated the effects of coatings on the optical and physical properties of combustion-generated black-carbon particles using a range of standard particle diagnostics, extinction, and time-resolved laser-induced incandescence (LII) measurements. Particles were generated in a co-flow diffusion flame, extracted, cooled, and coated with oleic acid. The diffusion flame produces highly dendritic soot aggregates with similar properties to those produced in diesel engines, diffusion flames, and most natural combustion processes. A thermodenuder was used to remove the coating. A scanning mobility particle sizer (SMPS) was used to monitor aggregate sizes; a centrifugal particle mass analyzer (CPMA) was used to measure coating mass fractions, and transmission electron microscopy (TEM) was used to characterize particle morphologies. The results demonstrate important differences in optical measurements between coated and uncoated particles.

  7. Online single particle measurements of black carbon coatings, structure and optical properties

    Science.gov (United States)

    Allan, James; Liu, Dantong; Taylor, Jonathan; Flynn, Michael; Williams, Paul; Morgan, William; Whitehead, James; Alfarra, Rami; McFiggans, Gordon; Coe, Hugh

    2016-04-01

    The impacts of black carbon on meteorology and climate remain a major source of uncertainty, owing in part to the complex relationship between the bulk composition of the particulates and their optical properties. A particular complication stems from how light interacts with particles in response to the microphysical configuration and any 'coatings', i.e. non-black carbon material that is either co-emitted or subsequently obtained through atmospheric processing. This may cause the particle to more efficiently absorb or scatter light and may even change the sign of its radiative forcing potential. While much insight has been gained through measurements of bulk aerosol properties, either while suspended or after collection on a filter or impactor substrate, this does not provide a complete picture and thus may not adequately constrain the system. Here we present an overview of recent work to better constrain the properties of black carbon using online, in situ measurements of single particles, primarily using a Single Particle Soot Photometer (SP2). We have developed novel methods of inverting the data produced and combining the different metrics derived so as to give the most effective insights into black carbon sources, processes and properties. We have also used this measurement in conjunction with other instruments (sometimes in series) and used the data to challenge many commonly used models of optical properties such as core-shell Mie, Rayleigh-Debeye-Gans and effective medium. This work has been carried out in a variety of atmospheric environments and with laboratory-produced soots, e.g. from a diesel engine rig. Highlights include the finding that with real-world atmospheric aerosols, bulk optical measurements may be insufficient to derive brown carbon parameters without detailed morphological data. We also show that the enhancement of absorption for both ambient and laboratory generated particles only occurs after the coating mass fraction reaches a certain

  8. Morphology and Mixing of Black Carbon Particles Collected in Central California During the CARES Field Study

    Energy Technology Data Exchange (ETDEWEB)

    Moffet, Ryan; O' Brien, Rachel; Alpert, Peter A.; Kelly, Stephen T.; Pham, Don Q.; Gilles, Mary K.; Knopf, Daniel A.; Laskin, Alexander

    2016-11-23

    Aerosol absorption is strongly dependent on the internal heterogeneity (mixing state) and morphology of individual particles containing black carbon (BC) and other non-absorbing species. Here, we examine an extensive microscopic data set collected in the California central valley during the CARES 2010 field campaign. During a period of high photochemical activity and pollution buildup, the particle mixing state and morphology were characterized using Scanning Transmission X-ray Microscopy (STXM) at the carbon K-edge. Observations of compacted BC core morphologies and thick organic coatings at both urban and rural sites provide evidence of the aged nature of the particles. Based on the observation of thick coatings and more convex BC inclusion morphology, the contribution of fresh BC emissions at the urban site was relatively small. These measurements of BC morphology and mixing state provide important constraints for the morphological effects on BC optical properties expected in aged urban plumes.

  9. Individual particle morphology, coatings, and impurities of black carbon aerosols in Antarctic ice and tropical rainfall

    Science.gov (United States)

    Ellis, Aja; Edwards, Ross; Saunders, Martin; Chakrabarty, Rajan K.; Subramanian, R.; Timms, Nicholas E.; Riessen, Arie; Smith, Andrew M.; Lambrinidis, Dionisia; Nunes, Laurie J.; Vallelonga, Paul; Goodwin, Ian D.; Moy, Andrew D.; Curran, Mark A. J.; Ommen, Tas D.

    2016-11-01

    Black carbon (BC) aerosols are a large source of climate warming, impact atmospheric chemistry, and are implicated in large-scale changes in atmospheric circulation. Inventories of BC emissions suggest significant changes in the global BC aerosol distribution due to human activity. However, little is known regarding BC's atmospheric distribution or aged particle characteristics before the twentieth century. Here we investigate the prevalence and structural properties of BC particles in Antarctic ice cores from 1759, 1838, and 1930 Common Era (C.E.) using transmission electron microscopy and energy-dispersive X-ray spectroscopy. The study revealed an unexpected diversity in particle morphology, insoluble coatings, and association with metals. In addition to conventionally occurring BC aggregates, we observed single BC monomers, complex aggregates with internally, and externally mixed metal and mineral impurities, tar balls, and organonitrogen coatings. The results of the study show BC particles in the remote Antarctic atmosphere exhibit complexity that is unaccounted for in atmospheric models of BC.

  10. Morphology and mixing of black carbon particles collected in central California during the CARES field study

    Science.gov (United States)

    Moffet, Ryan C.; O'Brien, Rachel E.; Alpert, Peter A.; Kelly, Stephen T.; Pham, Don Q.; Gilles, Mary K.; Knopf, Daniel A.; Laskin, Alexander

    2016-11-01

    Aerosol absorption is strongly dependent on the internal heterogeneity (mixing state) and morphology of individual particles containing black carbon (BC) and other non-absorbing species. Here, we examine an extensive microscopic data set collected in the California Central Valley during the CARES 2010 field campaign. During a period of high photochemical activity and pollution buildup, the particle mixing state and morphology were characterized using scanning transmission X-ray microscopy (STXM) at the carbon K-edge. Observations of compacted BC core morphologies and thick organic coatings at both urban and rural sites provide evidence of the aged nature of particles, highlighting the importance of highly aged particles at urban sites during periods of high photochemical activity. Based on the observation of thick coatings and more convex BC inclusion morphology, either the aging was rapid or the contribution of fresh BC emissions at the urban site was relatively small compared to background concentrations. Most particles were observed to have the BC inclusion close to the center of the host. However, host particles containing inorganic rich inclusions had the BC inclusion closer to the edge of the particle. These measurements of BC morphology and mixing state provide important constraints for the morphological effects on BC optical properties expected in aged urban plumes.

  11. Numerical modelling of the internal mixing by coagulation of black carbon particles in aircraft exhaust

    Energy Technology Data Exchange (ETDEWEB)

    Ohlsson, S.; Stroem, J. [Stockholm Univ. (Sweden). Dept. of Meteorology

    1997-12-31

    When exhaust gases from an aircraft engine mix with ambient air the humidity may reach water saturation and water droplets will form on the available cloud condensation nuclei (CCN). It is still not resolved if the CCN, on which the cloud droplets form, are mainly particles present in the ambient air or particles emitted by the aircraft. It the exhaust from a jet engine the particles are believed to consist mainly of black carbon (BC) and sulfate. The aim is to study, with the help of a numerical model, how a two-component aerosol (i.e. BC and sulfate) in an exhaust trail may be transformed in terms of hygroscopicity by coagulation mixing and how this may depend on the sulfur content in the fuel. (R.P.) 15 refs.

  12. Markedly enhanced direct radiative forcing of black carbon particles under polluted urban environments

    Science.gov (United States)

    Peng, Jianfei; Hu, Min; Guo, Song; Du, Zhuofei; Zheng, Jing; Shang, Dongjie; Zamora, Misti; Zeng, Liming; Shao, Min; Wu, Yusheng; Zheng, Jun; Wang, Yuan; Collins, Don; Zhang, Renyi

    2016-04-01

    Black carbon (BC) particles, produced from incomplete fossil fuel combustion and biomass burning, are ubiquitous in the atmosphere and have profound impacts on air quality, human health, weather, and climate. For example, in areas identified as aerosol hotspots, which include many urban centers and megacities worldwide, solar heating by BC particles has been shown to be comparable to warming due to the greenhouse gases2. Although BC represents a key short-lived climate forcer, its direct radiative forcing remains highly uncertain. In particular, the available results of absorption enhancement of BC particles during atmospheric aging are conflicting from the previous studies, leading to a large uncertainty in global radiative transfer calculation. Here, we quantified the aging and variation in the optical properties of BC particles under ambient conditions in Beijing, China and Houston, US, using a novel chamber approach. BC aging exhibits two distinct stages - initial transformation from a fractal to spherical morphology with little absorption variation and the subsequent growth of fully compact particles with a maximum absorption enhancement factor of 2.4. The variation in BC direct radiative forcing is highly dependent of the rate and timescale of aging, with an estimated increase of 0.45 (0.21 - 0.80) W m-2 from fresh to fully aged particles. Our results reveal a high climatic impact in polluted environments due to rapid aging and a clear distinction between urban cities in developed and developing countries for BC particles, highlighting a larger than recognized co-benefit in air quality improvement and climate protection by BC mediation.

  13. The identification of black carbon particles with the analytical scanning electron microscope. Methods and initial results

    Energy Technology Data Exchange (ETDEWEB)

    Stoffyn-Egli, P. [MicroChem, Geochemistry Consultants, East Jeddore, Nova Scotia (Canada); Potter, T.M.; Leonard, J.D.; Pocklington, R. [Department of Fisheries and Oceans, Bedford Institute of Oceanography, Dartmouth, Nova Scotia (Canada)

    1997-04-09

    Combustion of fossil fuel and vegetation produces large quantities of black carbon particles (BCP) which are dispersed by winds over large areas. Once deposited in the sediment, BCP constitute an historic record of anthropogenic activities and wildfires. For BCP to be significant environmental indicators, it is necessary to determine their source as precisely as possible. A method has been developed to differentiate BCP from other carbonaceous particles, and to assign them to coal, oil, or biomass combustion using a scanning electron microscope equipped with an elemental detector (Analytical Scanning Electron Microscope, ASEM). BCP were identified in the ASEM as particles with an O/C atomic ratio of less than 0.15. Morphology (shape and surface texture) and trace element content (S and Cl) were used to classify BCP according to source using samples of known origin (oil, coal and wood fly-ash) and marine sediment samples from Halifax Inlet, which has undergone progressive urbanisation and industrialization over the last 250 years. The method is applicable to a wide size range of BCP and complete isolation of the BCP from the rest of the sample is not necessary

  14. Black Carbon Particle Number Distribution Measurements during the ATHENS-2013 Winter Campaign

    Science.gov (United States)

    Gkatzelis, Georgios; Papanastasiou, Dimitris; Florou, Kalliopi; Kaltsonoudis, Christos; Louvaris, Eyaggelos; Bezentakos, Spiridon; Biskos, Georgios; Pandis, Spuros

    2014-05-01

    Black Carbon (BC) particles emitted by anthropogenic sources play an important role both in climate change and in air quality degradation. Open burning in forests and savannas, combustion of diesel and solid fuels for cooking and heating in homes represent the majority of BC emissions. Earlier work has focused on the BC atmospheric direct radiative forcing that is mostly related to its mass concentration and optical properties of the corresponding particles. A variety of measurement techniques are used to measure the mass concentration of BC by taking advantage of its optical or physical properties. Moreover, the carbonaceous particles containing BC are also important for the indirect forcing of climate. This effect is mostly related to the number concentration of BC particles. The number distribution of BC particles especially below 100 nm is quite uncertain due to limitations of the existing measurement techniques. In this work we employed a thermodenuder-based method as an approach for the measurement of the BC number distribution. More specifically, we combined a thermodenuder (TD) operating at temperatures up to 300 ° C, with a Scanning Mobility Particle Sizer (SMPS) and a High Resolution Time of Flight Aerosol Mass Spectrometer (HR-ToF AMS). Aerosol size and composition measurements were carried out both at ambient and at elevated TD temperatures in Athens field campaign during January and February of 2013. In parallel, a Multi-Angle Absorption Photometer (MAAP) provided information about the BC mass concentration while a Hygroscopic Tandem Differential Mobility Analyzer (HTDMA) measured the mixing state and the hygroscopicity of the particles as a function of their size. These measurements were then combined to estimate the number concentration of BC particles. Our analysis focused on different periods during the study. During some of them one source dominated the carbonaceous aerosol concentration. Such periods included rush hour traffic, nighttime wood

  15. On-bicycle exposure to particulate air pollution: Particle number, black carbon, PM2.5, and particle size

    Science.gov (United States)

    Hankey, Steve; Marshall, Julian D.

    2015-12-01

    Inhalation of air pollution during transport is an important exposure pathway, especially for certain modes of travel and types of particles. We measured concentrations of particulate air pollution (particle number [PN], black carbon [BC], fine particles [PM2.5], particle size) using a mobile, bicycle-based monitoring platform during morning and afternoon rush-hour to explore patterns of exposure while cycling (34 days between August 14 and October 16, 2012 in Minneapolis, MN). Measurements were geo-located at 1 ​s intervals along 3 prescribed monitoring routes totaling 85 h (1426 km) of monitoring. Mean morning [afternoon] on-road concentrations were 32,500 [16,600] pt cm-3, 2.5 [0.7] μg m-3 BC, 8.7 [8.3] μg m-3 PM2.5, and 42 [39] nm particle diameter. Concentrations were correlated with street functional class and declined within small distances from a major road (e.g., for PN and BC, mean concentration decreased ∼20% by moving 1 block away from major roads to adjacent local roads). We estimate the share of on-bicycle exposure attributable to near-traffic emissions (vs. regional pollution) is ∼50% for PN and BC; ∼25% for PM2.5. Regression models of instantaneous traffic volumes, derived from on-bicycle video recordings of nearby traffic, quantify the increase in particle-concentrations associated with each passing vehicle; for example, trucks were associated with acute, high concentration exposure events (average concentration-increase per truck: 31,000 pt cm-3, 1.0 μg m-3 PM2.5, 1.6 μg m-3 BC). Our findings could be used to inform design of low-exposure bicycle networks in urban areas.

  16. Near-edge X-ray absorption fine structure (NEXAFS) spectroscopy for mapping nano-scale distribution of organic carbon forms in soil: Application to black carbon particles

    Science.gov (United States)

    Lehmann, Johannes; Liang, Biqing; Solomon, Dawit; Lerotic, Mirna; LuizãO, Flavio; Kinyangi, James; SchäFer, Thorsten; Wirick, Sue; Jacobsen, Chris

    2005-03-01

    Small-scale heterogeneity of organic carbon (C) forms in soils is poorly quantified since appropriate analytical techniques were not available up to now. Specifically, tools for the identification of functional groups on the surface of micrometer-sized black C particles were not available up to now. Scanning Transmission X-ray Microscopy (STXM) using synchrotron radiation was used in conjunction with Near-Edge X-ray Absorption Fine Structure (NEXAFS) spectroscopy to investigate nano-scale distribution (50-nm resolution) of C forms in black C particles and compared to synchrotron-based FTIR spectroscopy. A new embedding technique was developed that did not build on a C-based embedding medium and did not pose the risk of heat damage to the sample. Elemental sulfur (S) was melted to 220°C until it polymerized and quenched with liquid N2 to obtain a very viscous plastic S in which the black C could be embedded until it hardened to a noncrystalline state and was ultrasectioned. Principal component and cluster analysis followed by singular value decomposition was able to resolve distinct areas in a black carbon particle. The core of the studied biomass-derived black C particles was highly aromatic even after thousands of years of exposure in soil and resembled the spectral characteristics of fresh charcoal. Surrounding this core and on the surface of the black C particle, however, much larger proportions of carboxylic and phenolic C forms were identified that were spatially and structurally distinct from the core of the particle. Cluster analysis provided evidence for both oxidation of the black C particle itself as well as adsorption of non-black C. NEXAFS spectroscopy has great potential to allow new insight into black C properties with important implications for biogeochemical cycles such as mineralization of black C in soils and sediments, and adsorption of C, nutrients, and pollutants as well as transport in the geosphere, hydrosphere, and atmosphere.

  17. Concentrations of fine, ultrafine, and black carbon particles in auto-rickshaws in New Delhi, India

    Science.gov (United States)

    Apte, Joshua, S.; Kirchstetter, Thomas W.; Reich, Alexander, H.; Deshpande, Shyam J.; Kaushik, Geetanjali; Chel, Arvind; Marshall, Julian D.; Nazaroff, William W.

    2011-08-01

    Concentrations of air pollutants from vehicles are elevated along roadways, indicating that human exposure in transportation microenvironments may not be adequately characterized by centrally located monitors. We report results from ˜180 h of real-time measurements of fine particle and black carbon mass concentration (PM 2.5, BC) and ultrafine particle number concentration (PN) inside a common vehicle, the auto-rickshaw, in New Delhi, India. Measured exposure concentrations are much higher in this study (geometric mean for ˜60 trip-averaged concentrations: 190 μg m -3 PM 2.5, 42 μg m -3 BC, 280 × 10 3 particles cm -3; GSD ˜1.3 for all three pollutants) than reported for transportation microenvironments in other megacities. In-vehicle concentrations exceeded simultaneously measured ambient levels by 1.5× for PM 2.5, 3.6× for BC, and 8.4× for PN. Short-duration peak concentrations (averaging time: 10 s), attributable to exhaust plumes of nearby vehicles, were greater than 300 μg m -3 for PM 2.5, 85 μg m -3 for BC, and 650 × 10 3 particles cm -3 for PN. The incremental increase of within-vehicle concentration above ambient levels—which we attribute to in- and near-roadway emission sources—accounted for 30%, 68% and 86% of time-averaged in-vehicle PM 2.5, BC and PN concentrations, respectively. Based on these results, we estimate that one's exposure during a daily commute by auto-rickshaw in Delhi is as least as large as full-day exposures experienced by urban residents of many high-income countries. This study illuminates an environmental health concern that may be common in many populous, low-income cities.

  18. Emissions of Black Carbon Particles from Biomass Burning and Their Physical and Chemical Properties

    Science.gov (United States)

    Kondo, Y.; Sahu, L.; Moteki, N.; Takegawa, N.; Zhao, Y.; Vay, S. A.; Diskin, G. S.; Wisthaler, A.; Huey, L. G.; Jimenez, J. L.

    2009-12-01

    Large amounts of aerosol, including black carbon (BC), are emitted from biomass burning. It is therefore important to understand the chemical composition, rate of emissions, and mixing state of aerosols generated by this combustion process to estimate the impacts of aerosols on climate. Thus far, these physical and chemical quantities have been compiled by combining the data from laboratory and field experiments, but the data from the Arctic region are still very limited. These parameters were measured by an SP2 instrument based on the laser-induced incandescence technique on board the NASA DC-8 during the ARCTAS campaign. Aircraft sampling was made in plumes emitted by wildfires in Canada and the USA, and in those transported over long distances from Russia. First, we extract biomass burning plumes using CH3CN and SO2 data. Then, we derived the slopes of the CO-CO2-CH3CN-aerosol correlations for each burning plume. Based on this, we derive the average CO/CO2, CH3CN/CO2, BC/CO2, and BC/CO ratios together with their variability in the plumes strongly influenced by forest fires over Siberia, California, and Canada. A similar analysis is made for light-scattering particles. Using these relationships, the transport efficiencies of BC particles from the boundary layer to the free troposphere are also estimated. It is found that the BC particles were thickly coated upon emission. From comparison with AMS measurements, the coating materials are found to be mainly composed of organic compounds. This indicates the importance of the enhanced light absorption by BC particles emitted by biomass burning.

  19. Optimized method for black carbon analysis in ice and snow using the Single Particle Soot Photometer

    Directory of Open Access Journals (Sweden)

    I. A. Wendl

    2014-03-01

    Full Text Available In this study we attempt to optimize the method for measuring black carbon (BC in snow and ice using a single particle soot photometer (SP2. Beside the previously applied ultrasonic (CETAC and Collison-type nebulizers we introduce a jet (APEX-Q nebulizer to aerosolize the aqueous sample for SP2 analysis. Both CETAC and APEX-Q require small sample volumes (few milliliters which makes them suitable for ice core analysis. The APEX-Q shows the least size-dependent nebulizing efficiency in the BC particle diameter range of 100–1000 nm. The CETAC has the advantage that air and liquid flows can be monitored continuously. All nebulizer-types require a calibration with BC standards for the determination of the BC mass concentration in unknown aqueous samples. We found Aquadag to be a suitable material for preparing calibration standards. Further, we studied the influence of different treatments for fresh discrete snow and ice samples as well as the effect of storage. The results show that samples are best kept frozen until analysis. Once melted, they should be sonicated for 25 min, immediately analyzed while being stirred and not be refrozen.

  20. Improvement of water/resin wettability of graphite using carbon black nano particles coating via ink media

    Energy Technology Data Exchange (ETDEWEB)

    Sharif, M., E-mail: Sharif_m@metaleng.iust.ac.i [Iran University of Science and Technology (Iran, Islamic Republic of); Golestani-Fard, F.; Sarpoolaky, H. [Iran University of Science and Technology (Iran, Islamic Republic of)

    2009-08-12

    Carbon coated graphite with high resin and water wettability characteristics could expand the refractory and carbon-carbon composites application in different fields. Improvement of water and resin wettability of graphite using carbon black coating via ink media is reported. Present method is based on preparing colloidal disperion of carbon black in ink followed by adding proper amount of graphite to the mixture which was dried and heat treated at 250 deg. C afterwards. The results showed that by controlling the amount of carbon black in ink and optimizing the process, a uniform coating with a thickness of 50 nm could be developed on the graphite surface. The wettability was evaluated by measuring contact angle and the microstructure of samples was characterized by optic microscope (OM) and scanning electron microscope (SEM). Also Raman spectroscopy was employed to support the results. The microstructure of coating was found to be uniform composed of carbon black nanoparticles. It was also demonstrated that the coating that could enhance the phenolic resin wettability was well. We also showed the coating could be applied on other ceramic particles such as MgO.

  1. Ambient black carbon particle hygroscopic properties controlled by mixing state and composition

    Directory of Open Access Journals (Sweden)

    D. Liu

    2012-11-01

    Full Text Available The wet removal of black carbon aerosol (BC in the atmosphere is a crucial factor in determining its atmospheric lifetime and thereby the vertical and horizontal distributions, dispersion on local and regional scales, and the direct, semi-direct and indirect radiative forcing effects. The in-cloud scavenging and wet deposition rate of freshly emitted hydrophobic BC will be increased on acquisition of more-hydrophilic components by coagulation or coating processes. The lifetime of BC is still subject to considerable uncertainty for most of the model inputs, which is largely due to the insufficient constraints on the BC hydrophobic-to-hydrophilic conversion process from observational field data. This study was conducted at a site along UK North Norfolk coastline, where the BC particles were transported from different regions within Western Europe. A hygroscopicity tandem differential mobility analyser (HTDMA was coupled with a single particle soot photometer (SP2 to measure the hygroscopic properties of BC particles and associated mixing state in real time. In addition, a Soot Particle AMS (SP-AMS measured the chemical compositions of additional material associated with BC particles. The ensemble of BC particles persistently contained a less-hygroscopic mode at a growth factor (gf of around 1.05 at 90% RH (dry diameter 163 nm. Importantly, a more-hygroscopic mode of BC particles was observed throughout the experiment, the gf of these BC particles extended up to ~1.4–1.6 with the minimum between this and the less hygroscopic mode at a gf ~1.25, or equivalent effective hygroscopicity parameter κ = ~0.1. The gf of BC particles (gfBC was highly influenced by the composition of associated soluble material: increases of gfBC were associated with secondary inorganic components, and these increases were more pronounced when ammonium nitrate was in the BC particles; however the presence of secondary organic matter suppressed the gf

  2. Collection efficiency of the Soot-Particle Aerosol Mass Spectrometer (SP-AMS for internally mixed particulate black carbon

    Directory of Open Access Journals (Sweden)

    M. D. Willis

    2014-05-01

    Full Text Available The soot-particle aerosol mass spectrometer (SP-AMS uses an intra-cavity infrared laser to vaporize refractory black carbon (rBC containing particles, making the particle beam–laser beam overlap critical in determining the collection efficiency (CE for rBC and associated non-refractory particulate matter (NR-PM. This work evaluates the ability of the SP-AMS to quantify rBC and NR-PM mass in internally mixed particles with different thicknesses of organic coating. Using apparent relative ionization efficiencies for uncoated and thickly coated rBC particles, we report measurements of SP-AMS sensitivity to NR-PM and rBC, for Regal Black, the recommended particulate calibration material. Beam width probe (BWP measurements are used to illustrate an increase in sensitivity for highly coated particles due to narrowing of the particle beam, which enhances the CE of the SP-AMS by increasing the laser beam–particle beam overlap. Assuming complete overlap for thick coatings, we estimate CE for bare Regal Black particles of 0.6 ± 0.1, which suggests that previously measured SP-AMS sensitivities to Regal Black were underestimated by up to a factor of two. The efficacy of the BWP measurements is highlighted by studies at a busy road in downtown Toronto and at a non-roadside location, which show particle beam widths similar to, but greater than that of bare Regal Black and coated Regal Black, respectively. Further BWP measurements at field locations will help to constrain the range of CE for fresh and aged rBC-containing particles. The ability of the SP-AMS to quantitatively assess the composition of internally mixed particles is validated through measurements of laboratory-generated organic coated particles, which demonstrate that the SP-AMS can quantify rBC and NR-PM over a wide range of particle compositions and rBC core sizes.

  3. Collection efficiency of the soot-particle aerosol mass spectrometer (SP-AMS for internally mixed particulate black carbon

    Directory of Open Access Journals (Sweden)

    M. D. Willis

    2014-12-01

    Full Text Available The soot-particle aerosol mass spectrometer (SP-AMS uses an intra-cavity infrared laser to vaporize refractory black carbon (rBC containing particles, making the particle beam–laser beam overlap critical in determining the collection efficiency (CE for rBC and associated non-refractory particulate matter (NR-PM. This work evaluates the ability of the SP-AMS to quantify rBC and NR-PM mass in internally mixed particles with different thicknesses of organic coating. Using apparent relative ionization efficiencies for uncoated and thickly coated rBC particles, we report measurements of SP-AMS sensitivity to NR-PM and rBC, for Regal Black, the recommended particulate calibration material. Beam width probe (BWP measurements are used to illustrate an increase in sensitivity for highly coated particles due to narrowing of the particle beam, which enhances the CE of the SP-AMS by increasing the laser beam–particle beam overlap. Assuming complete overlap for thick coatings, we estimate CE for bare Regal Black particles of 0.6 ± 0.1, which suggests that previously measured SP-AMS sensitivities to Regal Black were underestimated by up to a factor of 2. The efficacy of the BWP measurements is highlighted by studies at a busy road in downtown Toronto and at a non-roadside location, which show particle beam widths similar to, but greater than that of bare Regal Black and coated Regal Black, respectively. Further BWP measurements at field locations will help to constrain the range of CE for fresh and aged rBC-containing particles. The ability of the SP-AMS to quantitatively assess the composition of internally mixed particles is validated through measurements of laboratory-generated organic coated particles, which demonstrate that the SP-AMS can quantify rBC and NR-PM over a wide range of particle compositions and rBC core sizes.

  4. Exposure to ultrafine particles and black carbon in diesel-powered commuter trains

    Science.gov (United States)

    Jeong, Cheol-Heon; Traub, Alison; Evans, Greg J.

    2017-04-01

    Ultrafine particle (UFP), black carbon (BC) and lung deposited surface area (LDSA) concentrations measured during 43 trips on diesel-powered commuter trains revealed elevated exposures under some conditions. When the passenger coaches were pulled by a locomotive, the geometric mean concentrations of UFP, LDSA, and BC were 18, 10, and 6 times higher than the exposure levels when the locomotive pushed the coaches, respectively. In addition, UFP, LDSA, and BC concentrations in pull-trains were 5, 3, and 4 times higher than concentrations measured while walking on city sidewalks, respectively. Exposure to these pollutants was most elevated in the coach located closest to the locomotive: geometric means were 126,000 # cm-3 for UFP, 249 μm2 cm-3 for LDSA, and 17,800 ng m-3 of BC; these concentrations are much higher than those previously reported for other modes of public transportation. Markedly high levels of diesel exhaust are present in passenger trains powered by diesel locomotives operated in pull-mode. Thus, it is recommended that immediate steps be taken to evaluate, and where needed, mitigate exposure in diesel-powered passenger trains, both commuter and inter-city.

  5. Sensitivity of the Single Particle Soot Photometer to different black carbon types

    Directory of Open Access Journals (Sweden)

    M. Laborde

    2012-05-01

    Full Text Available Black carbon (BC is now mainly of anthropogenic origin. It is the dominant light absorbing component of atmospheric aerosols, playing an important role in the earth's radiative balance and therefore relevant to climate change studies. In addition, BC is known to be harmful to human beings making it relevant to policy makers. Nevertheless, the measurement of BC remains biased by the instrument-based definition of BC. The Single Particle Soot Photometer (SP2, allows the measurement of the refractory BC (rBC mass of individual particles using laser-induced incandescence. However, the SP2 needs an empirical calibration to retrieve the rBC mass from the incandescence signal and the sensitivity of the SP2 differs between different BC types. Ideally, for atmospheric studies, the SP2 should be calibrated using ambient particles containing a known mass of ambient rBC. However, such "ambient BC" calibration particles cannot easily be obtained and thus commercially available BC particles are commonly used for SP2 calibration instead. In this study we tested the sensitivity of the SP2 to different BC types in order to characterize the potential error introduced by using non-ambient BC for calibration. The sensitivity of the SP2 was determined, using an aerosol particle mass analyzer, for rBC from thermodenuded diesel exhaust, wood burning exhaust and ambient particles as well as for commercially available products: Aquadag® and fullerene soot.

    Thermodenuded, fresh diesel exhaust has been found to be ideal for SP2 calibration for two reasons. First, the small amount of non-BC matter upon emission reduces the risk of bias due to incomplete removal of non-BC matter and second, it is considered to represent atmospheric rBC in urban locations where diesel exhaust is the main source of BC. The SP2 was found to be up to 16% less sensitive to rBC from thermodenuded ambient particles (≤15 fg than rBC from diesel exhaust, however, at least part

  6. Sensitivity of the Single Particle Soot Photometer to different black carbon types

    Directory of Open Access Journals (Sweden)

    M. Laborde

    2012-01-01

    Full Text Available Black carbon (BC is nowadays mainly of anthropogenic origin. It is the dominant light absorbing component of atmospheric aerosols, playing an important role in the earth's radiative balance and therefore relevant to climate change studies. In addition, BC is known to be harmful to humans making it relevant to policy makers. Nevertheless, the measurement of BC remains biased by the instrument-based definition of BC. The Single Particle Soot Photometer (SP2, allows the measurement of the refractory BC (rBC mass of individual particle using laser-induced incandescence. However the SP2 needs an empirical calibration to retrieve the rBC mass from the incandescence signal and the sensitivity of the SP2 differs between different BC types. Ideally, for atmospheric studies, the SP2 should be calibrated using ambient particles containing a known mass of ambient rBC. However, such "ambient BC" calibration particles cannot easily be obtained and thus commercially available BC particles are commonly used for SP2 calibration instead. In this study we tested the sensitivity of the SP2 to different BC types in order to characterize the potential error introduced by using non-ambient BC for calibration. The sensitivity of the SP2 was determined for rBC from thermodenuded diesel exhaust, wood burning exhaust and ambient particles as well as for commercially available products: Aquadag® and fullerene soot.

    Thermodenuded, fresh diesel exhaust has been found to be ideal for SP2 calibration for two reasons. First, the small amount of non-BC matter upon emission reduces the risk of bias due to incomplete removal of non-BC matter and second, it is considered to represent atmospheric rBC as diesel exhaust is the main source of BC in most locations. The SP2 was found to be up to 16% less sensitive to rBC from thermodenuded ambient particles (≤15 fg than rBC from diesel exhaust, however, at least part of this difference can be explained by

  7. Measurement of Black Carbon and Particle Number Emission Factors from Individual Heavy-Duty Trucks

    Energy Technology Data Exchange (ETDEWEB)

    Ban-Weiss, George A.; Lunden, Melissa M.; Kirchstetter, Thomas W.; Harley, Robert A.

    2009-02-02

    Emission factors for black carbon (BC) and particle number (PN) were measured from 226 individual heavy-duty (HD) diesel-fueled trucks driving through a 1 km-long California highway tunnel in August 2006. Emission factors were based on concurrent increases in BC, PN, and CO{sub 2}B concentrations (measured at 1 Hz) that corresponded to the passage of individual HD trucks. The distributions of BC and PN emission factors from individual HD trucks are skewed, meaning that a large fraction of pollution comes from a small fraction of the in-use vehicle fleet. The highest-emitting 10% of trucks were responsible for {approx} 40% of total BC and PN emissions from all HD trucks. BC emissions were log-normally distributed with a mean emission factor of 1.7 g kg {sup -1} and maximum values of {approx} 10 g kg{sup -1}. Corresponding values for PN emission factors were 4.7 x 10{sup 15} and 4 x 10{sup 16} kg{sup -1}. There was minimal overlap among high-emitters of these two pollutants: only 1 of the 226 HD trucks measured was found to be among the highest 10% for both BC and PN. Monte Carlo resampling of the distribution of BC emission factors observed in this study revealed that uncertainties (1{sigma}) in extrapolating from a random sample of n HD trucks to a population mean emission factor ranged from {+-} 43% for n = 10 to {+-} 8% for n = 300, illustrating the importance of sufficiently large vehicle sample sizes in emissions studies. Studies with low sample sizes are also more easily biased due to misrepresentation of high-emitters. As vehicles become cleaner on average in future years, skewness of the emissions distributions will increase, and thus sample sizes needed to extrapolate reliably from a subset of vehicles to the entire in-use vehicle fleet are expected to become more of a challenge.

  8. Arctic Black Carbon Loading and Profile Using the Single-Particle Soot Photometer (SP2) Field Campaign Report

    Energy Technology Data Exchange (ETDEWEB)

    Sedlacek, Arthur J [Brookhaven National Lab. (BNL), Upton, NY (United States)

    2016-05-01

    One of the major issues confronting aerosol climate simulations of the Arctic and Antarctic cryospheres is the lack of detailed data on the vertical and spatial distribution of aerosols with which to test these models. This is due, in part, to the inherent difficulty of conducting such measurements in extreme environments. However given the pronounced sensitivity of the polar regions to radiative balance perturbations, it is incumbent upon our community to better understand and quantify these perturbations, and their unique feedbacks, so that robust model predictions of this region can be realized. One class of under-measured radiative forcing agents in the polar region is the absorbing aerosol—black carbon and brown carbon. Black carbon (BC; also referred to as light-absorbing carbon [LAC], refractory black carbon [rBC], and soot) is second only to CO2 as a positive forcing agent. Roughly 60% of BC emissions can be attributed to anthropogenic sources (fossil fuel combustion and open-pit cooking), with the remaining fraction being due to biomass burning. Brown carbon (BrC), a major component of biomass burning, collectively refers to non-BC carbonaceous aerosols that typically possess minimal light absorption at visible wavelengths but exhibit pronounced light absorption in the near-ultraviolet (UV) spectrum. Both species can be sourced locally or be remotely transported to the Arctic region and are expected to perturb the radiative balance. The work conducted in this field campaign addresses one of the more glaring deficiencies currently limiting improved quantification of the impact of BC radiative forcing in the cryosphere: the paucity of data on the vertical and spatial distributions of BC. By expanding the Gulfstream aircraft (G-1) payload for the U.S. Department of Energy (DOE) Atmospheric Radiation Measurement (ARM) Climate Research Facility-sponsored ACME-V campaign to include the Single-Particle Soot Photometer (SP2)) and leveraging the ACME-V campaign

  9. The Study on the Conductivity Performance and Shielding Effectiveness of Electro-magnetic Radiation of Polyethylene Film with Different Content of Carbon Black Particles

    Institute of Scientific and Technical Information of China (English)

    SUN Run-jun; LAI Kan; ZHANG Jian-chun; HUO Yan

    2004-01-01

    With the help of the testing apparatus made by ourselves for shielding electromagnetic radiation, the electric conductivity and shielding effectiveness of electromagnetic radiation of polyethylene film contained different content of carbon particles was systematically studied in this paper. The results indicate that the electric conductivity and shielding effectiveness of electromagnetic radiation of polyethylene /carbon film have closely relations with content of carbon black particles, which exists a critical content value as 14%~30% and its properties will have a tremendous change.

  10. Impact of Combustion Efficiency of Open Biomass Burning on the Mixing State of Black Carbon Containing Particles

    Science.gov (United States)

    PAN, X.; Kanaya, Y.; Taketani, F.; Miyakawa, T.; Inomata, S.; Komazaki, Y.; Tanimoto, H.; Uno, I.; Wang, Z.

    2014-12-01

    Open biomass burning (OBB) experiments were performed in the laboratory environment to investigate the mixing state of refractory black carbon (rBC) in fresh smoke and its dependence on combustion state. A Single-Particle Soot Photometer (SP2) was adopted to measure variation of number size distribution of rBC-containing particles in high temporal resolution. General combustion state of each OBB case was indicated by modified combustion efficiency (MCE) using accumulated enhancement of mixing ratios of carbon dioxide and carbon monoxide during the experiments. We found that mass equivalent diameter (MED) of rBC increased apparently with increase of MCE values, indicating the flaming-dominant combustion tend to produce the rBC particles with relative larger size, probably because of coagulation processes in high concentration condition. Coating thickness of rBC-containing particle was calculated by leading edge only fitting (LEO-fitting) method. In the present study we defined the rBC-containing particles with shell/core (S/C) ratio larger than 2 as "thickly coated" and that less then 1.5 as "thinly coated". As a result, thickly coated rBC particles normally had a relatively small core (MED of rBC less than 150 nm) and its number fraction showed an evident decrease as a function of MCE value, whereas, larger rBC particles (MED larger than 150 nm) were normally thinly coated. Number fraction of both thinly coated and uncoated rBC particles had an positive correlation with MCE value. Substantial amount of light scattering particles (LSP) observed in the smoldering-dominant OBB plumes could partially explain the increase of number fraction of coated rBC particles. ∆rBC/∆CO ratio showed a good positive correlation with MCE with an average value of 16.8 (1.2 - 51.6) ng/m3/ppbv, and ∆rBC/∆CO2 ratio was found 628.7 ng/m3/ppmv, generally consistent with previous studies.

  11. Effect of the secondary organic aerosol coatings on black carbon water uptake, cloud condensation nuclei activity, and particle collapse

    Science.gov (United States)

    The ability of black carbon aerosols to absorb water and act as a cloud condensation nuclei (CCN) directly controls their lifetime in the atmosphere as well as their impact on cloud formation, thus impacting the earth’s climate. Black carbon emitted from most combustion pro...

  12. Observational and laboratory studies of optical properties of black and brown carbon particles in the atmosphere using spectroscopic techniques

    Science.gov (United States)

    Nakayama, Tomoki; Matsumi, Yutaka

    2015-04-01

    Light absorption and scattering by aerosols are as an important contributor to radiation balance in the atmosphere. Black carbon (BC) is considered to be the most potent light absorbing material in the visible region of the spectrum, although light absorbing organic carbon (brown carbon or BrC) and mineral dust may also act as sources of significant absorption, especially in the ultraviolet (UV) and shorter visible wavelength regions. The optical properties of such particles depend on wavelength, particle size and shape, morphology, coating, and complex refractive index (or chemical composition), and therefore accurate in situ measurements of the wavelength dependence of the optical properties of particles are needed. Recently, cavity ring-down spectroscopy (CRDS) and photoacoustic spectroscopy (PAS) have been used for the direct measurements of extinction and absorption coefficients of particles suspended in air. We have applied these techniques to the observational studies of optical properties of BC and BrC in an urban site in Japan and to the laboratory studies of optical properties of secondary organic aerosols (SOAs) generated from a variety of biogenic and anthropogenic volatile organic compounds and those of diesel exhaust particles (DEPs). In the presentation, the basic principles of these techniques and the results obtained in our studies and in the recent literatures will be overviewed. References Guo, X. et al., Measurement of the light absorbing properties of diesel exhaust particles using a three-wavelength photoacoustic spectrometer, Atmos. Environ., 94, 428-437 (2014). Nakayama, T. et al., Measurements of aerosol optical properties in central Tokyo during summertime using cavity ring-down spectroscopy: Comparison with conventional techniques, Atmos. Environ., 44, 3034-3042 (2010). Nakayama, T. et al., Laboratory studies on optical properties of secondary organic aerosols generated during the photooxidation of toluene and the ozonolysis of alpha

  13. Admix Compatibility in Carbon Black Loaded Toners

    Institute of Scientific and Technical Information of China (English)

    Paul C. Julien

    2004-01-01

    In a xerographic system where the charge on the toner is controlled by the electrical nature of the carbon black used as a pigment, it is found that the speed with which added toner is charged to the proper level depends on the relative electrical negativity of the carbon black in the original and added toner. This is due to the fact that the incumbent toner typically shares its charge with the new toner through charge exchange among the conductive carbon black particles. If the carbon blacks are electrically dissimilar, this charge sharing may fail.Thus, a toner may work well by itself in a machine, but the same toner may fail when added to a machine already running with a toner from a different vendor or even a different lot of toner from the same vendor. Thus the electrical nature of the carbon black needs to be controlled. This can be done by controlling the oxidation of the carbon black.

  14. Effect of aggregation, morphology and mixing state on optical properties of bare and internally mixed Black Carbon particles

    Science.gov (United States)

    Scarnato, Barbara; China, Swarup; Mazzoleni, Claudio

    2014-05-01

    Black carbon (BC) is a small, dark particle that warms Earth's climate. BC is a distinct type of carbonaceous aerosol particle, product of combustion of fossil and biomass fuels. Upon emission into the atmosphere, BC internally mixes with other aerosol compounds. According to recent studies, internal mixing of BC with other aerosol materials in the atmosphere alters its aggregate shape, absorption of solar radiation, and radiative forcing. These mixing state effects are not yet fully understood. Laboratory and field studies have identified a strong variability in the observed absorption efficiencies of internally mixed BC. Additionally, there is a discrepancy between modeled and measured values using traditional modeling approaches. This talk will investigate the central role of parameterization of light interaction by BC particles in the assessment of its radiative forcing and present a sensitivity study of the effect of aggregation, morphology and mixing state on optical properties of bare and internally mixed BC with mineral dust, ammonium sulfate, sodium chloride and others. Optical properties of the different mixtures, sampled both in field campaigns and laboratory environment, are computed using Discrete Dipole Approximation model in accordance with BC aggregation, morphology and mixing observed at microscopes. The results of this work are relevant for several applications in atmospheric science, including but not limited to radiative transfer calculations, regional and global climate modeling and, the interpretation of remote sensing measurements.

  15. Size-resolved observations of refractory black carbon particles in cloud droplets at a marine boundary layer site

    Directory of Open Access Journals (Sweden)

    J. C. Schroder

    2014-05-01

    Full Text Available Size resolved observations of aerosol particles (including black carbon particles and cloud residuals were studied at a marine boundary layer site (251 m a.m.s.l. in La Jolla, CA during 2012. A counterflow virtual impactor was used to sample cloud residuals while a total inlet was used to sample both cloud residuals and interstitial particles. Two cloud events totaling ten hours of in-cloud sampling were analyzed. Since the CVI only sampled cloud droplets larger than ≈11 μm, less than 100% of the cloud droplets were sampled during the two cloud events (≈38% of the cloud droplets for the first cloud event and ≈24% of the cloud droplets for the second cloud were sampled. Back trajectories showed that air masses for both cloud events spent at least 96 h over the Pacific Ocean and traveled near, or over populated regions just before sampling. Based on bulk aerosol particle concentrations measured from the total inlet the two air masses sampled were classified as polluted marine air, a classification that was consistent with back trajectory analysis and the mass concentrations of refractory black carbon (rBC measured from the total inlet. The activated fraction of rBC, estimated from the measurements, ranged from 0.01 to 0.1 for core diameters ranging from 70 to 220 nm. Since the fraction of cloud droplets sampled by the CVI was less than 100%, the measured activated fractions of rBC should be considered as lower limits to the total fraction of rBC activated during the two cloud events. Size distributions of rBC sampled from the residual inlet show that sub-100 nm rBC cores were incorporated into the droplets in both clouds. The coating analysis shows that the rBC cores had average coating thicknesses of 75 nm for core diameters of 70 nm and 29 nm for core diameters of 220 nm. The presence of sub-100 nm rBC cores in the cloud residuals is consistent with kappa-Köhler theory and the measured coating thicknesses of the rBC cores.

  16. Source apportionment of wide range particle size spectra and black carbon collected at the airport of Venice (Italy)

    Science.gov (United States)

    Masiol, Mauro; Vu, Tuan V.; Beddows, David C. S.; Harrison, Roy M.

    2016-08-01

    Atmospheric particles are of high concern due to their toxic properties and effects on climate, and large airports are known as significant sources of particles. This study investigates the contribution of the Airport of Venice (Italy) to black carbon (BC), total particle number concentrations (PNC) and particle number size distributions (PNSD) over a large range (14 nm-20 μm). Continuous measurements were conducted between April and June 2014 at a site located 110 m from the main taxiway and 300 m from the runway. Results revealed no significantly elevated levels of BC and PNC, but exhibited characteristic diurnal profiles. PNSD were then analysed using both k-means cluster analysis and positive matrix factorization. Five clusters were extracted and identified as midday nucleation events, road traffic, aircraft, airport and nighttime pollution. Six factors were apportioned and identified as probable sources according to the size profiles, directional association, diurnal variation, road and airport traffic volumes and their relationships to micrometeorology and common air pollutants. Photochemical nucleation accounted for ∼44% of total number, followed by road + shipping traffic (26%). Airport-related emissions accounted for ∼20% of total PNC and showed a main mode at 80 nm and a second mode beyond the lower limit of the SMPS (pollution and local resuspension. An analysis of BC levels over different wind sectors revealed no especially significant contributions from specific directions associated with the main local sources, but a potentially significant role of diurnal dynamics of the mixing layer on BC levels. The approaches adopted in this study have identified and apportioned the main sources of particles and BC at an international airport located in area affected by a complex emission scenario. The results may underpin measures for improving local and regional air quality, and health impact assessment studies.

  17. Effects of Particle Filters and Accelerated Engine Replacement on Heavy-Duty Diesel Vehicle Emissions of Black Carbon, Nitrogen Oxides, and Ultrafine Particles

    Science.gov (United States)

    Kirchstetter, T.; Preble, C.; Dallmann, T. R.; DeMartini, S. J.; Tang, N. W.; Kreisberg, N. M.; Hering, S. V.; Harley, R. A.

    2013-12-01

    Diesel particle filters have become widely used in the United States since the introduction in 2007 of a more stringent exhaust particulate matter emission standard for new heavy-duty diesel vehicle engines. California has instituted additional regulations requiring retrofit or replacement of older in-use engines to accelerate emission reductions and air quality improvements. This presentation summarizes pollutant emission changes measured over several field campaigns at the Port of Oakland in the San Francisco Bay Area associated with diesel particulate filter use and accelerated modernization of the heavy-duty truck fleet. Pollutants in the exhaust plumes of hundreds of heavy-duty trucks en route to the Port were measured in 2009, 2010, 2011, and 2013. Ultrafine particle number, black carbon (BC), nitrogen oxides (NOx), and nitrogen dioxide (NO2) concentrations were measured at a frequency ≤ 1 Hz and normalized to measured carbon dioxide concentrations to quantify fuel-based emission factors (grams of pollutant emitted per kilogram of diesel consumed). The size distribution of particles in truck exhaust plumes was also measured at 1 Hz. In the two most recent campaigns, emissions were linked on a truck-by-truck basis to installed emission control equipment via the matching of transcribed license plates to a Port truck database. Accelerated replacement of older engines with newer engines and retrofit of trucks with diesel particle filters reduced fleet-average emissions of BC and NOx. Preliminary results from the two most recent field campaigns indicate that trucks without diesel particle filters emit 4 times more BC than filter-equipped trucks. Diesel particle filters increase emissions of NO2, however, and filter-equipped trucks have NO2/NOx ratios that are 4 to 7 times greater than trucks without filters. Preliminary findings related to particle size distribution indicate that (a) most trucks emitted particles characterized by a single mode of approximately

  18. Partitioning of Black Carbon between ultrafine and fine particle modes in an urban airport vs. urban background environment

    Science.gov (United States)

    Costabile, F.; Angelini, F.; Barnaba, F.; Gobbi, G. P.

    2015-02-01

    In this work, we characterize the Black Carbon (BC) aerosol in an urban airport vs. urban background environment with the objective to evaluate when and how the ultrafine BC dominates the bulk aerosol. Aerosol optical and microphysical properties were measured in a Mediterranean urban area (Rome) at sites impacted by BC sources including fossil fuels (FF), and biomass burning (BB). Experimental BC data were interpreted through measurement-constrained simulations of BC microphysics and optical properties. A "scheme" to separate the ultrafine BC was experimented on the basis of the relation found between changes in the BC partitioning between Aitken and accumulation mode particles, and relevant changes in particle size distribution and optical properties of the bulk aerosol. This separation scheme, applied to experimental data, proved useful to reveal the impact of airport and road traffic emissions. Findings may have important atmospheric implications. The experimented scheme can help separating different BC sources (FF, BB, "aged" BC) when BC size distributions may be very difficult to obtain (satellite, columnar observations, routine monitoring). Indeed, separating the ultrafine BC from the fine BC may provide significant benefits in addressing BC impact on air quality and climate.

  19. Variability of levels of PM, black carbon and particle number concentration in selected European cities

    Directory of Open Access Journals (Sweden)

    C. Reche

    2011-03-01

    Full Text Available In many large cities of Europe standard air quality limit values of particulate matter (PM are exceeded. Emissions from road traffic and biomass burning are frequently reported to be the major causes. As a consequence of these exceedances a large number of air quality plans, most of them focusing on traffic emissions reductions, have been implemented in the last decade. In spite of this implementation, a number of cities did not record a decrease of PM levels. Thus, is the efficiency of air quality plans overestimated? Or do we need a more specific metric to evaluate the impact of the above emissions on the levels of urban aerosols?

    This study shows the results of the interpretation of the 2009 variability of levels of PM, black carbon (BC, aerosol number concentration (N and a number of gaseous pollutants in seven selected urban areas covering road traffic, urban background, urban-industrial, and urban-shipping environments from southern, central and northern Europe.

    The results showed that variations of PM and N levels do not always reflect the variation of the impact of road traffic emissions on urban aerosols. However, BC levels vary proportionally with those of traffic related gaseous pollutants, such as CO, NO2 and NO. Due to this high correlation, one may suppose that monitoring the levels of these gaseous pollutants would be enough to extrapolate exposure to traffic-derived BC levels. However, the BC/CO, BC/NO2 and BC/NO ratios vary widely among the cities studied, as a function of distance to traffic emissions, vehicle fleet composition and the influence of other emission sources such as biomass burning. Thus, levels of BC should be measured at air quality monitoring sites.

    During traffic rush hours, a narrow variation in the N/BC ratio was evidenced, but a wide variation of this ratio was determined for the noon period. Although in central and northern Europe N and BC levels tend to vary

  20. Measurements of the impact of atmospheric aging on physical and optical properties of ambient black carbon particles in Los Angeles

    Science.gov (United States)

    Krasowsky, Trevor S.; McMeeking, Gavin R.; Wang, Dongbin; Sioutas, Constantinos; Ban-Weiss, George A.

    2016-10-01

    Understanding how physical and optical properties of atmospheric black carbon (BC) particles vary in time and space is critical for reducing uncertainty in climate forcing estimates from ambient BC. In this study, ambient BC was measured in Rubidoux, California, approximately 90 km (55 miles) downwind of downtown Los Angeles. Collocated NOx and NOy measurements were used to estimate the photochemical age of the sampled air. Sampling was conducted throughout entire days between February 3, 2015 and March 12, 2015 to capture diurnal and daily variations in ambient BC. Both ambient and thermally-denuded air was sampled in 15-min cycles to compare the physical and optical properties of coated versus uncoated BC particles. Physical properties of individual BC particles including mass and coating thickness were measured using a Single-Particle Soot Photometer (SP2), and BC optical properties were measured using a Photoacoustic Extinctiometer (PAX) at 870 nm. The mean BC mass concentration (±standard deviation) for the campaign was 0.12 ± 0.08 μg m-3. BC mass concentrations were higher on weekdays than weekends, though only differences between 11:00 and 17:00 h were statistically distinguishable. The fraction of total BC particles that were thickly-coated (f) was found to be relatively low, with a mean of 0.05 ± 0.02 over the campaign. Values for f peaked in the afternoon when photochemical pollutant concentrations are also generally at a maximum. Further, f at 15:00-16:00 h was found to be statistically higher on weekends than weekdays, potentially due to a higher relative amount of ambient SOA to BC on weekends versus weekdays, which would enhance SOA coating of primary BC particles as they age during transport from the western Los Angeles basin to our sampling site on weekends. Differences at other hours during the photochemically active period of the day (10:00-14:00 h) were not statistically different although the weekend values were systematically higher

  1. Black carbon: The reverse of its dark side

    NARCIS (Netherlands)

    Koelmans, A.A.; Jonker, M.T.O.; Cornelissen, G.; Bucheli, T.D.; Noort, van P.C.M.; Gustafsson, O.

    2006-01-01

    The emission of black carbon is known to cause major environmental problems. Black carbon particles contribute to global warming, carry carcinogenic compounds and cause serious health risks. Here, we show another side of the coin. We review evidence that black carbon may strongly reduce the risk pos

  2. Influence of Ingredients of Carbon Black Nano-Particle Suspension of Ammonia Solution on Viscosity of Nanofluid

    Institute of Scientific and Technical Information of China (English)

    CHENG Bo; DU Kai; ZHANG Xiao-song; YANG Liu

    2009-01-01

    A series of experiments were performed on the viscosity of a nanofluid,produced by mixing car-bon black and mulsifier OP-10 using ammonia-water with the ultrasonic dispersion.The results show that,when adding surfactant separately in low mass concentrations,at first the viscosity of solution decreases sharply compared with that of ammonia-water.then increases with increasing the concentration of OP-IO.In a certain concentration of surfactant,the viscosity of nanofluids increases with increasing the concentration of nanoparti·des.Based on Einstein model and Langrnuir absorption theory,a new model啪s summed up for nanoflukls.Compared with test values,the calcuhted values on the new model have verified that the model is suitable to predict the viscosity of rmnofluids.beoll.k.the maximum relative error is less than 5%.Nano-particles absorp-tion in the nanofluids is not only single-molecule layer adsorption,but aLso multi-layer molecular adsorption and other complicated adsorption.So the new model,ordy based on single-molecule layer adsorption theory of Lang-muir.is not fully in line with the real circumstances.

  3. INVESTIGATION OF MICROSTRUCTURE AND CONDUCTIVE MECHANISM OF HIGH DENSITY POLYETHYLENE/CARBON BLACK PARTICLE COMPOSITE BY POSITRON ANNIHILATION LIFETIME SPECTROSCOPY

    Institute of Scientific and Technical Information of China (English)

    Yang-mei Fan; Xian-fenga Zhang; Bang-jiao Ye; Xian-yi Zhou; Hui-min Weng; Jiang-feng Du; Rong-dian Han; Shao-jin Jia; Zhi-cheng Zhang

    2002-01-01

    The microstmcture and conductive mechanism of high density polyethylene/carbon black (HDPE/CB) composite were investigated by positron annihilation lifetime spectroscopy (PALS). The PALS were measured in two series of samples,one with various CB contents in the composites and the other with various γ-irradiation doses in HDPE/CB composite containing 20 wt% CB. It was found that CB particles distribute in the amorphous regions, the CB critical content value in HDPE/CB composite is about 16.7 wt% and the suitable γ-irradiation dose for improving the conductive behavior of HDPE/CB composite is about 20 Mrad. The result observed for the second set of samples suggests that γ-irradiation causes not only cross-linking in amorphous regions but also destruction of the partial crystalline structure. Therefore, a suitable irradiation dose, about 20 Mrad, can induce sufficient cross-linking in the amorphous regions without enhancing the decomposition of crystalline structure, so that the positive temperature coefficient (PTC) effect remains while the negative temperature coefficient (NTC) effect is suppressed. A new interpretation of the conductive mechanism, which might provide a more detailed explanation of the PTC effect and the NTC effect has been proposed.

  4. PAH, BTEX, carbonyl compound, black-carbon, NO2 and ultrafine particle dynamometer bench emissions for Euro 4 and Euro 5 diesel and gasoline passenger cars

    Science.gov (United States)

    Louis, Cédric; Liu, Yao; Tassel, Patrick; Perret, Pascal; Chaumond, Agnès; André, Michel

    2016-09-01

    Although implementing Diesel particulate filters (DPF) and other novel aftertreatment technologies makes it possible to achieve significant reductions in particle mass emissions, it may induce the release of ultrafine particles and emissions of many other unregulated compounds. This paper focuses on (i) ultrafine particles, black carbon, BTEX, PAH, carbonyl compounds, and NO2 emissions from Euro 4 and Euro 5 Diesel and gasoline passenger cars, (ii) the influence of driving conditions (e.g., cold start, urban, rural and motorway conditions), and (iii) the impact of additive and catalysed DPF devices on vehicle emissions. Chassis dynamometer tests were conducted on four Euro 5 vehicles and two Euro 4 vehicles: gasoline vehicles with and without direct injection system and Diesel vehicles equipped with additive and catalysed particulate filters. The results showed that compared to hot-start cycles, cold-start urban cycles increased all pollutant emissions by a factor of two. The sole exception was NO2, which was reduced by a factor of 1.3-6. Particulate and black carbon emissions from the gasoline engines were significantly higher than those from the Diesel engines equipped with DPF. Moreover, the catalysed DPF emitted about 3-10 times more carbonyl compounds and particles than additive DPF, respectively, during urban driving cycles, while the additive DPF vehicles emitted 2 and 5 times more BTEX and carbonyl compounds during motorway driving cycles. Regarding particle number distribution, the motorway driving cycle induced the emission of particles smaller in diameter (mode at 15 nm) than the urban cold-start cycle (mode at 80-100 nm). The results showed a clear positive correlation between particle, black carbon, and BTEX emissions, and a negative correlation between particles and NO2.

  5. Black carbon aerosol characterization in a coastal city in South China using a single particle soot photometer

    Science.gov (United States)

    Huang, Xiao-Feng; Sun, Tian-Le; Zeng, Li-Wu; Yu, Guang-He; Luan, Sheng-Ji

    2012-05-01

    Black carbon (BC) is the dominant light-absorbing aerosol component in the atmosphere and plays an important role in atmospheric pollution and climate change. The light-absorbing properties of BC rely on particle size, shape, composition, as well as the BC mixing state with other aerosol components, thus more thorough exploration of BC aerosol characteristics is critical in understanding its atmospheric sources and effects. In this study, a newly-developed Single Particle Soot Photometer (SP2) was deployed in Shenzhen, China, for continuous BC measurements to obtain the important information about size distribution and mixing state of BC under severe air pollution conditions of China. The mean BC mass concentrations were found to be 6.0 and 4.1 μg m-3 at an urban site (UT) in the fall and winter, respectively, while it is much lower (2.6 μg m-3) at a rural site (BG) in the fall. The mass size distributions of BC in volume equivalent diameter (VED) at the three sites showed a similar lognormal pattern, with the peak diameter at BG (222 nm) slightly larger than at the UT (210 nm) site. As to mixing state, the average percentage of internally mixed BC at the UT site was detected to be 40% and 46% in the fall and winter, respectively, while that at the BG site in the fall was only a slightly higher (47%), which implies that fresh local fossil fuel combustions were still significant at this rural site. The analysis of extremely high BC concentrations (>20 μg m-3) at UT indicates that they were a complex of comparable contributions from both local fresh emissions and regional transport under unfavorable meteorology. Other characteristics of BC aerosol and their influencing factors in Shenzhen were also discussed.

  6. Lack of acute phase response in the livers of mice exposed to diesel exhaust particles or carbon black by inhalation

    Directory of Open Access Journals (Sweden)

    Williams Andrew

    2009-04-01

    Full Text Available Abstract Background Epidemiologic and animal studies have shown that particulate air pollution is associated with increased risk of lung and cardiovascular diseases. Although the exact mechanisms by which particles induce cardiovascular diseases are not known, studies suggest involvement of systemic acute phase responses, including C-reactive protein (CRP and serum amyloid A (SAA in humans. In this study we test the hypothesis that diesel exhaust particles (DEP – or carbon black (CB-induced lung inflammation initiates an acute phase response in the liver. Results Mice were exposed to filtered air, 20 mg/m3 DEP or CB by inhalation for 90 minutes/day for four consecutive days; we have previously shown that these mice exhibit pulmonary inflammation (Saber AT, Bornholdt J, Dybdahl M, Sharma AK, Loft S, Vogel U, Wallin H. Tumor necrosis factor is not required for particle-induced genotoxicity and pulmonary inflammation., Arch. Toxicol. 79 (2005 177–182. As a positive control for the induction of an acute phase response, mice were exposed to 12.5 mg/kg of lipopolysaccharide (LPS intraperitoneally. Quantitative real time RT-PCR was used to examine the hepatic mRNA expression of acute phase proteins, serum amyloid P (Sap (the murine homologue of Crp and Saa1 and Saa3. While significant increases in the hepatic expression of Sap, Saa1 and Saa3 were observed in response to LPS, their levels did not change in response to DEP or CB. In a comprehensive search for markers of an acute phase response, we analyzed liver tissue from these mice using high density DNA microarrays. Globally, 28 genes were found to be significantly differentially expressed in response to DEP or CB. The mRNA expression of three of the genes (serine (or cysteine proteinase inhibitor, clade A, member 3C, apolipoprotein E and transmembrane emp24 domain containing 3 responded to both exposures. However, these changes were very subtle and were not confirmed by real time RT

  7. Joint measurements of black carbon and particle mass for heavy-duty diesel vehicles using a portable emission measurement system

    Science.gov (United States)

    Zheng, Xuan; Wu, Ye; Zhang, Shaojun; Baldauf, Richard W.; Zhang, K. Max; Hu, Jingnan; Li, Zhenhua; Fu, Lixin; Hao, Jiming

    2016-09-01

    The black carbon (BC) emitted from heavy-duty diesel vehicles (HDDVs) is an important source of urban atmospheric pollution and creates strong climate-forcing impacts. The emission ratio of BC to total particle mass (PM) (i.e., BC/PM ratio) is an essential variable used to estimate total BC emissions from historical PM data; however, these ratios have not been measured using portable emission measurement systems (PEMS) in order to obtain real-world measurements over a wide range of driving conditions. In this study, we developed a PEMS platform by integrating two Aethalometers and an electric low pressure impactor to realize the joint measurement of real-world BC and PM emissions for ten HDDVs in China. Test results showed that the average BC/PM ratio for five HDDVs equipped with mechanical fuel injection (MI) engines was 0.43 ± 0.06, significantly lower (P engines (0.56 ± 0.12). Traffic conditions also affected the BC/PM ratios with higher ratios on freeway routes than on local roads. Furthermore, higher ratios were observed for HDDVs equipped with EI engines than for the MI engines for the highway and local road routes. With an operating mode binning approach, we observed that the instantaneous BC/PM ratios of EI engine vehicles were above those of the MI engine vehicles in all operating modes except for the braking mode (i.e., Bin 0). Therefore, the complex impacts from engine technology and traffic conditions on BC/PM ratios should be carefully considered when estimating real-world BC emissions from HDDVs based on overall PM emissions data.

  8. Effects of Surface-modification of Carbon Black on the Characteristics of Polymerized Toner

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Eun Ho; Kim, Dae Su [Chungbuk National University, Cheongju (Korea, Republic of)

    2013-10-15

    Carbon black was surface-modified to prepare styrene-based suspension polymerized toner with excellent carbon black dispersibility inside toner particles. Carbon black was oxidized first to introduce hydroxyl groups on the surfaces, then esterification between the hydroxyl groups and carboxyl groups of organic acids (oleic acid, palmitic acid, acrylic acid) was followed to obtain organically surface-modified carbon black. The surface-modification of carbon black was confirmed by FTIR. Apparent carbon black dispersibility in the monomer mixture of the binder resin was tested and the particle size of dispersed carbon black was measured by particle size analyzer. Optical micrographs showed that carbon black dispersibility inside toner particles was improved considerably when the carbon black surface-modified with oleic acid was used. The polymerized toner prepared with the carbon black surface-modified with oleic acid showed ideal particle size and size distribution as a toner.

  9. Structurally Coloured Secondary Particles Composed of Black and White Colloidal Particles

    OpenAIRE

    2013-01-01

    This study investigated the colourful secondary particles formed by controlling the aggregation states of colloidal silica particles and the enhancement of the structural colouration of the secondary particles caused by adding black particles. We obtained glossy, partially structurally coloured secondary particles in the absence of NaCl, but matte, whitish secondary particles were obtained in the presence of NaCl. When a small amount of carbon black was incorporated into both types of seconda...

  10. Black Carbon, The Pyrogenic Clay Mineral?

    Science.gov (United States)

    Most soils contain significant amounts of black carbon, much of which is present as discrete particles admixed with the coarse clay fraction (0.2–2.0 µm e.s.d.) and can be physically separated from the more abundant diffuse biogenic humic materials. Recent evidence has shown that naturally occurring...

  11. 硫化胶中炭黑品种的粒径分布鉴别方法%Determination of Carbon Black Type in Vulcanized Compound by Particle Size Distribution Analysis

    Institute of Scientific and Technical Information of China (English)

    张翠翠; 苍飞飞; 邹滔; 高原; 马姜; 邓平晔

    2015-01-01

    The relationship between particle size distribution and carbon black type was established and the test method to determine the carbon black type in vulcanized compound was obtained by particle size distribution analysis. The carbon black in the vulcanized compound was recovered by pyrolysis and its particle size distribution was measured by laser diffraction nano-particle size analyzer. The results showed that peak value and standard deviation of different type of carbon black were different and the peak value and standard deviation fluctuated within a small range for the same type of carbon black. Thus the unknown carbon black could be identiifed by measuring its particle size distribution. This identiifcation method was suitable for analysis of carbon black in the vulcanized compound iflled with only one type of carbon black and it could not be applied to blended carbon black and carbon black N774.%探索炭黑粒径分布与炭黑品种之间的关系,建立通过炭黑粒径分布鉴别炭黑品种的方法。通过热裂解法回收硫化胶中的炭黑,将回收的炭黑加入分散剂制成悬浊液,利用纳米激光粒度分布仪进行粒径分布测试。结果表明,不同品种炭黑粒径分布的峰值和标准偏差不同,同种炭黑粒径分布的峰值和标准偏差在一个较小的范围内波动,这是硫化胶中未知炭黑品种鉴别的依据。本方法适用于单一炭黑品种硫化胶分析,不适用于并用炭黑及炭黑N774硫化胶分析。

  12. Ship-borne Observations of Atmospheric Black Carbon Aerosol Particles over the Arctic Ocean, Bering Sea, and North Pacific Ocean during September 2014

    Science.gov (United States)

    Taketani, F.; Miyakawa, T.; Takashima, H.; Komazaki, Y.; Kanaya, Y.; PAN, X.; Inoue, J.

    2015-12-01

    Measurements of refractory black carbon (rBC) aerosol particles using a highly sensitive online single particle soot photometer were performed on-board the R/V Mirai during a cruise across the Arctic Ocean, Bering Sea, and the North Pacific Ocean (31 August-9 October 2014). The measured rBC mass concentrations over the Arctic Ocean in the latitudinal region > 70°N were in the range 0-66 ng/m3 for 1-min averages, with an overall mean value of 1.0 ± 1.2 ng/m3. Single-particle-based observations enabled the measurement of such low rBC mass concentrations. The effects of long-range transport from continents to the Arctic Ocean were limited during the observed period, suggesting that such low rBC concentration levels would prevail over the Arctic Ocean. An analysis of rBC mixing states showed that particles with a non-shell/core structure made a significant contribution to the rBC particles detected over the Arctic Ocean.

  13. Shipborne observations of atmospheric black carbon aerosol particles over the Arctic Ocean, Bering Sea, and North Pacific Ocean during September 2014

    Science.gov (United States)

    Taketani, Fumikazu; Miyakawa, Takuma; Takashima, Hisahiro; Komazaki, Yuichi; Pan, Xiaole; Kanaya, Yugo; Inoue, Jun

    2016-02-01

    Measurements of refractory black carbon (rBC) aerosol particles using a highly sensitive online single particle soot photometer were performed on board the R/V Mirai during a cruise across the Arctic Ocean, Bering Sea, and North Pacific Ocean (31 August to 9 October 2014). The measured rBC mass concentrations over the Arctic Ocean in the latitudinal region > 70°N were in the range 0-66 ng/m3 for 1 min averages, with an overall mean value of 1.0 ± 1.2 ng/m3. Single-particle-based observations enabled the measurement of such low rBC mass concentrations. The effects of long-range transport from continents to the Arctic Ocean were limited during the observed period, which suggests that the low rBC concentration levels would prevail over the Arctic Ocean. An analysis of rBC mixing states showed that particles with a nonshell/noncore structure made a significant contribution to the rBC particles detected over the Arctic Ocean.

  14. Black carbon in aerosol during BIBLE B

    Science.gov (United States)

    Liley, J. Ben; Baumgardner, D.; Kondo, Y.; Kita, K.; Blake, D. R.; Koike, M.; Machida, T.; Takegawa, N.; Kawakami, S.; Shirai, T.; Ogawa, T.

    2003-02-01

    The Biomass Burning and Lightning Experiment (BIBLE) A and B campaigns over the tropical western Pacific during springtime deployed a Gulfstream-II aircraft with systems to measure ozone and numerous precursor species. Aerosol measuring systems included a MASP optical particle counter, a condensation nucleus (CN) counter, and an absorption spectrometer for black carbon. Aerosol volume was very low in the middle and upper troposphere during both campaigns, and during BIBLE A, there was little aerosol enhancement in the boundary layer away from urban areas. In BIBLE B, there was marked aerosol enhancement in the lowest 3 km of the atmosphere. Mixing ratios of CN in cloud-free conditions in the upper troposphere were in general higher than in the boundary layer, indicating new particle formation from gaseous precursors. High concentrations of black carbon were observed during BIBLE B, with mass loadings up to 40 μg m-3 representing as much as one quarter of total aerosol mass. Strong correlations with hydrocarbon enhancement allow the determination of a black carbon emission ratio for the fires at that time. Expressed as elemental carbon, it is about 0.5% of carbon dioxide and 6% of carbon monoxide emissions from the same fires, comparable to methane production, and greater than that of other hydrocarbons.

  15. Long-term observations of tropospheric particle number size distributions and equivalent black carbon mass concentrations in the German Ultrafine Aerosol Network (GUAN

    Directory of Open Access Journals (Sweden)

    W. Birmili

    2015-11-01

    Full Text Available The German Ultrafine Aerosol Network (GUAN is a cooperative atmospheric observation network, which aims at improving the scientific understanding of aerosol-related effects in the troposphere. The network addresses research questions dedicated to both, climate and health related effects. GUAN's core activity has been the continuous collection of tropospheric particle number size distributions and black carbon mass concentrations at seventeen observation sites in Germany. These sites cover various environmental settings including urban traffic, urban background, rural background, and Alpine mountains. In association with partner projects, GUAN has implemented a high degree of harmonisation of instrumentation, operating procedures, and data evaluation procedures. The quality of the measurement data is assured by laboratory intercomparisons as well as on-site comparisons with reference instruments. This paper describes the measurement sites, instrumentation, quality assurance and data evaluation procedures in the network as well as the EBAS repository, where the data sets can be obtained (doi:10.5072/guan.

  16. Black carbon radiative forcing at TOA decreased during aging

    Science.gov (United States)

    Wu, Yu; Cheng, Tianhai; Zheng, Lijuan; Chen, Hao

    2016-12-01

    During aging processing, black carbon (also called soot) particles may tend to be mixed with other aerosols, and highly influence their radiative forcing. In this study, freshly emitted soot particles were simulated as fractal aggregates composed of small spherical primary monomers. After aging in the atmosphere, soot monomers were coated by a thinly layer of sulfate as thinly coated soot particles. These soot particles were entirely embedded into large sulfate particle by further aging, and becoming heavily coated soot particles. In clear-sky conditions, black carbon radiative forcing with different aging states were investigated for the bottom and top of atmosphere (BOA and TOA). The simulations showed that black carbon radiative forcing increased at BOA and decreased at TOA after their aging processes. Thinly and heavily coated states increased up to ~12% and ~35% black carbon radiative forcing at BOA, and black carbon radiative forcing at TOA can reach to ~20% and ~100% smaller for thinly and heavily coated states than those of freshly emitted states, respectively. The effect of aging states of black carbon radiative forcing was varied with surface albedo, aerosol optical depth and solar zenith angles. These findings would be helpful for the assessments of climate change.

  17. Monitoring of black carbon and size-segregated particle number concentrations at 9-m and 65-m distances from a major road in Helsinki

    Energy Technology Data Exchange (ETDEWEB)

    Pakkanen, T.A.; Maekelae, T.; Hillamo, R.E. [Finnish Meteorological Inst., Helsinki (Finland); Virtanen, A.; Roenkkoe, T.; Keskinen, J. [Tampere Univ. of Technology, Inst. of Physics, Aerosol Physics Lab. , Tampere (Finland); Pirjola, L.; Parviainen, H. [Helsinki Polytechnic, Dept. of Technology, Helsinki (Finland); Hussein, T.; Haemeri, K. [Helsinki Univ., Dept. of Physical Sciences, Helsinki (Finland)

    2006-07-01

    In February and August 2003, black carbon (BC) and size-segregated particle number concentrations were monitored simultaneously at 9-m and 65-m distances from a major road in Helsinki, Finland, using aethalometers and electrical low-pressure impactors, respectively. During weekdays in winter, the average total particle number concentrations in the diameter range 0.007-1{mu}m increased during morning rush hours from the nighttime values of 17000 and 12000 cm{sup -3} to 190000 and 130000 cm{sup -3} at the 9-m and 65-m stations, respectively. The corresponding BC concentrations increased from 730 and 430 ng m{sup -3} to 2800 and 1550 ng m{sup -3}. Compared with those in winter, the average rush-hour particle number concentrations were much lower in summer, the likely reason being enhanced nucleation in cold winter conditions. BC concentrations were slightly higher during summer than during winter. Number size distributions measured at the 9-m and 65-m distances and at a background site had similar modal characteristics with the highest peak occurring below 0.03 {mu}m. Despite the different wind conditions in winter and summer, concentrations of total particle number and BC decreased similarly between the 9-m and 65-m stations, the likely principal mechanism being mixing with background air. The strong diurnal variation in concentrations during the weekdays, together with the large concentration difference between the 9-m and 65-m distances, suggests that local traffic was the main source of the measured pollutants, especially during rush hours at the 9-m site. In winter, the decrease in the particle number concentrations from the 9-m site to the 65-m site was most pronounced for the smallest exhaust particles. During an episodic pollution event in winter there were indications of condensational growth of 0.007-0.03 {mu}m particles, which increased the number concentration of 0.03-0.06 {mu}m particles at the 65-m site. (orig.)

  18. Effects of volatile coatings on the morphology and optical detection of combustion-generated black carbon particles.

    Energy Technology Data Exchange (ETDEWEB)

    Bambha, Ray.; Dansson, Mark A; Schrader, Paul E.; Michelsen, Hope A.

    2013-09-01

    We have measured time-resolved laser-induced incandescence (LII) from combustion-generated mature soot extracted from a burner and (1) coated with oleic acid or (2) coated with oleic acid and then thermally denuded using a thermodenuder. The soot samples were size selected using a differential mobility analyser and characterized with a scanning mobility particle sizer, centrifugal particle mass analyser, and transmission electron microscope. The results demonstrate a strong influence of coatings particle morphology and on the magnitude and temporal evolution of the LII signal. For coated particles higher laser fluences are required to reach LII signal levels comparable to those of uncoated particles. This effect is predominantly attributable to the additional energy needed to vaporize the coating while heating the particle. LII signals are higher and signal decay rates are significantly slower for thermally denuded particles relative to coated or uncoated particles, particularly at low and intermediate laser fluences.

  19. Particle accelerators inside spinning black holes.

    Science.gov (United States)

    Lake, Kayll

    2010-05-28

    On the basis of the Kerr metric as a model for a spinning black hole accreting test particles from rest at infinity, I show that the center-of-mass energy for a pair of colliding particles is generically divergent at the inner horizon. This shows not only that classical black holes are internally unstable, but also that Planck-scale physics is a characteristic feature within black holes at scales much larger that the Planck length. The novel feature of the divergence discussed here is that the phenomenon is present only for black holes with rotation, and in this sense it is distinct from the well-known Cauchy horizon instability.

  20. Black Hole - Moving Mirror II: Particle Creation

    OpenAIRE

    Good, Michael R. R.; Anderson, Paul R.; Evans, Charles R.

    2015-01-01

    There is an exact correspondence between the simplest solution to Einstein's equations describing the formation of a black hole and a particular moving mirror trajectory. In both cases the Bogolubov coefficients in 1+1 dimensions are identical and can be computed analytically. Particle creation is investigated by using wave packets. The entire particle creation history is computed, incorporating the early-time non-thermal emission due to the formation of the black hole (or the early-time acce...

  1. Phenology of a Vegetation Barrier and Resulting Impacts on Near-Highway Particle Number and Black Carbon Concentrations on a School Campus

    Directory of Open Access Journals (Sweden)

    Christina H. Fuller

    2017-02-01

    Full Text Available Traffic-related air pollution is a persistent concern especially in urban areas where populations live in close proximity to roadways. Innovative solutions are needed to minimize human exposure and the installation of vegetative barriers shows potential as a method to reduce near-road concentrations. This study investigates the impact of an existing stand of deciduous and evergreen trees on near-road total particle number (PNC and black carbon (BC concentrations across three seasons. Measurements were taken during spring, fall and winter on the campus of a middle school in the Atlanta (GA, USA area at distances of 10 m and 50 m from a major interstate highway. We identified consistent decreases in BC concentrations, but not for PNC, with increased distance from the highway. In multivariable models, hour of day, downwind conditions, distance to highway, temperature and relative humidity significantly predicted pollutant concentrations. The magnitude of effect of these variables differed by season, however, we were not able to show a definitive impact of the vegetative barrier on near-road concentrations. More detailed studies are necessary to further examine the specific configurations and scenarios that may produce pollutant and exposure reductions.

  2. Comparison of Spheroidal Carbonaceous Particle Data with Modelled Atmospheric Black Carbon Concentration and Deposition and Air Mass Sources in Northern Europe, 1850–2010

    Directory of Open Access Journals (Sweden)

    Meri Ruppel

    2013-01-01

    Full Text Available Spheroidal carbonaceous particles (SCP are a well-defined fraction of black carbon (BC, produced only by the incomplete combustion of fossil fuels such as coal and oil. Their past concentrations have been studied using environmental archives, but, additionally, historical trends of BC concentration and deposition can be estimated by modelling. These models are based on BC emission inventories, but actual measurements of BC concentration and deposition play an essential role in their evaluation and validation. We use the chemistry transport model OsloCTM2 to model historical time series of BC concentration and deposition from energy and industrial sources and compare these to sedimentary measurements of SCPs obtained from lake sediments in Northern Europe from 1850 to 2010. To determine the origin of SCPs we generated back trajectories of air masses to the study sites. Generally, trends of SCP deposition and modelled results agree reasonably well, showing rapidly increasing values from 1950, to a peak in 1980, and a decrease towards the present. Empirical SCP data show differences in deposition magnitude between the sites that are not captured by the model but which may be explained by different air mass transport patterns. The results highlight the need for numerous observational records to reliably validate model results.

  3. Assessing Single Particle Soot Photometer and Integrating Sphere/Integrating Sandwich Spectrophotometer measurement techniques for quantifying black carbon concentration in snow

    Directory of Open Access Journals (Sweden)

    J. P. Schwarz

    2012-11-01

    Full Text Available We evaluate the performance of the Single Particle Soot Photometer (SP2 and the Integrating Sphere/Integrating Sandwich Spectrophotometer (ISSW in quantifying the concentration of refractory black carbon (BC in snow samples. We find that the SP2 can be used to measure BC mass concentration in snow with substantially larger uncertainty (60% than for atmospheric sampling (<30%. Achieving this level of accuracy requires careful assessment of nebulizer performance and SP2 calibration with consideration of the fact that BC in snow can exist in larger sizes than typically observed in the atmosphere. Once these issues are addressed, the SP2 is able to measure the size distribution and mass concentration of BC in the snow. Laboratory comparison of the SP2 and the ISSW revealed significant biases in the estimate of BC concentration from the ISSW when test samples contained dust or non-absorbing particulates. These results suggest that current estimates of BC mass concentration in snow or ice formed from fallen snow using either the SP2 or the ISSW may be associated with significant underestimates of uncertainty.

  4. Phenology of a Vegetation Barrier and Resulting Impacts on Near-Highway Particle Number and Black Carbon Concentrations on a School Campus.

    Science.gov (United States)

    Fuller, Christina H; Carter, David R; Hayat, Matthew J; Baldauf, Richard; Watts Hull, Rebecca

    2017-02-08

    Traffic-related air pollution is a persistent concern especially in urban areas where populations live in close proximity to roadways. Innovative solutions are needed to minimize human exposure and the installation of vegetative barriers shows potential as a method to reduce near-road concentrations. This study investigates the impact of an existing stand of deciduous and evergreen trees on near-road total particle number (PNC) and black carbon (BC) concentrations across three seasons. Measurements were taken during spring, fall and winter on the campus of a middle school in the Atlanta (GA, USA) area at distances of 10 m and 50 m from a major interstate highway. We identified consistent decreases in BC concentrations, but not for PNC, with increased distance from the highway. In multivariable models, hour of day, downwind conditions, distance to highway, temperature and relative humidity significantly predicted pollutant concentrations. The magnitude of effect of these variables differed by season, however, we were not able to show a definitive impact of the vegetative barrier on near-road concentrations. More detailed studies are necessary to further examine the specific configurations and scenarios that may produce pollutant and exposure reductions.

  5. Prenatal Exposure to Carbon Black (Printex 90)

    DEFF Research Database (Denmark)

    Jackson, Petra; Vogel, Ulla; Wallin, Håkan;

    2011-01-01

    Maternal pulmonary exposure to ultrafine particles during pregnancy may affect the health of the child. Developmental toxicity of carbon black (Printex 90) nanoparticles was evaluated in a mouse model. Time-mated mice were intratracheally instilled with Printex 90 dispersed in Millipore water on ...... on gestation days (GD) 7, 10, 15 and 18, with total doses of 11, 54 and 268 mu g Printex 90/animal. The female offspring prenatally exposed to 268 mu g Printex 90/animal displayed altered habituation pattern during the Open field test....

  6. Emission rates of particle number, mass and black carbon by the Los Angeles International Airport (LAX) and its impact on air quality in Los Angeles

    Science.gov (United States)

    Shirmohammadi, Farimah; Sowlat, Mohammad H.; Hasheminassab, Sina; Saffari, Arian; Ban-Weiss, George; Sioutas, Constantinos

    2017-02-01

    This study describes a series of air monitoring measurements of particle number (PN), black carbon (BC) and PM2.5 mass concentrations in the vicinity of the Los Angeles International Airport (LAX) (roughly 150 m downwind of the LAX's south runways) as well as on-road measurements of the aforementioned pollutants using a mobile platform on three major freeways (i.e., I-110, I-105, and I-405) during May-July 2016. All measurements were performed in the "impact zone" of LAX with the predominant westerly winds from coast to inland. The overall impact of aircraft emissions from the LAX airport and its facilities in comparison to vehicular emissions from freeways on air quality was evaluated on a local scale (i.e. areas in the vicinity of the airport). PN concentration was, on average, 4.1 ± 1.2 times greater at the LAX site than on the studied freeways. Particle number emission factors for takeoffs and landings were comparable, with average values of 8.69 ×1015 particles/kg fuel and 8.16 ×1015 particles/kg fuel, respectively, and indicated a nearly 4-fold statistically significant reduction in PN emission factors for takeoffs during the past decade. BC emission factors were 0.12 ± 0.02 and 0.11 ± 0.01 g/kg fuel during takeoffs and landings, respectively. Additionally, the mean PM2.5 emission factor values for takeoffs and landings were also comparable, with values of 0.38 ± 0.04 and 0.40 ± 0.05 g/kg fuel, respectively. Within the impact zone of the airport, an area of roughly 100 km2 downwind of the LAX, measurements indicated that the LAX daily contributions to PN, BC, and PM2.5 were approximately 11, 2.5, and 1.4 times greater than those from the three surrounding freeways. These results underscore the significance of the LAX airport as a major source of pollution within its zone of impact comparing to freeway emissions.

  7. Characterization of Black Carbon Mixing State Field Campaign Report

    Energy Technology Data Exchange (ETDEWEB)

    Sedlacek, A. [Brookhaven National Lab. (BNL), Upton, NY (United States); Davidovits, P. [Boston College, Chestnut Hill, MA (United States); Lewis, E. R. [Brookhaven National Lab. (BNL), Upton, NY (United States); Onasch, T. B. [Aerodyne Research, Billerica, MA (United States)

    2016-04-01

    Interpreting the temporal relationship between the scattering and incandescence signals recorded by the Single Particle Soot Photometer (SP2), Sedlacek et al. (2012) reported that 60% of the refractory black carbon containing particles in a plume containing biomass burning tracers exhibited non-core-shell structure. Because the relationship between the rBC (refractory black carbon) incandescence and the scattering signals had not been reported in the peer-reviewed literature, and to further evaluate the initial interpretation by Sedlacek et al., a series of experiments was undertaken to investigate black carbon-containing particles of known morphology using Regal black (RB), a proxy for collapsed soot, as the light-absorbing substance to characterize this signal relationship. Particles were formed by coagulation of RB with either a solid substance (sodium chloride or ammonium sulfate) or a liquid substance (dioctyl sebacate), and by condensation with dioctyl sebacate, the latter experiment forming particles in a core-shell configuration. Each particle type experienced fragmentation (observed as negative lagtimes), and each yielded similar lagtime responses in some instances, confounding attempts to differentiate particle morphology using current SP2 lagtime analysis. SP2 operating conditions, specifically laser power and sample flow rate, which in turn affect the particle heating and dissipation rates, play an important role in the behavior of particles in the SP2, including probability of fragmentation. This behavior also depended on the morphology of the particles and on the thermochemical properties of the non-RB substance. Although these influences cannot currently be unambiguously separated, the SP2 analysis may still provide useful information on particle mixing states and black carbon particle sources. This work was communicated in a 2015 publication (Sedlacek et al. 2015)

  8. Lack of acute phase response in the livers of mice exposed to diesel exhaust particles or carbon black by inhalation

    DEFF Research Database (Denmark)

    Saber, Anne T; Halappanavar, Sabina; Folkmann, Janne K

    2009-01-01

    BACKGROUND: Epidemiologic and animal studies have shown that particulate air pollution is associated with increased risk of lung and cardiovascular diseases. Although the exact mechanisms by which particles induce cardiovascular diseases are not known, studies suggest involvement of systemic acute...... analyzed liver tissue from these mice using high density DNA microarrays. Globally, 28 genes were found to be significantly differentially expressed in response to DEP or CB. The mRNA expression of three of the genes (serine (or cysteine) proteinase inhibitor, clade A, member 3C, apolipoprotein E...

  9. On the diurnal cycle of urban aerosols, black carbon and the occurrence of new particle formation events in springtime São Paulo, Brazil

    Directory of Open Access Journals (Sweden)

    J. Backman

    2012-12-01

    Full Text Available Large conurbations are a significant source of the anthropogenic pollution and demographic differences between cities that result in a different pollution burden. The metropolitan area of São Paulo (MASP, population 20 million accounts for one fifth of the Brazilian vehicular fleet. A feature of MASP is the amount of ethanol used by the vehicular fleet, known to exacerbate air quality. The study describes the diurnal behaviour of the submicron aerosol and relies on total particle number concentration, particle number size distribution, light scattering and light absorption measurements. Modelled planetary boundary layer (PBL depth and air mass movement data were used to aid the interpretation. During morning rush-hour, stagnant air and a shallow PBL height favour the accumulation of aerosol pollution. During clear-sky conditions, there was a wind shift towards the edge of the city indicating a heat island effect with implications on particulate pollution levels at the site. The median total particle number concentration for the submicron aerosol typically varied in the range 1.6 × 104–3.2 × 104 cm−3 frequently exceeding 4 × 104 cm−3 during the day. During weekdays, nucleation-mode particles are responsible for most of the particles by numbers. The highest concentrations of total particle number concentrations and black carbon (BC were observed on Fridays. Median diurnal values for light absorption and light scattering (at 637 nm wavelength varied in the range 12–33 Mm−1 and 21–64 Mm−1, respectively. The former one is equal to 1.8–5.0 μg m−3 of BC. The growth of the PBL, from the morning rush-hour until noon, is consistent with the diurnal cycle of BC mass concentrations. Weekday hourly median single-scattering albedo (ω0 varied in the range 0.59–0.76. Overall, this suggests a top of atmosphere (TOA warming effect. However

  10. Adsorption of Remazol Black B dye on Activated Carbon Felt

    Directory of Open Access Journals (Sweden)

    Donnaperna Lucio

    2008-11-01

    Full Text Available The adsorption of Remazol Black B (anionic dye on a microporous activated carbon felt is investigated from its aqueous solution. The surface chemistry of activated carbon is studied using X-ray microanalysis, "Boehm" titrations and pH of PZC measurements which indicates that the surface oxygenated groups are mainly acidic in nature. The kinetics of Remazol Black B adsorption is observed to be pH dependent and governed by the diffusion of the dye molecules. The experimental data can be explained by "intra-particle diffusion model". For Remazol Black B, the Khan model is best suited to simulate the adsorption isotherms.

  11. MORPHOLOGY OF BLACK CARBON AEROSOLS AND UBIQUITY OF 50-NANOMETER BLACK CARBON AEROSOLS IN THE ATMOSPHERE

    Institute of Scientific and Technical Information of China (English)

    Fengfu Fu; Liangjun Xu; Wei Ye; Yiquan Chen; Mingyu Jiang; Xueqin Xu

    2006-01-01

    Different-sized aerosols were collected by an Andersen air sampler to observe the detailed morphology of the black carbon (BC) aerosols which were separated chemically from the other accompanying aerosols, using a Scanning Electron Microscope equipped with an Energy Dispersive X-ray Spectrometer (SEM-EDX). The results indicate that most BC aerosols are spherical particles of about 50 nm in diameter and with a homogeneous surface. Results also show that these particles aggregate with other aerosols or with themselves to form larger agglomerates in the micrometer range. The shape of these 50-nm BC spherical particles was found to be very similar to that of BC particles released from petroleum-powered vehicular internal combustion engines. These spherical BC particles were shown to be different from the previously reported fullerenes found using Matrix-Assisted Laser Desorption/Ionization Time-Of-Flight Mass Spectrometry (MALDI-TOF-MS).

  12. Black carbon, particle number concentration and nitrogen oxide emission factors of random in-use vehicles measured with the on-road chasing method

    Directory of Open Access Journals (Sweden)

    I. Ježek

    2015-06-01

    Full Text Available The chasing method was used in an on-road measurement campaign, and emission factors (EF of black carbon (BC, particle number (PN and nitrogen oxides (NOx were determined for 139 individual vehicles of different types encountered on the roads. The aggregated results provide EFs for BC, NOx and PN for three vehicle categories: goods vehicles, gasoline and diesel passenger cars. This is the first on-road measurement study where BC EFs of numerous individual diesel cars were determined in real-world driving conditions. We found good agreement between EFs of goods vehicles determined in this campaign and the results of previous studies that used either chasing or remote sensing measurement techniques. The composition of the sampled car fleet determined from the national vehicle registry information is reflective of Eurostat statistical data on the Slovenian and European vehicle fleet. The median BC EF of diesel and gasoline cars that were in use for less than 5 years, decreased by 60 and 47% from those in use for 5–10 years, respectively, the median NOx and PN EFs, of goods vehicles that were in use for less than five years, decreased from those in use for 5–10 years by 52 and 67%, respectively. The influence of engine maximum power of the measured EFs showed an increase in NOx EF from least to more powerful vehicles with diesel engines. Finally a disproportionate contribution of high emitters to the total emissions of the measured fleet was found; the top 25% of emitting diesel cars contributed 63, 47 and 61% of BC, NOx and PN emissions respectively. With the combination of relatively simple on-road measurements with sophisticated post processing individual vehicles EF can be determined and useful information about the fleet emissions can be obtained by exactly representing vehicles which contribute disproportionally to vehicle fleet emissions; and monitor how the numerous emission reduction approaches are reflected in on-road driving

  13. Applicability of a noise-based model to estimate in-traffic exposure to black carbon and particle number concentrations in different cultures.

    Science.gov (United States)

    Dekoninck, Luc; Botteldooren, Dick; Panis, Luc Int; Hankey, Steve; Jain, Grishma; S, Karthik; Marshall, Julian

    2015-01-01

    Several studies show that a significant portion of daily air pollution exposure, in particular black carbon (BC), occurs during transport. In a previous work, a model for the in-traffic exposure of bicyclists to BC was proposed based on spectral evaluation of mobile noise measurements and validated with BC measurements in Ghent, Belgium. In this paper, applicability of this model in a different cultural context with a totally different traffic and mobility situation is presented. In addition, a similar modeling approach is tested for particle number (PN) concentration. Indirectly assessing BC and PN exposure through a model based on noise measurements is advantageous because of the availability of very affordable noise monitoring devices. Our previous work showed that a model including specific spectral components of the noise that relate to engine and rolling emission and basic meteorological data, could be quite accurate. Moreover, including a background concentration adjustment improved the model considerably. To explore whether this model could also be used in a different context, with or without tuning of the model parameters, a study was conducted in Bangalore, India. Noise measurement equipment, data storage, data processing, continent, country, measurement operators, vehicle fleet, driving behavior, biking facilities, background concentration, and meteorology are all very different from the first measurement campaign in Belgium. More than 24h of combined in-traffic noise, BC, and PN measurements were collected. It was shown that the noise-based BC exposure model gives good predictions in Bangalore and that the same approach is also successful for PN. Cross validation of the model parameters was used to compare factors that impact exposure across study sites. A pooled model (combining the measurements of the two locations) results in a correlation of 0.84 when fitting the total trip exposure in Bangalore. Estimating particulate matter exposure with traffic

  14. Black Hole - Moving Mirror II: Particle Creation

    CERN Document Server

    Good, Michael R R; Evans, Charles R

    2015-01-01

    There is an exact correspondence between the simplest solution to Einstein's equations describing the formation of a black hole and a particular moving mirror trajectory. In both cases the Bogolubov coefficients in 1+1 dimensions are identical and can be computed analytically. Particle creation is investigated by using wave packets. The entire particle creation history is computed, incorporating the early-time non-thermal emission due to the formation of the black hole (or the early-time acceleration of the moving mirror) and the evolution to a Planckian spectrum.

  15. Particle creation rate for dynamical black holes

    Science.gov (United States)

    Firouzjaee, Javad T.; Ellis, George F. R.

    2016-11-01

    We present the particle creation probability rate around a general black hole as an outcome of quantum fluctuations. Using the uncertainty principle for these fluctuation, we derive a new ultraviolet frequency cutoff for the radiation spectrum of a dynamical black hole. Using this frequency cutoff, we define the probability creation rate function for such black holes. We consider a dynamical Vaidya model and calculate the probability creation rate for this case when its horizon is in a slowly evolving phase. Our results show that one can expect the usual Hawking radiation emission process in the case of a dynamical black hole when it has a slowly evolving horizon. Moreover, calculating the probability rate for a dynamical black hole gives a measure of when Hawking radiation can be killed off by an incoming flux of matter or radiation. Our result strictly suggests that we have to revise the Hawking radiation expectation for primordial black holes that have grown substantially since they were created in the early universe. We also infer that this frequency cut off can be a parameter that shows the primordial black hole growth at the emission moment.

  16. Particle creation rate for dynamical black holes

    Energy Technology Data Exchange (ETDEWEB)

    Firouzjaee, Javad T. [School of Astronomy, Institute for Research in Fundamental Sciences (IPM), Tehran (Iran, Islamic Republic of); University of Oxford, Department of Physics (Astrophysics), Oxford (United Kingdom); Ellis, George F.R. [University of Cape Town, Mathematics and Applied Mathematics Department, Rondebosch (South Africa)

    2016-11-15

    We present the particle creation probability rate around a general black hole as an outcome of quantum fluctuations. Using the uncertainty principle for these fluctuation, we derive a new ultraviolet frequency cutoff for the radiation spectrum of a dynamical black hole. Using this frequency cutoff, we define the probability creation rate function for such black holes. We consider a dynamical Vaidya model and calculate the probability creation rate for this case when its horizon is in a slowly evolving phase. Our results show that one can expect the usual Hawking radiation emission process in the case of a dynamical black hole when it has a slowly evolving horizon. Moreover, calculating the probability rate for a dynamical black hole gives a measure of when Hawking radiation can be killed off by an incoming flux of matter or radiation. Our result strictly suggests that we have to revise the Hawking radiation expectation for primordial black holes that have grown substantially since they were created in the early universe. We also infer that this frequency cut off can be a parameter that shows the primordial black hole growth at the emission moment. (orig.)

  17. Electromagnetic properties of carbon black and barium titanate composite materials

    Energy Technology Data Exchange (ETDEWEB)

    Wang Guiqin [School of Material Science and Engineering, Dalian University of Technology, Dalian 116023 (China)], E-mail: c2b2chen@163.com; Chen Xiaodong; Duan Yuping; Liu Shunhua [School of Material Science and Engineering, Dalian University of Technology, Dalian 116023 (China)

    2008-04-24

    Nanocrystalline carbon black/barium titanate compound particle (CP) was synthesized by sol-gel method. The phase structure and morphology of compound particle were investigated by X-ray diffraction (XRD), transmission electron microscope (TEM) and Raman spectrum measurements, the electroconductivity was test by trielectrode arrangement and the precursor powder was followed by differential scanning calorimetric measurements (DSC) and thermal gravimetric analysis (TGA). In addition, the complex relative permittivity and permeability of compound particle were investigated by reflection method. The compound particle/epoxide resin composite (CP/EP) with different contents of CP were measured. The results show barium titanate crystal is tetragonal phase and its grain is oval shape with 80-100 nm which was coated by carbon black film. As electromagnetic (EM) complex permittivity, permeability and reflection loss (RL) shown that the compound particle is mainly a kind of electric and dielectric lossy materials and exhibits excellent microwave absorption performance in the X- and Ku-bands.

  18. Black hole horizons and quantum charged particles

    CERN Document Server

    Jaramillo, José Luis

    2014-01-01

    We point out a structural similarity between the characterization of black hole apparent horizons as stable marginally outer trapped surfaces (MOTS) and the quantum description of a non-relativistic charged particle moving in given magnetic and electric fields on a closed surface. Specifically, the spectral problem of the MOTS-stability operator corresponds to a stationary quantum particle with a formal fine-structure constant $\\alpha$ of negative sign. We discuss how such analogy enriches both problems, illustrating this with the insights into the MOTS-spectral problem gained from the analysis of the spectrum of the quantum charged particle Hamiltonian.

  19. Three years of aerosol mass, black carbon and particle number concentrations at Montsec (southern Pyrenees, 1570 m a.s.l.)

    Science.gov (United States)

    Ripoll, A.; Pey, J.; Minguillón, M. C.; Pérez, N.; Pandolfi, M.; Querol, X.; Alastuey, A.

    2014-04-01

    Time variation of mass particulate matter (PM1 and PM1&minus10), black carbon (BC) and number of particles (N3: number of particles with an aerodynamic diameter higher than 3 nm, and N10: higher than 10 nm) concentrations at the high-altitude site of Montsec (MSC) in the southern Pyrenees was interpreted for the period 2010-2012. At MSC, PM10 (12 μg m-3) and N7 (2140 # cm-3) three-year arithmetic average concentrations were higher than those measured at other high-altitude sites in central Europe during the same period (PM10: 3-9 μg m-3 and N: 634-2070 # cm-3). By contrast, BC concentrations at MSC (0.2 μg m-3) were equal to or even lower than those measured at these European sites (0.2-0.4 μg m-3). These differences were attributed to the higher relevance of Saharan dust transport and to the higher importance of the biogenic precursor emissions and new particle formation (NPF) processes, and to the lower influence of anthropogenic emissions at MSC. The different time variation of PM and BC concentrations compared with that of N suggests that these aerosol parameters were governed by diverse factors at MSC. Both PM and BC concentrations showed marked differences for different meteorological scenarios, with enhanced concentrations under North African air outbreaks (PM1&minus10: 13 μg m-3, PM1: 8 μg m-3 and BC: 0.3 μg m-3) and low concentrations when Atlantic advections occurred (PM1-10: 5 μg m-3, PM1: 4 μg m-3 and BC: 0.1 μg m-3). PM and BC concentrations increased in summer, with a secondary maximum in early spring, and were at their lowest in winter, due to the contrasting origin of the air masses in the warmer seasons (spring and summer) and in the colder seasons (autumn and winter). The maximum in the warmer seasons was attributed to long-range transport processes that mask the breezes and regional transport breaking the daily cycles of these pollutants. By contrast, PM and BC concentrations showed clear diurnal cycles, with maxima at midday in the

  20. Carbon-Supported Iron Oxide Particles

    DEFF Research Database (Denmark)

    Meaz, T.; Mørup, Steen; Koch, C. Bender

    1996-01-01

    A carbon black ws impregnated with 6 wt% iron using an aqueous solution of iron nitrate. The impregnated carbon was initially dried at 125 C. The effect of heating of the iron oxide phase was investigated at temperatures between 200 and 600 C using Mossbauer spectroscopy. All heat treatments were...... done in an oxygen-containing atmosphere. Ferrihydrite is formed and is stable at and below a temperature of 300 C. At 600 C small particles of maghemite is the dominant iron oxide. A transformation reaction is suggested....

  1. Three years of aerosol mass, black carbon and particle number concentrations at Montsec (southern~Pyrenees, 1570 m a.s.l.

    Directory of Open Access Journals (Sweden)

    A. Ripoll

    2013-10-01

    Full Text Available Time variation of mass particulate matter (PM1 and PM1−10, black carbon (BC and particle number (N concentrations at the high altitude site of Montsec (MSC in the southern Pyrenees was interpreted for the period 2010–2012. The MSC site registered higher PM10 (12 μg m−3 and N > 7 nm (2209 # cm−3 concentrations than those measured at other high altitude sites in central Europe (PM10: 3–9 μg m−3 and N: 634–2070 # cm−3. By contrast, BC concentrations at MSC (0.2 μg m−3 were equal or even lower than those measured at these European sites (0.2–0.4 μg m−3. These differences were attributed to the lower influence of anthropogenic emissions and to the higher relevance of Saharan dust transport and new particle formation (NPF processes at MSC. The different time variation of PM and BC concentrations compared with that of N suggests that these aerosol parameters were governed by diverse factors at MSC. Both PM and BC concentrations showed marked differences for different meteorological scenarios, with enhanced concentrations under North African outbreaks (PM1−10: 13 μg m−3, PM1: 8 μg m−3 and BC: 0.3 μg m−3 and low concentrations when Atlantic advections occurred (PM1−10: 5 μg m−3, PM1: 4 μg m−3 and BC: 0.1 μg m−3. Because of the contrasting origin of the air masses in the warmer seasons (spring and summer and in the colder seasons (autumn and winter, PM and BC concentrations showed a marked increase in summer, with a secondary maximum in early spring, and were at their lowest during winter. The maximum in the warmer seasons was attributed to long-range transport processes which mask the breezes and regional transport breaking the daily cycles of these pollutants. By contrast, PM and BC concentrations showed clear diurnal cycles with maxima at midday in the colder seasons. A statistically significant weekly variation was also obtained for the BC concentrations, displaying a progressive increase from Tuesday to

  2. Three years of aerosol mass, black carbon and particle number concentrations at Montsec (southern~Pyrenees, 1570 m a.s.l.)

    Science.gov (United States)

    Ripoll, A.; Pey, J.; Minguillón, M. C.; Pérez, N.; Pandolfi, M.; Querol, X.; Alastuey, A.

    2013-10-01

    Time variation of mass particulate matter (PM1 and PM1-10), black carbon (BC) and particle number (N) concentrations at the high altitude site of Montsec (MSC) in the southern Pyrenees was interpreted for the period 2010-2012. The MSC site registered higher PM10 (12 μg m-3) and N > 7 nm (2209 # cm-3) concentrations than those measured at other high altitude sites in central Europe (PM10: 3-9 μg m-3 and N: 634-2070 # cm-3). By contrast, BC concentrations at MSC (0.2 μg m-3) were equal or even lower than those measured at these European sites (0.2-0.4 μg m-3). These differences were attributed to the lower influence of anthropogenic emissions and to the higher relevance of Saharan dust transport and new particle formation (NPF) processes at MSC. The different time variation of PM and BC concentrations compared with that of N suggests that these aerosol parameters were governed by diverse factors at MSC. Both PM and BC concentrations showed marked differences for different meteorological scenarios, with enhanced concentrations under North African outbreaks (PM1-10: 13 μg m-3, PM1: 8 μg m-3 and BC: 0.3 μg m-3) and low concentrations when Atlantic advections occurred (PM1-10: 5 μg m-3, PM1: 4 μg m-3 and BC: 0.1 μg m-3). Because of the contrasting origin of the air masses in the warmer seasons (spring and summer) and in the colder seasons (autumn and winter), PM and BC concentrations showed a marked increase in summer, with a secondary maximum in early spring, and were at their lowest during winter. The maximum in the warmer seasons was attributed to long-range transport processes which mask the breezes and regional transport breaking the daily cycles of these pollutants. By contrast, PM and BC concentrations showed clear diurnal cycles with maxima at midday in the colder seasons. A statistically significant weekly variation was also obtained for the BC concentrations, displaying a progressive increase from Tuesday to Saturday, followed by a significant

  3. Black carbon and organic carbon emissions from wildfires in Mexico

    OpenAIRE

    XÓCHITL CRUZ NÚÑEZ; LOURDES VILLERS RUIZ; CARLOS GAY GARCÍA

    2014-01-01

    In Mexico, approximately 7650 wildfires occur annually, affecting 263 115 hectares of land. In addition to their impact on land degradation, wildfires cause deforestation, damage to ecosystems and promote land use change; apart from being the source of emissions of toxic substances to the environment (i.e., hydrogen cya - nide, black carbon and organic carbon). Black carbon is a short-lived greenhouse pollutant that also promotes snow and ice melting and decreased rainfall; it has an estimate...

  4. A black potential for spin less particles

    Energy Technology Data Exchange (ETDEWEB)

    Ghatak, Ananya, E-mail: gananya04@gmail.com [Department of Physics, Banaras Hindu University, Varanasi 221005 (India); Hasan, Mohammad, E-mail: mohammadhasan786@gmail.com [ISRO Satellite Centre (ISAC), Bangalore 560017 (India); Mandal, Bhabani Prasad, E-mail: bhabani@bhu.ac.in [Department of Physics, Banaras Hindu University, Varanasi 221005 (India)

    2015-07-03

    We consider the most general non-Hermitian Hulthen potential to study the scattering of spin-less relativistic particles. The conditions for CC, SS and CPA are obtained analytically for this potential. We show that almost total absorption occurs for entire range of incidence energy for certain parameter ranges of the potential and hence term this as ‘black potential’. Time reversed of the same potential shows perfect emission for the entire range of particle energy. We also present the classical analog of this potential in terms of waveguide cross section. - Highlights: • Relativistic scattering properties of a spin zero particle due to most general non-Hermitian Hulthen potential are discussed. • Analytical conditions for CC, CPA and SS are obtained. • Broadband CPA is obtained for entire range of incidence energy. • Non-Hermitian Hulthen potential is parametrized in such a way to show broadband CPA and/or CC. • Waveguide analog of such potential is presented.

  5. High energy particle collisions near black holes

    Directory of Open Access Journals (Sweden)

    Zaslavskii O. B.

    2016-01-01

    Full Text Available If two geodesic particles collide near a rotating black hole, their energy in the centre of mass frame Ec.m. can become unbound under certain conditions (the so-called BSW effect. The special role is played here by so-called critical geodesics when one of particles has fine-tuned energy and angular momentum. The nature of geodesics reveals itself also in fate of the debris after collisions. One of particles moving to a remote observer is necessarily near-critical. We discuss, when such a collision can give rise not only unboud Ec.m. but also unbound Killing energy E (so-called super-Penrose process.

  6. Determination of black carbon in fine particles using a semi-continuous method at two sites in the city of Guadalajara, Mexico, during 2007.

    Science.gov (United States)

    Hernández-Mena, Leonel; Saldarriaga-Noreña, Hugo; Murillo-Tovar, Mario A; Amador-Muñoz, Omar; López-López, Alberto; Waliszewski, Stefan M

    2011-09-01

    The black carbon is a pollutant species primarily emitted from the combustion of fossil fuels (diesel). Their concentrations associated to PM2.5 were monitoring at two sites in the city of Guadalajara. From January to May (except April), downtown site shown 2.7, 2.6, 4.0 and 2.3 times higher monthly concentrations. The dry season two showed higher concentrations respect to at least one of the others seasons (p < 0.0001) at each site, probably due to atmospheric conditions less favorable for the dispersal of pollutants. During the 24 h period were observed at the year two peaks of concentrations: the highest morning peak and lower night peak, both probably related to anthropogenic activity.

  7. [Particle therapy: carbon ions].

    Science.gov (United States)

    Pommier, Pascal; Hu, Yi; Baron, Marie-Hélène; Chapet, Olivier; Balosso, Jacques

    2010-07-01

    Carbon ion therapy is an innovative radiation therapy. It has been first proposed in the forties by Robert Wilson, however the first dedicated centres for human care have been build up only recently in Japan and Germany. The interest of carbon ion is twofold: 1) the very sharp targeting of the tumour with the so called spread out Bragg peak that delivers most of the beam energy in the tumour and nothing beyond it, sparing very efficiently the healthy tissues; 2) the higher relative biological efficiency compared to X rays or protons, able to kill radioresistant tumour cells. Both properties make carbon ions the elective therapy for non resectable radioresistant tumours loco-regionally threatening. The technical and clinical experience accumulated during the recent decades is summarized in this paper along with a detailed presentation of the elective indications. A short comparison between conventional radiotherapy and hadrontherapy is proposed for the indications which are considered as priority for carbon ions.

  8. Black carbon in deep-Sea sediments

    Science.gov (United States)

    Masiello; Druffel

    1998-06-19

    Black carbon (BC) enters the ocean through aerosol and river deposition. BC makes up 12 to 31 percent of the sedimentary organic carbon (SOC) at two deep ocean sites, and it is 2400 to 13,900 carbon-14 years older than non-BC SOC deposited concurrently. BC is likely older because it is stored in an intermediate reservoir before sedimentary deposition. Possible intermediate pools are oceanic dissolved organic carbon (DOC) and terrestrial soils. If DOC is the intermediate reservoir, then BC is 4 to 22 percent of the DOC pool. If soils are the intermediate reservoir, then the importance of riverine carbon in the ocean carbon cycle has been underestimated.

  9. Schwarzschild black hole as particle accelerator of spinning particles

    CERN Document Server

    Zaslavskii, O B

    2016-01-01

    It is shown that in the Schwarzschild background there exists direct counterpart of the Ba\\~{n}ados-Silk-West effect for spinning particles. This means that if two particles collide near the black hole horizon, their energy in the centre of mass frame can grow unbound. In doing so, the crucial role is played by so-called near-critical trajectories when particle's parameters are almost fine-tuned. Direct scenario of the collision under discussion is possible with restriction on the energy-to-mass ratio \\thinspace $E/m<\\frac{1}{2\\sqrt{3}}$ only. However, if one takes into account multiple scattering, this becomes possible for $E\\geq m$ as well.

  10. Simulations of phenol adsorption on activated carbon and carbon black

    OpenAIRE

    Prosenjak, Claudia; Valente Nabais, Joao; Laginhas, Carlos; Carrott, Peter; Carrott, Manuela

    2010-01-01

    We use grand canonical Monte Carlo and molecular dynamics simulations to study the adsorption of phenol on carbon materials. Activated carbon is modelled by pore size distributions based on DFT methods; carbon black is represented by a single carbon slab with varying percentages of surface atoms removed. GCMC results for the adsorption from the corresponding gas phase gave reasonable agreement with experimental adsorption results. MD simulations, that studied the influence of the presence of ...

  11. Pyrolytic carbon black composite and method of making the same

    Energy Technology Data Exchange (ETDEWEB)

    Naskar, Amit K.; Paranthaman, Mariappan Parans; Bi, Zhonghe

    2016-09-13

    A method of recovering carbon black includes the step of providing a carbonaceous source material containing carbon black. The carbonaceous source material is contacted with a sulfonation bath to produce a sulfonated material. The sulfonated material is pyrolyzed to produce a carbon black containing product comprising a glassy carbon matrix phase having carbon black dispersed therein. A method of making a battery electrode is also disclosed.

  12. Black carbon and fine particle emissions in Finnish residential wood combustion: Emission projections, reduction measures and the impact of combustion practices

    Science.gov (United States)

    Savolahti, Mikko; Karvosenoja, Niko; Tissari, Jarkko; Kupiainen, Kaarle; Sippula, Olli; Jokiniemi, Jorma

    2016-09-01

    Residential wood combustion (RWC) is a major source of black carbon (BC) and PM2.5 emissions in Finland. Making a robust assessment of emissions on a national level is a challenge due to the varying heater technologies and the effect of users' combustion practices. In this paper we present an update of the emission calculation scheme for Finnish RWC, including technology-specific emission factors based on national measurements. Furthermore, we introduce a transparent method to assess the impact of poor combustion practices on emissions. Using a Finnish emission model, we assessed the emissions in 2000, 2010 and 2030, as well as the cost-efficiency of potential emission reduction measures. The results show that RWC is the biggest source of both PM2.5 and BC emissions in Finland, accounting for 37% and 55% of the total respective emissions. It will also remain the biggest source in the future, and it's role may become even more pronounced if wood consumption continues to increase. Sauna stoves cause the most emissions and also show the biggest potential for emission reductions. Informational campaigns targeted to improve heater users' combustion practices appear as a highly cost-efficient measure, although their impact on country-level emissions was estimated to be relatively limited.

  13. Microwave irradiation on carbon black: Studies on the transformation of particles into nano-balls, nano-sticks and nano-onion like structures

    Science.gov (United States)

    Asokan, Vijayshankar; Venkatachalapathy, Vishnukanthan; Rajavel, Krishnamoorthy; Madsen, Dorte Nørgaard

    2016-12-01

    The solid-state transformation behavior of carbon black (CB) nanoparticles after irradiated with microwave energy was studied with and without influence of a metal catalyst. The CB sample was exposed to microwave radiation at power of 900 W from the oven and collected after 15 min and after 30 min and 45 min of irradiation. The samples were characterized using X-ray diffraction measurements, Raman spectroscopy, scanning electron microscopy, high-resolution transmission electron microscopy (HRTEM) and thermogravimetric analysis. Characterization of the samples prepared without catalyst shows that microwave irradiation can transform CB nanoparticles into nano-balls and nano-stick like structures. While nanoballs of almost 300-500 nm diameter are visible in all the samples irrespective of microwave irradiation time, amorphous nano-stick like structure are present only in the sample collected after 30 min of microwave irradiation. CB irradiated together with a metal catalyst resulted in metal-encapsulated onion like structures with perfectly arranged graphene layers.

  14. Studies of activated carbon and carbon black for supercapacitor applications

    Energy Technology Data Exchange (ETDEWEB)

    Richner, R.; Mueller, S.; Koetz, R.; Wokaun, A. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1999-08-01

    Carbon Black and activated carbon materials providing high surface areas and a distinct pore distribution are prime materials for supercapacitor applications at frequencies < 0.5 Hz. A number of these materials were tested for their specific capacitance, surface and pore size distribution. High capacitance electrodes were manufactured on the laboratory scale with attention to ease of processability. (author) 1 fig., 1 ref.

  15. Black carbon in deep-sea sediments

    OpenAIRE

    1998-01-01

    Black carbon (BC) enters the ocean through aerosol and river deposition. BC makes up 12 to 31 percent of the sedimentary organic carbon (SOC) at two deep ocean sites, and it is 2400 to 13,900 carbon-14 years older than non-BC SOC deposited concurrently. BC is likely older because it is stored in an intermediate reservoir before sedimentary deposition. Possible intermediate pools are oceanic dissolved organic carbon (DOC) and terrestrial soils. If DOC is the intermediate reservoir, then BC is ...

  16. Black hole particle emission in higher-dimensional spacetimes

    CERN Document Server

    Cardoso, V; Gualtieri, L; Cardoso, Vitor; Cavaglia, Marco; Gualtieri, Leonardo

    2006-01-01

    In models with extra dimensions, a black hole evaporates both in the bulk and on the visible brane, where standard model fields live. The exact emissivities of each particle species are needed to determine how the black hole decay proceeds. We compute and discuss the absorption cross-sections, the relative emissivities and the total power output of all known fields in the evaporation phase. Graviton emissivity is highly enhanced as the spacetime dimensionality increases. Therefore, a black hole loses a significant fraction of its mass in the bulk. This result has important consequences for the phenomenology of black holes in models with extra dimensions and black hole detection in particle colliders.

  17. Are there "black holes" in carbonate deposystems?

    OpenAIRE

    Wright, V.P.; Cherns, L.

    2009-01-01

    The likelihood that extensive dissolution of aragonite (and high magnesian calcite) takes place during very early burial, even in relatively shallow tropical settings, has wide implications for interpreting and modelling ancient limestones. Some low energy environments may constitute net sinks (“black holes”) for carbonates. If this is the case attempts to model sediment budgets and develop depth-productivity profiles for carbonate systems require as yet unavailable quantitative data on the e...

  18. Modified carbon black materials for lithium-ion batteries

    Science.gov (United States)

    Kostecki, Robert; Richardson, Thomas; Boesenberg, Ulrike; Pollak, Elad; Lux, Simon

    2016-06-14

    A lithium (Li) ion battery comprising a cathode, a separator, an organic electrolyte, an anode, and a carbon black conductive additive, wherein the carbon black has been heated treated in a CO.sub.2 gas environment at a temperature range of between 875-925 degrees Celsius for a time range of between 50 to 70 minutes to oxidize the carbon black and reduce an electrochemical reactivity of the carbon black towards the organic electrolyte.

  19. Black carbon concentrations and mixing state in the Finnish Arctic

    Science.gov (United States)

    Raatikainen, T.; Brus, D.; Hyvärinen, A.-P.; Svensson, J.; Asmi, E.; Lihavainen, H.

    2015-09-01

    Atmospheric aerosol composition was measured using a Single Particle Soot Photometer (SP2) in the Finnish Arctic during winter 2011-2012. The Sammaltunturi measurement site at the Pallas GAW (Global Atmosphere Watch) station receives air masses from different source regions including the Arctic Ocean and continental Europe. The SP2 provides detailed information about mass distributions and mixing state of refractory black carbon (rBC). The measurements showed widely varying rBC mass concentrations (0-120 ng m-3), which were related to varying contributions of different source regions and aerosol removal processes. The rBC mass was log-normally distributed showing a relatively constant rBC core mass mean diameter with an average of 194 nm (75-655 nm sizing range). On average, the number fraction of particles containing rBC was 0.24 (integrated over 350-450 nm particle diameter range) and the average particle diameter to rBC core volume equivalent diameter ratio was 2.0 (averaged over particles with 150-200 nm rBC core volume equivalent diameters). These average numbers mean that the observed rBC core mass mean diameter is similar to those of aged particles, but the observed particles seem to have unusually high particle to rBC core diameter ratios. Comparison of the measured rBC mass concentration with that of the optically detected equivalent black carbon (eBC) using an Aethalometer and a MAAP showed that eBC was larger by a factor of five. The difference could not be fully explained without assuming that only a part of the optically detected light absorbing material is refractory and absorbs light at the wavelength used by the SP2. Finally, climate implications of five different black carbon mixing state representations were compared using the Mie approximation and simple direct radiative forcing efficiency calculations. These calculations showed that the observed mixing state means significantly lower warming effect or even a net cooling effect when compared with

  20. Massive particle radiation from Gibbons-Maeda black hole

    Institute of Scientific and Technical Information of China (English)

    Fang Heng-Zhong

    2010-01-01

    This paper investigated the massive particle radiation from Gibbous-Maeda black hole by using a semi-classical method. The calculations showed that, if the self-gravitation of the radiated particle is taken into account, the radiation spectrum deviates from exact black body spectrum and the rate of tunneling equals precisely the exponent of the difference of the black hole entropies before and after emission. The conclusion supports the viewpoint of information conservation.

  1. Opportunities and Challenges for Being a Carbon Black Great Power

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

    1. The "Uth Five-year Plan" Lay- ing the Foundation for Carbon Black Great Power 1.1 Rapid growth of carbon black output and production capacity During the "llth Five-year Plan" Period, China carbon black output was increased by 1.1 times and realized doubling; and the production capacity of carbon black realized an average annu- al growth of 16.9%. In 2011, the carbon black output was 3.853 million tons, increased by 14.2% compared with that of the last year, and the pro- portion of carbon black output in the world carbon black output was increased from 16% to 36%. The carbon black production capacity was 5.345 mil- lion tons, increased by 6% compared with that of the last year, and the proportion of carbon black production capacity in the world carbon black out- put reached 38%. Chinese carbon black output has been ranking the 1st place throughout the world for 6 years successively, and China has become a great power of carbon black production in the world.

  2. Short-term effects of tillage practices on soil organic carbon turnover assessed by δ13C abundance in particle-size fractions of black soils from northeast China.

    Science.gov (United States)

    Liang, Aizhen; Chen, Shenglong; Zhang, Xiaoping; Chen, Xuewen

    2014-01-01

    The combination of isotope trace technique and SOC fractionation allows a better understanding of SOC dynamics. A five-year tillage experiment consisting of no-tillage (NT) and mouldboard plough (MP) was used to study the changes in particle-size SOC fractions and corresponding δ (13)C natural abundance to assess SOC turnover in the 0-20 cm layer of black soils under tillage practices. Compared to the initial level, total SOC tended to be stratified but showed a slight increase in the entire plough layer under short-term NT. MP had no significant impacts on SOC at any depth. Because of significant increases in coarse particulate organic carbon (POC) and decreases in fine POC, total POC did not remarkably decrease under NT and MP. A distinct increase in silt plus clay OC occurred in NT plots, but not in MP plots. However, the δ (13)C abundances of both coarse and fine POC increased, while those of silt plus clay OC remained almost the same under NT. The C derived from C3 plants was mainly associated with fine particles and much less with coarse particles. These results suggested that short-term NT and MP preferentially enhanced the turnover of POC, which was considerably faster than that of silt plus clay OC.

  3. Cycling of black carbon in the ocean

    OpenAIRE

    2016-01-01

    Black carbon (BC) is a byproduct of combustion from wildfires and fossil fuels and is a slow-cycling component of the carbon cycle. Whether BC accumulates and ages on millennial timescales in the world oceans has remained unknown. Here, we quantified dissolved BC (DBC) in marine dissolved organic carbon (DOC) isolated by solid phase extraction (SPE) at several sites in the world ocean. We find that DBC in the Atlantic, Pacific and Arctic oceans ranges from 1.4 to 2.6 μM in the surface and is ...

  4. Retrieval of Black Carbon Absorption from Proposed Satellite Measurements Over the Ocean Glint

    Science.gov (United States)

    Kaufman, Y. J.; Matins, J. V.; Remer, L. A.; Schoeberl, M. R.; Yamasoe, M. A.; Lau, William K. M. (Technical Monitor)

    2001-01-01

    Haze and air pollution includes many chemicals that together form small particles suspended in the air called aerosols. One of the main ingredients found to affect climate and human health is Black Carbon. Black particles emitted from engines that do not burn the fuel completely, e.g. old trucks. Black carbon absorption of sunlight emerges as one of the key components of man-made forcing of climate. However, global characterization of black carbon emissions, distribution and pathways in which it can affect the amount of solar radiation absorbed by the atmosphere is very uncertain. A new method is proposed to measure sunlight absorption by fine aerosol particles containing black carbon over the ocean glint from a satellite mission designed for this purpose. The satellite will scan the same spot over the ocean in the glint plane and a plane 40 degrees off-glint a minute apart, collecting measurements of the reflected light across the solar spectrum. First the dark ocean off the glint is used to derive aerosol properties. Then the black carbon absorption is derived prop the attenuation of the bright glint by the aerosol layer. Such measurements if realized in a proposed future mission - COBRA are expected to produce global monthly climatology of black carbon absorption with high accuracy (110 to 15%) that can show their effect on climate.

  5. Massive Particle's Tunnelling from Black Hole with Topological Defect

    Institute of Scientific and Technical Information of China (English)

    HAN Yi-Wen

    2007-01-01

    We extend Zhang and Zhao's recent work to black hole with topological defect whose Arnowitt-Deser-Misner mass is no longer identical to its mass parameter. The behaviour of the tunnelling massive particles is investigated,and the emission rate at which massive particles tunnel across the event horizon of the black hole is calculated.The result is consistent with an underlying unitary theory, and takes the same functional form as that of mass-less particles.

  6. Effect of carbon-black treatment by radiation emulsion polymerization on temperature dependence of resistivity of carbon-black-filled polymer blends

    Energy Technology Data Exchange (ETDEWEB)

    Jia Shaojin [Key Lab of Insulation and Thermal of Aging of Shanghai, Department of Polymer Engineering and Science, Shanghai Jiao Tong University, Dongchuan Road 800, Shanghai 200240 (China) and Department of Chemical Engineering, Shanghai University, Chengzhong Road 20, Shanghai 201800 (China)]. E-mail: jiashaojin2@yahoo.com.cn; Jiang Pingkai [Key Lab of Insulation and Thermal of Aging of Shanghai, Department of Polymer Engineering and Science, Shanghai Jiao Tong University, Dongchuan Road 800, Shanghai 200240 (China); Zhang Zhicheng [Department of Polymer Science and Engineering, University of Science and Technology of China, Hefei, Anhui 230026 (China); Wang Zhongguang [Key Lab of Insulation and Thermal of Aging of Shanghai, Department of Polymer Engineering and Science, Shanghai Jiao Tong University, Dongchuan Road 800, Shanghai 200240 (China)

    2006-04-15

    High dispersibility and stability of carbon black particles in low-density-polyethylene (LDPE) matrix were obtained by radiation emulsion polymerization on carbon particles surface, and electrical resistivities of its simple were examined. First carbon particles treatment on radiation emulsion polymerization on surface were synthesized by the reaction with a polymer-emulsion systems containing reactive group in the molecular unit, carbon particles and emulsifier. Then, the carbon particles treatment on radiation emulsion polymerization on surface was dispersed into LDPE, and its composites were prepared for electrical measurements. The effect of radiation crosslinking of the composite on the Positive temperature coefficient (PTC) and negative temperature coefficient (NTC) phenomenon was investigated. The experimental results showed that PTC and NTC effects of the composites were obviously influenced by the irradiation dose. Various microstructure-exploring means were used to study the conductive composite, such as scanning electron microscopy (SEM), X-ray diffraction (XRD) and transmission electron microscopy (TEM)

  7. Effect of carbon-black treatment by radiation emulsion polymerization on temperature dependence of resistivity of carbon-black-filled polymer blends

    Science.gov (United States)

    Shaojin, Jia; Pingkai, Jiang; Zhicheng, Zhang; Zhongguang, Wang

    2006-04-01

    High dispersibility and stability of carbon black particles in low-density-polyethylene (LDPE) matrix were obtained by radiation emulsion polymerization on carbon particles surface, and electrical resistivities of its simple were examined. First carbon particles treatment on radiation emulsion polymerization on surface were synthesized by the reaction with a polymer-emulsion systems containing reactive group in the molecular unit, carbon particles and emulsifier. Then, the carbon particles treatment on radiation emulsion polymerization on surface was dispersed into LDPE, and its composites were prepared for electrical measurements. The effect of radiation crosslinking of the composite on the Positive temperature coefficient (PTC) and negative temperature coefficient (NTC) phenomenon was investigated. The experimental results showed that PTC and NTC effects of the composites were obviously influenced by the irradiation dose. Various microstructure-exploring means were used to study the conductive composite, such as scanning electron microscopy (SEM), X-ray diffraction (XRD) and transmission electron microscopy (TEM).

  8. Black carbon measurements using an integrating sphere

    Science.gov (United States)

    Hitzenberger, R.; Dusek, U.; Berner, A.

    1996-08-01

    An integrating sphere was used to determine the black carbon (BC) content of aerosol filter samples dissolved in chloroform (method originally described by Heintzenberg [1982]). The specific absorption coefficient Ba (equal to absorption per mass) of the samples was also measured using the sphere as an integrating detector for transmitted light. Comparing the Ba of ambient samples taken in Vienna, Austria, to the BC concentrations measured on the dissolved filters, a value of approximately 6 m2/g was found to be a reasonable value for the Ba of the black carbon found at the site. The size dependence of Ba of a nebulized suspension of soot was measured using a rotating impactor, and a reasonable agreement between measured and calculated values was found.

  9. Influence of sample composition on aerosol organic and black carbon determinations

    Energy Technology Data Exchange (ETDEWEB)

    Novakov, T.; Corrigan, C.E.

    1995-07-01

    In this paper we present results on characterization of filter-collected redwood (Sequoia sempevirens)-needle and eucalyptus smoke particles by thermal, optical, and solvent extraction methods. Our results demonstrate that organic and black carbon concentrations determined by thermal and optical methods are not only method dependent, but also critically influenced by the overall chemical composition of the samples. These conclusions are supported by the following: (1) the organic fraction of biomass smoke particles analyzed includes a component, ranging in concentration from about 6-20% of total carbon or from 16-30% of organic carbon, that is relatively non-volatile and has a combustion temperature close to that of black carbon; (2) presence of K or Na in biomass smoke samples lowers the combustion temperatures of this organic component and of black carbon, making their combustion properties indistinguishable; (3) about 20% of total organic material is nonvolatile when heated to 550{degrees}C in an inert atmosphere. Consequently, thermal methods that rely on a specific temperature to separate organic from black carbon may either underestimate or overestimate the black and organic carbon concentrations, depending on the amounts of Na and K and on the composition and concentration of organic material present in a sample. These analytical uncertainties and, under some conditions, absorption by organic material may contribute to the variability of empirically derived proportionality between light transmission through filter deposits and black carbon concentrations.

  10. Destroying Kerr-Sen black holes with test particles

    CERN Document Server

    Siahaan, Haryanto M

    2015-01-01

    By neglecting the self-force, self-energy, and radiative effects, it has been shown that an extremal or near-extremal Kerr-Newman black hole can turn to a naked singularity when it captures charged massive test particles with angular momentum. A straightforward question then arises, do charged and rotating black holes in string theory possess the same property? In this paper we adopt the Wald's gedanken experiment in an effort to destroy a Kerr-Newman black hole's horizon to the case of (near)-extremal Kerr-Sen black holes. We find that feeding a test particle into a (near)-extremal Kerr-Sen black hole could lead to a violation of the extremal bound for such black hole.

  11. Kerr black holes as particle accelerators to arbitrarily high energy.

    Science.gov (United States)

    Bañados, Máximo; Silk, Joseph; West, Stephen M

    2009-09-11

    We show that intermediate mass black holes conjectured to be the early precursors of supermassive black holes and surrounded by relic cold dark matter density spikes can act as particle accelerators with collisions, in principle, at arbitrarily high center-of-mass energies in the case of Kerr black holes. While the ejecta from such interactions will be highly redshifted, we may anticipate the possibility of a unique probe of Planck-scale physics.

  12. Black Carbon Contribution to Organic Carbon Stocks in Urban Soil

    DEFF Research Database (Denmark)

    Edmondson, Jill L.; Stott, Iain; Potter, Jonathan;

    2015-01-01

    Soil holds 75% of the total organic carbon (TOC) stock in terrestrial ecosystems. This comprises ecosystem-derived organic carbon (OC) and black carbon (BC), a recalcitrant product of the incomplete combustion of fossil fuels and biomass. Urban topsoils are often enriched in BC from historical...... increased with soil depth, and was enriched in topsoil under trees when compared to grassland. Our findings establish the importance of urban ecosystems in storing large amounts of OC in soils and that these soils also capture a large proportion of BC particulates emitted within urban areas....

  13. Characteristics of Black Carbon at Wuqing Observed by Single Particle Soot Photometer%天津武清地区单颗粒黑碳气溶胶特征观测分析

    Institute of Scientific and Technical Information of China (English)

    安林昌; 孙俊英; 张养梅; 沈小静; 王婷婷; 梁文德; 陈丽丽

    2011-01-01

    Black carbon (BC) plays a significant role in climate change, which has attracts increasing research interest. Single Particle Soot Photometer (SP2) is used at Wuqing Meteorological Station in Tianjin. SP2 u-tilizes the high optical power available intra-cavity from a Nd: YAG laser as the analytical technique. Light absorbing particles, mainly BC in atmosphere, absorb sufficient energy and are heated to the point of incandescence. The energy emitted in this incandescence is measured, and quantitatively determine the mass of the particle. SP2 operates in a single particle mode, measuring the light scattering and incandescence of each particle. Through the time delay between the two signals, the mixing state of BC particles can be obtained. SP2 is different from the traditional filter-based method which could provide more accurate information on single BC particle properties. First, SP2 could count the BC particles individually, so BC number concentration could be given; second, SP2 measures the mass of each BC particle, which could be converted to particle size; finally, SP2 could give the information on BC mixing state, which is important for estimating the aerosol effect on climate change.The observation taken at Wuqing in December 2009 shows that the average number concentration of BC is 1504 cm-3, with the maximum 5050 cm-3 and the minimum 46. 8 cm-3. The number of BC particles occupies 57. 2% of the aerosol particles measured by SP2. The average number concentration of non-absorbing aerosol is 1124 cm-3, with the maximum 3311 cm-3 and the minimum 70. 7 cm-3. The average mass concentration of BC is 8. 15 μg/m3. 51. 5% of BC particles are thickly coated. On a clear windy day, the daily average number concentration is 215 cm-3 ,the mass concentration is 1.17 μg/m3, and 40. 2% of them are mixed. However in the seriously polluted case, the daily average number concentration is 3169 cm-3 ,the mass concentration reaches 17. 2 μg/m3, and the ratio of mixed BC also

  14. Evaluation of Methods for the Determination of Black Carbon Emissions from an Aircraft Gas Turbine Engine

    Science.gov (United States)

    The emissions from aircraft gas turbine engines consist of nanometer size black carbon (BC) particles plus gas-phase sulfur and organic compounds which undergo gas-to-particle conversion downstream of the engine as the plume cools and dilutes. In this study, four BC measurement ...

  15. Modified Wave Particle Duality and Black Hole Physics

    Institute of Scientific and Technical Information of China (English)

    LI Xiang

    2007-01-01

    de Broglie relation is revisited, in consideration of a generalization of canonical commuting relation. The possible effects on particle's localization and black hole physics are also discussed, in a heuristic manner.

  16. Dynamics of Particles Near Black Hole with Higher Dimensions

    CERN Document Server

    Sharif, M

    2016-01-01

    This paper explores the dynamics of particles in higher dimensions. For this purpose, we discuss some interesting features related to the motion of particles near Myers-Perry black hole with arbitrary extra dimensions as well as single non-zero spin parameter. Assuming it as a supermassive black hole at the center of galaxy, we calculate red-blue shifts in the equatorial plane for the far away observer as well as corresponding black hole parameters of the photons. Next, we study the Penrose process and find that the energy gain of particle depends on the variation of black hole dimensions. Finally, we discuss the center of mass energy for eleven dimensions which indicates similar behavior as that of four dimensions but it is higher in four dimensions than five or more dimensions. We conclude that higher dimensions have a great impact on the particle dynamics.

  17. Tunneling of massive particles from noncommutative Schwarzschild black hole

    CERN Document Server

    Miao, Yan-Gang; Zhang, Shao-Jun

    2010-01-01

    We apply the generalization of the Parikh-Wilczek method to the tunneling of massive particles from noncommutative Schwarzschild black holes. By deriving the equation of radial motion of the tunneling particle directly, we calculate the emission rate which is shown to be dependent on the noncommutative parameter besides the energy and mass of the tunneling particle. After equating the emission rate to the Boltzmann factor, we obtain the modified Hawking temperature which relates to the noncommutativity and recovers the standard Hawking temperature in the commutative limit. We also discuss the entropy of the noncommutative Schwarzchild black hole and its difference after and before a massive particle's emission.

  18. Recommendations for the interpretation of "black carbon" measurements

    Directory of Open Access Journals (Sweden)

    A. Petzold

    2013-04-01

    Full Text Available Although black carbon (BC is one of the key atmospheric particulate components driving climate change and air quality, there is no agreement on the terminology that considers all aspects of specific properties, definitions, measurement methods, and related uncertainties. As a result, there is much ambiguity in the scientific literature of measurements and numerical models that refer to BC with different names and based on different properties of the particles, with no clear definition of the terms. The authors present here a recommended terminology to clarify the terms used for BC in atmospheric research, with the goal of establishing unambiguous links between terms, targeted material properties and associated measurement techniques.

  19. Characterization of PM2.5 particles originating from a modern waste incineration plant by factor analysis of chemical data, mass and black carbon in ambient aerosol

    DEFF Research Database (Denmark)

    Aboh, Innocent Joy Kwame; Henrikson, Dag; Laursen, Jens

    contribute to PM2.5 in urban air. Thus, the general problem is to characterise and identify the particle pollution, which can be attributed to gases and/or particles emitted by the waste incineration plant. For this reason aerosol samples, PM2.5, were collected and analyzed for concentrations of twenty...... are subject to restrictions are well below the allowed limits as stated by Swedish and European standards. The aim of the present work is to study the particle pollutants with emphasis on PM2.5 in the ambient air and to identify the specific contribution from the new incineration plant. Many different sources...

  20. Black holes are neither particle accelerators nor dark matter probes.

    Science.gov (United States)

    McWilliams, Sean T

    2013-01-04

    It has been suggested that maximally spinning black holes can serve as particle accelerators, reaching arbitrarily high center-of-mass energies. Despite several objections regarding the practical achievability of such high energies, and demonstrations past and present that such large energies could never reach a distant observer, interest in this problem has remained substantial. We show that, unfortunately, a maximally spinning black hole can never serve as a probe of high energy collisions, even in principle and despite the correctness of the original diverging energy calculation. Black holes can indeed facilitate dark matter annihilation, but the most energetic photons can carry little more than the rest energy of the dark matter particles to a distant observer, and those photons are actually generated relatively far from the black hole where relativistic effects are negligible. Therefore, any strong gravitational potential could probe dark matter equally well, and an appeal to black holes for facilitating such collisions is unnecessary.

  1. Carbon fuel particles used in direct carbon conversion fuel cells

    Science.gov (United States)

    Cooper, John F.; Cherepy, Nerine

    2012-10-09

    A system for preparing particulate carbon fuel and using the particulate carbon fuel in a fuel cell. Carbon particles are finely divided. The finely dividing carbon particles are introduced into the fuel cell. A gas containing oxygen is introduced into the fuel cell. The finely divided carbon particles are exposed to carbonate salts, or to molten NaOH or KOH or LiOH or mixtures of NaOH or KOH or LiOH, or to mixed hydroxides, or to alkali and alkaline earth nitrates.

  2. Simplifying the calculation of light scattering properties for black carbon fractal aggregates

    Directory of Open Access Journals (Sweden)

    A. J. A. Smith

    2014-08-01

    Full Text Available Black carbon fractal aggregates have complicated shapes that make the calculation of their optical properties particularly computationally expensive. Here, a method is presented to estimate fractal aggregate light scattering properties by optimising simplified models to full light scattering calculations. It is found that there are no possible spherical models (at any size or refractive index that well represent the light scattering in the visible or near-thermal infrared. As such, parameterisations of the light scattering as a function of the number of aggregate particles is presented as the most pragmatic choice for modelling distributions of black carbon when the large computational overheads of rigorous scattering calculations cannot be justified. This parameterisation can be analytically integrated to provide light scattering properties for lognormal distributions of black carbon fractal aggregates and return extinction cross sections with 0.1% accuracy for typical black carbon size distributions. Scattering cross sections and the asymmetry parameter can be obtained to within 3%.

  3. Simplifying the calculation of light scattering properties for black carbon fractal aggregates

    Science.gov (United States)

    Smith, A. J. A.; Grainger, R. G.

    2014-02-01

    Black carbon fractal aggregates have complicated shapes that make the calculation of their optical properties particularly computationally expensive. Here, a method is presented to estimate fractal aggregate light scattering properties by optimising simplified models to full light scattering calculations. It is found that there are no possible spherical models (at any size or refractive index) that well represent the light scattering in the visible, or near-thermal infrared. As such, parameterisations of the light scattering as a function of the number of aggregate particles is presented as the most pragmatic choice for modelling distributions of black carbon when the large computational overheads of rigorous scattering calculations cannot be justified. This parameterisation can be analytically integrated to provide light scattering properties for log-normal distributions of black carbon fractal aggregates and return extinction cross-sections with 0.1% accuracy for typical black carbon size distributions. Scattering cross-sections and the asymmetry parameter can be obtained to within 3%.

  4. Endothelial dysfunction in normal and prediabetic rats with metabolic syndrome exposed by oral gavage to carbon black nanoparticles

    DEFF Research Database (Denmark)

    Folkmann, Janne Kjærsgaard; Vesterdal, Lise Kristine; Sheykhzade, Majid

    2012-01-01

    Exposure to nanosized particles may increase the risk of cardiovascular diseases by endothelial dysfunction, particularly in susceptible subjects with metabolic syndrome. We investigated vasomotor dysfunction in aorta from obese and lean Zucker rats after oral exposure to nanosized carbon black (...

  5. Magnetized Particle Motion Around Black Hole in Braneworld

    CERN Document Server

    Rahimov, Ozodbek

    2010-01-01

    We investigate the motion of a magnetized particle orbiting around a black hole in braneworld placed in asymptotically uniform magnetic field. The influence of brane parameter on effective potential of the radial motion of magnetized spinning particle around the braneworld black hole using Hamilton-Jacobi formalism is studied. It is found that circular orbits for photons and slowly moving particles may become stable near $r = 3M$. It was argued that the radii of the innermost stable circular orbits are sensitive on the change of brane parameter. Similar discussion without Weil parameter has been considered by de Felice et all in~Ref. \\refcite{rs99,98}.

  6. Quantum hoop conjecture: Black hole formation by particle collisions

    Energy Technology Data Exchange (ETDEWEB)

    Casadio, Roberto, E-mail: casadio@bo.infn.it [Dipartimento di Fisica e Astronomia, Università di Bologna, via Irnerio 46, 40126 Bologna (Italy); I.N.F.N., Sezione di Bologna, viale Berti Pichat 6/2, 40127 Bologna (Italy); Micu, Octavian, E-mail: octavian.micu@spacescience.ro [Institute of Space Science, Bucharest, P.O. Box MG-23, RO-077125 Bucharest-Magurele (Romania); Scardigli, Fabio, E-mail: fabio@phys.ntu.edu.tw [Dipartimento di Matematica, Politecnico di Milano, Piazza L. da Vinci 32, 20133 Milano (Italy); Yukawa Institute for Theoretical Physics, Kyoto University, Kyoto 606-8502 (Japan)

    2014-05-01

    We address the issue of (quantum) black hole formation by particle collision in quantum physics. We start by constructing the horizon wave-function for quantum mechanical states representing two highly boosted non-interacting particles that collide in flat one-dimensional space. From this wave-function, we then derive a probability that the system becomes a black hole as a function of the initial momenta and spatial separation between the particles. This probability allows us to extend the hoop conjecture to quantum mechanics and estimate corrections to its classical counterpart.

  7. Study of Black Sand Particles from Sand Dunes in Badr, Saudi Arabia Using Electron Microscopy

    Directory of Open Access Journals (Sweden)

    Haider Abbas Khwaja

    2015-08-01

    Full Text Available Particulate air pollution is a health concern. This study determines the microscopic make-up of different varieties of sand particles collected at a sand dune site in Badr, Saudi Arabia in 2012. Three categories of sand were studied: black sand, white sand, and volcanic sand. The study used multiple high resolution electron microscopies to study the morphologies, emission source types, size, and elemental composition of the particles, and to evaluate the presence of surface “coatings or contaminants” deposited or transported by the black sand particles. White sand was comprised of natural coarse particles linked to wind-blown releases from crustal surfaces, weathering of igneous/metamorphic rock sources, and volcanic activities. Black sand particles exhibited different morphologies and microstructures (surface roughness compared with the white sand and volcanic sand. Morphological Scanning Electron Microscopy (SEM and Laser Scanning Microscopy (LSM analyses revealed that the black sand contained fine and ultrafine particles (50 to 500 nm ranges and was strongly magnetic, indicating the mineral magnetite or elemental iron. Aqueous extracts of black sands were acidic (pH = 5.0. Fe, C, O, Ti, Si, V, and S dominated the composition of black sand. Results suggest that carbon and other contaminant fine particles were produced by fossil-fuel combustion and industrial emissions in heavily industrialized areas of Haifa and Yanbu, and transported as cloud condensation nuclei to Douf Mountain. The suite of techniques used in this study has yielded an in-depth characterization of sand particles. Such information will be needed in future environmental, toxicological, epidemiological, and source apportionment studies.

  8. Overspinning BTZ black holes with test particles and fields

    Science.gov (United States)

    Düztaş, Koray

    2016-12-01

    It has been claimed that in a test of an asymptotically anti-de Sitter version of weak cosmic censorship conjecture by attempting to overspin a Bañados, Teitelboim, and Zanelli (BTZ) black hole with test particles, one finds that it is not possible to spin up the black hole past its extremal limit. The result of this analysis is restricted to the case where the initial black hole is extremal. We extend this analysis to find that massive test particles can overspin the black hole, if we start with a nearly extremal black hole, instead. We also consider the interaction of the BTZ black hole with test fields. We show that overspinning of nearly extremal black holes is possible whether or not there is super-radiance for the field. If there is super-radiance, overspinning occurs in a narrow range of frequencies bounded below by the super-radiant limit. However, if there is no super-radiance for the field, overspinning becomes generic and also applies to extremal black holes. This is in analogy with the Kerr case.

  9. Dynamics of particles around time conformal Schwarzschild black hole

    Energy Technology Data Exchange (ETDEWEB)

    Jawad, Abdul; Shahzad, M.U. [COMSATS Institute of Information Technology, Department of Mathematics, Lahore (Pakistan); Ali, Farhad [Kohat University of Science and Technology, Department of Mathematics, Kohat (Pakistan); Abbas, G. [The Islamia University of Bahawalpur, Department of Mathematics, Bahawalpur (Pakistan)

    2016-11-15

    In this work, we present the new technique for discussing the dynamical motion of neutral as well as charged particles in the absence/presence of a magnetic field around the time conformal Schwarzschild black hole. Initially, we find the numerical solutions of geodesics of the Schwarzschild black hole and the time conformal Schwarzschild black hole. We observe that the Schwarzschild spacetime admits the time conformal factor e{sup εf(t)}, where f(t) is an arbitrary function and ε is very small, which causes a perturbation in the spacetimes. This technique also re-scales the energy content of spacetime. We also investigate the thermal stability, horizons and energy conditions corresponding to time conformal Schwarzschild spacetime. Also, we examine the dynamics of a neutral and charged particle around a time conformal Schwarzschild black hole. We investigate the circumstances under which the particle can escape from the vicinity of a black hole after collision with another particle. We analyze the effective potential and effective force of a particle in the presence of a magnetic field with angular momentum graphically. (orig.)

  10. Supply Deficit of Feedstock Oils for Carbon Black

    Institute of Scientific and Technical Information of China (English)

    Li Bingyan

    2007-01-01

    @@ Feedstock oils used for carbon blackproduction mainly include ethylene tar,anthracene oil and coal tar. With thegrowing output of carbon black in re-cent years, demand for feedstock oilshas increased constantly.

  11. Surface analysis of carbon black waste materials from tire residues

    Science.gov (United States)

    Lee, W. H.; Kim, J. Y.; Ko, Y. K.; Reucroft, P. J.; Zondlo, J. W.

    1999-03-01

    X-ray photoelectron spectroscopy (XPS) has been used to obtain surface chemical state information on two carbon black waste materials in terms of the surface element distribution/concentration and chemical structure. Small amounts of sulfur in the form of CS 2 were detected on the surface (less than 1.7 mass %). C-H/C-C was the major carbon functional component on the surface of carbon black samples but other functional forms of carbon were also present such as CO and C-O. The surface of the carbon black obtained from a hydropyrolysis process was highly oxidized primarily in the form of carbon based oxygen groups. On the other hand, surface oxygen atoms on the surface of the carbon black obtained from a pyrolysis process in the absence of H 2 were in the form of both metal oxides and carbon based oxygen groups.

  12. Particle motion and collisions around rotating regular black hole

    CERN Document Server

    Toshmatov, Bobir; Ahmedov, Bobomurat; Stuchlík, Zdenek

    2014-01-01

    The neutral particle motion around rotating regular black hole that was derived from the Ay\\'{o}n-Beato-Garc\\'{i}a black hole solution by the Newman-Janis algorithm in the preceding paper [Phys. Rev. D 89, 104017, (2014)] has been studied. The dependencies of the ISCO (innermost stable circular orbits along geodesics) and unstable orbits on the value of the electric charge of the rotating regular black hole have been shown. Energy extraction from the rotating regular black hole through various processes has been examined. We have found expression of the center of mass energy for the colliding neutral particles coming from infinity, based on the BSW (Ba\\v{n}ados-Silk-West) mechanism. The electric charge $Q$ of rotating regular black hole decreases the potential of the gravitational field and the particle needs less bound energy at the circular geodesics. This causes the increase of efficiency of the energy extraction through BSW process in the presence of the electric charge $Q$ from rotating regular black hol...

  13. Effect of sterilization on mineralization of straw and black carbon

    DEFF Research Database (Denmark)

    Bobul'ská, Lenka; Bruun, Sander; Fazekašová, Danica

    2013-01-01

    The study was aimed at investigating the role of microorganisms in the degradation of BC (black carbon). CO evolution was measured under sterilized and non-sterilized soil using BC and straw amendments. Black carbon and straw were produced from homogenously C labelled roots of barley (Hordeum vul...... abiotic source must also be present perhaps abiotic mineralization of labile BC components....

  14. Preparation of Waterborne Nanoscale Carbon Black Dispersion with Sodium Carboxymethyl Cellulose

    Institute of Scientific and Technical Information of China (English)

    YUAN Xia; FANG Kuan-jun

    2006-01-01

    Waterborne nanoscale carbon black dispersion (NCBD) was widely used in inkjet printing, spun-dyeing fibers and coloration fabrics. In this paper, NCBD was prepared using sodium carboxymethyl cellulose (CMC) as dispersant.Effects of CMC viscosity, ultrasonic time and oxidation with hydrogen peroxide on carbon black (CB) particle size were discussed. The results showed that CB particle size decreased by mechanical agitation while it increased by ultrasonic with the increase of CMC viscosity. Ultrasonic is a more effective method to disperse CB particles than that of mechanical agitation. CB particle size obviously decreased with increasing ultrasonic time and arrived at about 160 nm for 60 min. In addition, oxidation with 2 mol/L of H2O2 and 0.2 wt% of CMC300 reduced CB particle size to 160 nm at 90℃ for 2.5 h.

  15. Thermal properties of carbon black aqueous nanofluids for solar absorption.

    Science.gov (United States)

    Han, Dongxiao; Meng, Zhaoguo; Wu, Daxiong; Zhang, Canying; Zhu, Haitao

    2011-07-18

    In this article, carbon black nanofluids were prepared by dispersing the pretreated carbon black powder into distilled water. The size and morphology of the nanoparticles were explored. The photothermal properties, optical properties, rheological behaviors, and thermal conductivities of the nanofluids were also investigated. The results showed that the nanofluids of high-volume fraction had better photothermal properties. Both carbon black powder and nanofluids had good absorption in the whole wavelength ranging from 200 to 2,500 nm. The nanofluids exhibited a shear thinning behavior. The shear viscosity increased with the increasing volume fraction and decreased with the increasing temperature at the same shear rate. The thermal conductivity of carbon black nanofluids increased with the increase of volume fraction and temperature. Carbon black nanofluids had good absorption ability of solar energy and can effectively enhance the solar absorption efficiency.

  16. Thermal properties of carbon black aqueous nanofluids for solar absorption

    Science.gov (United States)

    Han, Dongxiao; Meng, Zhaoguo; Wu, Daxiong; Zhang, Canying; Zhu, Haitao

    2011-07-01

    In this article, carbon black nanofluids were prepared by dispersing the pretreated carbon black powder into distilled water. The size and morphology of the nanoparticles were explored. The photothermal properties, optical properties, rheological behaviors, and thermal conductivities of the nanofluids were also investigated. The results showed that the nanofluids of high-volume fraction had better photothermal properties. Both carbon black powder and nanofluids had good absorption in the whole wavelength ranging from 200 to 2,500 nm. The nanofluids exhibited a shear thinning behavior. The shear viscosity increased with the increasing volume fraction and decreased with the increasing temperature at the same shear rate. The thermal conductivity of carbon black nanofluids increased with the increase of volume fraction and temperature. Carbon black nanofluids had good absorption ability of solar energy and can effectively enhance the solar absorption efficiency.

  17. Thermal properties of carbon black aqueous nanofluids for solar absorption

    Directory of Open Access Journals (Sweden)

    Han Dongxiao

    2011-01-01

    Full Text Available Abstract In this article, carbon black nanofluids were prepared by dispersing the pretreated carbon black powder into distilled water. The size and morphology of the nanoparticles were explored. The photothermal properties, optical properties, rheological behaviors, and thermal conductivities of the nanofluids were also investigated. The results showed that the nanofluids of high-volume fraction had better photothermal properties. Both carbon black powder and nanofluids had good absorption in the whole wavelength ranging from 200 to 2,500 nm. The nanofluids exhibited a shear thinning behavior. The shear viscosity increased with the increasing volume fraction and decreased with the increasing temperature at the same shear rate. The thermal conductivity of carbon black nanofluids increased with the increase of volume fraction and temperature. Carbon black nanofluids had good absorption ability of solar energy and can effectively enhance the solar absorption efficiency.

  18. Mesozoic black shales, source mixing and carbon isotopes

    Science.gov (United States)

    Suan, Guillaume

    2016-04-01

    Over the last decades, considerable attention has been devoted to the paleoenvironmental and biogeochemical significance of Mesozoic black shales. Black shale-bearing successions indeed often display marked changes in the organic carbon isotope composition (δ13Corg), which have been commonly interpreted as evidence for dramatic perturbations of global carbon budgets and CO2 levels. Arguably the majority of these studies have discarded some more "local" explanations when interpreting δ13Corg profiles, most often because comparable profiles occur on geographically large and distant areas. Based on newly acquired data and selected examples from the literature, I will show that the changing contribution of organic components with distinct δ13C signatures exerts a major but overlooked influence of Mesozoic δ13Corg profiles. Such a bias occurs across a wide spectrum of sedimentological settings and ages, as shown by the good correlation between δ13Corg values and proxies of kerogen proportions (such as rock-eval, biomarker, palynofacies and palynological data) recorded in Mesozoic marginal to deep marine successions of Triassic, Jurassic and Cretaceous age. In most of these successions, labile, 12C-enriched amorphous organic matter of marine origin dominates strata deposited under anoxic conditions, while oxidation-resistant, 13C-rich terrestrial particles dominate strata deposited under well-oxygenated conditions. This influence is further illustrated by weathering profiles of Toarcian (Lower Jurassic) black shales from France, where weathered areas dominated by refractory organic matter show dramatic 13C-enrichment (and decreased total organic carbon and pyrite contents) compared to non-weathered portions of the same horizon. The implications of these results for chemostratigraphic correlations and pCO2 reconstructions of Mesozoic will be discussed, as well as strategies to overcome this major bias.

  19. Wetting and Non-Wetting Models of Black Carbon Activation

    Science.gov (United States)

    Henson, B. F.; Laura, S.

    2006-12-01

    We present the results of recent modeling studies on the activation of black carbon (BC) aerosol to form cloud condensation nuclei (CCN). We use a model of BC activation based on a general modification of the Koehler equation for insoluble activation in which we introduce a term based on the activity of water adsorbed on the particle surface. We parameterize the model using the free energy of adsorption, a parameter directly comparable to laboratory measurements of water adsorption on carbon. Although the model of the water- surface interaction is general, the form of the activation equation that results depends upon a further model of the distribution of water on the particle. One possible model involves the symmetric growth of a water shell around the isoluble particle core (wetting). This model predicts upper and lower bounding curves for the activation supersaturation given by the range of water interaction energies from hydrophobic to hydrophilic which are in agreement with a large body of recent activation data. The resulting activation diameters are from 3 to 10 times smaller than activation of soluble particles of identical dry diameter. Another possible model involves an exluded liquid droplet growing in contact with the particle (non-wetting). The geometry of this model much more resembles classic assumptions of heterogeneous nucleation theory. This model can yield extremely high activation supersaturation as a function of diameter, as has been observed in some experiments, and enables calculations in agreement with some of these results. We discuss these two geometrical models of water growth, the different behaviors predicted by the resulting activation equation, and the means to determine which model of growth is appropriate for a given BC particle characterized by either water interaction energy or morphology. These simple models enable an efficient and physically reasonable means to calculate the activation of BC aerosol to form CCN based upon a

  20. Cycling of black carbon in the ocean

    Science.gov (United States)

    Coppola, Alysha I.; Druffel, Ellen R. M.

    2016-05-01

    Black carbon (BC) is a by-product of combustion from wildfires and fossil fuels and is a slow-cycling component of the carbon cycle. Whether BC accumulates and ages on millennial time scales in the world oceans has remained unknown. Here we quantified dissolved BC (DBC) in marine dissolved organic carbon isolated by solid phase extraction at several sites in the world ocean. We find that DBC in the Atlantic, Pacific, and Arctic oceans ranges from 1.4 to 2.6 μM in the surface and is 1.2 ± 0.1 μM in the deep Atlantic. The average 14C age of surface DBC is 4800 ± 620 14C years and much older in a deep water sample (23,000 ± 3000 14C years). The range of DBC structures and 14C ages indicates that DBC is not homogeneous in the ocean. We show that there are at least two distinct pools of marine DBC, a younger pool that cycles on centennial time scales and an ancient pool that cycles on >105 year time scales.

  1. Selection and Characterization of Carbon Black and Surfactants for Development of Small Scale Uranium Oxicarbide Kernels

    Energy Technology Data Exchange (ETDEWEB)

    Contescu, Cristian I [ORNL

    2006-01-01

    This report supports the effort for development of small scale fabrication of UCO (a mixture of UO{sub 2} and UC{sub 2}) fuel kernels for the generation IV high temperature gas reactor program. In particular, it is focused on optimization of dispersion conditions of carbon black in the broths from which carbon-containing (UO{sub 2} {center_dot} H{sub 2}O + C) gel spheres are prepared by internal gelation. The broth results from mixing a hexamethylenetetramine (HMTA) and urea solution with an acid-deficient uranyl nitrate (ADUN) solution. Carbon black, which is previously added to one or other of the components, must stay dispersed during gelation. The report provides a detailed description of characterization efforts and results, aimed at identification and testing carbon black and surfactant combinations that would produce stable dispersions, with carbon particle sizes below 1 {micro}m, in aqueous HMTA/urea and ADUN solutions. A battery of characterization methods was used to identify the properties affecting the water dispersability of carbon blacks, such as surface area, aggregate morphology, volatile content, and, most importantly, surface chemistry. The report introduces the basic principles for each physical or chemical method of carbon black characterization, lists the results obtained, and underlines cross-correlations between methods. Particular attention is given to a newly developed method for characterization of surface chemical groups on carbons in terms of their acid-base properties (pK{sub a} spectra) based on potentiometric titration. Fourier-transform infrared (FTIR) spectroscopy was used to confirm the identity of surfactants, both ionic and non-ionic. In addition, background information on carbon black properties and the mechanism by which surfactants disperse carbon black in water is also provided. A list of main physical and chemical properties characterized, samples analyzed, and results obtained, as well as information on the desired trend or

  2. Estimation and prediction of black carbon emissions in Beijing City

    Institute of Scientific and Technical Information of China (English)

    LIU Yuan; SHAO Min

    2007-01-01

    Black carbon is a by-product of incomplete combustion of carbon containing fuels. It can alter atmospheric radiation property and make adverse impacts on human health. The energy consumption in Beijing City depends largely on coal burning. Recently, Beijing City has been performing the municipal energy structure adjustment as a tool for air pollution abatement, aiming at the air quality goal for the Beijing 2008 Olympic Games. Based on Beijing energy use data in 2000, combined with emission factors of major sources of black carbon, the emission of black carbon in Beijing City is estimated to be 7.77 Gg. Coke, raw coal and biomass as non-commercial energy are the main contributors to municipal black carbon emissions. Based on Beijing energy planning in the year 2008, the emission of black carbon in 2008 will be 2.97 Gg if the contribution from biomass is not taken into account. Assuming that the black carbon emission from rural biomass in 2008 is the same as that in 2004, the biomass burning will be the largest emitter of black carbon to Beijing City in 2008.

  3. Discussion on Application of Modified Nano-particle Black Carbon for the Remediation of Soil Heavy Metals Pollution%改性纳米黑碳应用于钝化修复重金属污染土壤中的问题探讨

    Institute of Scientific and Technical Information of China (English)

    成杰民

    2011-01-01

    通过有关文献资料调研,综述纳米黑碳在钝化修复污染土壤中的应用,分析其应用于钝化修复重金属污染土壤时尚待弄清的几个问题.结果表明:(1)由于纳米黑碳是疏水的非极性吸附剂,选择纳米黑碳作为土壤重金属钝化修复剂时,需对其进行氧化改性,以进一步提高其钝化能力.目前常用的氧化剂为氧化性无机酸、酸性高锰酸钾、双氧水、臭氧等,强烈的氧化过程.会破坏纳米黑碳微孔结构.一定程度上降低其吸附量.(2)为了明确其应用的可能性和适用范围.需揭示改性纳米黑碳对土壤中重金属的钝化机理及其影响因素.土壤CEC、pH、重金属离子的性质等可能是影响改性纳米黑碳对土壤中重金属吸附件能的主要因素.(3)充分利用改性纳米黑碳在土壤修复中的有益作用的同时,还需考虑其可能存在的生态环境负面效应,研究其在土壤中的径流迁移、渗漏等,明确其污染地表水和地下水的可能性,研究其生物效应和将吸附钝化后的纳米黑碳从土壤中移除的可能性,明确其潜在的生态环境风险.%In this paper, application of modified nano-particle black carbon for the remediation of soil heavy metals pollution was summarized and several scientific problems needed to be discussed. Firstly, nano-particle black carbon, as a nonpolar and hydrophobic sorbent, needs to be modified with oxidizing agents to improve its absorption characteristic of heavy metals. Oxidizing agents most in use were inorganic oxyacids, KMnO4, H202 or 03. The microporous surface structure of nano-particle black carbon could be damaged in intense oxidation reaction and the adsorption capacity of heavy metals could be decreased. Secondly, absorption mechanism and influence factors should be illuminated to verify the feasibility and scope of application of modified nano-particle black carbon for the remediation of soil heavy metals pollution. The soil pH, CE

  4. 黑碳颗粒物表面SO2的非均相臭氧氧化%Heterogeneous Oxidation of SO2 by Ozone on the Surface of Black Carbon Particles

    Institute of Scientific and Technical Information of China (English)

    宋寒; 尚静; 朱彤; 赵黎; 叶俊辉

    2012-01-01

    采用漫反射红外傅里叶变换光谱(DRIFTS)结合离子色谱(IC)、X射线光电子能谱(XPS)研究了常温常压下SO2与O3在黑碳颗粒物(以Printex U为代表,简称UBC)表面的非均相反应.研究发现,在O3和水气存在的情况下,体系的反应产物主要是SO2-4,反应在一定时间内持续进行.UBC可提供反应活性位点,促进SO2在其表面的臭氧氧化.O3是关键的氧化剂,能显著提高SO2非均相氧化生成SO2-4的速率.水气的存在有利于表面活性位点再生,使反应持续发生.当SO2和O3的浓度为1014~1015molecule/cm3、相对湿度为40%时,SO2在UBC(1:400,以NaCl为稀释剂稀释400倍)表面非均相反应生成SO2-4的稳态摄取系数(γBET)为1~6×1O-6,SO2-4的生成速率为1014~1015 ion·s-1·g-1.%Black carbon(BC) produced by incomplete combustion processes is an important aerosol species. The heterogeneous reactions of gaseous pollutants (such as S02, 03 and N0x) on the surface of BC particles are of significance because these reactions can change the particles' morphology, chemical composition, hygro-scopicity and optical properties, and thus alter their climate or health effect, as well as these reactions can influence environmental chemical cycling. In this study, the heterogeneous oxidation of SO2 by O3 on the surface of black carbon (using Printex U as the model particles, denoted as UBC) was investigated by the method of Diffuse Reflectance Infrared Fourier Transform Spectroscopy ( DRIFTS) . The surface product was monitored, and confirmed by Ion Chromatographic(IC) and X-ray photoelectron spectroscopy (XPS) techniques. It was found that the main product of SO2 heterogeneous reaction on the surface of UBC or diluted UBC [ with one part of UBC diluted in 399 parts of infrared transparent NaCl powder, denoted as UBC (1 :400) ] was sulfate and the oxidation reaction rate could be greatly enhanced by O3. The simultaneous presence of ozone and water vapor are necessary for the

  5. Effect of molecular weight on the electrophoretic deposition of carbon black nanoparticles in moderately viscous systems.

    Science.gov (United States)

    Modi, Satyam; Panwar, Artee; Mead, Joey L; Barry, Carol M F

    2013-08-06

    Electrophoretic deposition from viscous media has the potential to produce in-mold assembly of nanoparticles onto three-dimensional parts in high-rate, polymer melt-based processes like injection molding. The effects of the media's molecular weight on deposition behavior were investigated using a model system of carbon black and polystyrene in tetrahydrofuran. Increases in molecular weight reduced the electrophoretic deposition of the carbon black particles due to increases in suspension viscosity and preferential adsorption of the longer polystyrene chains on the carbon black particles. At low deposition times (≤5 s), only carbon black deposited onto the electrodes, but the deposition decreased with increasing molecular weight and the resultant increases in suspension viscosity. For longer deposition times, polystyrene codeposited with the carbon black, with the amount of polystyrene increasing with molecular weight and decreasing with greater charge on the polystyrene molecules. This deposition behavior suggests that use of lower molecular polymers and control of electrical properties will permit electrophoretic deposition of nanoparticles from polymer melts for high-rate, one-step fabrication of nano-optical devices, biochemical sensors, and nanoelectronics.

  6. Preparation and application of active gangue's carbon black

    Institute of Scientific and Technical Information of China (English)

    ZHANG Xiang-lin; ZHANG Yi-dong

    2007-01-01

    After three-stage pulverization, dry-distillated activation and coupling agent surface modification, the kaolinite-typed gangue of Sichuan Hongni Coal Mine(SHCM) can be manufactured into activated gangue's carbon black. Its surface area is >25 m2/g, and possesses carbon black's carbon framework and structure. It can be used as strengthening agent of high polymer material such as rubber.

  7. Addressing inconsistencies in black carbon literature

    Science.gov (United States)

    Shonkoff, S. B.; Chafe, Z.; Smith, K. R.

    2010-12-01

    The literature describing black carbon (BC) emissions, and their effect on Earth’s climate, is growing rapidly. Unfortunately, inconsistencies in definitions; data collection and characterization; system boundaries; and time horizons have led to confusion about the relative importance of BC compared to other climate-active pollutant (CAPs). We discuss three sources of confusion: 1) Currently available BC inventories are not directly comparable to those used by the IPCC to track the greenhouse gases (GHGs) considered in the Kyoto Protocol (CO2, CH4, N2O). In particular, BC inventories often include all emissions: natural and anthropogenic in origin, controllable and non-controllable. IPCC inventories include only anthropogenic emissions. This BC accounting is appropriate for atmospheric science deliberations, but risks being interpreted as an overstatement against official Kyoto GHG inventories in a policy or control context. The IPCC convention of using 1750 as the starting year for emission inventories further complicates matters: significant BC emissions were emitted previous to that date by both human and natural sources. Though none of the pre-1750 BC emissions remain in the atmosphere today, their legacy presents challenges in assigning historical responsibility for associated global warming among sectors and regional populations. 2) Inconsistencies exist in the specific emissions sources considered in atmospheric models used to predict net BC forcing often lead to widely varying climate forcing estimates. For example, while some analyses consider only fossil fuel 1, others include both open biomass burning and fossil fuel combustion 2, and yet others include sources beyond biomass and fossil fuel burning 3. 3) Inconsistencies exist in how analyses incorporate the relationship between BC emissions and the associated cooling aerosols and processes, such as organic carbon (OC), and aerosol indirect effects (AIE). Unlike Kyoto GHGs, BC is rarely emitted in pure

  8. Long-term airborne black carbon measurements on a Lufthansa passenger aircraft

    Science.gov (United States)

    Ditas, Jeannine; Su, Hang; Scharffe, Dieter; Wang, Siwen; Zhang, Yuxuan; Brenninkmeijer, Carl; Pöschl, Ulrich; Cheng, Yafang

    2016-04-01

    Aerosol particles containing black carbon are the most absorbing component of incoming solar radiation and exert a significant positive radiative forcing thus forming next to CO² the strongest component of current global warming (Bond, 2013). Nevertheless, the role of black carbon particles and especially their complex interaction with clouds needs further research which is hampered by the limited experimental data, especially observations in the free and upper troposphere, and in the UTLS (upper troposphere and lower stratosphere). Many models underestimate the global atmospheric absorption attributable to black carbon by a factor of almost 3 (Bond, 2013). In August 2014, a single particle soot photometer was included in the extensive scientific payload of the CARIBIC (Civil Aircraft for the Regular Investigation of the atmosphere Based on an Instrument Container) project. CARIBIC is in operation since 1997 (with an interruption for 2002-2005) and carries out systematic observations at 10-12 km altitude. For this a special air freight container combining different instruments is transported on a monthly basis using a Lufthansa Airbus A340-600 passenger aircraft with destinations from 120°W to 120°E and 10°N to 75°N. The container has equipment for trace gas analyses and sampling and aerosol analyses and sampling and is connected to an inlet system that is part of the aircraft which contains a camera and DOAS remote sensing system. The integration of a single particle soot photometer (SP2) offers the possibility for the first long-term measurement of global distribution of black carbon and so far flights up to November 2015 have been conducted with more than 400 flight hours. So far the SP2 measurements have been analysed for flights over four continents from Munich to San Francisco, Sao Paulo, Tokyo, Beijing, Cape Town, Los Angeles and Hong Kong). The first measurements show promising results of black carbon measurements. Background concentrations in the UTLS

  9. Elementary particles under the lens of the black holes

    OpenAIRE

    Matsas, George Emanuel Avraam [UNESP

    2004-01-01

    After a brief review of the historical development and CLASSICAL properties of the BLACK HOLES, we discuss how our present knowledge of some of their QUANTUM properties shed light on the very concept of ELEMENTARY PARTICLE. As an illustration, we discuss in this context the decay of accelerated protons, which may be also relevant to astrophysics.

  10. Tunneling of Dirac Particles from Kaluza-Klein Black Hole

    Institute of Scientific and Technical Information of China (English)

    ZENG Xiao-Xiong; LI Qiang

    2009-01-01

    Applying the fermions tunneling method, proposed by Kerner and Mann recently, we discuss the tunneling characteristics of Dirac particles from the stationary Kaluza-Klein black hole. To choose Gamma matrix conveniently and avoid the ergosphere dragging effect, we perform it in the dragging coordinate frame. The result shows that Hawking temperature in this case also can be reproduced by the general Dirac equation.

  11. Quantification of black carbon mixing state from traffic: implications for aerosol optical properties

    Science.gov (United States)

    Willis, Megan D.; Healy, Robert M.; Riemer, Nicole; West, Matthew; Wang, Jon M.; Jeong, Cheol-Heon; Wenger, John C.; Evans, Greg J.; Abbatt, Jonathan P. D.; Lee, Alex K. Y.

    2016-04-01

    The climatic impacts of black carbon (BC) aerosol, an important absorber of solar radiation in the atmosphere, remain poorly constrained and are intimately related to its particle-scale physical and chemical properties. Using particle-resolved modelling informed by quantitative measurements from a soot-particle aerosol mass spectrometer, we confirm that the mixing state (the distribution of co-emitted aerosol amongst fresh BC-containing particles) at the time of emission significantly affects BC-aerosol optical properties even after a day of atmospheric processing. Both single particle and ensemble aerosol mass spectrometry observations indicate that BC near the point of emission co-exists with hydrocarbon-like organic aerosol (HOA) in two distinct particle types: HOA-rich and BC-rich particles. The average mass fraction of black carbon in HOA-rich and BC-rich particle classes was < 0.1 and 0.8, respectively. Notably, approximately 90 % of BC mass resides in BC-rich particles. This new measurement capability provides quantitative insight into the physical and chemical nature of BC-containing particles and is used to drive a particle-resolved aerosol box model. Significant differences in calculated single scattering albedo (an increase of 0.1) arise from accurate treatment of initial particle mixing state as compared to the assumption of uniform aerosol composition at the point of BC injection into the atmosphere.

  12. Spinning particles moving around black holes: integrability and chaos

    CERN Document Server

    Lukes-Gerakopoulos, Georgios

    2016-01-01

    The motion of a stellar compact object around a supermassive black hole can be approximated by the motion of a spinning test particle. The equations of motion describing such systems are in general non-integrable, and therefore, chaotic motion should be expected. This article discusses the integrability issue of the spinning particle for the cases of Schwarzschild and Kerr spacetime, and then it focuses on a canonical Hamiltonian formalism where the spin of the particle is included only up to the linear order.

  13. Effects of carbon blacks with various structures on vulcanization and reinforcement of filled ethylene-propylene-diene rubber

    Directory of Open Access Journals (Sweden)

    2008-10-01

    Full Text Available The effects of carbon blacks on vulcanization and mechanical properties of filled ethylene-propylene-diene rubber (EPDM are investigated, by comparing with five types of rubber-grade carbon blacks. Curing kinetics is studied by rheometer and the results indicate that the curing characteristics are influenced by combination of surface area of carbon black and sulphur content on the filler surface, because the former one enhances the physical cross-linking and the latter one introduces the additional chemical cross-linking. Both the degree of cross-linking and cure rate increase with increasing surface area and sulphur content, whereas the optimum cure time and scorch time decrease. The reinforcing nature of the carbon black is assessed from mechanical measurements. It is suggested that the surface area of carbon blacks strongly affects the physical properties of EPDM/carbon black composites. Conductive carbon black (N472 can be used as desirable reinforcing filler due to the higher degree of cross-linking of EPDM with N472 than other EPDM/carbon black composites. The morphology and distribution of particles are studied by using scanning electron microscope. The sound reinforcing ability of N472 is also supported by scanning electron microscope due to the notable dispersibility of N472 within EPDM matrix. N472 ensures the EPDM/N472 composite the most conductive sample among the five composites.

  14. Universality in chaos of particle motion near black hole horizon

    Science.gov (United States)

    Hashimoto, Koji; Tanahashi, Norihiro

    2017-01-01

    The motion of a particle near a horizon of a spherically symmetric static black hole is shown to possess a universal Lyapunov exponent of chaos bounded by its surface gravity. To probe the horizon, we introduce an electromagnetic or scalar force to the particle so that it does not fall into the horizon. There appears an unstable maximum of the total potential where the evaluated maximal Lyapunov exponent is found to be to the surface gravity of the black hole. This value is independent of the external forces, the particle mass and background geometry, and in this sense this Lyapunov exponent is universal. Unless there are other sources of chaos, the Lyapunov exponent is subject to an inequality λ ≤2 π TBH/ℏ, which is identical to the bound recently discovered by Maldacena, Shenker, and Stanford.

  15. Universality in Chaos of Particle Motion near Black Hole Horizon

    CERN Document Server

    Hashimoto, Koji

    2016-01-01

    Motion of a particle near a horizon of a spherically symmetric black hole is shown to possess a universal Lyapunov exponent of a chaos provided by its surface gravity. To probe the horizon, we introduce electromagnetic or scalar force to the particle so that it does not fall into the horizon. There appears an unstable maximum of the total potential where the evaluated maximal Lyapunov exponent is found to be independent of the external forces and the particle mass. The Lyapunov exponent is universally given by the surface gravity of the black hole. Unless there are other sources of a chaos, the Lyapunov exponent is subject to an inequality $\\lambda \\leq 2\\pi T_{\\rm BH}/\\hbar$, which is identical to the bound recently discovered by Maldacena, Shenker and Stanford.

  16. Nanohybrid TiO2/carbon black sensor for NO2 gas

    Institute of Scientific and Technical Information of China (English)

    Wei-Jen Liou; Hong-Ming Lin

    2007-01-01

    A nanohybrid sensor of nanosized TiO2-coated carbon black particles, prepared by sol-gel technology for the detection of NO2 gas, has been developed. The response of the electric resistance of the hybrid sensor to NO2 concentration is investigated, showing that the sensitivity of the hybrid sensor is raised as certain ratio of the TiO2 content in the sensor. Easy and cheap to fabricate, the hybrid TiO2/carbon black promises to be a practical sensor for detecting NO2 gas.

  17. Chemical and biological oxidative effects of carbon black nanoparticles.

    Science.gov (United States)

    Koike, Eiko; Kobayashi, Takahiro

    2006-11-01

    Several studies show that ultrafine particles have a larger surface area than coarse particles, thus causing a greater inflammatory response. In this study, we investigated chemical and biological oxidative effects of nanoparticles in vitro. Carbon black (CB) nanoparticles with mean aerodynamic diameters of 14, 56, and 95nm were examined. The innate oxidative capacity of the CB nanoparticles was measured by consumption of dithiothreitol (DTT) in cell-free system. The expression of heme oxygenase-1 (HO-1) in rat alveolar type II epithelial cell line (SV40T2) and alveolar macrophages (AM) exposed to CB nanoparticles was measured by ELISA. DTT consumption of 14nm CB was higher than that of other CB nanoparticles having the same particle weight. However, DTT consumption was directly proportional to the particle surface area. HO-1 protein in SV40T2 cells was significantly increased by the 14nm and 56nm CB, however, 95nm CB did not affect. HO-1 protein in AM was significantly increased by the 14, 56, and 95nm CB. The increase in HO-1 expression was diminished by N-acetyl-l-cysteine (NAC) treatment of each CB nanoparticles before exposure although the difference between the effects of NAC-treated and untreated 14nm CB did not achieve significant. In conclusion, CB nanoparticles have innate oxidative capacity that may be dependent on the surface area. CB nanoparticles can induce oxidative stress in alveolar epithelial cells and AM that is more prominent with smaller particles. The oxidative stress may, at least partially, be mediated by surface function of particles.

  18. Partner particles for moving mirror radiation and black hole evaporation

    Science.gov (United States)

    Hotta, M.; Schützhold, R.; Unruh, W. G.

    2015-06-01

    The partner mode with respect to a vacuum state for a given mode (like that corresponding to one of the thermal particles emitted by a black hole) is defined and calculated. The partner modes are explicitly calculated for a number of cases, in particular for the modes corresponding to a particle detector being excited by turn-on/turn-off transients, or with the thermal particles emitted by the accelerated mirror model for black hole evaporation. One of the key results is that the partner mode in general is just a vacuum fluctuation, and one can have the partner mode be located in a region where the state cannot be distinguished from the vacuum state by any series of local measurements, including the energy density. For example, "information" (the correlations with the thermal emissions) need not be associated with any energy transport. The idea that black holes emit huge amounts of energy in their last stages because of all the information which must be emitted under the assumption of black hole unitarity is found to not necessarily be the case.

  19. A particle-like description of Planckian black holes

    CERN Document Server

    Spallucci, Euro

    2016-01-01

    In this paper we abandon the idea that even a "quantum" black hole, of Planck size, can still be described as a classical, more or less complicated, geometry. Rather, we consider a genuine quantum mechanical approach where a Planckian black hole is, by all means, just another "particle", even if with a distinguishing property: its linear size increases with the energy. The horizon dynamics is equivalently described in terms of a particle moving in gravitational potential derived from the horizon equation itself in a self-consistent manner. The particle turning-points match the radius of the inner and outer horizons of a charged black hole. This classical model pave the way towards the wave equation for a truly quantum black hole. We compute the exact form of the wave function and determine the energy spectrum. Finally, we describe the classical limit in which the quantum picture correctly approaches the classical geometric formulation. We find that the quantum-to-classical transition occurs far above the Plan...

  20. Observation of black carbon, ozone and carbon monoxide in the Kali Gandaki Valley Nepal

    Science.gov (United States)

    Dhungel, S.; Panday, A. K.; Kathayat, B.

    2014-12-01

    The increased melting of snow and ice in the arctic and the Himalaya is a growing concern for all of the earth's population. Deposition of black carbon (BC) on the snow and ice surface accelerates melting by absorbing the radiative energy and directly transferring all that energy onto the underlying surface. During pre-monsoon season, satellite images show a thick layer of haze covering the Indo-Gangetic plain (IGP) and the Himalayan foothills. Sub-micron particles are transported to the Himalaya from the IGP predominantly driven by the thermal valley wind system. The Himalayas consist of some of the tallest mountain ranges in the world, over 8000m tall that reach the stratosphere. The Kali Gandaki Valley in Nepal is one of the deepest gorges in the world, and has some of the highest up-valley winds in the world. It is also one of the most open connecting points for air from IGP to reach the Tibetan Plateau. In 2010 the University of Virginia, in collaboration with ICIMOD and Nepal Wireless, established an atmospheric research station in Jomsom, Nepal (28.78N, 83.42E, 2900 m.a.s.l.) half-way along the Kali Gandaki valley. The station is equipped to measure black carbon (BC), carbon monoxide (CO), and ozone concentrations. It also has an automated weather station, a filter sampler, and a NASA Aeronet Sunphotometer. Here we present our observations of black carbon, ozone, carbon monoxide at Jomsom to show the diurnal and seasonal variability of the pollutants. The results show diurnal patterns in the concentration of these pollutants and also episodes of high pollutant transport along the valley. These transport episodes are more common during the pre-monsoon season which indicates that deep mountain valleys like the Kali Gandaki valley facilitate the transport of pollutants and thus promote snow and glacial melting.

  1. Estimates of increased black carbon emissions from electrostatic precipitators during powdered activated carbon injection for mercury emissions control.

    Science.gov (United States)

    Clack, Herek L

    2012-07-03

    The behavior of mercury sorbents within electrostatic precipitators (ESPs) is not well-understood, despite a decade or more of full-scale testing. Recent laboratory results suggest that powdered activated carbon exhibits somewhat different collection behavior than fly ash in an ESP and particulate filters located at the outlet of ESPs have shown evidence of powdered activated carbon penetration during full-scale tests of sorbent injection for mercury emissions control. The present analysis considers a range of assumed differential ESP collection efficiencies for powdered activated carbon as compared to fly ash. Estimated emission rates of submicrometer powdered activated carbon are compared to estimated emission rates of particulate carbon on submicrometer fly ash, each corresponding to its respective collection efficiency. To the extent that any emitted powdered activated carbon exhibits size and optical characteristics similar to black carbon, such emissions could effectively constitute an increase in black carbon emissions from coal-based stationary power generation. The results reveal that even for the low injection rates associated with chemically impregnated carbons, submicrometer particulate carbon emissions can easily double if the submicrometer fraction of the native fly ash has a low carbon content. Increasing sorbent injection rates, larger collection efficiency differentials as compared to fly ash, and decreasing sorbent particle size all lead to increases in the estimated submicrometer particulate carbon emissions.

  2. Carbon-rich particles in Comet Halley

    Science.gov (United States)

    Clark, Benton C.

    1990-01-01

    The majority of particles detected in the coma of Comet Halley contain carbon atoms; many of these grains appear to consist preponderately or only of light elements. These light-element particles may be composed of organic compounds. Of the possible combinations of the elements hydrogen, carbon, nitrogen, and oxygen, numerous examples are found of particles containing the combinations (H,C,O,N), (H,C,N), (H,C,O), and (H,C). These results may bear on the recent detection of polyoxymethylene fragments, the observation of cyanojets (CN patterns consistent with release from solid particles), the possible presence of cyanopolyacetylenes or HCN polymer and the make-up of the CHON particles. If cometary matter could reach the surface of the earth without complete disruption, these diverse organic and mixed particles could create unique microenvironments, possibly with significant or even pivotal prebiotic chemical activity. Here a speculative insight into possible relationships between carbon in comets and carbon in life is given, as well as a brief overview of on-going analysis of data from the highly successful Particle Impact Analyzer (PIA) experiment flown on the Giotto spacecraft for the flyby of Comet Halley (development and implementation of PIA was under the direction of J. Kissel of the Max Planck Institute for Kernphysik, Heidelberg). PIA is a time-of-flight analyzer which obtains mass spectra of ions from individual particles impacting on a Pt-Ag foil target within the instrument.

  3. Black Carbon Contribution to Organic Carbon Stocks in Urban Soil.

    Science.gov (United States)

    Edmondson, Jill L; Stott, Iain; Potter, Jonathan; Lopez-Capel, Elisa; Manning, David A C; Gaston, Kevin J; Leake, Jonathan R

    2015-07-21

    Soil holds 75% of the total organic carbon (TOC) stock in terrestrial ecosystems. This comprises ecosystem-derived organic carbon (OC) and black carbon (BC), a recalcitrant product of the incomplete combustion of fossil fuels and biomass. Urban topsoils are often enriched in BC from historical emissions of soot and have high TOC concentrations, but the contribution of BC to TOC throughout the urban soil profile, at a regional scale is unknown. We sampled 55 urban soil profiles across the North East of England, a region with a history of coal burning and heavy industry. Through combined elemental and thermogravimetic analyses, we found very large total soil OC stocks (31-65 kg m(-2) to 1 m), exceeding typical values reported for UK woodland soils. BC contributed 28-39% of the TOC stocks, up to 23 kg C m(-2) to 1 m, and was affected by soil texture. The proportional contribution of the BC-rich fraction to TOC increased with soil depth, and was enriched in topsoil under trees when compared to grassland. Our findings establish the importance of urban ecosystems in storing large amounts of OC in soils and that these soils also capture a large proportion of BC particulates emitted within urban areas.

  4. Optical Properties of Small Ice Crystals with Black Carbon Inclusions

    Science.gov (United States)

    Yang, X.; Geier, M.; Arienti, M.

    2013-12-01

    The optical properties of ice crystals play a fundamental role in modeling atmospheric radiation and hydrological cycle, which are critical in monitoring climate change. While Black Carbon (BC) is recognized as the dominant absorber with positive radiative forcing (warming) (Ramanathan & Carmichael, 2008), in-situ observations (Cappa, et al, 2012) indicate that the characterization of the mixing state of BC with ice crystals and other non-BC particles in global climate models (Ghan & Schwartz, 2007) needs further investigation. The limitation in the available mixing models is due to the drastically different absorbing properties of BC compared to other aerosols. We explore the scattering properties of ice crystals (in shapes commonly found in cirrus clouds and contrails - Yang, et al. 2012) with the inclusion of BC particles. The Discrete Dipole Approximation (DDA) (Yurkin & Hoekstra, 2011) is utilized to directly calculate the optical properties of the crystals with multiple BC inclusions, modeled as a distribution of spheres. The results are then compared with the most popular models of internal and external mixing (Liou, et al. 2011). The DDA calculations are carried out over a broad range of BC particle sizes and volume fractions within the crystal at the 532 nm wavelength and for ice crystals smaller than 50 μm. The computationally intensive database generated in this study is critical for understanding the effect of different types of BC inclusions on the atmosphere radiative forcing. Examples will be discussed to illustrate the modification of BC optical properties by encapsulation in ice crystals and how the parameterization of the BC mixing state in global climate models can be improved. Acknowledgements Support by Sandia National Laboratories' LDRD (Laboratory Directed Research and Development) is gratefully acknowledged. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of

  5. Source attribution of black carbon in Arctic snow.

    Science.gov (United States)

    Hegg, Dean A; Warren, Stephen G; Grenfell, Thomas C; Doherty, Sarah J; Larson, Timothy V; Clarke, Antony D

    2009-06-01

    Snow samples obtained at 36 sites in Alaska, Canada, Greenland, Russia, and the Arctic Ocean in early 2007 were analyzed for light-absorbing aerosol concentration together with a suite of associated chemical species. The light absorption data, interpreted as black carbon concentrations, and other chemical data were input into the EPA PMF 1.1 receptor model to explore the sources for black carbon in the snow. The analysis found four factors or sources: two distinct biomass burning sources, a pollution source, and a marine source. The first three of these were responsible for essentially all of the black carbon, with the two biomass sources (encompassing both open and closed combustion) together accounting for >90% of the black carbon.

  6. The uptake of ethyl iodide on black carbon surface

    Institute of Scientific and Technical Information of China (English)

    YIN Shi; WANG WeiGang; GE MaoFa

    2008-01-01

    The importance of the iodine chemistry in the atmosphere has been demonstrated by recent observations. The uptake of ethyl iodine on black carbon surface was investigated at 298 K for the first time. Degussa FW2 (an amorphous black carbon comprising medium oxides) was used as black carbon sample. Black carbon surface was found to be deactivated in reaction with C2H5I, and the uptake coefficient (γ) was dependent on the time of exposure. The value of (2.3±0.9)×10-2 was determined for the initial uptake coefficient (γ0). The result suggests that the heterogeneous loss of C2H5I on carbonaceous aerosols may be important under the atmospheric conditions.

  7. Thickness effect on electric resistivity on polystyrene and carbon black- based composites

    Energy Technology Data Exchange (ETDEWEB)

    Hernandez-Lopez, S; Vigueras-Santiago, E [Laboratorio de Investigacion y Desarrollo de Materiales Avanzados (LIDMA) Facultad de Quimica, Paseo Colon Esquina con Paseo Tollocan, s/n, CP 50000, Toluca (Mexico); Mayorga-Rojas, M; Reyes-Contreras, D, E-mail: eviguerass@uaemex.m [Facultad de Ciencias, Universidad Autonoma del Estado de Mexico. Av. Instituto Literario 100 Ote. C. P. 50000, Toluca (Mexico)

    2009-05-01

    Changes on electrical resistivity were experimentally studied for polystyrene and carbon black-based composites respect to the temperature. 22% w/w carbon black composite films at 30{mu}m, 2mm y 1cm thick were submitted to thermal heating-cooling cycles from room temperature to 100 deg. C, slightly up to T{sub g} of the composite. For each cycle changes on electrical resistivity constituent a hysteresis loop that depends on the sample thickness. The changes during the heating stage could be explained as a consequence of the thermal expansion and mobility of the polymer chains at T{sub g}, producing a disconnecting of the electrical contacts among carbon black particles and an important increasing (200%) of the electrical resistivity. For each cycle, the hysteresis loop was observed in thicker samples, whereas for 30 mu m thickness sample the hysteresis loop was lost after four cycles.

  8. Electric anisotropy in high density polyethylene + carbon black composites induced by mechanical deformation

    Energy Technology Data Exchange (ETDEWEB)

    Vigueras-Santiago, E; Hernandez-Lopez, S; Camacho-Lopez, M A; Lara-Sanjuan, O, E-mail: eviguerass@uaemex.m [Laboratorio de Investigacion y Desarrollo de Materiales Avanzados (LIDMA), Facultad de Quimica, UAEM. Paseo Colon esq. con Paseo Tollocan, s/n. C.P. 50000, Toluca (Mexico)

    2009-05-01

    High density polyethylene + carbon black composites with electrical anisotropy was studied. Electrical anisotropy was induced by uniaxial mechanical deformation and injection moulding. We show that anisotropy depends on the carbon black concentration and percentage deformation. Resistivity had the highest anisotropy resistivity around the percolation threshold. Perpendicular resistivity showed two magnitude orders higher than parallel resistivity for injected samples, whereas resistivity showed an inverse behaviour for 100% tensile samples. Both directions were set respect to the deformation axe. Anisotropy could be explained in terms of the molecular deformation (alignment) of the polymer chains as a response of the deformation process originating a redistribution of the carbon black particles in both directions. Alignment of the polymer chains was evidenced by polarized Raman spectroscopy.

  9. A method for monitoring mass concentration of black carbon particulate matter using photothermal interferometry.

    Science.gov (United States)

    Li, Baosheng; Wang, Yicheng; Li, Zhengqiang

    2016-03-01

    A method for measurements of mass concentration of black carbon particulate matter (PM) is proposed based on photothermal interferometry (PTI). A folded Jamin photothermal interferometer was used with a laser irradiation of particles deposited on a filter paper. The black carbon PM deposited on the filter paper was regarded as a film while the quartz filter paper was regarded as a substrate to establish a mathematical model for measuring the mass concentration of PM using a photothermal method. The photothermal interferometry system was calibrated and used to measure the atmospheric PM concentration corresponding to different dust-treated filter paper. The measurements were compared to those obtained using β ray method and were found consistent. This method can be particularly relevant to polluted atmospheres where PM is dominated by black carbon.

  10. Global civil aviation black carbon emissions.

    Science.gov (United States)

    Stettler, Marc E J; Boies, Adam M; Petzold, Andreas; Barrett, Steven R H

    2013-09-17

    Aircraft black carbon (BC) emissions contribute to climate forcing, but few estimates of BC emitted by aircraft at cruise exist. For the majority of aircraft engines the only BC-related measurement available is smoke number (SN)-a filter based optical method designed to measure near-ground plume visibility, not mass. While the first order approximation (FOA3) technique has been developed to estimate BC mass emissions normalized by fuel burn [EI(BC)] from SN, it is shown that it underestimates EI(BC) by >90% in 35% of directly measured cases (R(2) = -0.10). As there are no plans to measure BC emissions from all existing certified engines-which will be in service for several decades-it is necessary to estimate EI(BC) for existing aircraft on the ground and at cruise. An alternative method, called FOX, that is independent of the SN is developed to estimate BC emissions. Estimates of EI(BC) at ground level are significantly improved (R(2) = 0.68), whereas estimates at cruise are within 30% of measurements. Implementing this approach for global civil aviation estimated aircraft BC emissions are revised upward by a factor of ~3. Direct radiative forcing (RF) due to aviation BC emissions is estimated to be ~9.5 mW/m(2), equivalent to ~1/3 of the current RF due to aviation CO2 emissions.

  11. Protective effects of pulmonary epithelial lining fluid on oxidative stress and DNA single-strand breaks caused by ultrafine carbon black, ferrous sulphate and organic extract of diesel exhaust particles

    Energy Technology Data Exchange (ETDEWEB)

    Chuang, Hsiao-Chi [School of Respiratory Therapy, College of Medicine, Taipei Medical University, Taipei, Taiwan (China); Division of Pulmonary Medicine, Department of Internal Medicine, Shuang Ho Hospital, Taipei Medical University, Taipei, Taiwan (China); Cheng, Yi-Ling; Lei, Yu-Chen [Institute of Occupational Medicine and Industrial Hygiene, College of Public Health, National Taiwan University, Taipei, Taiwan (China); Chang, Hui-Hsien [Institute of Environmental Health, College of Public Health, National Taiwan University, Taipei, Taiwan (China); Cheng, Tsun-Jen, E-mail: tcheng@ntu.edu.tw [Institute of Occupational Medicine and Industrial Hygiene, College of Public Health, National Taiwan University, Taipei, Taiwan (China); Department of Public Health, College of Public Health, National Taiwan University, Taipei, Taiwan (China)

    2013-02-01

    Pulmonary epithelial lining fluid (ELF) is the first substance to make contact with inhaled particulate matter (PM) and interacts chemically with PM components. The objective of this study was to determine the role of ELF in oxidative stress, DNA damage and the production of proinflammatory cytokines following physicochemical exposure to PM. Ultrafine carbon black (ufCB, 15 nm; a model carbonaceous core), ferrous sulphate (FeSO{sub 4}; a model transition metal) and a diesel exhaust particle (DEP) extract (a model organic compound) were used to examine the acellular oxidative potential of synthetic ELF and non-ELF systems. We compared the effects of exposure to ufCB, FeSO{sub 4} and DEP extract on human alveolar epithelial Type II (A549) cells to determine the levels of oxidative stress, DNA single-strand breaks and interleukin-8 (IL-8) production in ELF and non-ELF systems. The effects of ufCB and FeSO{sub 4} on the acellular oxidative potential, cellular oxidative stress and DNA single-strand breakage were mitigated significantly by the addition of ELF, whereas there was no decrease following treatment with the DEP extract. There was no significant effect on IL-8 production following exposure to samples that were suspended in ELF/non-ELF systems. The results of the present study indicate that ELF plays an important role in the initial defence against PM in the pulmonary environment. Experimental components, such as ufCB and FeSO{sub 4}, induced the production of oxidative stress and led to DNA single-strand breaks, which were moderately prevented by the addition of ELF. These findings suggest that ELF plays a protective role against PM-driven oxidative stress and DNA damage. -- Highlights: ► To determine the role of ELF in ROS, DNA damage and IL-8 after exposure to PM. ► ufCB, FeSO{sub 4} and DEP extract were used to examine the protective effects of ELF. ► PM-driven oxidative stress and DNA single-strand breakage were mitigated by ELF. ► The findings

  12. Comparative DEMS study on the electrochemical oxidation of carbon blacks

    DEFF Research Database (Denmark)

    Ashton, Sean James; Arenz, Matthias

    2012-01-01

    heat-treated between 2100 and 3200 °C, such as those typically used as corrosion resistant carbon (CRC) supports for polymer electrolyte membrane fuel cell (PEMFC) catalysts. A methodology combining cyclic voltammetry (CV) and differential electrochemical mass spectrometry (DEMS) is used, which allows...... the characterisation and comparison of the complete electrochemical oxidation rates and behaviours of the various carbon blacks. It is observed that the behaviour of the carbon black towards electrochemical oxidation is highly dynamic, and dependent on the properties of the pristine carbon back, the degree...

  13. Human lung epithelial cell A549 proteome data after treatment with titanium dioxide and carbon black.

    Science.gov (United States)

    Vuong, Ngoc Q; Goegan, Patrick; Mohottalage, Susantha; Breznan, Dalibor; Ariganello, Marianne; Williams, Andrew; Elisma, Fred; Karthikeyan, Subramanian; Vincent, Renaud; Kumarathasan, Premkumari

    2016-09-01

    Here, we have described the dataset relevant to the A549 cellular proteome changes after exposure to either titanium dioxide or carbon black particles as compared to the non-exposed controls, "Proteomic changes in human lung epithelial cells (A549) in response to carbon black and titanium dioxide exposures" (Vuong et al., 2016) [1]. Detailed methodologies on the separation of cellular proteins by 2D-GE and the subsequent mass spectrometry analyses using MALDI-TOF-TOF-MS are documented. Particle exposure-specific protein expression changes were measured via 2D-GE spot volume analysis. Protein identification was done by querying mass spectrometry data against SwissProt and RefSeq protein databases using Mascot search engine. Two-way ANOVA analysis data provided information on statistically significant A549 protein expression changes associated with particle exposures.

  14. Human lung epithelial cell A549 proteome data after treatment with titanium dioxide and carbon black

    Directory of Open Access Journals (Sweden)

    Ngoc Q. Vuong

    2016-09-01

    Full Text Available Here, we have described the dataset relevant to the A549 cellular proteome changes after exposure to either titanium dioxide or carbon black particles as compared to the non-exposed controls, “Proteomic changes in human lung epithelial cells (A549 in response to carbon black and titanium dioxide exposures” (Vuong et al., 2016 [1]. Detailed methodologies on the separation of cellular proteins by 2D-GE and the subsequent mass spectrometry analyses using MALDI-TOF-TOF-MS are documented. Particle exposure-specific protein expression changes were measured via 2D-GE spot volume analysis. Protein identification was done by querying mass spectrometry data against SwissProt and RefSeq protein databases using Mascot search engine. Two-way ANOVA analysis data provided information on statistically significant A549 protein expression changes associated with particle exposures.

  15. New mechanism of acceleration of particles by stellar black holes

    CERN Document Server

    Osmanov, Z

    2016-01-01

    In this paper we study efficiency of particle acceleration in the magnetospheres of stellar mass black holes. For this purpose we consider the linearized set of the Euler equation, continuity equation and Poisson equation respectively. After introducing the varying relativistic centrifugal force, we show that the charge separation undergoes the parametric instability, leading to generation of centrifugally excited Langmuir waves. It is shown that these waves, via the Langmuir collapse damp by means of the Landau damping, as a result energy transfers to particles accelerating them to energies of the order of $10^{16}$eV.

  16. Dirac Particles' Hawking Radiation from a Schwarzschild Black Hole

    Institute of Scientific and Technical Information of China (English)

    HE Xiao-Kai; LIU Wen-Biao

    2007-01-01

    @@ Considering energy conservation and the backreaction of particles to spacetime, we investigate the massless/massive Dirac particles' Hawking radiation from a Schwarzschild black hole. The exact expression of the emission rate near the horizon is obtained and the result indicates that Hawking radiation spectrum is not purely thermal. The result obtained is consistent with the results obtained before. It satisfies the underlying unitary theory and offers a possible mechanism to explain the information loss paradox. Whereas the improved Damour-Ruffini method is more concise and understandable.

  17. Atmospheric black carbon and sulfate concentrations in Northeast Greenland

    Directory of Open Access Journals (Sweden)

    A. Massling

    2015-04-01

    Full Text Available Measurements of Black Carbon (BC in aerosols at the high Arctic field site Villum Research Station (VRS at Station Nord in North Greenland showed a seasonal variation in BC concentrations with a maximum in winter and spring at ground level. The data was obtained using a Multi Angle Absorption Photometer (MAAP. A similar seasonal pattern was found for sulfate concentrations with a maximum level during winter and spring analyzed by ion chromatography. A correlation between BC and sulfate concentrations was observed over the years 2011 to 2013. This finding gives the hint that most likely transport of primary emitted BC particles to the Arctic was accompanied by aging of the aerosols through condensational processes. This process may have led to the formation of secondary inorganic matter and further transport of BC particles as cloud processing and further washout of particles is less likely based on the typically observed transport patterns of air masses arriving at VRS. Additionally, concentrations of EC (elemental carbon based on a thermo-optical method were determined and compared to BC measurements. Model estimates of the climate forcing due to BC in the Arctic are based on contributions of long-range transported BC during spring and summer. The measured concentrations were here compared with model results obtained by the Danish Hemispheric Model, DEHM. Good agreement between measured and modeled concentrations of both BC and sulfate was observed. The dominant source is found to be combustion of fossil fuel with biomass burning as a minor though significant source. During winter and spring the Arctic atmosphere is known to be impacted by long-range transport of BC and associated with the Arctic haze phenomenon.

  18. Artificial black opal fabricated from nanoporous carbon spheres.

    Science.gov (United States)

    Yamada, Yuri; Ishii, Masahiko; Nakamura, Tadashi; Yano, Kazuhisa

    2010-06-15

    A nanocasting method via chemical vapor deposition of acetonitrile was successfully employed to fabricate porous carbon colloidal crystal using colloidal crystal from monodispersed mesoporous silica spheres (MMSS) as a sacrificial scaffold. The mesostructure as well as periodic arrays within (111) plane of MMSS were replicated for the carbon colloidal crystal (black opal) with the length scale in the centimeter range. Brilliant iridescent colors were clearly observed for the first time on the black carbon colloidal crystal fabricated from porous carbon spheres, and they changed dramatically in accordance with the observation angle, like natural black opals. Reflection spectra measurements based on 2D surface diffraction and Bragg diffraction in the mirror mode were conducted for the fabricated carbon periodic arrays. The periodicity in the (111) plane as well as in the direction perpendicular to the (111) plane of the colloidal crystal was evaluated by comparing the results obtained from these two measurements. It was found that the periodicity in the direction perpendicular to the (111) surface is not high for the obtained black carbon opal. On the other hand, the relationship between the incident angles and the peak wavelengths of the reflection spectra, collected in the condition where the incident light and the reflected light pass through in the same direction, is governed by an approximation based on 2D surface diffraction. The results imply that the origin of the iridescent colors on the fabricated black carbon opal is derived from the periodicity not in the direction perpendicular to the (111) plane but within the (111) plane.

  19. Black carbon mixing state impacts on cloud microphysical properties: effects of aerosol plume and environmental conditions

    Energy Technology Data Exchange (ETDEWEB)

    Ching, Ping Pui; Riemer, Nicole; West, Matthew

    2016-05-27

    Black carbon (BC) is usually mixed with other aerosol species within individual aerosol particles. This mixture, along with the particles' size and morphology, determines the particles' optical and cloud condensation nuclei properties, and hence black carbon's climate impacts. In this study the particle-resolved aerosol model PartMC-MOSAIC was used to quantify the importance of black carbon mixing state for predicting cloud microphysical quantities. Based on a set of about 100 cloud parcel simulations a process level analysis framework was developed to attribute the response in cloud microphysical properties to changes in the underlying aerosol population ("plume effect") and the cloud parcel cooling rate ("parcel effect"). It shows that the response of cloud droplet number concentration to changes in BC emissions depends on the BC mixing state. When the aerosol population contains mainly aged BC particles an increase in BC emission results in increasing cloud droplet number concentrations ("additive effect"). In contrast, when the aerosol population contains mainly fresh BC particles they act as sinks for condensable gaseous species, resulting in a decrease in cloud droplet number concentration as BC emissions are increased ("competition effect"). Additionally, we quantified the error in cloud microphysical quantities when neglecting the information on BC mixing state, which is often done in aerosol models. The errors ranged from -12% to +45% for the cloud droplet number fraction, from 0% to +1022% for the nucleation-scavenged black carbon (BC) mass fraction, from -12% to +4% for the effective radius, and from -30% to +60% for the relative dispersion.

  20. An Important Supplement to NAA in Study on Atmosphere Pollution:Determination of Black Carbon

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    <正>Light absorption in the atmosphere is dominated by elemental carbon (EC), sometimes called black carbon (BC). Black carbon is an important indication of man-made pollution in airborne particulate matter

  1. Black Carbon in Seasonal Snow across Northern Xinjiang, Northwestern China

    Science.gov (United States)

    Ye, H.; Zhang, R.; Shi, J.; Huang, J.; Warren, S. G.; Fu, Q.

    2012-12-01

    Black carbon (BC) particles in snow can significantly reduce the snow albedo and enhance the absorption of solar radiation, with important impacts on climate and the hydrological cycle. A field campaign was carried out to measure the BC content in seasonal snow in Qinghai and Xinjiang provinces of western China, in January and February, 2012. About 300 snow samples were collected at 38 sites, 6 in Qinghai and 32 in Xinjiang. The observational results at the sites in Xinjiang, where the dominant absorbing impurities in snow are BC particles, are reported in this paper. The BC mass-fractions in seasonal snow across northern Xinjiang have a median value of ~70 ng/g, lower than those in northeast China but comparable to those in snow on glaciers of the Tianshan Mountains. The estimated concentration of BC at the cleanest site in Xinjiang is 20 ng/g, which is similar to that found along the coast of the Arctic Ocean. In general, the BC content of snow decreases with altitude. The data from this field campaign should be useful for testing transport models and climate models for the simulated BC in snow.

  2. Increased fire frequency optimization of black carbon mixing and storage

    Science.gov (United States)

    Pyle, Lacey; Masiello, Caroline; Clark, Kenneth

    2016-04-01

    Soil carbon makes up a substantial part of the global carbon budget and black carbon (BC - produced from incomplete combustion of biomass) can be significant fraction of soil carbon. Soil BC cycling is still poorly understood - very old BC is observed in soils, suggesting recalcitrance, yet in short term lab and field studies BC sometimes breaks down rapidly. Climate change is predicted to increase the frequency of fires, which will increase global production of BC. As up to 80% of BC produced in wildfires can remain at the fire location, increased fire frequency will cause significant perturbations to soil BC accumulation. This creates a challenge in estimating soil BC storage, in light of a changing climate and an increased likelihood of fire. While the chemical properties of BC are relatively well-studied, its physical properties are much less well understood, and may play crucial roles in its landscape residence time. One important property is density. When BC density is less than 1 g/cm3 (i.e. the density of water), it is highly mobile and can easily leave the landscape. This landscape mobility following rainfall may inflate estimates of its degradability, making it crucial to understand both the short- and long term density of BC particles. As BC pores fill with minerals, making particles denser, or become ingrown with root and hyphal anchors, BC is likely to become protected from erosion. Consequently, how quickly BC is mixed deeper into the soil column is likely a primary controller on BC accumulation. Additionally the post-fire recovery of soil litter layers caps BC belowground, protecting it from erosional forces and re-combustion in subsequent fires, but still allowing bioturbation deeper into the soil column. We have taken advantage of a fire chronosequence in the Pine Barrens of New Jersey to investigate how density of BC particles change over time, and how an increase in fire frequency affects soil BC storage and soil column movement. Our plots have

  3. Black Carbon Measurements of Flame-Generated Soot as Determinedby Optical, Thermal-Optical, Direct Absorption,and Laser Incandescence Methods

    Science.gov (United States)

    Black carbon (BC), light absorbing particles emitted primarily from incomplete combustion, is operationally defined through a variety of instrumental measurements rather than with a universal definition set forth by the research or regulatory communities. To examine the consiste...

  4. Black hole lightning due to particle acceleration at subhorizon scales

    CERN Document Server

    Aleksić, J; Antonelli, L A; Antoranz, P; Babic, A; Bangale, P; Barrio, J A; González, J Becerra; Bednarek, W; Bernardini, E; Biasuzzi, B; Biland, A; Blanch, O; Bonnefoy, S; Bonnoli, G; Borracci, F; Bretz, T; Carmona, E; Carosi, A; Colin, P; Colombo, E; Contreras, J L; Cortina, J; Covino, S; Da Vela, P; Dazzi, F; De Angelis, A; De Caneva, G; De Lotto, B; Wilhelmi, E de Oña; Mendez, C Delgado; Prester, D Dominis; Dorner, D; Doro, M; Einecke, S; Eisenacher, D; Elsaesser, D; Fonseca, M V; Font, L; Frantzen, K; Fruck, C; Galindo, D; López, R J García; Garczarczyk, M; Terrats, D Garrido; Gaug, M; Godinović, N; Muñoz, A González; Gozzini, S R; Hadasch, D; Hanabata, Y; Hayashida, M; Herrera, J; Hildebrand, D; Hose, J; Hrupec, D; Idec, W; Kadenius, V; Kellermann, H; Kodani, K; Konno, Y; Krause, J; Kubo, H; Kushida, J; La Barbera, A; Lelas, D; Lewandowska, N; Lindfors, E; Lombardi, S; Longo, F; López, M; López-Coto, R; López-Oramas, A; Lorenz, E; Lozano, I; Makariev, M; Mallot, K; Maneva, G; Mankuzhiyil, N; Mannheim, K; Maraschi, L; Marcote, B; Mariotti, M; Martínez, M; Mazin, D; Menzel, U; Miranda, J M; Mirzoyan, R; Moralejo, A; Munar-Adrover, P; Nakajima, D; Niedzwiecki, A; Nilsson, K; Nishijima, K; Noda, K; Orito, R; Overkemping, A; Paiano, S; Palatiello, M; Paneque, D; Paoletti, R; Paredes, J M; Paredes-Fortuny, X; Persic, M; Poutanen, J; Moroni, P G Prada; Prandini, E; Puljak, I; Reinthal, R; Rhode, W; Ribó, M; Rico, J; Garcia, J Rodriguez; Rügamer, S; Saito, T; Saito, K; Satalecka, K; Scalzotto, V; Scapin, V; Schultz, C; Schweizer, T; Shore, S N; Sillanpää, A; Sitarek, J; Snidaric, I; Sobczynska, D; Spanier, F; Stamatescu, V; Stamerra, A; Steinbring, T; Storz, J; Strzys, M; Takalo, L; Takami, H; Tavecchio, F; Temnikov, P; Terzić, T; Tescaro, D; Teshima, M; Thaele, J; Tibolla, O; Torres, D F; Toyama, T; Treves, A; Uellenbeck, M; Vogler, P; Zanin, R; Kadler, M; Schulz, R; Ros, E; Bach, U; Krauß, F; Wilms, J

    2014-01-01

    Supermassive black holes with masses of millions to billions of solar masses are commonly found in the centers of galaxies. Astronomers seek to image jet formation using radio interferometry, but still suffer from insufficient angular resolution. An alternative method to resolve small structures is to measure the time variability of their emission. Here, we report on gamma-ray observations of the radio galaxy IC 310 obtained with the MAGIC telescopes revealing variability with doubling time scales faster than 4.8 min. Causality constrains the size of the emission region to be smaller than 20\\% of the gravitational radius of its central black hole. We suggest that the emission is associated with pulsar-like particle acceleration by the electric field across a magnetospheric gap at the base of the radio jet.

  5. Protection of porous carbon fuel particles from boudouard corrosion

    Energy Technology Data Exchange (ETDEWEB)

    Cooper, John F.

    2015-05-26

    A system for producing energy that includes infusing porous carbon particles produced by pyrolysis of carbon-containing materials with an off-eutectic salt composition thus producing pore-free carbon particles, and reacting the carbon particles with oxygen in a fuel cell according to the reaction C+O.sub.2=CO.sub.2 to produce electrical energy.

  6. Particle acceleration in the vacuum gaps in black hole magnetospheres

    CERN Document Server

    Ptitsyna, K

    2015-01-01

    We consider particle acceleration in vacuum gaps in magnetospheres of black holes powered through Blandford-Znajek mechanism and embedded into radiatively-inefficient accretion flow (RIAF) environment. In such situation the gap height is limited by the onset of gamma-gamma pair production on the infrared photons originating from the RIAF. We numerically calculate acceleration and propagation of charged particles taking into account the detailed structure of electric and magnetic field in the gap and in the entire black hole magnetosphere, radiative energy losses and interactions of gamma rays produced by the propagated charged particles with the background radiation field of RIAF. We show that the presence of the vacuum gap has clear observational signatures. The spectra of emission from gaps embedded into a relatively high luminosity RIAF are dominated by the inverse Compton emission with a sharp, super-exponential cut-off in the very-high-energy gamma-ray band. The cut-off energy is determined by the proper...

  7. Particle film affects black pecan aphid (Homoptera: Aphididae) on pecan.

    Science.gov (United States)

    Cottrell, Ted E; Wood, Bruce W; Reilly, Charles C

    2002-08-01

    Three species of aphids attack pecan foliage, Carya illinoensis (Wang.) K. Koch, and cause economic damage. We tested a kaolin-based particle film against one of these aphid species, black pecan aphid, Melanocallis caryaefoliae (Davis). Effect of particle film on host selection, adult mortality, and production of nymphs by M. caryaefoliae was tested on seedling pecans in the laboratory. Fewer M. caryaefoliae adults selected treated foliage compared with untreated foliage. A higher percentage of adults that did select treated foliage were recovered from upper leaf surfaces compared with the percentage of adults recovered from upper leaf surfaces of untreated leaves. Observations with a microscope revealed an accumulation of particle film on aphid body parts, especially on tarsi, and strongly suggests that aphid mobility was restricted. Adult mortality was higher on treated foliage and led to an overall decrease in production of nymphs on those seedlings. In addition, we measured spectral properties of treated seedling pecan foliage. Light reflectance by treated foliage was increased and absorptance decreased compared with control foliage whereas transmittance of light through control and particle film-treated leaves was similar. We did not detect any phytotoxic effect on pecan due to application of particle film.

  8. Rotating Charged Hairy Black Hole in (2+1) Dimensions and Particle Acceleration

    Science.gov (United States)

    Sadeghi, J.; Pourhassan, B.; Farahani, H.

    2014-09-01

    In this paper, we construct rotating charged hairy black hole in (2+1) dimensions for infinitesimal black hole charge and rotation parameters. Then we consider this black hole as particle accelerator and calculate the center-of-mass energy of two colliding test particles near the rotating charged hairy black hole in (2+1) dimensions. As we expected, the center-of-mass energy has infinite value.

  9. Rotating charged hairy black hole in (2+1) dimensions and particle acceleration

    CERN Document Server

    Sadeghi, J; Farahani, H

    2013-01-01

    In this paper we construct rotating charged hairy black hole in (2+1) dimensions for infinitesimal black hole charge and rotation parameters. Then we consider this black hole as particle accelerator and calculate the center-of-mass energy of two colliding test particles near the rotating charged hairy black hole in (2+1) dimensions. As we expected, the center-of-mass energy has infinite value.

  10. Simplifying the calculation of light scattering properties for black carbon fractal aggregates

    Directory of Open Access Journals (Sweden)

    A. J. A. Smith

    2014-02-01

    Full Text Available Black carbon fractal aggregates have complicated shapes that make the calculation of their optical properties particularly computationally expensive. Here, a method is presented to estimate fractal aggregate light scattering properties by optimising simplified models to full light scattering calculations. It is found that there are no possible spherical models (at any size or refractive index that well represent the light scattering in the visible, or near-thermal infrared. As such, parameterisations of the light scattering as a function of the number of aggregate particles is presented as the most pragmatic choice for modelling distributions of black carbon when the large computational overheads of rigorous scattering calculations cannot be justified. This parameterisation can be analytically integrated to provide light scattering properties for log-normal distributions of black carbon fractal aggregates and return extinction cross-sections with 0.1% accuracy for typical black carbon size distributions. Scattering cross-sections and the asymmetry parameter can be obtained to within 3%.

  11. Using measurements for evaluation of black carbon modeling

    Directory of Open Access Journals (Sweden)

    S. Gilardoni

    2010-04-01

    Full Text Available The ever increasing use of air quality and climate model assessments to underpin economic, public health, and environmental policy decisions makes effective model evaluation critical. This paper discusses the properties of black carbon and light attenuation and absorption observations that are the key to a reliable evaluation of black carbon model and compares parametric and nonparametric statistical tools for the quantification of the agreement between models and observations. Black carbon concentrations are simulated with TM5/M7 global model from July 2002 to June 2003 at four remote sites (Alert, Jungfraujoch, Mace Head, and Trinidad Head and two regional background sites (Bondville and Ispra. Equivalent black carbon (EBC concentrations are calculated using light attenuation measurements from January 2000 to December 2005. Seasonal trends in the measurements are determined by fitting sinusoidal functions and the representativeness of the period simulated by the model is verified based on the scatter of the experimental values relative to the fit curves. When the resolution of the model grid is larger than 1°×1°, it is recommended to verify that the measurement site is representative of the grid cell. For this purpose, equivalent black carbon measurements at Alert, Bondville and Trinidad Head are compared to light absorption and elemental carbon measurements performed at different sites inside the same model grid cells. Comparison of these equivalent black carbon and elemental carbon measurements indicates that uncertainties in black carbon optical properties can compromise the comparison between model and observations. During model evaluation it is important to examine the extent to which a model is able to simulate the variability in the observations over different integration periods as this will help to identify the most appropriate timescales. The agreement between model and observation is accurately described by the overlap of

  12. Using measurements for evaluation of black carbon modeling

    Directory of Open Access Journals (Sweden)

    S. Gilardoni

    2011-01-01

    Full Text Available The ever increasing use of air quality and climate model assessments to underpin economic, public health, and environmental policy decisions makes effective model evaluation critical. This paper discusses the properties of black carbon and light attenuation and absorption observations that are the key to a reliable evaluation of black carbon model and compares parametric and nonparametric statistical tools for the quantification of the agreement between models and observations. Black carbon concentrations are simulated with TM5/M7 global model from July 2002 to June 2003 at four remote sites (Alert, Jungfraujoch, Mace Head, and Trinidad Head and two regional background sites (Bondville and Ispra. Equivalent black carbon (EBC concentrations are calculated using light attenuation measurements from January 2000 to December 2005. Seasonal trends in the measurements are determined by fitting sinusoidal functions and the representativeness of the period simulated by the model is verified based on the scatter of the experimental values relative to the fit curves. When the resolution of the model grid is larger than 1° × 1°, it is recommended to verify that the measurement site is representative of the grid cell. For this purpose, equivalent black carbon measurements at Alert, Bondville and Trinidad Head are compared to light absorption and elemental carbon measurements performed at different sites inside the same model grid cells. Comparison of these equivalent black carbon and elemental carbon measurements indicates that uncertainties in black carbon optical properties can compromise the comparison between model and observations. During model evaluation it is important to examine the extent to which a model is able to simulate the variability in the observations over different integration periods as this will help to identify the most appropriate timescales. The agreement between model and observation is accurately described by the overlap of

  13. Radiocarbon Studies of Black Carbon in the Marine Environment

    OpenAIRE

    2015-01-01

    The incomplete combustion of biomass and fossil fuels produces black carbon (BC). BC is recalcitrant and serves as a long term holding pool for carbon, with a mean residence time of one to two orders of magnitude greater than unburnt carbon on land. Yet the known sources of BC are far larger than the known sinks, which led to studies of BC in the ocean’s dissolved organic carbon (DOC) reservoir. The goal of this dissertation was to measure the abundance and residence times of BC in sedime...

  14. Black hole physics. Black hole lightning due to particle acceleration at subhorizon scales.

    Science.gov (United States)

    Aleksić, J; Ansoldi, S; Antonelli, L A; Antoranz, P; Babic, A; Bangale, P; Barrio, J A; Becerra González, J; Bednarek, W; Bernardini, E; Biasuzzi, B; Biland, A; Blanch, O; Bonnefoy, S; Bonnoli, G; Borracci, F; Bretz, T; Carmona, E; Carosi, A; Colin, P; Colombo, E; Contreras, J L; Cortina, J; Covino, S; Da Vela, P; Dazzi, F; De Angelis, A; De Caneva, G; De Lotto, B; de Oña Wilhelmi, E; Delgado Mendez, C; Dominis Prester, D; Dorner, D; Doro, M; Einecke, S; Eisenacher, D; Elsaesser, D; Fonseca, M V; Font, L; Frantzen, K; Fruck, C; Galindo, D; García López, R J; Garczarczyk, M; Garrido Terrats, D; Gaug, M; Godinović, N; González Muñoz, A; Gozzini, S R; Hadasch, D; Hanabata, Y; Hayashida, M; Herrera, J; Hildebrand, D; Hose, J; Hrupec, D; Idec, W; Kadenius, V; Kellermann, H; Kodani, K; Konno, Y; Krause, J; Kubo, H; Kushida, J; La Barbera, A; Lelas, D; Lewandowska, N; Lindfors, E; Lombardi, S; Longo, F; López, M; López-Coto, R; López-Oramas, A; Lorenz, E; Lozano, I; Makariev, M; Mallot, K; Maneva, G; Mankuzhiyil, N; Mannheim, K; Maraschi, L; Marcote, B; Mariotti, M; Martínez, M; Mazin, D; Menzel, U; Miranda, J M; Mirzoyan, R; Moralejo, A; Munar-Adrover, P; Nakajima, D; Niedzwiecki, A; Nilsson, K; Nishijima, K; Noda, K; Orito, R; Overkemping, A; Paiano, S; Palatiello, M; Paneque, D; Paoletti, R; Paredes, J M; Paredes-Fortuny, X; Persic, M; Poutanen, J; Prada Moroni, P G; Prandini, E; Puljak, I; Reinthal, R; Rhode, W; Ribó, M; Rico, J; Rodriguez Garcia, J; Rügamer, S; Saito, T; Saito, K; Satalecka, K; Scalzotto, V; Scapin, V; Schultz, C; Schweizer, T; Shore, S N; Sillanpää, A; Sitarek, J; Snidaric, I; Sobczynska, D; Spanier, F; Stamatescu, V; Stamerra, A; Steinbring, T; Storz, J; Strzys, M; Takalo, L; Takami, H; Tavecchio, F; Temnikov, P; Terzić, T; Tescaro, D; Teshima, M; Thaele, J; Tibolla, O; Torres, D F; Toyama, T; Treves, A; Uellenbeck, M; Vogler, P; Zanin, R; Kadler, M; Schulz, R; Ros, E; Bach, U; Krauß, F; Wilms, J

    2014-11-28

    Supermassive black holes with masses of millions to billions of solar masses are commonly found in the centers of galaxies. Astronomers seek to image jet formation using radio interferometry but still suffer from insufficient angular resolution. An alternative method to resolve small structures is to measure the time variability of their emission. Here we report on gamma-ray observations of the radio galaxy IC 310 obtained with the MAGIC (Major Atmospheric Gamma-ray Imaging Cherenkov) telescopes, revealing variability with doubling time scales faster than 4.8 min. Causality constrains the size of the emission region to be smaller than 20% of the gravitational radius of its central black hole. We suggest that the emission is associated with pulsar-like particle acceleration by the electric field across a magnetospheric gap at the base of the radio jet.

  15. Aerosol light absorption, black carbon, and elemental carbon at the Fresno Supersite, California

    Science.gov (United States)

    Chow, Judith C.; Watson, John G.; Doraiswamy, Prakash; Chen, Lung-Wen Antony; Sodeman, David A.; Lowenthal, Douglas H.; Park, Kihong; Arnott, W. Patrick; Motallebi, Nehzat

    2009-08-01

    Particle light absorption ( bap), black carbon (BC), and elemental carbon (EC) measurements at the Fresno Supersite during the summer of 2005 were compared to examine the equivalency of current techniques, evaluate filter-based bap correction methods, and determine the EC mass absorption efficiency (σ ap) and the spectral dependence of bap. The photoacoustic analyzer (PA) was used as a benchmark for in-situ bap. Most bap measurement techniques were well correlated ( r ≥ 0.95). Unadjusted Aethalometer (AE) and Particle Soot Absorption Photometer (PSAP) bap were up to seven times higher than PA bap at similar wavelengths because of absorption enhancement by backscattering and multiple scattering. Applying published algorithms to correct for these effects reduced the differences to 24 and 17% for the AE and PSAP, respectively, at 532 nm. The Multi-Angle Absorption Photometer (MAAP), which accounts for backscattering effects, overestimated bap relative to the PA by 51%. BC concentrations determined by the AE, MAAP, and Sunset Laboratory semi-continuous carbon analyzer were also highly correlated ( r ≥ 0.93) but differed by up to 57%. EC measured with the IMPROVE/STN thermal/optical protocols, and the French two-step thermal protocol agreed to within 29%. Absorption efficiencies determined from PA bap and EC measured with different analytical protocols averaged 7.9 ± 1.5, 5.4 ± 1.1, and 2.8 ± 0.6 m 2/g at 532, 670, and 1047 nm, respectively. The Angström exponent (α) determined from adjusted AE and PA bap ranged from 1.19 to 1.46. The largest values of α occurred during the afternoon hours when the organic fraction of total carbon was highest. Significant biases associated with filter-based measurements of bap, BC, and EC are method-specific. Correcting for these biases must take into account differences in aerosol concentration, composition, and sources.

  16. Atmospheric black carbon and sulfate concentrations in Northeast Greenland

    Science.gov (United States)

    Massling, A.; Nielsen, I. E.; Kristensen, D.; Christensen, J. H.; Sørensen, L. L.; Jensen, B.; Nguyen, Q. T.; Nøjgaard, J. K.; Glasius, M.; Skov, H.

    2015-08-01

    Measurements of equivalent black carbon (EBC) in aerosols at the high Arctic field site Villum Research Station (VRS) at Station Nord in North Greenland showed a seasonal variation in EBC concentrations with a maximum in winter and spring at ground level. Average measured concentrations were about 0.067 ± 0.071 for the winter and 0.011 ± 0.009 for the summer period. These data were obtained using a multi-angle absorption photometer (MAAP). A similar seasonal pattern was found for sulfate concentrations with a maximum level during winter and spring analyzed by ion chromatography. Here, measured average concentrations were about 0.485 ± 0.397 for the winter and 0.112 ± 0.072 for the summer period. A correlation between EBC and sulfate concentrations was observed over the years 2011 to 2013 stating a correlation coefficient of R2 = 0.72. This finding gives the hint that most likely transport of primary emitted BC particles to the Arctic was accompanied by aging of the aerosols through condensational processes. BC and sulfate are known to have only partly similar sources with respect to their transport pathways when reaching the high Arctic. Aging processes may have led to the formation of secondary inorganic matter and further transport of BC particles as cloud processing and further washout of particles is less likely based on the typically observed transport patterns of air masses arriving at VRS. Additionally, concentrations of EC (elemental carbon) based on a thermo-optical method were determined and compared to EBC measurements. EBC measurements were generally higher, but a correlation between EC and EBC resulted in a correlation coefficient of R2 = 0.64. Model estimates of the climate forcing due to BC in the Arctic are based on contributions of long-range transported BC during spring and summer. The measured concentrations were here compared with model results obtained by the Danish Eulerian Hemispheric Model, DEHM. Good agreement between measured and

  17. Costs and global impacts of black carbon abatement strategies

    OpenAIRE

    K. Rypdal; Rive, N.; T. K. Berntsen; Z. Klimont; Mideksa, T.K.; G. Myhre; R. B. Skeie

    2009-01-01

    Abatement of particulate matter has traditionally been driven by health concerns rather than its role in global warming. Here we assess future abatement strategies in terms of how much they reduce the climate impact of black carbon (BC) and organic carbon (OC) from contained combustion. We develop global scenarios which take into account regional differences in climate impact, costs of abatement and ability to pay, as well as both the direct and indirect (snow-albedo) climate impact of BC ...

  18. Molecular simulation of polycyclic aromatic hydrocarbon sorption to black carbon

    NARCIS (Netherlands)

    Haftka, J.J.H.; Parsons, J.R.; Govers, H.A.J.

    2009-01-01

    Strong sorption of hydrophobic organic contaminants to soot or black carbon (BC) is an important environmental process limiting the bioremediation potential of contaminated soils and sediments. Reliable methods to predict BC sorption coefficients for organic contaminants are therefore required. A co

  19. Exposure of pregnant mice to carbon black by intratracheal instillation

    DEFF Research Database (Denmark)

    Jackson, Petra; Hougaard, Karin S.; Vogel, Ulla;

    2011-01-01

    -induced response, such as inflammation during gestation, leads to secondary effects in the fetus. Time-mated C57BL/6BomTac mice were exposed by intratracheal instillation to vehicle (Nanopure water) or one of three concentrations (2.75, 13.5 or 67μg in 40μl Nanopure water) of carbon black Printex 90 (CB...

  20. Evaluation of black carbon estimations in global aerosol models

    NARCIS (Netherlands)

    Koch, D.; Schulz, M.; McNaughton, C.; Spackman, J.R.; Balkanski, Y.; Bauer, S.; Krol, M.C.

    2009-01-01

    We evaluate black carbon (BC) model predictions from the AeroCom model intercomparison project by considering the diversity among year 2000 model simulations and comparing model predictions with available measurements. These model-measurement intercomparisons include BC surface and aircraft concentr

  1. Potential impacts of black carbon on the marine microbial community

    NARCIS (Netherlands)

    Malits, A.; Cattaneo, R.; Sintes, E.; Gasol, J.M.; Herndl, G.J.; Weinbauer, M.G.

    2015-01-01

    Black carbon (BC) is the carbonaceous residue of the incomplete combustion of fossil fuels and biomass and encompasses a range of chemically heterogeneous substances from partly charred plant material to highly condensed soot aerosols. We addressed the potential role of BC aerosol deposition on mari

  2. Black silicon maskless templates for carbon nanotube forests

    DEFF Research Database (Denmark)

    Wierzbicki, Rafal; Schmidt, Michael Stenbæk; Boisen, Anja

    2013-01-01

    We present here a proof of concept for a novel fabrication method of vertically aligned carbon nanotube forests, utilizing black silicon nanograss (a forest of silicon nanometer-sized spikes created with reactive ion etching) coated with titanium tungsten diffusion barrier as a template. The meth...

  3. Dynamics of Particles Around a Regular Black Hole with Nonlinear Electrodynamics

    CERN Document Server

    Jawad, Abdul; Jamil, Mubasher; Debnath, Ujjal

    2016-01-01

    We investigate the dynamics of a charged particle being kicked off from its circular orbit around a regular black hole by an incoming massive particle in the presence of magnetic field. The resulting escape velocity, escape energy and the effective potential is analyzed. It is shown that the presence of even a very weak magnetic field helps the charged particles in escaping the gravitational field of the black hole. Moreover the effective force acting on the particle visibly reduces with distance. Thus particle near the black hole will experience higher effective force as compared to when it is far away.

  4. Hawking radiation of spin-1 particles from a three-dimensional rotating hairy black hole

    Energy Technology Data Exchange (ETDEWEB)

    Sakalli, I.; Ovgun, A., E-mail: ali.ovgun@emu.edu.tr [Eastern Mediterranean University Famagusta, North Cyprus, Department of Physics (Turkey)

    2015-09-15

    We study the Hawking radiation of spin-1 particles (so-called vector particles) from a three-dimensional rotating black hole with scalar hair using a Hamilton–Jacobi ansatz. Using the Proca equation in the WKB approximation, we obtain the tunneling spectrum of vector particles. We recover the standard Hawking temperature corresponding to the emission of these particles from a rotating black hole with scalar hair.

  5. Hawking radiation of scalar particles from accelerating and rotating black holes

    Energy Technology Data Exchange (ETDEWEB)

    Gillani, Usman A.; Rehman, Mudassar; Saifullah, K., E-mail: mani_precious2001@yahoo.com, E-mail: mudassar051@yahoo.com, E-mail: saifullah@qau.edu.pk [Department of Mathematics, Quaid-i-Azam University, Islamabad (Pakistan)

    2011-06-01

    Hawking radiation of uncharged and charged scalar particles from accelerating and rotating black holes is studied. We calculate the tunneling probabilities of these particles from the rotation and acceleration horizons of these black holes. Using this method we recover the correct Hawking temperature as well.

  6. Phase Transformations of Graphite and Carbon Black by Laser with Low Power Density

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The structure phase transformations of graphite and carbon black induced by pulsed laser were studied in this paper. Under irradiation with laser beam of 1.06μm wavelength and power density of 106 W· cm- 2, both graphite structure and carbon black structure were changed obviously. The results of Raman analyses and Transmission Electron Microscopy (TEM) observations show that graphite transforms into nanodiamond about 5 nm and carbon black is graphitized. It is demonstrated that graphite is the intermediate phase in the transformation from carbon black to diamond, and graphite is easier to transform into diamond by laser irradiation than carbon black.

  7. Effective density of Aquadag and fullerene soot black carbon reference materials used for SP2 calibration

    Directory of Open Access Journals (Sweden)

    M. Gysel

    2011-12-01

    Full Text Available The mass and effective density of black carbon (BC particles generated from aqueous suspensions of Aquadag and fullerene soot was measured and parametrized as a function of their mobility diameter. The measurements were made by two independent research groups by operating a differential mobility analyser (DMA in series with an aerosol particle mass analyser (APM or a Couette centrifugal particle mass analyser (CPMA. Consistent and reproducible results were found in this study for different production lots of Aquadag, indicating that the effective density of these particles is a stable quantity and largely unaffected by differences in aerosol generation procedures and suspension treatments. The effective density of fullerene soot particles from one production lot was also found to be stable and independent of suspension treatments. Some differences to previous literature data were observed for both Aquadag and fullerene soot at larger particle diameters. Knowledge of the exact relationship between mobility diameter and particle mass is of great importance, as DMAs are commonly used to size-select particles from BC reference materials for calibration of single particle soot photometers (SP2, which quantitatively detect the BC mass in single particles.

  8. Effective density of Aquadag and fullerene soot black carbon reference materials used for SP2 calibration

    Directory of Open Access Journals (Sweden)

    M. Gysel

    2011-08-01

    Full Text Available The mass and effective density of black carbon (BC particles generated from aqueous suspensions of Aquadag and fullerene soot was measured and parametrized as a function of their mobility diameter. The measurements were made by two independent research groups by operating a differential mobility analyser (DMA in series with an aerosol particle mass analyser (APM or a Couette centrifugal particle mass analyser (CPMA. Consistent and reproducible results were found in this study for different production lots of Aquadag, indicating that the effective density of these particles is a stable quantity and largely unaffected by differences in aerosol generation procedures and suspension treatments. The effective density of fullerene soot particles from one production lot was also found to be stable and independent of suspension treatments. Some difference to previous literature data was observed for both Aquadag and fullerene soot at larger particle diameters. Knowledge of the exact relationship between mobility diameter and particle mass is of great importance, as DMAs are commonly used to size-select particles from BC reference materials for calibration of single particle soot photometers (SP2, which quantitatively detect the BC mass in single particles.

  9. Hawking Radiation of Vector Particles via Tunneling From 4-Dimensional And 5-Dimensional Black Holes

    CERN Document Server

    Feng, Zhongwen; Zu, Xiaotao

    2016-01-01

    Using Proca equation and WKB approximation, we investigate Hawking radiation of vector particles via tunneling from 4-dimensional Kerr-de Sitter black hole and 5-dimensional Schwarzschild-Tangherlini black hole. The results show that the tunneling rates and Hawking temperatures are depended on the properties of spacetime (event horizon, mass and angular momentum). Besides, our results are the same as scalars and fermions tunneling from 4-dimensional Kerr-de Sitter black hole and 5-dimensional Schwarzschild-Tangherlini black hole.

  10. Centennial black carbon turnover observed in a Russian steppe soil

    Directory of Open Access Journals (Sweden)

    K. Hammes

    2008-02-01

    Full Text Available Black carbon (BC, from incomplete combustion of fuels and biomass, has been considered highly recalcitrant and a substantial sink for carbon dioxide. Recent studies have shown that BC can be degraded. We use soils sampled 100 years apart in a Russian steppe preserve to generate the first whole-profile estimate of BC stocks and turnover in the field. BC stocks (initially 2.5 kg m-2 decreased 25% with cessation of biomass burning. BC turnover in the soil was 293 y (best estimate; range 212–541 y, much faster than inert/passive carbon in soil models. Such results provide a new constraint on theories of soil carbon stabilization. Most importantly, BC cannot be assumed chemically recalcitrant in all soils; other explanations for very old soil carbon are needed.

  11. Study on Microwave Dielectric Property of Carbon Black and Short Carbon Fibers

    Institute of Scientific and Technical Information of China (English)

    WU Hong-huan; ZHU Dong-mei; LUO Fa; ZHOU Wan-cheng; WANG Xiao-yan

    2006-01-01

    Carbon black and carbon fibers of different lengths were introduced in different matrices at different ratios to explore their microwave dielectric properties under 8.2 GHz-12.4 GHz. It is found that the actual dielectric constants of the samples containing carbon black are in a two-order function of the contents of carbon black ((з)′,(з)″=Av2+Bv+C) and the complex dielectric constants show an obvious frequency response. Of the added fibers of different lengths, the 4 mm-long one could well disperse in the matrices having not only good frequency response, but also larger real parts, imaginary parts and loss values. The imaginary parts and the loss values (tanδ) of the samples with 4 mm-long carbon fibers added increase linearly with the contents of fiber increasing. So it is practicable to adjust the dielectric parameters of the material in a wide range by changing the added amount of carbon black, and the carbon fiber or altering the lengths of the carbon fiber added.

  12. Dependence of climate forcing and response on the altitude of black carbon aerosols

    Science.gov (United States)

    Ban-Weiss, George A.; Cao, Long; Bala, G.; Caldeira, Ken

    2012-03-01

    Black carbon aerosols absorb solar radiation and decrease planetary albedo, and thus can contribute to climate warming. In this paper, the dependence of equilibrium climate response on the altitude of black carbon is explored using an atmospheric general circulation model coupled to a mixed layer ocean model. The simulations model aerosol direct and semi-direct effects, but not indirect effects. Aerosol concentrations are prescribed and not interactive. It is shown that climate response of black carbon is highly dependent on the altitude of the aerosol. As the altitude of black carbon increases, surface temperatures decrease; black carbon near the surface causes surface warming, whereas black carbon near the tropopause and in the stratosphere causes surface cooling. This cooling occurs despite increasing planetary absorption of sunlight (i.e. decreasing planetary albedo). We find that the trend in surface air temperature response versus the altitude of black carbon is consistent with our calculations of radiative forcing after the troposphere, stratosphere, and land surface have undergone rapid adjustment, calculated as "regressed" radiative forcing. The variation in climate response from black carbon at different altitudes occurs largely from different fast climate responses; temperature dependent feedbacks are not statistically distinguishable. Impacts of black carbon at various altitudes on the hydrological cycle are also discussed; black carbon in the lowest atmospheric layer increases precipitation despite reductions in solar radiation reaching the surface, whereas black carbon at higher altitudes decreases precipitation.

  13. Size-selected black carbon mass distributions and mixing state in polluted and clean environments of northern India

    Science.gov (United States)

    Raatikainen, Tomi; Brus, David; Hooda, Rakesh K.; Hyvärinen, Antti-Pekka; Asmi, Eija; Sharma, Ved P.; Arola, Antti; Lihavainen, Heikki

    2017-01-01

    We have measured black carbon properties by using a size-selected single-particle soot photometer (SP2). The measurements were conducted in northern India at two sites: Gual Pahari is located at the Indo-Gangetic Plain (IGP) and Mukteshwar at the Himalayan foothills. Northern India is known as one of the absorbing aerosol hot spots, but detailed information about absorbing aerosol mixing state is still largely missing. Previous equivalent black carbon (eBC) mass concentration measurements are available for this region, and these are consistent with our observations showing that refractory black carbon (rBC) concentrations are about 10 times higher in Gual Pahari than those at Mukteshwar. Also, the number fraction of rBC-containing particles is higher in Gual Pahari, but individual rBC-containing particles and their size distributions are fairly similar. These findings indicate that particles at both sites have similar local and regional emission sources, but aerosols are also transported from the main source regions (IGP) to the less polluted regions (Himalayan foothills). Detailed examination of the rBC-containing particle properties revealed that they are most likely irregular particles such as fractal aggregates, but the exact structure remains unknown.

  14. Academic Training Lectures | Black Holes from a Particle Physics Perspective | 18-19 November

    CERN Multimedia

    2014-01-01

    Black Holes from a Particle Physics Perspective by Georgi Dvali   Tuesday 18 and Wednesday 19 November 2014 from 11 am to 12 noon at CERN ( 40-S2-A01 - Salle Anderson ) Description: We will review the physics of black holes, both large and small, from a particle physicist's perspective, using particle physics tools for describing concepts such as entropy, temperature and quantum information processing. We will also discuss microscopic pictures of black hole formation in high energy particle scattering, potentially relevant for high-energy accelerator experiments, and some differences and similarities with the signatures of other BSM physics. See the Indico page here.

  15. Oxidation behavior of a kind of carbon black

    Institute of Scientific and Technical Information of China (English)

    TANG JunShi; SONG Qiang; HE BaiLei; YAO Qiang

    2009-01-01

    The DTG curves of a kind of carbon black during TPO tests were found to have multiple peaks with an unusual sharp peak after the main peak. TPO tests with different sample loads, oxygen fractions and heating rates were carried out to study the influence of the experimental parameters on the sharp peak. The results show that the sharp peak is not caused by heat and mass transfer limitations, but by the intrinsic oxidation kinetics of the carbon black. The evolution of the specific surface area during the intrinsic kinetic controlled oxidation process was then analyzed using isothermal oxidation at low temperatures which showed that the sharp peak is caused by the increase of the specific surface area. The pore structure changes greatly influence the oxidation process when the reaction is controlled by the intrinsic kinetics. When there were no heat and mass transfer limitations, the different oxidation processes result in the same specific surface area evolution.

  16. Characteristics of PAH tar oil contaminated soils-Black particles, resins and implications for treatment strategies.

    Science.gov (United States)

    Trellu, Clément; Miltner, Anja; Gallo, Rosita; Huguenot, David; van Hullebusch, Eric D; Esposito, Giovanni; Oturan, Mehmet A; Kästner, Matthias

    2017-04-05

    Tar oil contamination is a major environmental concern due to health impacts of polycyclic aromatic hydrocarbons (PAH) and the difficulty of reaching acceptable remediation end-points. Six tar oil-contaminated soils with different industrial histories were compared to investigate contamination characteristics by black particles. Here we provide a simple method tested on 6 soils to visualize and identify large amounts of black particles (BP) as either solid aggregates of resinified and weathered tar oil or various wood/coke/coal-like materials derived from the contamination history. These materials contain 2-10 times higher PAH concentrations than the average soil and were dominantly found in the sand fraction containing 42-86% of the total PAH. The PAH contamination in the different granulometric fractions was directly proportional to the respective total organic carbon content, since the PAH were associated to the carbonaceous particulate materials. Significantly lower (bio)availability of PAH associated to these carbonaceous phases is widely recognized, thus limiting the efficiency of remediation techniques. We provide a conceptual model of the limited mass transfer of PAH from resinated tar oil phases to the water phase and emphasize the options to physically separate BP based on their lower bulk density and slower settling velocity.

  17. Estimating particulate black carbon concentrations using two offline light absorption methods applied to four types of filter media

    Science.gov (United States)

    Davy, Pamela M.; Tremper, Anja H.; Nicolosi, Eleonora M. G.; Quincey, Paul; Fuller, Gary W.

    2017-03-01

    Atmospheric particulate black carbon has been linked to adverse health outcomes. Additional black carbon measurements would aid a better understanding of population exposure in epidemiological studies as well as the success, or otherwise, of relevant abatement technologies and policies. Two light absorption measurement methods of particles collected on filters have been applied to four different types of filters to provide estimations of particulate black carbon concentrations. The ratio of transmittance (lnI0/I) to reflectance (lnR0/R) varied by filter type and ranged from close to 0.5 (as expected from simple theory) to 1.35 between the four filter types tested. The relationship between light absorption and black carbon, measured by the thermal EC(TOT) method, was nonlinear and differed between filter type and measurement method. This is particularly relevant to epidemiological studies that use light absorption as an exposure metric. An extensive archive of filters was used to derive loading factors and mass extinction coefficients for each filter type. Particulate black carbon time series were then calculated at locations where such measurements were not previously available. When applied to two roads in London, black carbon concentrations were found to have increased between 2011 and 2013, by 0.3 (CI: -0.1, 0.5) and 0.4 (CI: 0.1, 0.9) μg m-3 year-1, in contrast to the expectation from exhaust abatement policies. New opportunities using archived or bespoke filter collections for studies on the health effects of black carbon and the efficacy of abatement strategies are created.

  18. Evaluation of the genetic activity of industrially produced carbon black.

    Science.gov (United States)

    Kirwin, C J; LeBlanc, J V; Thomas, W C; Haworth, S R; Kirby, P E; Thilagar, A; Bowman, J T; Brusick, D J

    1981-06-01

    Commercially produced oil furnace carbon black (Chemical Abstract Service Registry No. 1333-86-4) has been evaluated by five different assay for genetic activity. These were the Ames Salmonella typhimurium reverse mutation test, sister chromatid exchange test in CHO cells, mouse lymphoma test, cell transformation assay in C3H/10T1/2 cells, and assay for genetic effects in Drosophila melanogaster. Limited cellular toxicity was exhibited but no significant genetic activity was noted.

  19. Massive particles' tunnelling radiation from the black hole with a mass-quadruple moment

    Institute of Scientific and Technical Information of China (English)

    Han Yi-Wen

    2007-01-01

    In this paper, we extend Zhang and Zhao's recent work to the black hole with a mass-quadruple moment. The behaviour of the tunnelling massive particles is investigated, and the emission rate at which massive particles tunnel across the event horizon of the black hole is calculated. The result is consistent with an underlying unitary theory, and takes the same functional form as that of a massless particle.

  20. Single particle studies of black liquor gasification under pressurized conditions

    Energy Technology Data Exchange (ETDEWEB)

    Whitty, K.; Backman, R.; Hupa, M.; Backman, P.; Ek, P.; Hulden, S.T.; Kullberg, M.; Sorvari, V.

    1997-10-01

    The purpose of this project is to provide experimental data relevant to pressurized black liquor gasification concepts. Specifically, the following two goals will be achieved: Data on swelling, char yields and component release during pressurized pyrolysis of small samples of black liquor will be obtained. The reactivity and physical behavior of single black liquor droplets during simultaneous pyrolysis and gasification will be investigated. The structure and composition of black liquor char during formation and conversion will be studied. (orig.)

  1. Barrow Black Carbon Source and Impact Study Final Campaign Report

    Energy Technology Data Exchange (ETDEWEB)

    Barrett, Tate [Baylor Univ., Waco, TX (United States)

    2014-07-01

    The goal of the Barrow Black Carbon Source and Impact (BBCSI) Study was to characterize the concentration and isotopic composition of carbonaceous atmospheric particulate matter (PM) at the Atmospheric Radiation Measurement site in Barrow, AK. The carbonaceous component was characterized via measurement of the organic and black carbon (OC and BC) components of the total PM. To facilitate complete characterization of the particulate matter, filter-based collections were used, including a medium volume PM2.5 sampler and a high volume PM10 sampler. Thirty-eight fine (PM2.5) and 49 coarse (PM10) particulate matter fractions were collected at weekly and bi-monthly intervals. The PM2.5 sampler operated with minimal maintenance during the 12 month campaign. The PM10 sampler used for the BBCSI used standard Tisch hi-vol motors which have a known lifetime of ~1 month under constant use; this necessitated monthly maintenance and it is suggested that the motors be upgraded to industrial blowers for future deployment in the Arctic. The BBCSI sampling campaign successfully collected and archived 87 ambient atmospheric particulate matter samples from Barrow, AK from July 2012 to June 2013. Preliminary analysis of the organic and black carbon concentrations has been completed. This campaign confirmed known trends of high BC lasting from the winter through to spring haze periods and low BC concentrations in the summer.

  2. Adsorption ability of the carbon black for nickel ions uptake from aqueous solution

    OpenAIRE

    Rađenović Ankica; Malina Jadranka

    2013-01-01

    Surface modification can be performed by adsorption of certain organic compounds on the surface of carbon. The main objective of this work was to compare the adsorption ability of acid-modified carbon black with the non-modified one. Modification process was performed by adsorption of acetic acid onto commercial carbon black surface. A batch adsorption system was applied to study the both adsorption reaction, acetic acid and Ni(II) adsorption onto the carbon black. Adsorption isotherms ...

  3. Analysis of transpacific transport of black carbon during HIPPO-3: implications for black carbon aging

    Directory of Open Access Journals (Sweden)

    Z. Shen

    2014-01-01

    Full Text Available Long-range transport of black carbon (BC is a growing concern as a result of the efficiency of BC in warming the climate and its adverse impact on human health. We study transpacific transport of BC during HIPPO-3 using a combination of inverse modeling and sensitivity analysis. We use the GEOS-Chem chemical transport model and its adjoint to constrain Asian BC emissions and estimate the source of BC over the North Pacific. We find that different sources of BC dominate the transport to the North Pacific during the southbound (29 March 2010 and northbound (13 April 2010 measurements in HIPPO-3. While biomass burning in Southeast Asia (SE contributes about 60% of BC in March, more than 90% of BC comes from fossil fuel and biofuel combustion in East Asia (EA during the April mission. GEOS-Chem simulations generally resolve the spatial and temporal variation of BC concentrations over the North Pacific, but are unable to reproduce the low and high tails of the observed BC distribution. We find that the optimized BC emissions derived from inverse modeling fail to improve model simulations significantly. This failure indicates that uncertainties in BC transport, rather than in emissions, account for the major biases in GEOS-Chem simulations of BC. The aging process, transforming BC from hydrophobic into hydrophilic form, is one of the key factors controlling wet scavenging and remote concentrations of BC. Sensitivity tests on BC aging suggest that the aging time scale of anthropogenic BC from EA is several hours, faster than assumed in most global models, while the aging process of biomass burning BC from SE may occur much slower, with a time scale of a few days. To evaluate the effects of BC aging and wet deposition on transpacific transport of BC, we develop an idealized model of BC transport. We find that the mid-latitude air masses sampled during HIPPO-3 may have experienced a series of precipitation events, particularly near the EA and SE source

  4. Particle Collisions in the Lower Dimensional Rotating Black Hole Space-Time with the Cosmological Constant

    Directory of Open Access Journals (Sweden)

    Jie Yang

    2014-01-01

    Full Text Available We study the effect of ultrahigh energy collisions of two particles with different energies near the horizon of a 2+1 dimensional BTZ black hole (BSW effect. We find that the particle with the critical angular momentum could exist inside the outer horizon of the BTZ black hole regardless of the particle energy. Therefore, for the nonextremal BTZ black hole, the BSW process is possible on the inner horizon with the fine tuning of parameters which are characterized by the motion of particle, while, for the extremal BTZ black hole, the particle with the critical angular momentum could only exist on the degenerated horizon, and the BSW process could also happen there.

  5. Sulfonated carbon black-based composite membranes for fuel cell applications

    Indian Academy of Sciences (India)

    Hacer Doǧan; Emel Yildiz; Metin Kaya; Tülay Y Inan

    2013-08-01

    Two different commercial grade carbon black samples, Cabot Regal 400R (C1) and Cabot Mogul L (C2), were sulfonated with diazonium salt of sulfanilic acid. The resultant sulfonated carbon black samples (S–C) were characterized by Fourier transform infrared spectroscopy (FTIR) and thermal gravimetric analysis (TGA). Composite membranes were then prepared using S–C as fillers and sulfonated poly(ether ether ketone) (SPEEK) as polymer matrix with three different sulfonation degrees (DS = 60, 70 and 82%). Structure and properties of the composite membranes were characterized by FTIR, TGA, scanning electron microscopy, proton conduction, water uptake, ion exchange capacity and chemical stability. Incorporation of S–C particles above 0.25 wt% caused decrease in chemical stability. Pristine and composite membranes prepared from SPEEK82 decomposed completely in <1 h, which is undesirable for fuel cell applications. SPEEK60 membrane having wt% of 0.25–0.5 with S–C particles led to higher proton conductivity than that of pristine membrane. No positive effect was observed on the properties of the composite membranes with the addition of S–C particles at high concentrations due to the agglomeration problems and decrease in the content of conductive polymer matrix.

  6. Some Interesting Behaviour of Accreting Particles in the Gap Region of Black Hole Accretion Discs

    Institute of Scientific and Technical Information of China (English)

    WANG Ding-Xiong; XIAO Kan; LEI Wei-Hua

    2001-01-01

    Some interesting behaviour of accreting particles in the gap region between the horizon of the Kerr black hole and the inner edge of the surrounding disc is investigated. The following results are obtained. (i) Spacetime coincidence of the maximum of angular velocity of accreting particles and that of the black hole horizon is extended to the more general disc-accretion. (ii) The possibility is discussed of negative energy of accreting particles in prograde orbit inside the ergosphere of the Kerr black hole, which is surrounded by strong enough magnetic field.

  7. High Voltage Surface Degradation on Carbon Blacks in Lithium Ion Batteries

    DEFF Research Database (Denmark)

    Younesi, Reza

    In order to increase the power density of Li-ion batteries, much research is focused on developing cathode materials that can operate at high voltages above 4.5 V with a high capacity, high cycling stability, and rate capability. However, at high voltages all the components of positive electrodes...... including carbon black (CB) additives have a potential risk of degradation. Though the weight percentage of CB in commercial batteries is generally very small, the volumetric amount and thus the surface area of CB compose a rather large part of a cathode due to its small particle size (≈ 50 nm) and high...

  8. Carbon Fiber Damage in Particle Beam

    CERN Document Server

    Dehning, B; Kroyer, T; Meyer, M; Sapinski, M

    2011-01-01

    Carbon fibers are commonly used as moving targets in beam wire scanners. The heating of the fiber due to energy loss of the particles travelling through is simulated with Geant4. The heating induced by the beam electromagnetic field is estimated with ANSYS. The heat transfer and sublimation processes are modelled. Due to the model nonlinearity, a numerical approach based on discretization of the wire movement is used to solve it for particular beams. Radiation damage to the fiber is estimated with SRIM. The model is tested with available SPS and LEP data and a dedicated damage test on the SPS beam is performed followed by a post-mortem analysis of the wire remnants. Predictions for the LHC beams are made.

  9. The onset of chaotic motion of a spinning particle around the Schwarzchild black hole

    Energy Technology Data Exchange (ETDEWEB)

    Kao, J.-K. [Department of Physics, Tamkang University, Tamsui, Taipei, Taiwan (China)]. E-mail: g3180011@tkgis.tku.edu.tw; Cho, H.T. [Department of Physics, Tamkang University, Tamsui, Taipei, Taiwan (China)]. E-mail: htcho@mail.tku.edu.tw

    2005-03-07

    In the Schwarzschild black hole spacetime, we show that chaotic motion can be triggered by the spin of a particle. Taking the spin of the particle as a perturbation and using the Melnikov method, we find that the perturbed stable and unstable orbits are entangled with each other and that illustrates the onset of chaotic behavior in the motion of the particle.

  10. The Onset of Chaotic Motion of a Spinning Particle around the Schwarzchild Black Hole

    CERN Document Server

    Kao, J K

    2005-01-01

    In the Schwarzchild black hole spacetime, we show that chaotic motion can be triggered by the spin of a particle. Taking the spin of the particle as a perturbation and using the Melnikov method, we find that the perturbed stable and unstable orbits are entangled with each other and that illustrates the onset of chaotic behavior in the motion of the particle.

  11. Decreases in elemental carbon and fine particle mass in the United States

    Directory of Open Access Journals (Sweden)

    D. M. Murphy

    2011-01-01

    Full Text Available Observations at national parks and other remote sites show that average elemental carbon and fine particle mass concentrations in the United States both decreased by over 25% between 1990 and 2004. Percentage decreases in elemental carbon were much larger in winter than in summer. These data suggest that emissions controls have been effective in reducing particulate concentrations not only in polluted areas but also across the United States. Despite the reduction in elemental carbon, the simultaneous decrease in non-absorbing particles implies that the overall radiative forcing from these changes was toward warming. The use of a 2005 instead of 1990 as a baseline for climate-relevant emissions from the United States would imply a significantly lower baseline for aerosol emissions. The use of older data will overestimate the possibility for future reductions in warming due to black carbon controls.

  12. Decreases in elemental carbon and fine particle mass in the United States

    Directory of Open Access Journals (Sweden)

    D. M. Murphy

    2011-05-01

    Full Text Available Observations at national parks and other remote sites show that average elemental carbon and fine particle mass concentrations in the United States both decreased by over 25 % between 1990 and 2004. Percentage decreases in elemental carbon were much larger in winter than in summer. These data suggest that emissions controls have been effective in reducing particulate concentrations not only in polluted areas but also across the United States. Despite the reduction in elemental carbon, the simultaneous decrease in non-absorbing particles implies that the overall radiative forcing from these changes was toward warming. The use of a 2005 instead of 1990 as a baseline for climate-relevant emissions from the United States would imply a significantly lower baseline for aerosol emissions. The use of older data will overestimate the possibility for future reductions in warming due to black carbon controls.

  13. Thermal Analysis Characterization of Elastomers and Carbon Black Filled Rubber Composites for Army Applications

    Science.gov (United States)

    1985-06-01

    Organ~ce, 60.40 % Carbon Black, 36.15 450(S) 2 Carbon black, 36.40 500 % Residue, 2.09 410(SH) 2 Residue, 3.20 22 2 Organica , 64.99 2 Organics, 62.97 2...64.92 1 Organics, 62.30 I Carbon Black, 31.42 395(S) I Carbon Black, 34.02 420 Z Residue, 3.66 440(SR) 1 Reuidue, 3.69 73 - C I Organica , 6’.33 470... Organica , 62.80 % Organics, 62.80 % Carbon black, 36.27 470(S) 2 Carbon black, It.60 505 2 Residue, 0.963 435(51) 2 Residue, 1.60 Iii 2 Organics

  14. Black Carbon in Estuarine (Coastal) High-molecular-weight Dissolved Organic Matter

    Science.gov (United States)

    Mannino, Antonio; Harvey, H. Rodger

    2003-01-01

    Dissolved organic matter (DOM) in the ocean constitutes one of the largest pools of organic carbon in the biosphere, yet much of its composition is uncharacterized. Observations of black carbon (BC) particles (by-products of fossil fuel combustion and biomass burning) in the atmosphere, ice, rivers, soils and marine sediments suggest that this material is ubiquitous, yet the contribution of BC to the ocean s DOM pool remains unknown. Analysis of high-molecular-weight DOM isolated from surface waters of two estuaries in the northwest Atlantic Ocean finds that BC is a significant component of DOM, suggesting that river-estuary systems are important exporters of BC to the ocean through DOM. We show that BC comprises 4-7% of the dissolved organic carbon (DOC) at coastal ocean sites, which supports the hypothesis that the DOC pool is the intermediate reservoir in which BC ages prior to sedimentary deposition. Flux calculations suggest that BC could be as important as vascular plant-derived lignin in terms of carbon inputs to the ocean. Production of BC sequesters fossil fuel- and biomass-derived carbon into a refractory carbon pool. Hence, BC may represent a significant sink for carbon to the ocean.

  15. Factors Controlling Black Carbon Deposition in Snow in the Arctic

    Science.gov (United States)

    Qi, L.; Li, Q.; He, C.; Li, Y.

    2015-12-01

    This study evaluates the sensitivity of black carbon (BC) concentration in snow in the Arctic to BC emissions, dry deposition and wet scavenging efficiency using a 3D global chemical transport model GEOS-Chem driven by meteorological field GEOS-5. With all improvements, simulated median BC concentration in snow agrees with observation (19.2 ng g-1) within 10%, down from -40% in the default GEOS-Chem. When the previously missed gas flaring emissions (mainly located in Russia) are included, the total BC emission in the Arctic increases by 70%. The simulated BC in snow increases by 1-7 ng g-1, with the largest improvement in Russia. The discrepancy of median BC in snow in the whole Arctic reduces from -40% to -20%. In addition, recent measurements of BC dry deposition velocity suggest that the constant deposition velocity of 0.03 cm s-1 over snow and ice used in the GEOS-Chem is too low. So we apply resistance-in-series method to calculate the dry deposition velocity over snow and ice and the resulted dry deposition velocity ranges from 0.03 to 0.24 cm s-1. However, the simulated total BC deposition flux in the Arctic and BC in snow does not change, because the increased dry deposition flux has been compensated by decreased wet deposition flux. However, the fraction of dry deposition to total deposition increases from 16% to 25%. This may affect the mixing of BC and snow particles and further affect the radative forcing of BC deposited in snow. Finally, we reduced the scavenging efficiency of BC in mixed-phase clouds to account for the effect of Wegener-Bergeron-Findeisen (WBF) process based on recent observations. The simulated BC concentration in snow increases by 10-100%, with the largest increase in Greenland (100%), Tromsø (50%), Alaska (40%), and Canadian Arctic (30%). Annual BC loading in the Arctic increases from 0.25 to 0.43 mg m-2 and the lifetime of BC increases from 9.2 to 16.3 days. This indicates that BC simulation in the Arctic is really sensitive to

  16. Evaluation of black carbon estimations in global aerosol models

    Directory of Open Access Journals (Sweden)

    Y. Zhao

    2009-11-01

    Full Text Available We evaluate black carbon (BC model predictions from the AeroCom model intercomparison project by considering the diversity among year 2000 model simulations and comparing model predictions with available measurements. These model-measurement intercomparisons include BC surface and aircraft concentrations, aerosol absorption optical depth (AAOD retrievals from AERONET and Ozone Monitoring Instrument (OMI and BC column estimations based on AERONET. In regions other than Asia, most models are biased high compared to surface concentration measurements. However compared with (column AAOD or BC burden retreivals, the models are generally biased low. The average ratio of model to retrieved AAOD is less than 0.7 in South American and 0.6 in African biomass burning regions; both of these regions lack surface concentration measurements. In Asia the average model to observed ratio is 0.7 for AAOD and 0.5 for BC surface concentrations. Compared with aircraft measurements over the Americas at latitudes between 0 and 50N, the average model is a factor of 8 larger than observed, and most models exceed the measured BC standard deviation in the mid to upper troposphere. At higher latitudes the average model to aircraft BC ratio is 0.4 and models underestimate the observed BC loading in the lower and middle troposphere associated with springtime Arctic haze. Low model bias for AAOD but overestimation of surface and upper atmospheric BC concentrations at lower latitudes suggests that most models are underestimating BC absorption and should improve estimates for refractive index, particle size, and optical effects of BC coating. Retrieval uncertainties and/or differences with model diagnostic treatment may also contribute to the model-measurement disparity. Largest AeroCom model diversity occurred in northern Eurasia and the remote Arctic, regions influenced by anthropogenic sources. Changing emissions, aging, removal, or optical properties within a single model

  17. Evaluation of black carbon estimations in global aerosol models

    Directory of Open Access Journals (Sweden)

    D. Koch

    2009-07-01

    Full Text Available We evaluate black carbon (BC model predictions from the AeroCom model intercomparison project by considering the diversity among year 2000 model simulations and comparing model predictions with available measurements. These model-measurement intercomparisons include BC surface and aircraft concentrations, aerosol absorption optical depth (AAOD from AERONET and Ozone Monitoring Instrument (OMI retrievals and BC column estimations based on AERONET. In regions other than Asia, most models are biased high compared to surface concentration measurements. However compared with (column AAOD or BC burden retreivals, the models are generally biased low. The average ratio of model to retrieved AAOD is less than 0.7 in South American and 0.6 in African biomass burning regions; both of these regions lack surface concentration measurements. In Asia the average model to observed ratio is 0.6 for AAOD and 0.5 for BC surface concentrations. Compared with aircraft measurements over the Americas at latitudes between 0 and 50 N, the average model is a factor of 10 larger than observed, and most models exceed the measured BC standard deviation in the mid to upper troposphere. At higher latitudes the average model to aircraft BC is 0.6 and underestimates the observed BC loading in the lower and middle troposphere associated with springtime Arctic haze. Low model bias for AAOD but overestimation of surface and upper atmospheric BC concentrations at lower latitudes suggests that most models are underestimating BC absorption and should improve estimates for refractive index, particle size, and optical effects of BC coating. Retrieval uncertainties and/or differences with model diagnostic treatment may also contribute to the model-measurement disparity. Largest AeroCom model diversity occurred in northern Eurasia and the remote Arctic, regions influenced by anthropogenic sources. Changing emissions, aging, removal, or optical properties within a single model generated a

  18. Evaluation of Black Carbon Estimations in Global Aerosol Models

    Energy Technology Data Exchange (ETDEWEB)

    Koch, D.; Schulz, M.; Kinne, Stefan; McNaughton, C. S.; Spackman, J. R.; Balkanski, Y.; Bauer, S.; Berntsen, T.; Bond, Tami C.; Boucher, Olivier; Chin, M.; Clarke, A. D.; De Luca, N.; Dentener, F.; Diehl, T.; Dubovik, O.; Easter, Richard C.; Fahey, D. W.; Feichter, J.; Fillmore, D.; Freitag, S.; Ghan, Steven J.; Ginoux, P.; Gong, S.; Horowitz, L.; Iversen, T.; Kirkevag, A.; Klimont, Z.; Kondo, Yutaka; Krol, M.; Liu, Xiaohong; Miller, R.; Montanaro, V.; Moteki, N.; Myhre, G.; Penner, J.; Perlwitz, Ja; Pitari, G.; Reddy, S.; Sahu, L.; Sakamoto, H.; Schuster, G.; Schwarz, J. P.; Seland, O.; Stier, P.; Takegawa, Nobuyuki; Takemura, T.; Textor, C.; van Aardenne, John; Zhao, Y.

    2009-11-27

    We evaluate black carbon (BC) model predictions from the AeroCom model intercomparison project by considering the diversity among year 2000 model simulations and comparing model predictions with available measurements. These model-measurement intercomparisons include BC surface and aircraft concentrations, aerosol absorption optical depth (AAOD) from AERONET and OMI retrievals and BC column estimations based on AERONET. In regions other than Asia, most models are biased high compared to surface concentration measurements. However compared with (column) AAOD or BC burden retreivals, the models are generally biased low. The average ratio of model to retrieved AAOD is less than 0.7 in South American and 0.6 in African biomass burning regions; both of these regions lack surface concentration measurements. In Asia the average model to observed ratio is 0.6 for AAOD and 0.5 for BC surface concentrations. Compared with aircraft measurements over the Americas at latitudes between 0 and 50N, the average model is a factor of 10 larger than observed, and most models exceed the measured BC standard deviation in the mid to upper troposphere. At higher latitudes the average model to aircraft BC is 0.6 and underestimate the observed BC loading in the lower and middle troposphere associated with springtime Arctic haze. Low model bias for AAOD but overestimation of surface and upper atmospheric BC concentrations at lower latitudes suggests that most models are underestimating BC absorption and should improve estimates for refractive index, particle size, and optical effects of BC coating. Retrieval uncertainties and/or differences with model diagnostic treatment may also contribute to the model-measurement disparity. Largest AeroCom model diversity occurred in northern Eurasia and the remote Arctic, regions influenced by anthropogenic sources. Changing emissions, aging, removal, or optical properties within a single model generated a smaller change in model predictions than the

  19. Measuring morphology and density of internally mixed black carbon with SP2 and VTDMA: new insight to absorption enhancement of black carbon in the atmosphere

    Directory of Open Access Journals (Sweden)

    Y. X. Zhang

    2015-11-01

    Full Text Available The morphology and density of black carbon (BC cores in internally mixed BC (In-BC particles affects their mixing state and absorption enhancement. In this work, we developed a new method to measure the morphology and effective density of BC cores of ambient In-BC particles using a single particle soot photometer (SP2 and a volatility tandem differential mobility analyzer (VTDMA, during the CAREBeijing-2013 campaign from 8 to 27 July 2013 at Xianghe Observatory. The new measurement system can select size-resolved ambient In-BC particles and measure the mobility size and mass of In-BC cores. The morphology and effective density of ambient In-BC cores are then calculated. For In-BC cores in the atmosphere, changes in the dynamic shape factor (χ and effective density (ρeff can be characterized as a function of aging process (Dp ⁄ Dc measured by SP2 and VTDMA. During an intensive field study, the ambient In-BC cores had an average χ of ∼ 1.2 and an average density of ∼ 1.2 g cm−3, indicating that ambient In-BC cores have a near-spherical shape with an internal void of ∼ 30 %. With the measured morphology and density, the average shell ⁄ core ratio and absorption enhancement (Eab from ambient black carbon were estimated to be 2.1–2.7 and 1.6–1.9 for different sizes of In-BC particles at 200–350 nm. When assuming the In-BC cores have a void-free BC sphere with a density of 1.8 g cm−3, the shell ⁄ core ratio and Eab could be overestimated by ∼ 13 and ∼ 17 % respectively. The new approach developed in this work will help improve calculations of mixing state and optical properties of ambient In-BC particles by quantification of changes in morphology and density of ambient In-BC cores during aging process.

  20. Black Carbon in Estuarine and Coastal Ocean Dissolved Organic Matter

    Science.gov (United States)

    Mannino, Antonio; Harvey, H. Rodger

    2003-01-01

    Black carbon (BC) in ultrafiltered high-molecular-weight DOM (UDOM) was measured in surface waters of Delaware Bay, Chesapeake Bay and the adjacent Atlantic Ocean (USA) to ascertain the importance of riverine and estuarine DOM as a source of BC to the ocean. BC comprised 5-72% of UDOM-C (27+/-l7%) and on average 8.9+/-6.5% of dissolved organic carbon (DOC) with higher values in the turbid region of the Delaware Estuary and lower yields in the river and coastal ocean. The spatial and seasonal distributions of BC along the salinity gradient of Delaware Bay suggest that the higher levels of BC in surface water UDOM originated from localized sources, possibly from atmospheric deposition or released from resuspended sediments. Black carbon comprised 4 to 7% of the DOC in the coastal Atlantic Ocean, revealing that river-estuary systems are important exporters of colloidal BC to the ocean. The annual flux of BC from Delaware Bay UDOM to the Atlantic Ocean was estimated at 2.4x10(exp 10) g BC yr(exp -1). The global river flux of BC through DOM to the ocean could be on the order of 5.5x1O(exp 12)g BC yr (exp -1). These results support the hypothesis that the DOC pool is the intermediate reservoir in which BC ages prior to sedimentary deposition.

  1. Biomass burning in boreal forests and peatlands: Effects on ecosystem carbon losses and soil carbon stabilization as black carbon

    Science.gov (United States)

    Turetsky, M. R.; Kane, E. S.; Benscoter, B.

    2011-12-01

    Climate change has increased both annual area burned and the severity of biomass combustion in some boreal regions. For example, there has been a four-fold increase in late season fires in boreal Alaska over the last decade relative to the previous 50 years. Such changes in the fire regime are expected to stimulate ecosystem carbon losses through fuel combustion, reduced primary production, and increased decomposition. However, biomass burning also will influence the accumulation of black carbon in soils, which could promote long-term soil carbon sequestration. Variations in slope and aspect regulate soil temperatures and drainage conditions, and affect the development of permafrost and thick peat layers. Wet soil conditions in peatlands and permafrost forests often inhibit combustion during wildfires, leading to strong positive correlations between pre- and post- fire organic soil thickness that persist through multiple fire cycles. However, burning can occur in poorly drained ecosystems through smouldering combustion, which has implications for emission ratios of CO2:CH4:CO as well as black carbon formation. Our studies of combustion severity and black carbon concentrations in boreal soils show a negative relationship between concentrations of black carbon and organic carbon in soils post-fire. Relative to well drained stands, poorly drained sites with thick peat layers (such as north-facing stands) had less severe burning and low concentrations of black carbon in mineral soils post-fire. Conversely, drier forests lost a greater proportion of their organic soils during combustion but retained larger black carbon stocks following burning. Overall, we have quantified greater black carbon concentrations in surface mineral soil horizons than in organic soil horizons. This is surprising given that wildfires typically do not consume the entire organic soil layer in boreal forests, and could be indicative of the vulnerability of black carbon formed in organic horizons

  2. Corrected Hawking Radiation of Dirac Particles from a General Static Riemann Black Hole

    Directory of Open Access Journals (Sweden)

    Ge-Rui Chen

    2013-01-01

    Full Text Available Considering energy conservation and the back reaction of radiating particles to the spacetime, we investigate the massive Dirac particles' Hawking radiation from a general static Riemann black hole using improved Damour-Ruffini method. A direct consequence is that the radiation spectrum is not strictly thermal. The correction to the thermal spectrum is consistent with an underlying unitary quantum theory and this may have profound implications for the black hole information loss paradox.

  3. Massive vector particles tunneling from Kerr and Kerr-Newman black holes

    CERN Document Server

    Li, Xiang-Qian

    2015-01-01

    In this paper, we investigate the Hawking radiation of massive spin-1 particles from 4-dimensional Kerr and Kerr-Newman black holes. By applying the Hamilton-Jacobi ansatz and the WKB approximation to the field equations of the massive bosons in Kerr and Kerr-Newman space-time, the quantum tunneling method is successfully implemented. As a result, we obtain the tunneling rate of the emitted vector particles and recover the standard Hawking temperature of both the two black holes.

  4. Massive vector particles tunneling from Kerr and Kerr–Newman black holes

    Energy Technology Data Exchange (ETDEWEB)

    Li, Xiang-Qian, E-mail: lixiangqian13b@mails.ucas.ac.cn [School of Physics, University of Chinese Academy of Sciences, Beijing 100049 (China); Chen, Ge-Rui [College of Science, Central South University of Forestry and Technology, Changsha 410004 (China)

    2015-12-17

    In this paper, we investigate the Hawking radiation of massive spin-1 particles from 4-dimensional Kerr and Kerr–Newman black holes. By applying the Hamilton–Jacobi ansatz and the WKB approximation to the field equations of the massive bosons in Kerr and Kerr–Newman space-time, the quantum tunneling method is successfully implemented. As a result, we obtain the tunneling rate of the emitted vector particles and recover the standard Hawking temperature of both the two black holes.

  5. Centennial black carbon turnover observed in a Russia steppe soil

    Energy Technology Data Exchange (ETDEWEB)

    Hammes, K.; Torn, M.S.; Lapenas, A.G.; Schmidt, M.W.I.

    2008-09-15

    Black carbon (BC), from incomplete combustion of fuels and biomass, has been considered highly recalcitrant and a substantial sink for carbon dioxide. Recent studies have shown that BC can be degraded in soils. We use two soils with very low spatial variability sampled 100 years apart in a Russian steppe preserve to generate the first whole-profile estimate of BC stocks and turnover in the field. Quantities of fire residues in soil changed significantly over a century. Black carbon stock was 2.5 kg m{sup -2}, or about 7-10% of total organic C in 1900. With cessation of biomass burning, BC stocks decreased 25% over a century, which translates into a centennial soil BC turnover (293 years best estimate; range 182-541 years), much faster than so-called inert or passive carbon in ecosystem models. The turnover time presented here is for loss by all processes, namely decomposition, leaching, and erosion, although the latter two were probably insignificant in this case. Notably, at both time points, the peak BC stock was below 30 cm, a depth interval, which is not typically accounted for. Also, the quality of the fire residues changed with time, as indicated by the use benzene poly carboxylic acids (BPCA) as molecular markers. The proportions of less-condensed (and thus more easily degradable) BC structures decreased, whereas the highly condensed (and more recalcitrant) BC structures survived unchanged over the 100-year period. Our results show that BC cannot be assumed chemically recalcitrant in all soils, and other explanations for very old soil carbon are needed.

  6. Atmospheric deposition of organic and black carbon to the global oceans

    Science.gov (United States)

    Jurado, Elena; Dachs, Jordi; Duarte, Carlos M.; Simó, Rafel

    Atmospheric deposition of total organic carbon (OC) and black carbon (BC) is lacking or not fully accounted in most current models of the global carbon cycling, specially those fluxes related to gas phase OC. Here, we develop and apply a methodology to estimate wet and dry deposition of total OC to the oceans, based on monthly satellite measurements of aerosol size distributions, wind speed, etc., and estimates of deposition for aerosols and organic compounds. The parameterization of dry deposition velocities account for the dependence of turbulent transport with aerosol diameter, wind speed and the formation of marine aerosol, etc. Gravitational settling is estimated as a function of wet particle diameter, thus including hygroscopic growth due to ambient humidity. Global dry deposition of aerosol OC is estimated to be 11 Tg C y -1 and wet deposition of particle and gaseous OC are estimated as 47 and 187 Tg C y -1, respectively. Due to their pulsing variability, wet deposition fluxes can be important locally and as a temporal source of OC to surface waters. Dry and wet deposition of black carbon to the global ocean are estimated to be 2 and 10 Tg C yr -1, respectively, with higher fluxes in the northern hemisphere and for inter-tropical regions. Finally, considerations on the potential magnitude of the hitherto neglected gross air-sea diffusive exchange fluxes of OC are discussed. Even though the magnitude and direction of these cannot be constrained here, evidence of its important role is given. This study, thus, shows that there is an important spatial and temporal variability in atmosphere-ocean exchanges of OC and BC at different scales, and calls for the need for further research on the important role that these exchanges play in the global carbon cycle.

  7. Seasonal features of black carbon measured at Syowa Station, Antarctica

    Science.gov (United States)

    Hara, K.; Osada, K.; Yabuki, M.; Shiobara, M.; Yamanouchi, T.

    2015-12-01

    Black carbon (BC) is one of important aerosol constituents because the strong light absorption ability. Low concentrations of aerosols and BC let BC make insignificant contribution to aerosol radiative forcing in the Antarctica at the moment. Because of less or negligible source strength of BC in the Antarctic circle, BC can be used as a tracer of transport from the mid-latitudes. This study aims to understand seasonal feature, transport pathway, and origins of black carbon in the Antarctic coats. Black carbon measurement has been made using 7-wavelength aethalometer at Syowa Station, Antarctica since February, 2005. Mass BC concentrations were estimated from light attenuation by Weingartner's correction procedure (Weingartner et al., 2003) in this study. Detection limit was 0.2 - 0.4 ng/m3 in our measurement conditions (2-hour resolution and flow rate of ca. 10LPM). BC concentrations ranged from near detection limit to 55.7 ng/m3 at Syowa Station, Antarctica during the measurements. No trend has been observed since February, 2005. High BC concentrations were coincident with poleward flow from the mid-latitudes under the storm conditions by cyclone approach, whereas low BC concentrations were found in transport from coastal regions and the Antarctic continent. Considering that outflow from South America and Southern Africa affect remarkably air quality in the Southern Ocean of Atlantic and Indian Ocean sectors, BC at Syowa Station might be originated from biomass burning and human activity on South America and Southern Africa. Seasonal features of BC at Syowa Station shows maximum in September - October and lower in December - April. Spring maximum in September - October was obtained at the other Antarctic stations (Neumayer, Halley, South pole, and Ferraz). Although second maximum was found in January at the other stations, the maximum was not observed at Syowa Station.

  8. Barrow Black Carbon Source and Impact Study Final Campaign Report

    Energy Technology Data Exchange (ETDEWEB)

    Barrett, Tate

    2014-07-01

    The goal of the Barrow Black Carbon Source and Impact campaign was to characterize the concentration and isotopic composition of carbonaceous atmospheric particulate matter (PM) at the Atmospheric Radiation Measurement (ARM) Climate Research Facility site in Barrow, Alaska. The carbonaceous component was characterized by measuring the organic and black carbon (OC and BC) components of the total PM. To facilitate complete characterization of the PM, filter-based collections were used, including a medium volume PM2.5 sampler and a high volume PM10 sampler. Thirty-eight fine PM fractions (PM2.5) and 49 coarse (PM10) PM fractions were collected at weekly and bi-monthly intervals. The PM2.5 sampler operated with minimal maintenance during the 12 month campaign. The PM10 sampler used for the Barrow Black Carbon Source and Impact (BBCSI) study used standard Tisch “hi-vol” motors that have a known lifetime of approximately 1 month under constant use; this necessitated monthly maintenance, and it is suggested that, for future deployment in the Arctic, the motors be upgraded to industrial blowers. The BBCSI sampling campaign successfully collected and archived 87 ambient atmospheric PM samples from Barrow, Alaska, from July 2012 to June 2013. Preliminary analysis of the OC and BC concentrations has been completed. This campaign confirmed known trends of high BC lasting from the winter through to spring haze periods and low BC concentrations in the summer. However, the annual OC concentrations had a very different seasonal pattern with the highest concentrations during the summer, lowest concentrations during the fall, and increased concentrations during the winter and spring (Figure 1).

  9. Chaotic motion of particles in the accelerating and rotating black holes spacetime

    CERN Document Server

    Chen, Songbai; Jing, Jiliang

    2016-01-01

    We have investigated the motion of timelike particles along geodesic in the background of accelerating and rotating black hole spacetime. We confirmed that the chaos exists in the geodesic motion of the particles by Poincar\\'e sections, the power spectrum, the fast Lyapunov exponent indicator and the bifurcation diagram. Moreover, we probe the effects of the acceleration and rotation parameters on the chaotic behavior of a timelike geodesic particle in the black hole spacetime. Our results show that the acceleration brings richer physics for the geodesic motion of particles.

  10. World Carbon Black Output to Reach 12.7 Million Tons in 2015

    Institute of Scientific and Technical Information of China (English)

    Zhu Yongkang

    2012-01-01

    From April 13 to April 17, "Carbon Black China of 2012" (CBC2012) was held in Hangzhou, China. Mr. Paul Ita, the president of US marketing research institution Notch Consulting Group, announced that the prospect of carbon black industry was closely linked with the development of auto industry and tire industry. The demand for carbon black of 2010 increased by 15% compared with that of 2009; the growth rate of demand for carbon black was 5.8% in 2011 and the total output was 10.7 million tons, which increased by about 5.5% compared with that of 2010.

  11. Climate effects of black carbon aerosols in China and India.

    Science.gov (United States)

    Menon, Surabi; Hansen, James; Nazarenko, Larissa; Luo, Yunfeng

    2002-09-27

    In recent decades, there has been a tendency toward increased summer floods in south China, increased drought in north China, and moderate cooling in China and India while most of the world has been warming. We used a global climate model to investigate possible aerosol contributions to these trends. We found precipitation and temperature changes in the model that were comparable to those observed if the aerosols included a large proportion of absorbing black carbon ("soot"), similar to observed amounts. Absorbing aerosols heat the air, alter regional atmospheric stability and vertical motions, and affect the large-scale circulation and hydrologic cycle with significant regional climate effects.

  12. Modal character of atmospheric black carbon size distributions

    Science.gov (United States)

    Berner, A.; Sidla, S.; Galambos, Z.; Kruisz, C.; Hitzenberger, R.; ten Brink, H. M.; Kos, G. P. A.

    1996-08-01

    Samples of atmospheric aerosols, collected with cascade impactors in the urban area of Vienna (Austria) and at a coastal site on the North Sea, were investigated for black carbon (BC) as the main component of absorbing material and for mass. The size distributions are structured. The BC distributions of these samples show a predominant mode, the accumulation aerosol, in the upper submicron size range, a less distinct finer mode attributable to fresh emissions from combustion sources, and a distinct coarse mode of unclear origin. It is important to note that some parameters of the accumulation aerosol are related statistically, indicating the evolution of the atmospheric accumulation aerosol.

  13. Utilization of the Net Heat Process Tail Gases in the Reactor for the Production of Oil-Furnace Carbon Black

    Directory of Open Access Journals (Sweden)

    Bosak, Z.

    2011-02-01

    Full Text Available Tail gases of low calorific value, which are the by-product of oil-furnace carbon black industrial production, can be efficiently used as energy before their final release into the atmosphere. Apart from being used mainly for heating dryers, production of steam, electricity, or flared, they can also be used as a substitute for fuel in the reactor for the production of oil-furnace carbon blacks, thus increasing the efficiency of the hydrocarbon raw feedstock.This technical paper represents the technical-technological solution for applying the waste heat of the low calorific tail gases in the reactor for the production of "hard" grade oil-furnace carbon blacks with savings of the hydrocarbon raw feedstock.The introduction of the preheated low calorific tail gases in the reactor for the production of "hard" grade oil-furnace carbon blacks is achieved by serial cascading of four fans. The system consists of fans designed to pneumatically transport the mixture of process tail gases and oil-furnace carbon black dust particles. This ensures a stable technological process for the introduction of the low calorific process tail gases into the reaction zone where the natural gas and preheated air are combusted.In the production of oil-furnace carbon black N220, it is shown that by using low calorific process tail gases in the amount from 1000 to 2000 m3 h–1 per reactor, savings from 10 to 20 % of natural gas and simultaneously 7 to 9 % of the hydrocarbon raw feedstoks were achieved.

  14. Catalytic Enhancement of Carbon Black and Coal-Fueled Hybrid Direct Carbon Fuel Cells

    DEFF Research Database (Denmark)

    Deleebeeck, Lisa; Ippolito, Davide; Kammer Hansen, Kent

    2015-01-01

    was investigated using current-voltage-power density curves. In the anode chamber, catalysts are mixed with the carbon-carbonate mixture. These catalysts include various manganese oxides (MnO2, Mn2O3, Mn3O4, MnO), metal carbonates (Ag2CO3, MnCO3, Ce2(CO3)3), metals (Ag, Ce, Ni), doped-ceria (CeO2, Ce1-xGdxO2-x/2......, Ce1-xREExO2-δ (REE = Pr, Sm)) and metal oxides (LiMn2O4, Ag2O). Materials showing the highest activity in carbon black (Mn2O3, CeO2, Ce0.6Pr0.4O2-δ, Ag2O) were subsequently tested for catalytic activity toward bituminous coal, as revealed by both I-V-P curves and electrochemical impedance......Hybrid direct carbon fuel cells (HDCFCs) consisting of a solid carbon (carbon black)-molten carbonate ((62–38 wt% Li-K)2CO3) mixtures in the anode chamber of an anode-supported solid oxide fuel cell type full-cell are tested for their electrochemical performance between 700 and 800°C. Performance...

  15. Hawking Radiation of Spin-1 Particles From Three Dimensional Rotating Hairy Black Hole

    CERN Document Server

    Sakalli, I

    2015-01-01

    In the present article, we study the Hawking radiation (HR) of spin-1 particles -- so-called vector particles -- from a three dimensional (3D) rotating black hole with scalar hair (RBHWSH) using Hamilton-Jacobi (HJ) ansatz. Putting the Proca equation amalgamated with the WKB approximation in process, the tunneling spectrum of vector particles is obtained. We recover the standard Hawking temperature corresponding to the emission of these particles from RBHWSH.

  16. Synthesis of Cordierite by Decomposition of Metal Nitrates on the Surface of Carbon Black Powder

    Institute of Scientific and Technical Information of China (English)

    XIE Zhi-yong; LIANG Hui; XU Ming-xia; XU Ting-xian

    2004-01-01

    Cordierite precursor was obtained through a process, which involved the decomposition of metal nitrates on the surface of ultrafine carbon black powder between 100-300℃ and the gasification of the carbon black at higher temperature in air. The average size of the particles, which were heat-treated at 700℃ for 10h, is about 1020nm, and the specific surface area is about 129m2/g. The experimental results show that the ultrafine particles of cordierite precursor can be produced by this process. The precursor powder was calcined at different temperatures. X-ray diffraction examination indicates that β-quartz is crystallized from the amorphous matrix around 850℃ firstly and then MgO-Al2O3 spinel and α-cordierite appears. Above 1000℃, MgO-Al2O3 spinel and cristobalite disappear gradually and form an intermediate phase (sapphirine). At around 1300℃, the main phase is α-cordierite, and no other phase is detected.

  17. Pseudo-capacitance of ruthenium oxide/carbon black composites for electrochemical capacitors

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Hydrous ruthenium oxide was formed by a new process.The precursor was obtained by mixing the aqueous solutions of RuCl3·xH20 and NaHCO3.The addition of NaHCO3 led to the formation of an oxide with extremely free RuO2 particles forming a porous network structure in the oxide electrode.Polyethylene glycol was added as a controller to partly inhibit the sol-gel reaction.The rate capacitance of 530 F·g-1 was measured for the powder formed at an optimal annealing temperature of 210~C.Several details concerning this new material,including crystal structure,particle size as a function of temperature,and electrochemical properties,were also reported.In addition,the rote capacitance of the composite electrode reached 800 F·g-1 after carbon black was added.By using the modified electrode of a RuO2/carbon black composite electrode,the electrochemical capacitor exhibits high energy density and stable power characteristics.The values of specific energy and maximum specific power of 24 Wh·kg-1 and 4 kW·kg-1,respectively,are demonstrated for a cell voltage between 0 and 1 V.

  18. Absorption Cross Section of Static Einstein-Maxwell Dilation Axion Black Hole for Scalar Particles

    Institute of Scientific and Technical Information of China (English)

    LIU Chang-Qing; JING Ji-Liang

    2007-01-01

    The absorption cross section of the static Einstein-Maxwell dilaton axion (EMDA) black hole for scalar particles is investigated.It is shown that the ratio of the absorption cross section of the EMDA black hole to that of the Schwarzschild black hole decreases as the absolute value of the dilaton increases,and it becomes zero as the dilaton tends to its extremal value.It is also shown that the absorption cross section decreases as both the v and the absolute value of the dilaton increase,and it decreases as the mass of the particle decreases.

  19. A photochemically resistant component in riverine dissolved black carbon

    Science.gov (United States)

    Dittmar, Thorsten; Riedel, Thomas; Niggemann, Jutta; Vähätalo, Anssi

    2015-04-01

    Rivers transport combustion-derived dissolved black carbon (DBC) to the oceans at an annual flux that is much higher than required to balance the oceanic inventory of DBC. To resolve this mismatch we studied the long-term stability of DBC in ten major world rivers that together account for approximately 1/3 of the global freshwater discharge to the oceans. Riverine DBC was remarkably resistant against microbial degradation, but decomposition of nearly all chromophoric dissolved organic matter under extensive irradiation with simulated sunlight removed almost 80% of DBC. Photochemically transformed DBC was further microbially decomposed by more than 10% in a subsequent one-year long bioassay. Based on these findings, on a global scale, the estimated riverine flux of microbially degraded and photo-resistant DBC is sufficient to replenish the oceans with DBC and likely contributes to the dissolved organic matter pool that persists in the oceans and sequesters carbon for centuries to millennia.

  20. Effect of the Purple carbon black on the properties of NR/BR blend

    Science.gov (United States)

    Yanfang, Zhao; Dan, Liu; Shengbo, Lin; Binjian; Yinmei, Zhao; Shuangquan, Liao

    2014-08-01

    Purple black is light colored mineral filler mining in recent years in Hainan. The effect of the dosage of the purple carbon black and purple carbon black modificated by Si69 on the vulcanization characteristics, mechanical properties, thermal stability, the damping performance of NR/BR blend rubber were studied, and the blending adhesive tensile sections were analyzed by SEM. Research showed that, with the increasing dosage of the purple carbon black, vulcanization characteristics of NR/BR blend had a little change. Adding the purple carbon black into blending had a reinforcing effect. when the dosage of the purple carbon black was 20, the mechanical properties of blending adhesive was good; Coupling agent Si69 had a modification effect on the purple carbon black. With increasing dosage of Si69, performance of the rubber was improved initially and then decreased; when the mass fraction of Si69 was 8% of the dosage of the purple carbon black, rubber performance was optimal. Purple carbon black had no obvious effect on thermal stability of the rubber, but it improved the damping rubber temperature and damping factor.

  1. Black carbon emissions from in-use ships: a California regional assessment

    Directory of Open Access Journals (Sweden)

    G. M. Buffaloe

    2013-09-01

    Full Text Available Black carbon (BC mass emission factors (EFBC; g-BC (kg-fuel−1 from a variety of ocean going vessels have been determined from measurements of BC and carbon dioxide (CO2 concentrations in ship plumes intercepted by the R/V Atlantis during the 2010 California Nexus (CalNex campaign. The ships encountered were all operating within 24 nautical miles of the California coast and were utilizing relatively low sulphur fuels. Black carbon concentrations within the plumes, from which EFBC values are determined, were measured using four independent instruments: a photoacoustic spectrometer and a particle soot absorption photometer, which measure light absorption, and a single particle soot photometer and soot particle aerosol mass spectrometer, which measure the mass concentration of refractory BC directly. The measured EFBC have been divided into vessel type categories and engine type categories, from which averages have been determined. The geometric average EFBC, determined from over 71 vessels and 135 plumes encountered, was 0.31 g-BC (kg-fuel−1. The most frequent engine type encountered was the slow speed diesel (SSD, and the most frequent SSD vessel type was the cargo ship sub-category. Average and median EFBC values from the SSD category are compared with previous observations from the Texas Air Quality Study (TexAQS in 2006, during which the ships encountered were predominately operating on high sulphur fuels. There is a statistically significant difference between the EFBC values from CalNex and TexAQS for SSD vessels and for the cargo and tanker ship types within this engine category. The CalNex EFBC values are lower than those from TexAQS, suggesting that operation on lower sulphur fuels is associated with smaller EFBC values.

  2. Birchwood biochar as partial carbon black replacement in styrene-butadiene rubber composites

    Science.gov (United States)

    Birchwood feedstock was used to make slow pyrolysis biochar that contained 89% carbon and rubber. Composites made from blended fillers of 25/75 biochar/carbon black were equivalent to or superior to their 100% carbo...

  3. Collisions near Kerr black holes: lower limit of energy between orbiting and incoming particles

    Science.gov (United States)

    Rutkowski, Mieszko

    2017-01-01

    In our paper we investigate the lower limit of collisional energy of test particles near the Kerr black hole. In particular we examine the minimal Lorentz factor between the freely falling particles and the particles orbiting around a black hole. We consider collisions on the innermost stable circular orbit and examine near-extreme case, where collisions take place near an event horizon. By fine-tuning the particles' angular momentum, the Lorentz factor of the collision can always be minimized to a value dependent on the black hole's spin. We identified that this minimal value is always less than 2√{2}-1/√{3} and more than √{12}-1/√{6} (the limits are the values for an extreme Kerr and Schwarzschild, respectively). It implies that this kind of collisions of compact objects are expected to be highly energetic near supermassive black holes. In addition, we show that an interaction between black hole's and particle's spins has an influence on minimal Lorentz factor. This contribution is nonnegligible for near-extreme black holes. We also discuss the relation between our results and sci-fi movie Interstellar.

  4. Oxidation behavior of a kind of carbon black

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    The DTG curves of a kind of carbon black during TPO tests were found to have multiple peaks with an unusual sharp peak after the main peak.TPO tests with different sample loads,oxygen fractions and heating rates were carried out to study the influence of the experimental parameters on the sharp peak.The results show that the sharp peak is not caused by heat and mass transfer limitations,but by the intrinsic oxidation kinetics of the carbon black.The evolution of the specific surface area during the intrinsic kinetic controlled oxidation process was then analyzed using isothermal oxidation at low temperatures which showed that the sharp peak is caused by the increase of the specific surface area.The pore structure changes greatly influence the oxidation process when the reaction is controlled by the intrinsic kinetics.When there were no heat and mass transfer limitations,the different oxidation processes result in the same specific surface area evolution.

  5. High Black Carbon (BC) Concentrations along Indian National Highways

    Science.gov (United States)

    Kumar, S.; Singh, A. K.; Singh, R. P.

    2015-12-01

    Abstract:Black carbon (BC), the optically absorbing component of carbonaceous aerosol, has direct influence on radiation budget and global warming. Vehicular pollution is one of the main sources for poor air quality and also atmospheric pollution. The number of diesel vehicles has increased on the Indian National Highways during day and night; these vehicles are used for the transport of goods from one city to another city and also used for public transport. A smoke plume from the vehicles is a common feature on the highways. We have made measurements of BC mass concentrations along the Indian National Highways using a potable Aethalometer installed in a moving car. We have carried out measurements along Varanasi to Kanpur (NH-2), Varanasi to Durgapur (NH-2), Varanasi to Singrauli (SH-5A) and Varanasi to Ghazipur (NH-29). We have found high concentration of BC along highways, the average BC mass concentrations vary in the range 20 - 40 µg/m3 and found high BC mass concentrations up to 600 μg/m3. Along the highways high BC concentrations were characteristics of the presence of industrial area, power plants, brick kilns and slow or standing vehicles. The effect of increasing BC concentrations along the National Highways and its impact on the vegetation and human health will be presented. Key Words: Black Carbon; Aethalometer; mass concentration; Indian National Highways.

  6. A Black-Hole Primer: Particles, Waves, Critical Phenomena and Superradiant Instabilities

    CERN Document Server

    Berti, Emanuele

    2014-01-01

    These notes were prepared for a lecture on black holes delivered at the DPG Physics School "General Relativity @ 99" (Physikzentrum Bad Honnef, Germany, September 2014). The common thread of the lecture is the relation between geodesic stability and black-hole perturbations in the geometric optics limit. Chapter 1 establishes notation and discusses a common misconception on Michell's "Newtonian black holes". Chapters 2 and 3 deal with particle dynamics and wave dynamics in black-hole spacetimes, respectively. All calculations should be simple enough that they can be done with pen and paper. Chapter 4 builds on this introduction to discuss two exciting topics in current research: critical phenomena in black-hole mergers and the black-hole bomb instability.

  7. Changing Export of Dissolved Black Carbon from Arctic Rivers

    Science.gov (United States)

    Stubbins, A.; Spencer, R. G.; Mann, P. J.; Dittmar, T.; Niggemann, J.; Holmes, R. M.; McClelland, J. W.

    2014-12-01

    Arctic rivers carry black carbon (BC) from Arctic soils to the ocean, linking two of the largest carbon stores on Earth. Wildfires have charred biomass since land plants emerged. BC, a refractory component of char, has accumulated in soils. In the oceans, dissolved BC (DBC) has also accumulated. Here we use samples and data collected as part of the long-term, high temporal resolution Arctic Great Rivers Observatory to model export of DBC from the six largest Arctic Rivers. Scaling to the pan-Arctic catchment, we report that ~3 million tons of DBC are delivered to the Arctic Ocean each year, which is ~8% of dissolved organic carbon loads to the Arctic Ocean. We suggest the transfer of Arctic river DBC to areas of deep water formation is a major source of DBC to the deep ocean carbon store. As the Arctic warms, greater wildfire occurrence is expected to produce more BC and changing hydrology and permafrost thaw to promote DBC export. Thus, the transfer of BC from Arctic soils to the ocean is predicted to increase.

  8. On the partner particles for moving mirror radiation and black hole evaporation

    OpenAIRE

    Hotta, M.; Schützhold, R.; Unruh, W. G.

    2015-01-01

    The partner mode with respect to a vacuum state for a given mode (like that corresponding to one of the thermal particles emitted by a black hole) is defined and calculated. The partner modes are explicitly calculated for a number of cases, in particular for the modes corresponding to a particle detector being excited by turn-on/turn-off transients, or with the thermal particles emitted by the accelerated mirror model for black hole evaporation. One of the key results is that the partner mode...

  9. Tunnelling of scalar and Dirac particles from squashed charged rotating Kaluza-Klein black holes

    Energy Technology Data Exchange (ETDEWEB)

    Stetsko, M.M. [Ivan Franko National University of Lviv, Department of Theoretical Physics, Lviv (Ukraine)

    2016-02-15

    The thermal radiation of scalar particles and Dirac fermions from squashed charged rotating five-dimensional black holes is considered. To obtain the temperature of the black holes we use the tunnelling method. In the case of scalar particles we make use of the Hamilton-Jacobi equation. To consider tunnelling of fermions the Dirac equation was investigated. The examination shows that the radial parts of the action for scalar particles and fermions in the quasi-classical limit in the vicinity of horizon are almost the same and as a consequence it gives rise to identical expressions for the temperature in the two cases. (orig.)

  10. Tunnelling of scalar and Dirac particles from squashed charged rotating Kaluza-Klein black holes

    Science.gov (United States)

    Stetsko, M. M.

    2016-02-01

    The thermal radiation of scalar particles and Dirac fermions from squashed charged rotating five-dimensional black holes is considered. To obtain the temperature of the black holes we use the tunnelling method. In the case of scalar particles we make use of the Hamilton-Jacobi equation. To consider tunnelling of fermions the Dirac equation was investigated. The examination shows that the radial parts of the action for scalar particles and fermions in the quasi-classical limit in the vicinity of horizon are almost the same and as a consequence it gives rise to identical expressions for the temperature in the two cases.

  11. Photo-lability of deep ocean dissolved black carbon

    Directory of Open Access Journals (Sweden)

    A. Stubbins

    2012-01-01

    Full Text Available Dissolved black carbon (DBC, defined here as condensed aromatics isolated from seawater via PPL solid phase extraction and quantified as benzene polycarboxylic acid oxidation products, is a significant component of the oceanic dissolved organic carbon (DOC pool. These condensed aromatics are widely distributed in the open ocean and appear to be tens of thousands of years old. As such DBC is regarded as highly refractory. In the current study, the photo-lability of DBC, DOC and coloured dissolved organic matter (CDOM; ultraviolet-visible absorbance were determined over the course of a 28 d irradiation of North Atlantic Deep Water under a solar simulator. During the irradiation DBC fell from 1044 ± 164 nM C to 55 ± 15 nM C, a 20-fold decrease in concentration. Dissolved black carbon photo-degradation was more rapid and more extensive than for bulk CDOM and DOC. Further, the photo-lability of components of the DBC pool increased with their degree of aromatic condensation. These trends indicate that a continuum of compounds of varying photo-lability exists within the marine DOC pool. In this continuum, photo-lability scales with aromatic character, specifically the degree of condensation. Scaling the rapid photo-degradation of DBC to rates of DOC photo-mineralisation for the global ocean leads to an estimated photo-chemical half-life for oceanic DBC of less than 800 yr. This is more than an order of magnitude shorter than the apparent age of DBC in the ocean. Photo-degradation is therefore posited as the primary sink for oceanic DBC and the survival of DBC molecules in the oceans for millennia appears to be facilitated not by their inherent inertness but by the rate at which they are cycled through the surface ocean's photic zone.

  12. Sources of uncertainties in modelling black carbon at the global scale

    NARCIS (Netherlands)

    Vignati, E.; Karl, M.; Krol, M.C.; Wilson, J.; Stier, P.; Cavalli, F.

    2010-01-01

    Our understanding of the global black carbon (BC) cycle is essentially qualitative due to uncertainties in our knowledge of its properties. This work investigates two source of uncertainties in modelling black carbon: those due to the use of different schemes for BC ageing and its removal rate in th

  13. Plasma Polymerization Surface Modification of Carbon Black and its Effect in Elastomers

    NARCIS (Netherlands)

    Mathew, T.; Datta, R.N.; Dierkes, W.K.; Talma, A.G.; Ooij, van W.J.; Noordermeer, J.W.M.

    2011-01-01

    Surface modification of carbon black by plasma polymerization was aimed to reduce its surface energy in order to compatibilize the filler with various elastomers. A fullerenic carbon black was used for the modification process. Thermogravimetric analysis, wetting behavior with liquids of known surfa

  14. Carbon black nanoparticle instillation induces sustained inflammation and genotoxicity in mouse lung and liver

    DEFF Research Database (Denmark)

    Bourdon, Julie A; Saber, Anne T; Jacobsen, Nicklas R;

    2012-01-01

    Widespread occupational exposure to carbon black nanoparticles (CBNPs) raises concerns over their safety. CBNPs are genotoxic in vitro but less is known about their genotoxicity in various organs in vivo.......Widespread occupational exposure to carbon black nanoparticles (CBNPs) raises concerns over their safety. CBNPs are genotoxic in vitro but less is known about their genotoxicity in various organs in vivo....

  15. Climate Response due to Black Carbon Aerosols and Black-Carbon-induced SST Effects in MIROC5.0

    Science.gov (United States)

    Yu, Y.; Nakajima, T.; Goto, D.

    2014-12-01

    This study used the Models for Interdisciplinary Research on Climate, MIROC5.0, one member of the Coupled Model Intercomparison Project (CMIP5), to investigate the effects of black carbon (BC) aerosols on atmospheric circulations and climate including intricate feedback mechanism. The simulations with and without BC were conducted and the difference between these two runs is the corresponding response due to BC. Both atmosphere-ocean coupled general circulation model simulation (CGCM with full ocean) and the fixed SST runs (AGCM with prescribed sea surface temperature and sea ice temperature) were used to study the effects from ocean boundary conditions. The regional effects due to BC may be much larger than models have assumed (Andreae and Ramanathan, 2013; Bond et al., 2013). There are many studies used simplified mixed-layer ocean under prescribed surface heat flux to estimate the climate effect of BC (Kim et al., 2014), however these ocean-atmosphere coupled processes act on seasonal and annual time scales more real than non-ocean-atmosphere coupled models. Our results showed that the comprehensively sea-air interaction amplified the heating effect of black carbon aerosols; the presence of BC affected climate not only at local source areas but also at remote regions due to changes on energy transport processes and atmospheric circulations; we also discussed how the feedback of SST induced by BC affected on the distribution and magnitudes of climate response such as temperature, precipitation and cloud coverage between CGCM and AGCM runs.

  16. Is marine dissolved organic matter the "missing sink" for soil-derived black carbon?

    Science.gov (United States)

    Dittmar, Thorsten; Suryaputra, I. Gusti N. A.; Niggemann, Jutta

    2010-05-01

    The thermal alteration of biomass during wildfires can be an important factor for the stabilization of organic matter in soils. Black carbon, i.e. biochars and soot, is more resistant to biodegradation than unaltered biomass, and it can therefore accumulate in soils and sediments. Our knowledge on the turnover of black carbon is still very fragmentary, and the known loss rates do not account for the estimated production rates. Major loss mechanisms remain unidentified or have been underestimated. Recently, we have identified a major thermogenic component in dissolved organic matter (DOM) of the deep ocean. We hypothesize that black carbon in soils is solubilized over time, probably via microbial interaction, and transported via rivers into the ocean. DOM, one of the largest organic carbon pools on earth, could therefore be an important transport medium of soil-derived black carbon. A case study was performed in the Suwannee River estuary and adjacent oceanic shelf (Florida, USA). The Suwannee River drains extensive wetlands and fire-impacted forests. The fate of dissolved black carbon was traced from the river through its estuary into the open Gulf of Mexico. Black carbon was molecularly quantified as benzenepolycarboxylic acids after nitric acid oxidation via a new UPLC method (ultra-performance liquid chromatography). The molecular analysis was accompanied by optical (excitation-emission matrix fluorescence and absorbance spectroscopy) and elemental characterization of DOM. A major component (approx. 10% on a carbon basis) of Suwannee River DOM could be identified as black carbon. The concentration of black carbon decreased offshore, and on the open ocean only about 1% of DOM could be identified as black carbon. In the deep ocean, the thermogenic component of DOM is higher and approx. 2.4% of DOM. The surface ocean must therefore be an efficient sink for dissolved black carbon. We hypothesize that sunlight may initiate photochemical reactions that cause a loss of

  17. Optical properties of black carbon aggregates with non-absorptive coating

    Science.gov (United States)

    Liu, Chao; Li, Ji; Yin, Yan; Zhu, Bin; Feng, Qian

    2017-01-01

    This study develops an idealized model to account for the effects of non-absorptive coating on the optical properties of black carbon (BC) aggregates. The classic fractal aggregate is applied to represent realistic BC particles, and the coating is assumed to be spherical. To accelerate the single-scattering simulation, BC monomers that were overlapped with coating sphere (not those completely inside the coating) are slightly moved to avoid overlapping. The multiple-sphere T-matrix method (MSTM) becomes applicable to calculate the optical properties of inhomogeneous particles with any coating amount, and is generally two orders of magnitude faster than the discrete-dipole approximation for particles we considered. Furthermore, the simple spherical coating is found to have similar effects on the optical properties to those based on more complicated coating structure. With the simple particle model and the efficient MSTM, it becomes possible to consider the influence of coating with much more details. The non-absorptive coating of BC aggregates can significantly enhance BC extinction and absorption, which is consistent with previous studies. The absorption of coated aggregates can be over two times stronger than that of BC particles without coating. Besides the coating volume, the relative position between the mass centers of BC aggregate and coating also plays an important role on the optical properties, and should obviously be considered in further studies.

  18. Distinguishing black carbon from biogenic humic substances in soil clay fractions

    Science.gov (United States)

    Laird, D.A.; Chappell, M.A.; Martens, D.A.; Wershaw, R. L.; Thompson, M.

    2008-01-01

    Most models of soil humic substances include a substantial component of aromatic C either as the backbone of humic heteropolymers or as a significant component of supramolecular aggregates of degraded biopolymers. We physically separated coarse (0.2-2.0????m e.s.d.), medium (0.02-0.2????m e.s.d.), and fine (> 0.02????m e.s.d.) clay subfractions from three Midwestern soils and characterized the organic material associated with these subfractions using 13C-CPMAS-NMR, DTG, SEM-EDX, incubations, and radiocarbon age. Most of the C in the coarse clay subfraction was present as discrete particles (0.2-5????m as seen in SEM images) of black carbon (BC) and consisted of approximately 60% aromatic C, with the remainder being a mixture of aliphatic, anomeric and carboxylic C. We hypothesize that BC particles were originally charcoal formed during prairie fires. As the BC particles aged in soil their surfaces were oxidized to form carboxylic groups and anomeric and aliphatic C accumulated in the BC particles either by adsorption of dissolved biogenic compounds from the soil solution or by direct deposition of biogenic materials from microbes living within the BC particles. The biogenic soil organic matter was physically separated with the medium and fine clay subfractions and was dominated by aliphatic, anomeric, and carboxylic C. The results indicate that the biogenic humic materials in our soils have little aromatic C, which is inconsistent with the traditional heteropolymer model of humic substances.

  19. Collision of two general particles around a rotating regular Hayward's black holes

    Energy Technology Data Exchange (ETDEWEB)

    Amir, Muhammed; Ahmed, Fazlay [Center for Theoretical Physics, Jamia Millia Islamia, New Delhi (India); Ghosh, Sushant G. [Center for Theoretical Physics, Jamia Millia Islamia, New Delhi (India); University of KwaZulu-Natal, Astrophysics and Cosmology Research Unit, School of Mathematics, Statistics and Computer Science, Private Bag X54001, Durban (South Africa)

    2016-10-15

    The rotating regular Hayward's spacetime, apart from mass (M) and angular momentum (a), has an additional deviation parameter (g) due to the magnetic charge, which generalizes the Kerr black hole when g ≠ 0; for g = 0 it goes over to the Kerr black hole. We analyze how the ergoregion is affected by the parameter g to show that the area of the ergoregion increases with increasing values of g. Further, for each g, there exists a critical a{sub E}, which corresponds to a regular extremal black hole with degenerate horizons r = r{sup E}{sub H}. a{sub E} decreases whereas r{sup E}{sub H} increases with an increase in the parameter g. Banados, Silk, and West (BSW) demonstrated that the extremal Kerr black hole can act as a particle accelerator with arbitrarily high center-of-mass energy (E{sub CM}) when the collision of two particles takes place near the horizon. We study the BSW process for two particles with different rest masses, m{sub 1} and m{sub 2}, moving in the equatorial plane of the extremal Hayward's black hole for different values of g, to show that E{sub CM} is arbitrarily high when one of the particles takes a critical value of the angular momentum. Our result, in the limit g → 0, reduces to that of the Kerr black hole. (orig.)

  20. Factors controlling black carbon distribution in the Arctic

    Science.gov (United States)

    Qi, Ling; Li, Qinbin; Li, Yinrui; He, Cenlin

    2017-01-01

    We investigate the sensitivity of black carbon (BC) in the Arctic, including BC concentration in snow (BCsnow, ng g-1) and surface air (BCair, ng m-3), as well as emissions, dry deposition, and wet scavenging using the global three-dimensional (3-D) chemical transport model (CTM) GEOS-Chem. We find that the model underestimates BCsnow in the Arctic by 40 % on average (median = 11.8 ng g-1). Natural gas flaring substantially increases total BC emissions in the Arctic (by ˜ 70 %). The flaring emissions lead to up to 49 % increases (0.1-8.5 ng g-1) in Arctic BCsnow, dramatically improving model comparison with observations (50 % reduction in discrepancy) near flaring source regions (the western side of the extreme north of Russia). Ample observations suggest that BC dry deposition velocities over snow and ice in current CTMs (0.03 cm s-1 in the GEOS-Chem) are too small. We apply the resistance-in-series method to compute a dry deposition velocity (vd) that varies with local meteorological and surface conditions. The resulting velocity is significantly larger and varies by a factor of 8 in the Arctic (0.03-0.24 cm s-1), which increases the fraction of dry to total BC deposition (16 to 25 %) yet leaves the total BC deposition and BCsnow in the Arctic unchanged. This is largely explained by the offsetting higher dry and lower wet deposition fluxes. Additionally, we account for the effect of the Wegener-Bergeron-Findeisen (WBF) process in mixed-phase clouds, which releases BC particles from condensed phases (water drops and ice crystals) back to the interstitial air and thereby substantially reduces the scavenging efficiency of clouds for BC (by 43-76 % in the Arctic). The resulting BCsnow is up to 80 % higher, BC loading is considerably larger (from 0.25 to 0.43 mg m-2), and BC lifetime is markedly prolonged (from 9 to 16 days) in the Arctic. Overall, flaring emissions increase BCair in the Arctic (by ˜ 20 ng m-3), the updated vd more than halves BCair (by ˜ 20 ng m-3

  1. Light Absorption in Arctic Sea Ice - Black Carbon vs Chlorophyll

    Science.gov (United States)

    Ogunro, O. O.; Wingenter, O. W.; Elliott, S.; Hunke, E. C.; Flanner, M.; Wang, H.; Dubey, M. K.; Jeffery, N.

    2015-12-01

    The fingerprint of climate change is more obvious in the Arctic than any other place on Earth. This is not only because the surface temperature there has increased at twice the rate of global mean temperature but also because Arctic sea ice extent has reached a record low of 49% reduction relative to the 1979-2000 climatology. Radiation absorption through black carbon (BC) deposited on Arctic snow and sea ice surface is one of the major hypothesized contributors to the decline. However, we note that chlorophyll-a absorption owing to increasing biology activity in this region could be a major competitor during boreal spring. Modeling of sea-ice physical and biological processes together with experiments and field observations promise rapid progress in the quality of Arctic ice predictions. Here we develop a dynamic ice system module to investigate discrete absorption of both BC and chlorophyll in the Arctic, using BC deposition fields from version 5 of Community Atmosphere Model (CAM5) and vertically distributed layers of chlorophyll concentrations from Sea Ice Model (CICE). To this point, our black carbon mixing ratios compare well with available in situ data. Both results are in the same order of magnitude. Estimates from our calculations show that sea ice and snow around the Canadian Arctic Archipelago and Baffin Bay has the least black carbon absorption while values at the ice-ocean perimeter in the region of the Barents Sea peak significantly. With regard to pigment concentrations, high amounts of chlorophyll are produced in Arctic sea ice by the bottom microbial community, and also within the columnar pack wherever substantial biological activity takes place in the presence of moderate light. We show that the percentage of photons absorbed by chlorophyll in the spring is comparable to the amount attributed to BC, especially in areas where the total deposition rates are decreasing with time on interannual timescale. We expect a continuous increase in

  2. SP2 Deployment at Boston College—Aerodyne-Led Coated Black Carbon Study (BC4) Final Campaign Summary

    Energy Technology Data Exchange (ETDEWEB)

    Onasch, T. B. [Aerodyne Research, Inc., Billerica, MA (United States); Sedlacek, A. J. [Brookhaven National Lab. (BNL), Upton, NY (United States)

    2016-03-01

    The main objective of the Boston College-Aerodyne led laboratory study (BC4) was to measure the optical properties of black carbon (BC) particles from a diffusion flame directly and after being coated with secondary organic and inorganic material and to achieve optical closure with model predictions. The measurements of single particle BC mass and population mixing states provided by a single particle soot photometer (SP2) was central to achieving the laboratory-based study’s objective. Specifically, the DOE ARM SP2 instrument participated in the BC4 project to address the following scientific questions: 1. What is the mass-specific absorption coefficient as a function of secondary organic and inorganic material coatings? 2. What is the spread in the population mixing states within our carefully generated laboratory particles? 3. How does the SP2 instrument respond to well-characterized, internally mixed BC-containing particles?

  3. Stormwater and fire as sources of black carbon nanoparticles to Lake Tahoe.

    Science.gov (United States)

    Bisiaux, Marion M; Edwards, Ross; Heyvaert, Alan C; Thomas, James M; Fitzgerald, Brian; Susfalk, Richard B; Schladow, S Geoffrey; Thaw, Melissa

    2011-03-15

    Emitted to the atmosphere through fire and fossil fuel combustion, refractory black carbon nanoparticles (rBC) impact human health, climate, and the carbon cycle. Eventually these particles enter aquatic environments, where they may affect the fate of other pollutants. While ubiquitous, the particles are still poorly characterized in freshwater systems. Here we present the results of a study determining rBC in waters of the Lake Tahoe watershed in the western United States from 2007 to 2009. The study period spanned a large fire within the Tahoe basin, seasonal snowmelt, and a number of storm events, which resulted in pulses of urban runoff into the lake with rBC concentrations up to 4 orders of magnitude higher than midlake concentrations. The results show that rBC pulses from both the fire and urban runoff were rapidly attenuated suggesting unexpected aggregation or degradation of the particles. We find that those processes prevent rBC concentrations from building up in the clear and oligotrophic Lake Tahoe. This rapid removal of rBC soon after entry into the lake has implications for the transport of rBC in the global aquatic environment and the flux of rBC from continents to the global ocean.

  4. Brief Analysis on the Production & Operation Situation of Chinese Carbon Black Industry in the First Half Year

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    At present, there are about 120 carbon black manufacturing enterprises in China with the production capacity of 3.41 million tons, accounting for 78% of the total production capacity of the country, in which there are 31 carbon black enterprises with the production capacity of over 50,000 tons. Compared with the international carbon black industry, our carbon black industry has a low intensification.

  5. Absorption probabilities associated with spin-3/2 particles near $N$-dimensional Schwarzschild black holes

    CERN Document Server

    Harmsen, G E; Cho, H T; Cornell, A S

    2016-01-01

    In June 2015 the Large Hadron Collider was able to produce collisions with an energy of 13TeV, where collisions at these energy levels may allow for the formation of higher dimensional black holes. In order to detect these higher dimensional black holes we require an understanding of their emission spectra. One way of determining this is by looking at the absorption probabilities associated with the black hole. In this proceedings we will look at the absorption probability for spin-3/2 particles near $N$-dimensional Schwarzschild black holes. We will show how the Unruh method is used to determine these probabilities for low energy particles. We then use the Wentzel-Kramers-Brillouin approximation in order to determine these absorption probabilities for the entire possible energy range.

  6. Analysis of the Thermal Conductivity of Polymer Nanocomposites Filled with Carbon Nanotubes and Carbon Black

    Directory of Open Access Journals (Sweden)

    R.V. Dinzhos

    2014-04-01

    Full Text Available Experimental results and theoretical studies of thermophysical characteristics crystalline polyethylene nanocomposites containing from 0.3 to 2.5 wt. % carbon black and nanocomposites containing from 0.2 to 1.5 wt. % carbon nanotubes is done in the article. The fundamentals of the effective medium theory and percolation theory and how they correlate with the experimental data is shown. The features of the structure’s influence of polymer composites on their thermal properties is studied. A comparative analysis of the thermal conductivity of the compositions according to the geometry of the filler is done.

  7. Black Carbon in Marine Dissolved Organic Carbon: Abundance and Radiocarbon Measurements in the Global Ocean

    Science.gov (United States)

    Coppola, A. I.; Walker, B. D.; Druffel, E. R. M.

    2014-12-01

    Compound specific radiocarbon analysis is a powerful tool for understanding the cycling of individual components, such as black carbon (BC) produced from biomass burning and fossil fuel combustion, within bulk pools, like the marine dissolved organic carbon pool. Here, we use a solid phase extraction method and a wide range of solvent polarities to concentrate dissolved organic carbon from seawater. Then we isolate BC in sufficient quantities for radiocarbon analysis. We report the radiocarbon age of BC, concentrations and its relative structure, from coastal and open ocean surface samples. We will discuss our progress towards measuring these quantities in dissolved organic carbon collected from the Pacific and Atlantic oceans to understand the fate, transformation and cycling of BC in the world ocean. These measurements are paired with bulk DOC Δ14C profiles, providing insight into the role of BC as a missing sink in the ultra-refractory DOC pool.

  8. Black carbon aerosol-induced Northern Hemisphere tropical expansion

    Science.gov (United States)

    Kovilakam, Mahesh; Mahajan, Salil

    2015-06-01

    Global climate models (GCMs) underestimate the observed trend in tropical expansion. Recent studies partly attribute it to black carbon (BC) aerosols, which are poorly represented in GCMs. We conduct a suite of idealized experiments with the Community Atmosphere Model version 4 coupled to a slab ocean model forced with increasing BC concentrations covering a large swath of the estimated range of current BC radiative forcing while maintaining their spatial distribution. The Northern Hemisphere (NH) tropics expand poleward nearly linearly as BC radiative forcing increases (0.7° W-1 m2), indicating that a realistic representation of BC could reduce GCM biases. We find support for the mechanism where BC-induced midlatitude tropospheric heating shifts the maximum meridional tropospheric temperature gradient poleward resulting in tropical expansion. We also find that the NH poleward tropical edge is nearly linearly correlated with the location of the Intertropical Convergence Zone, which shifts northward in response to increasing BC.

  9. Electrical properties of foamed polypropylene/carbon black composites

    Science.gov (United States)

    Iliev, M.; Kotzev, G.; Vulchev, V.

    2016-02-01

    Polypropylene composites containing carbon black fillers were produced by vibration assisted extrusion process. Solid (unfoamed) composite samples were molded by conventional injection molding method, while structural foams were molded by a low pressure process. The foamed samples were evidenced to have a solid skin-foamed core structure which main parameters were found to depend on the quantity of material injected in the mold. The average bubbles' sizes and their distribution were investigated by scanning electron microscopy. It is established that the conductivity of the foamed samples gradually decreases when reducing the sample density. Nevertheless, the conductivity is found to be lower than the conductivity of the unfoamed samples both being of the same order. The flexural properties of the composites were studied and the results were discussed in the context of the structure parameters of the foamed samples.

  10. Black Carbon Vertical Profiles Strongly Affect Its Radiative Forcing Uncertainty

    Science.gov (United States)

    Samset, B. H.; Myhre, G.; Schulz, M.; Balkanski, Y.; Bauer, S.; Berntsen, T. K.; Bian, H.; Bellouin, N.; Diehl, T.; Easter, R. C.; Ghan, S. J.; Iversen, T.; Kinne, S.; Kirkevag, A.; Lamarque, J.-F.; Lin, G.; Liu, X.; Penner, J. E.; Seland, O.; Skeie, R. B.; Stier, P.; Takemura, T.; Tsigaridis, K.; Zhang, K.

    2013-01-01

    The impact of black carbon (BC) aerosols on the global radiation balance is not well constrained. Here twelve global aerosol models are used to show that at least 20% of the present uncertainty in modeled BC direct radiative forcing (RF) is due to diversity in the simulated vertical profile of BC mass. Results are from phases 1 and 2 of the global aerosol model intercomparison project (AeroCom). Additionally, a significant fraction of the variability is shown to come from high altitudes, as, globally, more than 40% of the total BC RF is exerted above 5 km. BC emission regions and areas with transported BC are found to have differing characteristics. These insights into the importance of the vertical profile of BC lead us to suggest that observational studies are needed to better characterize the global distribution of BC, including in the upper troposphere.

  11. Black hole radiation of spin-1 particles in (1+2) dimensions

    CERN Document Server

    Kruglov, S I

    2014-01-01

    The radiation of vector particles by black holes in (1+2) dimensions is investigated within the WKB approximation. We consider the process of quantum tunnelling of bosons through an event horizon of the black hole. The emission temperature for the Schwarzschild background geometry coincides with the Hawking temperature and for the Rindler space-time the temperature is the Unruh temperature. We also obtain the radiation temperatures for the de Sitter space-time.

  12. Massive vector particles tunneling from black holes influenced by the generalized uncertainty principle

    CERN Document Server

    Li, Xiang-Qian

    2016-01-01

    Considering the generalized uncertainty principle which incorporates the central idea of Large eXtra Dimensions, the processes of massive spin-1 particles tunneling from Reissner-Nordstrom and Kerr black holes are investigated. For the black hole, the quantum gravity correction decelerates the increase of the temperature. When the mass of the black hole approaches the order of the higher dimensional Planck mass $M_f$, it stops radiating and leads to a black hole remnant. To $\\mathcal{O}(\\frac{1}{M_f^2})$, the corrected temperatures are affected by the mass and angular momentum of emitted vector bosons. Meanwhile, the temperature of the Kerr black hole becomes uneven due to the rotation.

  13. Massive vector particles tunneling from black holes influenced by the generalized uncertainty principle

    Science.gov (United States)

    Li, Xiang-Qian

    2016-12-01

    This study considers the generalized uncertainty principle, which incorporates the central idea of large extra dimensions, to investigate the processes involved when massive spin-1 particles tunnel from Reissner-Nordstrom and Kerr black holes under the effects of quantum gravity. For the black hole, the quantum gravity correction decelerates the increase in temperature. Up to O (1Mf/2), the corrected temperatures are affected by the mass and angular momentum of the emitted vector bosons. In addition, the temperature of the Kerr black hole becomes uneven due to rotation. When the mass of the black hole approaches the order of the higher dimensional Planck mass Mf, it stops radiating and yields a black hole remnant.

  14. Dynamics of particles around a Schwarzschild-like black hole in the presence of quintessence and magnetic field

    Energy Technology Data Exchange (ETDEWEB)

    Jamil, Mubasher; Hussain, Saqib; Majeed, Bushra [National University of Sciences and Technology (NUST), School of Natural Sciences (SNS), Islamabad (Pakistan)

    2015-01-01

    We have investigated the dynamics of a neutral and a charged particle around a static and spherically symmetric black hole in the presence of quintessence matter and external magnetic field. We explore the conditions under which the particle moving around the black hole could escape to infinity after colliding with another particle. The innermost stable circular orbit (ISCO) for the particles are studied in detail. Mainly the dependence of ISCO on dark energy and on the presence of external magnetic field in the vicinity of black hole is discussed. By using the Lyapunov exponent, we compare the stabilities of the orbits of the particles in the presence and absence of dark energy and magnetic field. The expressions for the center of mass energies of the colliding particles near the horizon of the black hole are derived. The effective force on the particle due to dark energy and magnetic field in the vicinity of black hole is also discussed. (orig.)

  15. Sources of uncertainties in modelling Black Carbon at the global scale

    Directory of Open Access Journals (Sweden)

    F. Cavalli

    2009-11-01

    Full Text Available Our understanding of the global black carbon cycle is essentially qualitative due to uncertainties in our knowledge of the properties of black carbon. This work investigates uncertainties related to modelling black carbon: due to the use of different schemes for BC ageing and its removal rate in the global Transport-Chemistry model TM5 and due to the uncertainties in the definition and quantification of observed black carbon, which propagate through to both the emission inventories, and the measurements used for the model evaluation.

    The schemes for the atmospheric processing of black carbon that have been tested with the model are (i a simple approach considering black carbon as bulk aerosol and a simple treatment in the removal and (ii a more complete description of microphysical aging within an aerosol dynamics model, where removal is coupled to the microphysical properties of the aerosol. In the first approach a fixed 70% of black carbon is scavenged in clouds and removed when rain is present. The second leads to a global average of 40% black carbon that is scavenged in clouds and subsequently removed by rain, thus resulting in a longer lifetime. This difference is reflected in comparisons between both sets of modelled results and the measurements. Close to the sources, both anthropogenic and vegetation fire source regions, the model results do not differ significantly, showing that the emissions are the prevailing mechanism determining the concentrations and the choice of the aerosol scheme does not influence the levels. In more remote areas such as oceanic and polar regions the differences can be orders of magnitude, due to the differences between the two schemes. The more complete description reproduces the seasonal trend of the black carbon observations in those areas, although not always the magnitude of the signal, while the more simplified approach underestimates black carbon concentrations by orders of magnitude.

  16. Adsorption ability of the carbon black for nickel ions uptake from aqueous solution

    Directory of Open Access Journals (Sweden)

    Rađenović Ankica

    2013-01-01

    Full Text Available Surface modification can be performed by adsorption of certain organic compounds on the surface of carbon. The main objective of this work was to compare the adsorption ability of acid-modified carbon black with the non-modified one. Modification process was performed by adsorption of acetic acid onto commercial carbon black surface. A batch adsorption system was applied to study the both adsorption reaction, acetic acid and Ni(II adsorption onto the carbon black. Adsorption isotherms of acetic acid and Ni(II adsorption onto the non-modified and modified carbon black were fitted by classical adsorption models, such as Freundlich and Langmuir models. Modified carbon black surface become more active for Ni(II ions removal from aqueous solutions. The results showed that modification by acetic acid increases the adsorption capacity of carbon black from 18.3823 mg Ni(II g-1 to 86.9566 mg Ni(II g-1. SEM analysis enabled the observation of any surface changes in the carbon black that have occurred due to either acid modification or Ni(II adsorption.

  17. Sensitivity of Stratospheric Geoengineering with Black Carbon to Aerosol Size and Altitude of Injection

    Science.gov (United States)

    Kravitz, Ben; Robock, Alan; Shindell, Drew T.; Miller, Mark A.

    2012-01-01

    Simulations of stratospheric geoengineering with black carbon (BC) aerosols using a general circulation model with fixed sea surface temperatures show that the climate effects strongly depend on aerosol size and altitude of injection. 1 Tg BC/a injected into the lower stratosphere would cause little surface cooling for large radii but a large amount of surface cooling for small radii and stratospheric warming of over 60 C. With the exception of small particles, increasing the altitude of injection increases surface cooling and stratospheric warming. Stratospheric warming causes global ozone loss by up to 50% in the small radius case. The Antarctic shows less ozone loss due to reduction of polar stratospheric clouds, but strong circumpolar winds would enhance the Arctic ozone hole. Using diesel fuel to produce the aerosols is likely prohibitively expensive and infeasible. Although studying an absorbing aerosol is a useful counterpart to previous studies involving sulfate aerosols, black carbon geoengineering likely carries too many risks to make it a viable option for deployment.

  18. Contribution of regional transport to the black carbon aerosol during winter haze period in Beijing

    Science.gov (United States)

    Wang, Qiyuan; Huang, Ru-Jin; Cao, Junji; Tie, Xuexi; Shen, Zhenxing; Zhao, Shuyu; Han, Yongming; Li, Guohui; Li, Zhengqiang; Ni, Haiyan; Zhou, Yaqing; Wang, Meng; Chen, Yang; Su, Xiaoli

    2016-05-01

    The mass concentrations of atmospheric refractory black carbon (rBC), an important absorber of solar radiation, were continuously measured with a single particle soot photometer (SP2) during wintertime haze period to investigate the transport of pollution to Beijing. The average mass concentration of rBC was 6.1 ± 3.9 μg m-3 during hazy periods, which was 4.7 times higher than it during non-hazy periods. Cluster analysis showed that the air parcels arriving at Beijing mainly originated from the northwest, passed through the south and brought the most polluted air to Beijing. Concentration-weighted trajectory analyses indicated that the central North China Plain were the most likely source region for the rBC that impacted Beijing. Furthermore, the Weather Research and Forecasting-Black Carbon model showed that 71.4-82.0% of the rBC at Beijing was from regional transport during the high rBC episodes and that 47.9-56.8% of the rBC can be attributed to sources in the central North China Plain. These results suggest that regional transport from the central North China Plain, rather than local emissions, was a more important source for rBC pollution in Beijing.

  19. Fluxes of soot black carbon to South Atlantic sediments

    Science.gov (United States)

    Lohmann, Rainer; Bollinger, Kevyn; Cantwell, Mark; Feichter, Johann; Fischer-Bruns, Irene; Zabel, Matthias

    2009-03-01

    Deep sea sediment samples from the South Atlantic Ocean were analyzed for soot black carbon (BC), total organic carbon (TOC), stable carbon isotope ratios (δ13C), and polycyclic aromatic hydrocarbons (PAHs). Soot BC was present at low concentrations (0.04-0.17% dry weight), but accounted for 3-35% of TOC. Fluxes of soot BC were calculated on the basis of known sedimentation rates and ranged from 0.5 to 7.8 μg cm-2 a-1, with higher fluxes near Africa compared to South America. Values of δ13C indicated a marine origin for the organic carbon but terrestrial sources for the soot BC. PAH ratios implied a pyrogenic origin for most samples and possibly a predominance of traffic emissions over wood burning off the African coast. A coupled ocean-atmosphere-aerosol-climate model was used to determine fluxes of BC from 1860 to 2000 to the South Atlantic. Model simulation and measurements both yielded higher soot BC fluxes off the African coast and lower fluxes off the South American coast; however, measured sedimentary soot BC fluxes exceeded simulated values by ˜1 μg cm-2 a-1 on average (within a factor of 2-4). For the sediments off the African coast, soot BC delivery from the Congo River could possibly explain the higher flux rates, but no elevated soot BC fluxes were detected in the Amazon River basin. In total, fluxes of soot BC to the South Atlantic were ˜480-700 Gg a-1 in deep sea sediments. Our results suggest that attempts to construct a global mass balance of BC should include estimates of the atmospheric deposition of BC.

  20. Influence of the black hole spin on the chaotic particle dynamics within a dipolar halo

    CERN Document Server

    Nag, Sankhasubhra; Ananda, Deepika B; Das, Tapas K

    2016-01-01

    We investigate the role of the spin angular momentum of astrophysical black holes in controlling the special relativistic chaotic dynamics of test particles moving under the influence of a post-Newtonian pseudo-Kerr black hole potential, along with a perturbative potential created by a asymmetrically placed (dipolar) halo. Proposing a Lyapunov-like exponent to be the effective measure of the degree of chaos observed in the system under consideration, it has been found that black hole spin anti-correlates with the degree of chaos for the aforementioned dynamics. Our findings have been explained applying the general principles of dynamical systems analysis.

  1. Influence of the black hole spin on the chaotic particle dynamics within a dipolar halo

    Science.gov (United States)

    Nag, Sankhasubhra; Sinha, Siddhartha; Ananda, Deepika B.; Das, Tapas K.

    2017-04-01

    We investigate the role of the spin angular momentum of astrophysical black holes in controlling the special relativistic chaotic dynamics of test particles moving under the influence of a post-Newtonian pseudo-Kerr black hole potential, along with a perturbative potential created by an asymmetrically placed (dipolar) halo. Proposing a Lyapunov-like exponent to be the effective measure of the degree of chaos observed in the system under consideration, it has been found that black hole spin anti-correlates with the degree of chaos for the aforementioned dynamics. Our findings have been explained applying the general principles of dynamical systems analysis.

  2. Nature of Microscopic Black Holes and Gravity in Theories with Particle Species

    CERN Document Server

    Dvali, Gia

    2010-01-01

    Relying solely on unitarity and the consistency with large-distance black hole physics, we derive model-independent properties of the microscopic black holes and of short-distance gravity in theories with N particle species. In this class of theories black holes can be as light as M_{Planck}/\\sqrt{N} and be produced in particle collisions above this energy. We show, that the micro black holes must come in the same variety as the species do, although their label is not associated with any conserved charge measurable at large distances. In contrast with big Schwarzschildian ones, the evaporation of the smallest black holes is maximally undemocratic and is biased in favor of particular species. With an increasing mass the democracy characteristic to the usual macro black holes is gradually regained. The lowest possible mass above which black holes become Einsteinian is \\sqrt{N} M_{Planck}. This fact uncovers the new fundamental scale (below the quantum gravity scale) above which gravity changes classically, and ...

  3. 高结构炭黑酸化改性的研究%Research on High Structure Carbon Black Modification of Acidification

    Institute of Scientific and Technical Information of China (English)

    孟春财; 陈建; 金永中; 张敬雨; 伍雅峰

    2012-01-01

    The experimental samples were made by changing the reaction time and acid concentration and acidizing to modify different high structure carbon black. The dispersion and stability of the modified carbon black in aqueous solution was determined by natural sedimentation method. The shading rate of each modified carbon black was detected by the laser particle size analyzer. The relationship between the surface groups of carbon black and its dispersion was analysed quantitatively by acid-base titratioa And the performance indicators were compared between the modified carbon black and carbon black pigment. The results showed that, the modified carbon black, which was prepared by the N234 carbon black and 6mol/L sulfuric acid for 8 hours, dispersed best, due to the content increase of phenolic hydroxyl and lactone. Comparing the dispersion of carbon black and the price, the modified carbon black was better than the pigment carbon black.%通过改变时间、硫酸浓度等反应条件,酸化改性不同品种炭黑,得到了实验所需试样.采用自然沉降法测定了酸化改性高结构炭黑在水溶液中的分散性及稳定性.利用激光粒度分布仪检测了每种改性炭黑的遮光率,根据酸碱滴定法定量分析了炭黑表面基团与分散性的关系,并比较了改性炭黑与色素炭黑之间的性能指标.结果表明,炭黑N234与6mol/L硫酸反应8h制备的改性炭黑分散性最佳,原因是其表面的酚羟基和内酯基含量有所增加.通过比较炭黑的分散性及市场价格,得知改性炭黑优于色素炭黑.

  4. Carbon black dispersion pre-plating technology for printed wire board manufacturing. Final technology evaluation report

    Energy Technology Data Exchange (ETDEWEB)

    Folsom, D.W.; Gavaskar, A.R.; Jones, J.A.; Olfenbuttel, R.F.

    1993-10-01

    The project compared chemical use, waste generation, cost, and product quality between electroless copper and carbon-black-based preplating technologies at the printed wire board (PWB) manufacturing facility of McCurdy Circuits in Orange, CA. The carbon-black based preplating technology evaluated is used as an alternative process for electroless copper (EC) plating of through-holes before electrolytic copper plating. The specific process used at McCurdy is the BlackHole (BH) technology process, which uses a dispersion of carbon black in an aqueous solution to provide a conductive surface for subsequent electrolytic copper plating. The carbon-black dispersion technology provided effective waste reduction and long-term cost savings. The economic analysis determined that the new process was cost efficient because chemical use was reduced and the process proved more efficient; the payback period was less than 4 yrs.

  5. Markedly enhanced absorption and direct radiative forcing of black carbon under polluted urban environments

    Science.gov (United States)

    Peng, Jianfei; Hu, Min; Guo, Song; Du, Zhuofei; Zheng, Jing; Shang, Dongjie; Levy Zamora, Misti; Zeng, Limin; Shao, Min; Wu, Yu-Sheng; Zheng, Jun; Wang, Yuan; Glen, Crystal R.; Collins, Donald R.; Molina, Mario J.

    2016-04-01

    Black carbon (BC) exerts profound impacts on air quality and climate because of its high absorption cross-section over a broad range of electromagnetic spectra, but the current results on absorption enhancement of BC particles during atmospheric aging remain conflicting. Here, we quantified the aging and variation in the optical properties of BC particles under ambient conditions in Beijing, China, and Houston, United States, using a novel environmental chamber approach. BC aging exhibits two distinct stages, i.e., initial transformation from a fractal to spherical morphology with little absorption variation and subsequent growth of fully compact particles with a large absorption enhancement. The timescales to achieve complete morphology modification and an absorption amplification factor of 2.4 for BC particles are estimated to be 2.3 h and 4.6 h, respectively, in Beijing, compared with 9 h and 18 h, respectively, in Houston. Our findings indicate that BC under polluted urban environments could play an essential role in pollution development and contribute importantly to large positive radiative forcing. The variation in direct radiative forcing is dependent on the rate and timescale of BC aging, with a clear distinction between urban cities in developed and developing countries, i.e., a higher climatic impact in more polluted environments. We suggest that mediation in BC emissions achieves a cobenefit in simultaneously controlling air pollution and protecting climate, especially for developing countries.

  6. Flowing along the edge: spinning up black holes in AdS spacetimes with test particles

    CERN Document Server

    Rocha, Jorge V

    2014-01-01

    We investigate the consequences of throwing point particles into odd-dimensional Myers-Perry black holes in asymptotically anti-de Sitter (AdS) backgrounds. We restrict our attention to the case in which the angular momenta of the background geometry are all equal. This process allows us to test the generalization of the weak cosmic censorship conjecture to asymptotically AdS spacetimes in higher dimensions. We find no evidence for overspinning in D = 5, 7, 9 and 11 dimensions. Instead, test particles carrying the maximum possible angular momentum that still fall into an extremal rotating black hole generate a flow along the curve of extremal solutions.

  7. A perspective on Black Hole Horizons from the Quantum Charged Particle

    CERN Document Server

    Jaramillo, José Luis

    2016-01-01

    Black hole apparent horizons possess a natural notion of stability, whose spectral characterization can be related to the problem of the stationary quantum charged particle. Such mathematical relation leads to an "analyticity conjecture" on the dependence of the spectral properties on a complex "fine-structure-constant" parameter, that can reduce the study of the spectrum of the (non-selfadjoint) MOTS-stability operator to that of the (selfadjoint) Hamiltonian of the quantum charged particle. Moreover, this perspective might open an avenue to the spinorial treatment of apparent horizon (MOTS-)stability and to the introduction of semiclassical tools to explore some of the qualitative aspects of this black hole spectral problem.

  8. Motion of particles on a $z=2$ Lifshitz black hole in 3+1 dimensions

    CERN Document Server

    Olivares, Marco; Villanueva, J R; Moncada, Felipe

    2013-01-01

    We study the geodesic structure of a $z=2$ Lifshitz black hole in 3+1 spacetime dimensions that is an exact solution to the Einstein-scalar-Maxwell theory. We investigate the motion of massless and massive particles in this background using the standard Lagrangian procedure. Analytical expressions are obtained for radial and angular motions of the test particles, where the polar trajectories are given in terms of the $\\wp$ - Weierstrass elliptic function. It is shown that confined orbits are not allowed on this spacetime, this result agrees with the obtained recently in the literature for other Lifshitz black holes.

  9. Tunneling of massive and charged particles from noncommutative Reissner-Nordstr\\"{o}m black hole

    CERN Document Server

    Nozari, Kourosh

    2012-01-01

    Massive charged and uncharged particles tunneling from commutative Reissner-Nordstrom black hole horizon has been studied with details in literature. Here, by adopting the coherent state picture of spacetime noncommutativity, we study tunneling of massive and charged particles from a noncommutative inspired Reissner-Nordstrom black hole horizon. We show that Hawking radiation in this case is not purely thermal and there are correlations between emitted modes. These correlations may provide a solution to the information loss problem. We also study thermodynamics of noncommutative horizon in this setup.

  10. Dissolved Black Carbon in the South China Sea

    Science.gov (United States)

    Fang, Z.; Yang, W.; Chen, M.; Ma, H.

    2015-12-01

    Dissolved black carbon (DBC) has been ubiquitously reported in dissolved organic matter (DOM). However, the abundance and provenance of DBC in the ocean are not well understood. Here, DBC in the South China Sea (SCS) was determined at molecular level using the benzenepolycarboxylic acids (BPCAs) method. DBC showed high concentrations in the upper 100 m seawater with the average of 1.13 μmol l-1 (n=55). In the intermediate seawater (200-1500 m), DBC ranged from 0.67 to 0.89 μmol l-1 with the average of 0.78 μmol l-1 (n=9), exhibiting nearly homogeneous distributions. The vertical distribution pattern indicated that DBC significantly degraded in the photic zone, corresponding to an attenuate constant of 12.5±4.9 km-1. The ratios of B6CA/B3CAs increased downward, implying that aromatic condensation degree of DBC increase during transport from surface to deep water. Using the standing crops of DBC in the upper 200 m and the residence time of seawater, atmospheric deposition of DBC was estimated to be 1.94 TgC yr-1, accounting for around 16% of the global BC deposition. Our study highlights that DBC could be an important component of ocean carbon cycling in Pacific Asia Marginal Seas.

  11. Multiple scattering of light by water cloud droplets with external and internal mixing of black carbon aerosols

    Institute of Scientific and Technical Information of China (English)

    Wang Hai-Hua; Sun Xian-Ming

    2012-01-01

    The mixture of water cloud droplets with black carbon impurities is modeled by external and internal mixing models.The internal mixing model is modeled with a two-layered sphere(water cloud droplets containing black carbon(BC)inclusions),and tihe single scattering and absorption characteristics are calculated at the visible wavelength of 0.55 μm by using the Lorenz Mie theory.The external mixing model is developed assuming that the same amount of BC particles are mixed with the water droplets externally.The multiple scattering characteristics we computed by using the Monte Carlo method.The results show that when the size of the BC aerosol is small,the reflection intensity of the internal mixing model is bigger than that of the external mixing model.However,if the size of the BC aerosol is big,the absorption of the internal mixing model will be larger than that of the external mixing model.

  12. Photo-lability of deep ocean dissolved black carbon

    Science.gov (United States)

    Stubbins, A.; Niggemann, J.; Dittmar, T.

    2012-05-01

    Dissolved black carbon (DBC), defined here as condensed aromatics isolated from seawater via PPL solid phase extraction and quantified as benzenepolycarboxylic acid (BPCA) oxidation products, is a significant component of the oceanic dissolved organic carbon (DOC) pool. These condensed aromatics are widely distributed in the open ocean and appear to be tens of thousands of years old. As such DBC is regarded as highly refractory. In the current study, the photo-lability of DBC, DOC and coloured dissolved organic matter (CDOM; ultraviolet-visible absorbance) were determined over the course of a 28 day irradiation of North Atlantic Deep Water under a solar simulator. During the irradiation DBC fell from 1044 ± 164 nM-C to 55 ± 15 nM-C, a 20-fold decrease in concentration. Dissolved black carbon photo-degradation was more rapid and more extensive than for bulk CDOM and DOC. The concentration of DBC correlated with CDOM absorbance and the quality of DBC indicated by the ratios of different BPCAs correlated with CDOM absorbance spectral slope, suggesting the optical properties of CDOM may provide a proxy for both DBC concentrations and quality in natural waters. Further, the photo-lability of components of the DBC pool increased with their degree of aromatic condensation. These trends indicate that a continuum of compounds of varying photo-lability exists within the marine DOC pool. In this continuum, photo-lability scales with aromatic character, specifically the degree of condensation. Scaling the rapid photo-degradation of DBC to rates of DOC photo-mineralisation for the global ocean leads to an estimated photo-chemical half-life for oceanic DBC of less than 800 years. This is more than an order of magnitude shorter than the apparent age of DBC in the ocean. Consequently, photo-degradation is posited as the primary sink for oceanic DBC and the apparent survival of DBC molecules in the oceans for millennia appears to be facilitated not by their inherent inertness but

  13. Photo-lability of deep ocean dissolved black carbon

    Directory of Open Access Journals (Sweden)

    A. Stubbins

    2012-05-01

    Full Text Available Dissolved black carbon (DBC, defined here as condensed aromatics isolated from seawater via PPL solid phase extraction and quantified as benzenepolycarboxylic acid (BPCA oxidation products, is a significant component of the oceanic dissolved organic carbon (DOC pool. These condensed aromatics are widely distributed in the open ocean and appear to be tens of thousands of years old. As such DBC is regarded as highly refractory. In the current study, the photo-lability of DBC, DOC and coloured dissolved organic matter (CDOM; ultraviolet-visible absorbance were determined over the course of a 28 day irradiation of North Atlantic Deep Water under a solar simulator. During the irradiation DBC fell from 1044 ± 164 nM-C to 55 ± 15 nM-C, a 20-fold decrease in concentration. Dissolved black carbon photo-degradation was more rapid and more extensive than for bulk CDOM and DOC. The concentration of DBC correlated with CDOM absorbance and the quality of DBC indicated by the ratios of different BPCAs correlated with CDOM absorbance spectral slope, suggesting the optical properties of CDOM may provide a proxy for both DBC concentrations and quality in natural waters. Further, the photo-lability of components of the DBC pool increased with their degree of aromatic condensation. These trends indicate that a continuum of compounds of varying photo-lability exists within the marine DOC pool. In this continuum, photo-lability scales with aromatic character, specifically the degree of condensation. Scaling the rapid photo-degradation of DBC to rates of DOC photo-mineralisation for the global ocean leads to an estimated photo-chemical half-life for oceanic DBC of less than 800 years. This is more than an order of magnitude shorter than the apparent age of DBC in the ocean. Consequently, photo-degradation is posited as the primary sink for oceanic DBC and the apparent survival of DBC molecules in the oceans for millennia appears to be facilitated not by their

  14. Absorption Cross Section of Einstein-Maxwell Dilation Axion Black Hole for Dirac Particles

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The absorption cross section of the Einstein-Maxwell Dilaton Axion (EMDA) black hole for Dirac particles is investigated. It is shown that the absorption cross section decreases as both the v and the absolute value of the dilaton increase, but it increases as the mass of the particle increases. It is also shown that the absorption cross section for the masslcss Dirac particles is 1/8 of the area of the horizon, which may be an universal property for minimally coupled massless Dirac particles.

  15. Hawking Radiation of the Charged Particle via Tunneling from the Kaluza-Klein Black Hole

    Science.gov (United States)

    Pu, Jin; Han, Yan

    2016-08-01

    In this paper, by applying the Lagrangian analysis on the action, we first redefine the geodesic equation of the charged massive particle. Then, basing on the new definition of the geodesic equation, we revisit the Hawking radiation of the charged massive particle via tunneling from the event horizon of the Kaluza-Klein black hole. In our treatment, the geodesic equation of the charged massive particle is defined uniformly with that of the massless particle, which overcomes the shortcomings of its previous definition, and is more suitable for the tunneling mechanism. The highlight of our work is a new and important development for the Parikh-Wilczek's tunneling method.

  16. Hawking Radiation of the Charged Particle via Tunneling from the Kaluza-Klein Black Hole

    Science.gov (United States)

    Pu, Jin; Han, Yan

    2016-12-01

    In this paper, by applying the Lagrangian analysis on the action, we first redefine the geodesic equation of the charged massive particle. Then, basing on the new definition of the geodesic equation, we revisit the Hawking radiation of the charged massive particle via tunneling from the event horizon of the Kaluza-Klein black hole. In our treatment, the geodesic equation of the charged massive particle is defined uniformly with that of the massless particle, which overcomes the shortcomings of its previous definition, and is more suitable for the tunneling mechanism. The highlight of our work is a new and important development for the Parikh-Wilczek's tunneling method.

  17. Molecular Characterization of Brown Carbon in Biomass Burning Aerosol Particles

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Peng; Aiona, Paige K.; Li, Ying; Shiraiwa, Manabu; Laskin, Julia; Nizkorodov, Sergey A.; Laskin, Alexander

    2016-11-01

    Emissions from biomass burning are a significant source of brown carbon (BrC) in the atmosphere. In this study, we investigate the molecular composition of freshly-emitted biomass burning organic aerosol (BBOA) samples collected during test burns of selected biomass fuels: sawgrass, peat, ponderosa pine, and black spruce. We characterize individual BrC chromophores present in these samples using high performance liquid chromatography coupled to a photodiode array detector and a high-resolution mass spectrometer. We demonstrate that both the overall BrC absorption and the chemical composition of light-absorbing compounds depend significantly on the type of biomass fuels and burning conditions. Common BrC chromophores in the selected BBOA samples include nitro-aromatics, polycyclic aromatic hydrocarbon derivatives, and polyphenols spanning a wide range of molecular weights, structures, and light absorption properties. A number of biofuel-specific BrC chromophores are observed, indicating that some of them may be used as potential markers of BrC originating from different biomass burning sources. On average, ~50% of the light absorption above 300 nm can be attributed to a limited number of strong BrC chromophores, which may serve as representative light-absorbing species for studying atmospheric processing of BrC aerosol. The absorption coefficients of BBOA are affected by solar photolysis. Specifically, under typical atmospheric conditions, the 300 nm absorbance decays with a half-life of 16 hours. A “molecular corridors” analysis of the BBOA volatility distribution suggests that many BrC compounds in the fresh BBOA have low volatility (<1 g m-1) and will be retained in the particle phase under atmospherically relevant conditions.

  18. Analysis and Implementation of Particle-to-Particle (P2P) Graphics Processor Unit (GPU) Kernel for Black-Box Adaptive Fast Multipole Method

    Science.gov (United States)

    2015-06-01

    Particle-to- Particle (P2P) Graphics Processor Unit (GPU) Kernel for Black-Box Adaptive Fast Multipole Method by Richard H Haney and Dale Shires......ARL-TR-7315 ● JUNE 2015 US Army Research Laboratory Analysis and Implementation of Particle-to- Particle (P2P) Graphics Processor

  19. Feasibility study of production of radioactive carbon black or carbon nanotubes in cyclotron facilities for nanobioscience applications.

    Science.gov (United States)

    Abbas, K; Simonelli, F; Holzwarth, U; Cydzik, I; Bulgheroni, A; Gibson, N; Kozempel, J

    2013-03-01

    A feasibility study regarding the production of radioactive carbon black and nanotubes has been performed by proton beam irradiation. Experimental and theoretical excitation functions of the nuclear reaction (nat)C(p,x)(7)Be in the proton energy range 24-38 MeV are reported, with an acceptable agreement. We have demonstrated that sufficient activities of (7)Be radioisotope can be produced in carbon black and nanotube that would facilitate studies of their possible impact on human and environment.

  20. Inflammation and Vascular Effects after Repeated Intratracheal Instillations of Carbon Black and Lipopolysaccharide

    DEFF Research Database (Denmark)

    Christophersen, Daniel Vest; Jacobsen, Nicklas Raun; Jensen, Ditte Marie;

    2016-01-01

    .5% plasma extracted from CB-exposed ApoE-/- mice caused vasoconstriction in aorta rings isolated from naïve mice; this effect was abolished by the treatment with the serotonin receptor antagonist Ketanserin. In conclusion, repeated pulmonary exposure to nanosized CB and LPS caused lung inflammation without......Inflammation and oxidative stress are considered the main drivers of vasomotor dysfunction and progression of atherosclerosis after inhalation of particulate matter. In addition, new studies have shown that particle exposure can induce the level of bioactive mediators in serum, driving vascular......- and systemic toxicity. We aimed to investigate if pulmonary inflammation would accelerate nanoparticle-induced atherosclerotic plaque progression in Apolipoprotein E knockout (ApoE-/-) mice. ApoE -/- mice were exposed to vehicle, 8.53 or 25.6 μg nanosized carbon black (CB) alone or spiked with LPS (0.2 μg...

  1. NONLINEAR CURRENT-VOLTAGE CHARACTERISTICS OF CONDUCTIVE POLYETHYLENE COMPOSITES WITH CARBON BLACK FILLED PET MICROFIBRILS

    Institute of Scientific and Technical Information of China (English)

    Qian-ying Chen; Jing Gao; Kun Dai; Huan Pang; Jia-zhuang Xu; Jian-hua Tang; Zhong-ming Li

    2013-01-01

    Current-voltage electrical behavior of in situ microfibrillar carbon black (CB)/poly(ethylene terephthalate)(PET)/polyethylene (PE) (m-CB/PET/PE) composites with various CB concentrations at ambient temperatures was studied under a direct-current electric field.The current-voltage (Ⅰ-Ⅴ) curves exhibited nonlinearity beyond a critical value of voltage.The dynamic random resistor network (DRRN) model was adopted to semi-qualitatively explain the nonlinear conduction behavior of m-CB/PET/PE composites.Macroscopic nonlinearity originated from the interracial interactions between CB/PET micro fibrils and additional conduction channels.Combined with the special conductive networks,an illustration was proposed to interpret the nonlinear Ⅰ-Ⅴ characteristics by a field emission or tunneling mechanism between CB particles in the CB/PET microfibers intersections.

  2. Solvent transport through carbon black filled poly(ethylene-co-vinyl acetate composites

    Directory of Open Access Journals (Sweden)

    2008-05-01

    Full Text Available Poly(ethylene-co-vinyl acetate (EVA was reinforced with three different types of carbon black viz. semi-reinforcing furnace (SRF, high abrasion furnace (HAF and intermediate super abrasion furnace (ISAF. The solvent transport by the composites were analyzed using benzene, toluene and xylene as penetrant molecules. The observed cure characteristics and solvent uptake behaviour of the composites has been explained on the basis of particle size of the filler and bound rubber content. The mode of transport in all the cases was found to be anomalous. A sorption-desorption-resorption (S-D-RS experiment was carried out to study the physical changes in the polymer matrix, associated with the transport of the solvents through the composites.

  3. Impact of brown and clear carbon on light absorption enhancement, single scatter albedo and absorption wavelength dependence of black carbon

    Directory of Open Access Journals (Sweden)

    D. A. Lack

    2010-01-01

    Full Text Available The presence of clear coatings on atmospheric black carbon (BC particles is known to enhance the magnitude of light absorption by the BC cores. Based on calculations using core/shell Mie theory, we demonstrate the enhancement of light absorption (EAbs by atmospheric black carbon (BC when coated in mildly absorbing material (CBrown is reduced, relative to the enhancement by non-absorbing coatings (CClear. This reduction, sensitive to CBrown shell thickness and imaginary refractive index (RI, can be up to 50% for 400 nm radiation and 25% averaged across the visible radiation spectrum for reasonable core/shell diameters. The enhanced direct radiative forcing possible due to the enhancement effect of CClear is therefore reduced if the coating is absorbing. Additionally, the need to explicitly treat BC as an internal, as opposed to external, mixture with CBrown is shown to be important to the calculated single scatter albedo only whensub models treat BC as large spherical cores (>50 nm. For smaller BC cores (or fractal agglomerates consideration of the BC and CBrown as an external mixture leads to relatively small errors in the particle single scatter albedo of <0.03. It is often assumed that observation of an absorption Angstrom exponent (AAE >1 indicates non-BC absorption. Here, it is shown that BC cores coated in CClearcan reasonably have an AAE of up to 1.6, a result that complicates the attribution of observed light absorption to CBrown within ambient particles. However, an AAE<1.6 does not exclude the possibility of CBrown, rather CBrown cannot be confidently assigned unless AAE>1.6. Comparison of these results to some ambient AAE data shows that large-scale attribution of CBrown is a challenging task using current in-situ measurement methods. We suggest that coincident measurements of particle core and

  4. Organic carbon isotopes of the Sinian and Early Cambrian black shales on Yangtze Platform, China

    Institute of Scientific and Technical Information of China (English)

    李任伟; 卢家烂; 张淑坤; 雷加锦

    1999-01-01

    Organic matter of the Sinian and early Cambrian black shales on the Yangtze Platform belongs to the light carbon group of isotopes with the δ13C values from - 27 % to -35 % , which are lower than those of the contemporaneously deposited carbonates and phosphorites. A carbon isotope-stratified paleooceanographic model caused by upwelling is proposed, which can be used not only to interpret the characteristics of organic carbon isotopic compositions of the black shales, but also to interpret the paleogeographic difference in the organic carbon isotope compositions of various types of sedimentary rocks.

  5. An approach to a black carbon emission inventory for Mexico by two methods.

    Science.gov (United States)

    Cruz-Núñez, Xochitl

    2014-05-01

    A black carbon (BC) emission inventory for Mexico is presented. Estimate was performed by using two approaches, based on fuel consumption and emission factors in a top-down scheme, and the second from PM25 emission data and its correlation with black carbon by source category, assuming that black carbon=elemental carbon. Results show that black carbon emissions are in interval 53-473Gg using the fuel consumption approach and between 62 and 89 using the sector method. Black carbon key sources come from biomass burning in the rural sector, with 47 percent share to the National total. Mobile sources emissions account to 16% to the total. An opportunity to reduce, in the short-term, carbon dioxide equivalent (CO2-eq) emissions by reducing black carbon emissions would be obtained in reducing emissions mainly from biomass burning in rural housing sector and diesel emissions in the transport sector with important co-benefits in direct radiative forcing, public health and air quality.

  6. The impact of black wattle encroachment of indigenous grasslands on soil carbon, Eastern Cape, South Africa

    DEFF Research Database (Denmark)

    Oelofse, Myles; Birch-Thomsen, Torben; Magid, Jakob;

    2016-01-01

    adverse environmental impacts in South Africa. Little is known about the effects of black wattle encroachment on soil carbon, therefore the aim of this study was to investigate the impact of black wattle encroachment of natural grassland on soil carbon stocks and dynamics. Focussing on two sites...... in the Eastern Cape, South Africa, the study analysed carbon stocks in soil and litter on a chronosequence of black wattle stands of varying ages (up to >50 years) and compared these with adjacent native grassland. The study found that woody encroachment of grassland at one site had an insignificant effect...

  7. Grafted, cross-linked carbon black as a double-layer capacitor electrode material

    Energy Technology Data Exchange (ETDEWEB)

    Richner, R.; Mueller, S.; Wokaun, A.

    2001-03-01

    Isocyanate prepolymers readily react with oxidic functional groups on carbon black. On carbon black grafted with diisocyanates, reactive isocyanate groups are available for cross-linking to a polyurethane system. This cross-linked carbon black was considered as a new active material for electrochemical electrodes. Active material for electric double-layer capacitor electrodes was produced which had values of specific capacitance of up to 200 F/g. Cross-linking efficiencies of up to 58 % of the polymers utilised were achieved. (author)

  8. Black carbon or brown carbon? The nature of light-absorbing carbonaceous aerosols

    Directory of Open Access Journals (Sweden)

    M. O. Andreae

    2006-01-01

    Full Text Available Although the definition and measurement techniques for atmospheric 'black carbon' ('BC' or 'elemental carbon'' ('EC' have long been subjects of scientific controversy, the recent discovery of light-absorbing carbon that is not black ('brown carbon, Cbrown' makes it imperative to reassess and redefine the components that make up light-absorbing carbonaceous matter (LAC in the atmosphere. Evidence for the atmospheric presence of Cbrown comes from (1 spectral aerosol light absorption measurements near specific combustion sources, (2 observations of spectral properties of water extracts of continental aerosol, (3 laboratory studies indicating the formation of light-absorbing organic matter in the atmosphere, and (4 indirectly from the chemical analogy of aerosol species to colored natural humic substances. We show that brown carbon may severely bias measurements of 'BC' and 'EC' over vast parts of the troposphere, especially those strongly polluted by biomass burning, where the mass concentration of Cbrown is high relative to that of soot carbon. Chemical measurements to determine 'EC' are biased by the refractory nature of Cbrown as well as by complex matrix interferences. Optical measurements of 'BC' suffer from a number of problems: (1 many of the presently used instruments introduce a substantial bias into the determination of aerosol light absorption, (2 there is no unique conversion factor between light absorption and 'EC' or 'BC' concentration in ambient aerosols, and (3 the difference in spectral properties between the different types of LAC, as well as the chemical complexity of Cbrown, lead to several conceptual as well as practical complications. We also suggest that due to the sharply increasing absorption of Cbrown towards the UV, single-wavelength light absorption measurements may not be adequate for the assessment of absorption of solar radiation in the troposphere. We discuss the possible consequences of these effects for our

  9. Tailoring the morphology of raspberry-like carbon black/polystyrene composite microspheres for fabricating superhydrophobic surface

    Energy Technology Data Exchange (ETDEWEB)

    Bao, Yubin [Polymer Alloy Lab., School of Material Science and Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237 (China); Li, Qiuying, E-mail: liqy@ecust.edu.cn [Polymer Alloy Lab., School of Material Science and Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237 (China); Shanghai Key Laboratory Polymeric Materials (China); Key Laboratory of Ultrafine Materials of Ministry of Education (China); Xue, Pengfei; Huang, Jianfeng; Wang, Jibin; Guo, Weihong; Wu, Chifei [Polymer Alloy Lab., School of Material Science and Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237 (China)

    2011-05-15

    In our previous report, raspberry-like carbon black/polystyrene (CB/PS) composite microsphere was prepared through heterocoagulation process. Based on the previous study, in the present work, the morphology of raspberry-like CB/PS particle is tailored through adjusting the polarity and the concentration ratio of CB/PS colloidal suspension with the purpose to prepare particulate film for the fabrication of superhydrophobic surface. Scanning electron microscope (SEM) confirms the morphology of raspberry-like particle and the coverage of CB. Rough surfaces fabricated by raspberry-like particles with proper morphology are observed by SEM and clear evidence of superhydrophobic surface is shown. The structure of raspberry-like particle is analyzed by atom force microscope. The proposed relationship between the hydrophobicity and the structure of CB aggregates on the surface of PS microsphere is discussed in details.

  10. Signatures of energy flux in particle production: a black hole birth cry and death gasp

    Science.gov (United States)

    Good, Michael R. R.; Ong, Yen Chin

    2015-07-01

    It is recently argued that if the Hawking radiation process is unitary, then a black hole's mass cannot be monotonically decreasing. We examine the time dependent particle count and negative energy flux in the non-trivial conformal vacuum via the moving mirror approach. A new, exactly unitary solution is presented which emits a characteristic above-thermal positive energy burst, a thermal plateau, and negative energy flux. It is found that the characteristic positive energy flare and thermal plateau is observed in the particle outflow. However, the results of time dependent particle production show no overt indication of negative energy flux. Therefore, a black hole's birth cry is detectable by asymptotic observers via particle count, whereas its death gasp is not.

  11. Signatures of Energy Flux in Particle Production: A Black Hole Birth Cry and Death Gasp

    CERN Document Server

    Good, Michael R R

    2015-01-01

    It is recently argued that if the Hawking radiation process is unitary, then a black hole's mass cannot be monotonically decreasing. We examine the time dependent particle count and negative energy flux in the non-trivial conformal vacuum via the moving mirror approach. A new, exactly unitary solution is presented which emits a characteristic above-thermal positive energy burst, a thermal plateau, and negative energy flux. It is found that the characteristic positive energy flare and thermal plateau is observed in the particle outflow. However, the results of time dependent particle production show no overt indication of negative energy flux. Therefore, a black hole's birth cry is detectable by asymptotic observers via particle count, whereas its death gasp is not.

  12. Preparation of porous carbon particle with shell/core structure

    Directory of Open Access Journals (Sweden)

    2007-05-01

    Full Text Available Porous carbon particles with a shell/core structure have been prepared successfully by controlled precipitation of the polymer from droplets of oil-in-water emulsion, followed by curing and carbonization. The droplets of the oil phase are composed of phenolic resin (PFR, a good solvent (ethyl acetate and porogen (Poly(methyl methacrylate, PMMA. The microstructure was characterized in detail by scanning electron microscopy (SEM, transmission electron microscopy (TEM, nitrogen adsorption, and thermo gravimetric analysis (TGA. The obtained carbon particles have a capsular structure with a microporous carbon shell and a mesoporous carbon core. The BET surface area and porous volume are calculated to be 499 m2g-1 and 0.56 cm3g-1, respectively. The effects of the amount of porogen (PMMA, co-solvent (acetone and surfactant on the resultant structure were studied in detail.

  13. Variable effects of labile carbon on the carbon use of different microbial groups in black slate degradation

    Science.gov (United States)

    Seifert, Anne-Gret; Trumbore, Susan; Xu, Xiaomei; Zhang, Dachung; Kothe, Erika; Gleixner, Gerd

    2011-05-01

    Weathering of ancient organic matter contributes significantly to biogeochemical carbon cycles over geological times. The principle role of microorganisms in this process is well recognized. However, information is lacking on the contribution of individual groups of microorganisms and on the effect of labile carbon sources to the degradation process. Therefore, we investigated the contribution of fungi, Gram-positive and Gram-negative bacteria in the degradation process using a column experiment. Investigations were performed on low metamorphic black slates. All columns contained freshly crushed, sieved (0.63-2 mm), not autoclaved black slates. Two columns were inoculated with the lignite-degrading fungus Schizophyllum commune and received a culture medium containing 13C labeled glucose, two columns received only this culture medium and two control columns received only water. The total mass balance was calculated from all carbon added to the slate and the CO 2 and DOC losses. Phospholipid fatty acids (PLFA) were extracted to investigate microbial communities. We used both the compound specific 14C and 13C signal of the PLFA to quantify carbon uptake from black slates and the glucose of the culture medium, respectively. The total carbon loss in these columns exceeded the amount of added carbon by approximately 60%, indicating that black slate carbon has been used. PLFA associated with Gram-positive bacteria dominated the indigenous community and took up 22% of carbon from black slate carbon, whereas PLFA of Gram-negative bacteria used only 8% of carbon from the slates. PLFA of Gram-negative bacteria and fungi were both mostly activated by the glucose addition. The added Schizophyllum did not establish well in the columns and was overgrown by the indigenous microbial community. Our results suggest that especially Gram-positive bacteria are able to live on and degrade black slate material. They also benefit from easy degradable carbon from the nutrient broth. In

  14. Carbon black networking in elastomers monitored by simultaneous rheological and dielectric investigations

    Science.gov (United States)

    Steinhauser, Dagmar; Möwes, Markus; Klüppel, Manfred

    2016-12-01

    The rheo-dielectric response of carbon black filled elastomer melts is investigated by dielectric relaxation spectroscopy in the frequency range from 0.1 Hz up to 10 MHz during oszillatory shearing in a plate-plate rheometer. Various concentrations and types of carbon blacks dispersed in a non-crosslinked EPDM melt are considered. It is demonstrated that during heat treatment at low strain amplitude a pronounced flocculation of filler particles takes place leading to a successive increase of the shear modulus and conductivity. Followed up by a strain sweep, the filler network breaks up and both quantities decrease simultaneously with increasing strain amplitude. Two relaxation times, obtained from a Cole-Cole fit of the dielectric spectra, are identified, which both decrease strongly with increasing flocculation time. This behaviour is analyzed in the frame of fractal network models, describing the effect of structural disorder of the conducting carbon black network on the diffusive charge transport. Significant deviations from the predictions of percolation theory are observed, which are traced back to a superimposed cluster-cluster aggregation process (CCA). During flocculation, a universal scaling behaviour holds between the conductivity and the corresponding high frequency relaxation time, which fits all the measured data. The scaling exponent agrees fairly well with the prediction obtained from CCA. It is demonstrated that the underlying basic mechanism is a change of the correlation length of the filler network, i.e. the size of the fractal heterogeneities. This decreases during flocculation due to the formation of additional conductive paths, making the system more homogeneous. An addition less pronounced effect is found from nanoscopic gaps between adjacent filler particles, which decrease during flocculation. The same universal scaling behaviour, as obtained for flocculation, is found for temperature-dependent dielectric measurements of the cured

  15. Gravitational waves emitted by a particle rotating around a Schwarzschild black hole: A semiclassical approach

    Science.gov (United States)

    Bernar, Rafael P.; Crispino, Luís C. B.; Higuchi, Atsushi

    2017-03-01

    We analyze the gravitational radiation emitted from a particle in circular motion around a Schwarzschild black hole using the framework of quantum field theory in curved spacetime at tree level. The gravitational perturbations are written in a gauge-invariant formalism for spherically symmetric spacetimes. We discuss the results, comparing them to the radiation emitted by a particle when it is assumed to be orbiting a massive object due to a Newtonian force in flat spacetime.

  16. Aerosol optical properties and mixing state of black carbon in the Pearl River Delta, China

    Science.gov (United States)

    Tan, Haobo; Liu, Li; Fan, Shaojia; Li, Fei; Yin, Yan; Cai, Mingfu; Chan, P. W.

    2016-04-01

    Aerosols contribute the largest uncertainty to the total radiative forcing estimate, and black carbon (BC) that absorbs solar radiation plays an important role in the Earth's energy budget. This study analysed the aerosol optical properties from 22 February to 18 March 2014 at the China Meteorological Administration Atmospheric Watch Network (CAWNET) station in the Pearl River Delta (PRD), China. The representative values of dry-state particle scattering coefficient (σsp), hemispheric backscattering coefficient (σhbsp), absorption coefficient (σabsp), extinction coefficient (σep), hemispheric backscattering fraction (HBF), single scattering albedo (SSA), as well as scattering Ångström exponent (α) were presented. A comparison between a polluted day and a clean day shows that the aerosol optical properties depend on particle number size distribution, weather conditions and evolution of the mixing layer. To investigate the mixing state of BC at the surface, an optical closure study of HBF between measurements and calculations based on a modified Mie model was employed for dry particles. The result shows that the mixing state of BC might be between the external mixture and the core-shell mixture. The average retrieved ratio of the externally mixed BC to the total BC mass concentration (rext-BC) was 0.58 ± 0.12, and the diurnal pattern of rext-BC can be found. Furthermore, considering that non-light-absorbing particles measured by a Volatility-Tandem Differential Mobility Analyser (V-TDMA) exist independently with core-shell and homogenously internally mixed BC particles, the calculated optical properties were just slightly different from those based on the assumption that BC exist in each particle. This would help understand the influence of the BC mixing state on aerosol optical properties and radiation budget in the PRD.

  17. Effect of a biological activated carbon filter on particle counts

    Institute of Scientific and Technical Information of China (English)

    Su-hua WU; Bing-zhi DONG; Tie-jun QIAO; Jin-song ZHANG

    2008-01-01

    Due to the importance of biological safety in drinking water quality and the disadvantages which exist in traditional methods of detecting typical microorganisms such as Cryptosporidium and Giardia,it is necessary to develop an alternative.Particle counts is a qualitative measurement of the amount of dissolved solids in water.The removal rate of particle counts was previously used as an indicator of the effectiveness of a biological activated carbon(BAC)filter in removing Cryptosporidium and Giardia.The particle counts in a BAC filter effluent over one operational period and the effects of BAC filter construction and operational parameters were investigated with a 10 m3/h pilot plant.The results indicated that the maximum particle count in backwash remnant water was as high as 1296 count/ml and it needed about 1.5 h to reduce from the maximum to less than 50 count/ml.During the standard filtration period,particle counts stay constant at less than 50 count/ml for 5 d except when influ-enced by sand filter backwash remnant water.The removal rates of particle counts in the BAC filter are related to characteristics of the carbon.For example,a columned carbon and a sand bed removed 33.3% and 8.5% of particles,respectively,while the particle counts in effluent from a cracked BAC filter was higher than that of the influent.There is no significant difference among particle removal rates with different filtration rates.High post-ozone dosage(>2 mg/L)plays an important role in particle count removal;when the dosage was 3 mg/L,the removal rates by carbon layers and sand beds decreased by 17.5% and increased by 9.5%,respectively,compared with a 2 mg/L dosage.

  18. Particle radiotherapy with carbon ion beams.

    Science.gov (United States)

    Ohno, Tatsuya

    2013-03-04

    Carbon ion radiotherapy offers superior dose conformity in the treatment of deep-seated malignant tumours compared with conventional X-ray therapy. In addition, carbon ion beams have a higher relative biological effectiveness compared with protons or X-ray beams. The algorithm of treatment planning and beam delivery system is tailored to the individual parameters of the patient. The present article reviews the available literatures for various disease sites including the head and neck, skull base, lung, liver, prostate, bone and soft tissues and pelvic recurrence of rectal cancer as well as physical and biological properties.

  19. Chemical Bonding and Structural Information of Black CarbonReference Materials and Individual Carbonaceous AtmosphericAerosols

    Energy Technology Data Exchange (ETDEWEB)

    Hopkins, Rebecca J.; Tivanski, Alexei V.; Marten, Bryan D.; Gilles, Mary K.

    2007-04-25

    The carbon-to-oxygen ratios and graphitic nature of a rangeof black carbon standard reference materials (BC SRMs), high molecularmass humic-like substances (HULIS) and atmospheric particles are examinedusing scanning transmission X-ray microscopy (STXM) coupled with nearedge X-ray absorption fine structure (NEXAFS) spectroscopy. UsingSTXM/NEXAFS, individual particles with diameter>100 nm are studied,thus the diversity of atmospheric particles collected during a variety offield missions is assessed. Applying a semi-quantitative peak fittingmethod to the NEXAFS spectra enables a comparison of BC SRMs and HULIS toparticles originating from anthropogenic combustion and biomass burns,thus allowing determination of the suitability of these materials forrepresenting atmospheric particles. Anthropogenic combustion and biomassburn particles can be distinguished from one another using both chemicalbonding and structural ordering information. While anthropogeniccombustion particles are characterized by a high proportion ofaromatic-C, the presence of benzoquinone and are highly structurallyordered, biomass burn particles exhibit lower structural ordering, asmaller proportion of aromatic-C and contain a much higher proportion ofoxygenated functional groups.

  20. Black carbon, a 'hidden' player in the global C cycle

    Science.gov (United States)

    Santín, C.; Doerr, S. H.

    2012-04-01

    During the 2011 alone more than 600 scientific papers about black carbon (BC) were published, half of them dealing with soils (ISI Web of Knowledge, accessed 15/01/2012). If the search is extended to the other terms by which BC is commonly named (i.e. biochar, charcoal, pyrogenic C or soot), the number of 2011 publications increases to >2400, 20% of them also related to soils. These figures confirm BC as a well-known feature in the scientific literature and, thus, in our research community. In fact, there is a wide variety of research topics where BC is currently studied: from its potential as long-term C reservoir in soils (man-made biochar), to its effects on the Earth's radiation balance (soot-BC), including its value as indicator in paleoenvironmental studies (charcoal) or, even surprisingly, its use in suicide attempts. BC is thus relevant to many aspects of our environment, making it a very far-reaching, but also very complex topic. When focusing 'only' on the role of BC in the global C cycle, numerous questions arise. For example: (i) how much BC is produced by different sources (i.e. vegetation fires, fossil fuel and biofuel combustion); (ii) what are the main BC forms and their respective proportions generated (i.e. proportion of atmospheric BC [BC-soot] and the solid residues [char-BC]); (iii) where does this BC go (i.e. main mobilization pathways and sinks); (iv) how long does BC stay in the different systems (i.e. residence times in soils, sediments, water and atmosphere); (v) which are the BC stocks and its main transformations within and between the different systems (i.e. BC preservation, alteration and mineralization); (vi) what is the interaction of BC with other elements and how does this influence BC half-life (i.e. physical protection, interaction with pollutants, priming effects in other organic materials)? These questions, and some suggestions about how to tackle these, will be discussed in this contribution. It will focus in particular on the

  1. Comment on "Kerr Black Holes as Particle Accelerators to Arbitrarily High Energy"

    CERN Document Server

    Berti, Emanuele; Gualtieri, Leonardo; Pretorius, Frans; Sperhake, Ulrich

    2009-01-01

    It has been suggested that rotating black holes could serve as particle colliders with arbitrarily high center-of-mass energy. Astrophysical limitations on the maximal spin, back-reaction effects and sensitivity to the initial conditions impose severe limits on the likelihood of such collisions.

  2. Short-Range-Order Mineral Physical Protection On Black Carbon Stabilization

    Science.gov (United States)

    Liang, B.; Weng, Y. T.; Wang, C. C.; Song, Y. F.; Lehmann, J.; Wang, C. H.

    2015-12-01

    Soil organic matter is one of the largest reservoirs in global carbon cycle, and black carbon (BC) represents a chemical resistant component. Black C plays an important role in global climate change. Generally considered recalcitrant due to high aromaticity, the reactive surface and functional groups of BC are crucial for carbon sequestration in soils. Mineral sorption and physical protection is an important mechanism for BC long term stabilization and sequestration in environments. Previous studies on mineral protection of BC were limited to analysis techniques in two-dimensions, for example, by SEM, TEM, and NanoSIMS. Little is known about the scope of organo-mineral association, the in-situ distribution and forms of minerals, and the ultimate interplay of BC and minerals. The aim of this study is to investigate the three-dimensional interaction of organic C and minerals in submicron scale using synchrotron-based Transmission X-ray Microcopy (TXM) and Fourier-Transform Infrared Spectroscopy (FTIR). Abundant poorly-crystallined nano-minerals particles were observed. These short-range-order (SRO) minerals also aggregate into clusters and sheets, and form envelops-like structures on the surface of BC. On top of large surface contact area, the intimate interplay between BC and minerals reinforces the stability of both organic C and minerals, resulting from chemical bonding through cation bridging and ligand exchange. The mineral protection enhances BC stabilization and sequestration and lowers its bioavailability in environment. The results suggest that mineral physical protection for BC sequestration may be more important than previous understanding.

  3. Distribution and Sources of Black Carbon in the Arctic

    Science.gov (United States)

    Qi, Ling

    The Arctic is warming at twice the global rate over recent decades. To slow down this warming trend, there is growing interest in reducing the impact from short-lived climate forcers, such as black carbon (BC), because the benefits of mitigation are seen more quickly relative to CO2 reduction. To propose efficient mitigation policies, it is imperative to improve our understanding of BC distribution in the Arctic and to identify the sources. In this dissertation, we investigate the sensitivity of BC in the Arctic, including BC concentrations in snow (BCsnow) and BC concentrations in air (BCair), to emissions, dry deposition and wet scavenging using a global 3-D chemical transport model (CTM) GEOS-Chem. By including flaring emissions, estimating dry deposition velocity using resistance-in-series method, and including Wegener-Bergeron-Findeisen (WBF) in wet scavenging, simulated BCsnow in the eight Arctic sub-regions agree with the observations within a factor of two, and simulated BCair fall within the uncertainty range of observations. Specifically, we find that natural gas flaring emissions in Western Extreme North of Russia (WENR) strongly enhance BCsnow (by up to ?50%) and BCair (by 20-32%) during snow season in the so-called 'Arctic front', but has negligible impact on BC in the free troposphere. The updated dry deposition velocity over snow and ice is much larger than those used in most of global CTMs and agrees better with observation. The resulting BCsnow changes marginally because of the offsetting of higher dry and lower wet deposition fluxes. In contrast, surface BCair decreases strongly due to the faster dry deposition (by 27-68%). WBF occurs when the environmental vapor pressure is in between the saturation vapor pressure of ice crystals and water drops in mixed-phase clouds. As a result, water drops evaporate and releases BC particles in them back into the interstitial air. In most CTMs, WBF is either missing or represented by a uniform and low BC

  4. Attribution of aerosol light absorption to black carbon, brown carbon, and dust in China – interpretations of atmospheric measurements during EAST-AIRE

    Directory of Open Access Journals (Sweden)

    M. Yang

    2009-03-01

    Full Text Available Black carbon, brown carbon, and mineral dust are three of the most important light absorbing aerosols. Their optical properties differ greatly and are distinctive functions of the wavelength of light. Most optical instruments that quantify light absorption, however, are unable to distinguish one type of absorbing aerosol from another. It is thus instructive to separate total absorption from these different light absorbers to gain a better understanding of the optical characteristics of each aerosol type. During the EAST-AIRE (East Asian Study of Tropospheric Aerosols: an International Regional Experiment campaign near Beijing, we measured light scattering using a nephelometer, and light absorption using an aethalometer and a particulate soot absorption photometer. We also measured the total mass concentrations of carbonaceous (elemental and organic carbon and inorganic particulates, as well as aerosol number and mass distributions. We were able to identify periods during the campaign that were dominated by dust, biomass burning, fresh (industrial chimney plumes, other coal burning pollution, and relatively clean (background air for Northern China. Each of these air masses possessed distinct intensive optical properties, including the single scatter albedo and Ångstrom exponents. Based on the wavelength-dependence and particle size distribution, we apportioned total light absorption to black carbon, brown carbon, and dust; their mass absorption efficiencies at 550 nm were estimated to be 9.5, 0.5 (a lower limit value, and 0.03 m2/g, respectively. While agreeing with the common consensus that black carbon is the most important light absorber in the mid-visible, we demonstrated that brown carbon and dust could also cause significant absorption, especially at shorter wavelengths.

  5. Modeling water column partitioning of polychlorinated biphenyls to natural organic matter and black carbon.

    Science.gov (United States)

    Greene, Richard W; Di Toro, Dominic M; Farley, Kevin J; Phillips, Kathy L; Tomey, Cynthia

    2013-06-18

    High volume in situ surface water samples were collected from a tidal tributary of the Delaware Estuary using an Infiltrex sampling system equipped with a 1 μm particle filter and a XAD-2 resin column. Particulate and dissolved phase polychlorinated biphenyl (PCB) congeners were analyzed using high resolution gas chromatography/high resolution mass spectrometry to obtain detection levels in the femtograms per liter range. The data were fit to a four-phase equilibrium partitioning model including freely dissolved PCB, PCB bound to particulate organic carbon (POC), PCB bound to dissolved organic carbon (DOC), and PCB bound to black carbon (BC). Isotherms were assumed to be linear for POC and DOC and nonlinear for BC. The partition coefficient between BC and dissolved PCB was assumed to depend on the dihedral angle between the phenyl rings. Following parameter optimization, the correlation coefficient between the log of the modeled and measured apparent distribution coefficient Kp,app was 0.94, and the RMSE was 0.189 log units. Including BC in the model reduces the dissolved PCB phase concentration in the water column for all congeners, especially for the non-ortho and mono-ortho substituted congeners.

  6. On-road black carbon instrument intercomparison and aerosol characteristics by driving environment

    Science.gov (United States)

    Holder, Amara L.; Hagler, Gayle S. W.; Yelverton, Tiffany L. B.; Hays, Michael D.

    2014-05-01

    Large spatial variations of black carbon (BC) concentrations in the on-road and near-road environments necessitate measurements with high spatial resolution to assess exposure accurately. A series of measurements was made comparing the performance of several different BC instruments (Single Particle Soot Photometer, Photo-Acoustic Soot Spectrometer, and Aethalometer) for high time resolution mobile measurements, capable of mapping spatial gradients. All instruments were highly correlated at high time resolution (r2 = 0.80-0.89 at a 2-s resolution), however the slope ranged from 0.52 to 1.03, with the Single Particle Soot Photometer (SP2) consistently reporting the lowest BC concentrations. BC and ultrafine particle (UFP) concentrations were two-fold higher on the highway compared to surrounding roads with lower traffic counts. The BC size distribution had a mass median diameter of approximately 120 nm, which was smaller and less coated than aged urban BC. Mean UFP and BC concentrations were 2 and 1.4 times greater, respectively, during free flowing traffic on the highway compared with times when there was stop-and-go congestion, providing evidence that transit time is not a good predictor of BC or UFP exposure.

  7. Characterizing black carbon in rain and ice cores using coupled tangential flow filtration and transmission electron microscopy

    Directory of Open Access Journals (Sweden)

    A. Ellis

    2015-06-01

    Full Text Available Antarctic ice cores have been used to study the history of black carbon (BC, but little is known with regards to the physical and chemical characteristics of these particles in the remote atmosphere. Characterization remains limited by ultra-trace concentrations in ice core samples and the lack of adequate methods to isolate the particles unaltered from the melt water. To investigate the physical and chemical characteristics of these particles, we have developed a tangential flow filtration (TFF method combined with transmission electron microscopy (TEM. Tests using ultrapure water and polystyrene latex particle standards resulted in excellent blanks and significant particle recovery. This approach has been applied to melt water from Antarctic ice cores as well as tropical rain from Darwin, Australia with successful results: TEM analysis revealed a variety of BC particle morphologies, insoluble coatings, and the attachment of BC to mineral dust particles. The TFF-based concentration of these particles has proven to give excellent results for TEM studies of BC particles in Antarctic ice cores and can be used for future studies of insoluble aerosols in rainwater and ice core samples.

  8. Russia's black carbon emissions: focus on diesel sources

    Science.gov (United States)

    Kholod, Nazar; Evans, Meredydd; Kuklinski, Teresa

    2016-09-01

    Black carbon (BC) is a significant climate forcer with a particularly pronounced forcing effect in polar regions such as the Russian Arctic. Diesel combustion is a major global source of BC emissions, accounting for 25-30 % of all BC emissions. While the demand for diesel is growing in Russia, the country's diesel emissions are poorly understood. This paper presents a detailed inventory of Russian BC emissions from diesel sources. Drawing on a complete Russian vehicle registry with detailed information about vehicle types and emission standards, this paper analyzes BC emissions from diesel on-road vehicles. We use the COPERT emission model (COmputer Programme to calculate Emissions from Road Transport) with Russia-specific emission factors for all types of on-road vehicles. On-road diesel vehicles emitted 21 Gg of BC in 2014: heavy-duty trucks account for 60 % of the on-road BC emissions, while cars represent only 5 % (light commercial vehicles and buses account for the remainder). Using Russian activity data and fuel-based emission factors, the paper also presents BC emissions from diesel locomotives and ships, off-road engines in industry, construction and agriculture, and generators. The study also factors in the role of superemitters in BC emissions from diesel on-road vehicles and off-road sources. The total emissions from diesel sources in Russia are estimated to be 49 Gg of BC and 17 Gg of organic carbon (OC) in 2014. Off-road diesel sources emitted 58 % of all diesel BC in Russia.

  9. Black carbon reduction will weaken the aerosol net cooling effect

    Directory of Open Access Journals (Sweden)

    Z. L. Wang

    2014-12-01

    Full Text Available Black carbon (BC, a distinct type of carbonaceous material formed from the incomplete combustion of fossil and biomass based fuels under certain conditions, can interact with solar radiation and clouds through its strong light-absorption ability, thereby warming the Earth's climate system. Some studies have even suggested that global warming could be slowed down in a short term by eliminating BC emission due to its short lifetime. In this study, we estimate the influence of removing some sources of BC and other co-emitted species on the aerosol radiative effect by using an aerosol-climate coupled model BCC_AGCM2.0.1_CUACE/Aero, in combination with the aerosol emissions from the Representative Concentration Pathways (RCPs scenarios. We find that the global annual mean aerosol net cooling effect at the top of the atmosphere (TOA will be enhanced by 0.12 W m−2 compared with present-day conditions if the BC emission is reduced exclusively to the level projected for 2100 based on the RCP2.6 scenario. This will be beneficial for the mitigation of global warming. However, the global annual mean aerosol net cooling effect at the TOA will be weakened by 1.7–2.0 W m−2 relative to present-day conditions if emissions of BC and co-emitted sulfur dioxide and organic carbon are simultaneously reduced as the most close conditions to the actual situation to the level projected for 2100 in different ways based on the RCP2.6, RCP4.5, and RCP8.5 scenarios. Because there are no effective ways to remove the BC exclusively without influencing the other co-emitted components, our results therefore indicate that a reduction in BC emission can lead to an unexpected warming on the Earth's climate system in the future.

  10. Micromorphological evidence of black carbon in colluvial soils from NW Spain

    NARCIS (Netherlands)

    Kaal, J.; van Mourik, J.M.

    2008-01-01

    Biomass burning produces a residue called black carbon (BC). Black C is generally considered to be highly resistant against biodegradation and has a potential role in the global C cycle, but is difficult to identify and quantify when subjected to prolonged degradation in terrestrial sediments. The c

  11. Improved piezoelectricity of PVDF-HFP/carbon black composite films

    Science.gov (United States)

    Wu, Liangke; Yuan, Weifeng; Hu, Ning; Wang, Zhongchang; Chen, Chunlin; Qiu, Jianhui; Ying, Ji; Li, Yuan

    2014-04-01

    We report a substantial improvement of piezoelectricity for poly(vinylidene fluoride-hexafluoropropylene) (PVDF-HFP) copolymer films by introducing carbon black (CB) into the PVDF-HFP to form PVDF-HFP/CB composite films. The optimized output voltage of the composite film at an optimal CB content of 0.5 wt% is found to be 204% of the pristine PVDF-HFP film. Its harvested electrical power density is 464% and 561% of the pristine PVDF-HFP film by using ac and dc circuits, respectively. Through Fourier transform infrared spectroscopy analysis, differential scanning calorimetry analysis, and polarized optical microscopy observations, we clarify the enhancement mechanism of piezoelectricity for the PVDF-HFP/CB composite films. We find that the added CB acts as nucleating agent during the initial formation of crystals, but imposes an insignificant effect on the α-β phase transformation during stretching. We also demonstrate that the addition of optimal CB reduces crystal size yet increases the number of crystals in the composite films. This is beneficial for the formation of elongated, oriented and fibrillar crystalline morphology during stretching and consequently results in a highly efficient poling process. The addition of overdosed CB leads to the formation of undersized crystals, lowered crystallinity, and hence reduced piezoelectric performance of the PVDF-HFP/CB composite films.

  12. Characterization of PZT/PVC Composites Added with Carbon Black

    Institute of Scientific and Technical Information of China (English)

    LIU Xiaofang; XIONG Chuanxi; SUN Huajun; DONG Lijie; LI Rui; LIU Yang

    2005-01-01

    A new three-phase PZT/ C/ PVC composite comprising PZT (50vol%), nanocrystalline PVC (50 vol% ) and a small volume fraction f of carbon black (C) was prepared by the hot-pressing technique. The dielectric property of the composite as a function of the frequency and the dielectric and piezoelectric properties as a function of the volume fraction f of C were studied. The measured dielectric property demonstrates that a percolation transition occurs in the three-phase composites as in normal two-phase metal-insulator continuum media. The dielectric constant varies slightly with f at f < 0.1 and increases rapidly when f is close to the percolation threshold at 1 kHz. The optimum properties were obtained for f = 0.5 before the percolation threshold in the PZT/ C/ PVC (50/f/(50 - f) vol% ) composite with its d33 (20 pC/N) being 50% higher than that of the PZT/ PVC (50/50vol% ), and its g33(47.23 × 10-3 Vm/N) and Kp (0.25) much higher than the earlier reported values.XRD patterns and P-E hysteresis loops were used to interpret the experimental results.

  13. Black Carbon Trends over Several Decades at Multiple Locations

    Science.gov (United States)

    Preble, C. V.; Hadley, O. L.; Bond, T. C.; Kirchstetter, T.

    2012-12-01

    Archived air quality data in the U.S. and Europe can be used to reconstruct past trends in black carbon (BC), an indicator of fossil fuel combustion and biomass burning. Here, we consider coefficient of haze (COH) data that was extensively measured in California, New Jersey, and other North American locations from the mid-1960s to the turn of the century. We reinstated COH monitors alongside aethalometers in Vallejo and San Jose, California, and after two years of air monitoring determined that COH is proportional to and, thus, can be used to infer past concentrations of BC. Analyzing COH data sets, we found that BC concentrations markedly decreased from 1965 to 2000 in both California and New Jersey. The opposing trend of increasing energy consumption over the same period indicates successful regulatory control of sources and a shift from dirtier to cleaner fuels. As air quality improved over four decades, a seasonal trend of maximum BC concentrations in winter persisted in California but, somewhat surprisingly, disappeared in New Jersey. A strong weekly cycle of lowest BC concentrations on weekends was evident in California and New Jersey, suggesting that diesel traffic, which exhibits a similar weekly cycle, has been a major source of BC in both states. Our extended analysis will include BC trends in other regions of North America and Europe and will be applied to understand BC radiative forcing in California and deposition of pollutants in the Arctic.

  14. Factors controlling seasonal variations in Arctic black carbon

    Science.gov (United States)

    Shen, Z.; Ming, Y.; Horowitz, L. W.

    2015-12-01

    Arctic haze has a distinct seasonality with higher concentrations in winter and spring. This study evaluates how different processes of large-scale circulation and removal control seasonal variations in Arctic black carbon (BC) using the Geophysical Fluid Dynamics Laboratory (GFDL) atmospheric general circulation model (AM3). We find that transport and wet deposition play unequal roles in determining Arctic BC seasonal cycle. Despite seasonal differences in general circulation patterns, the eddy-driven BC transport changes little throughout the year, and the seasonal cycle of Arctic BC is attributed to wet removal. BC hydrophilic fraction affected by the aging process and hydrophilic BC (BCpi) wet deposition rate affected by cloud microphysics determine wet deposition. Both low hydrophilic fraction and low wet deposition rate account for the peak of BC in winter. The transition to low BC in summer results from an increase in wet deposition rate, while the return of BC in late autumn is mainly caused by a sharp decrease in hydrophilic fraction. The results suggest that the concentrations of Arctic aerosols as well as their climate impacts may be susceptible to modification in a future climate.

  15. Black carbon absorption effects on cloud cover, review and synthesis

    Directory of Open Access Journals (Sweden)

    D. Koch

    2010-03-01

    Full Text Available Absorbing aerosols (AA's such as black carbon (BC or dust absorb incoming solar radiation, perturb the temperature structure of the atmosphere, and influence cloud cover. Previous studies have described conditions where AA's either increase or decrease cloud cover. The effect depends on several factors, including the altitude of the AA relative to the cloud and on the cloud type. Cloud cover is decreased if the AA's are embedded in the cloud layer. AA's below cloud may enhance convection and cloud cover. AA's over cloud-level stabilize the underlying layer and tend to enhance stratocumulus clouds but may reduce cumulus clouds. AA's can also promote cloud cover in convergent regions as they enhance deep convection and low level convergence as it draws in moisture from ocean to land regions. Most global model studies indicate a regional variation in the cloud response but generally increased cloud cover over oceans and some land regions, with net increased low-level and/or reduced upper level cloud cover. The result is net negative radiative forcing from cloud response to AA's. In some of these climate model studies, the cooling effect of BC due to cloud changes was strong enough to essentially cancel the warming direct effects.

  16. Field Measurements of Black Carbon Yields from Gas Flaring.

    Science.gov (United States)

    Conrad, Bradley M; Johnson, Matthew R

    2017-02-07

    Black carbon (BC) emissions from gas flaring in the oil and gas industry are postulated to have critical impacts on climate and public health, but actual emission rates remain poorly characterized. This paper presents in situ field measurements of BC emission rates and flare gas volume-specific BC yields for a diverse range of flares. Measurements were performed during a series of field campaigns in Mexico and Ecuador using the sky-LOSA optical measurement technique, in concert with comprehensive Monte Carlo-based uncertainty analyses. Parallel on-site measurements of flare gas flow rate and composition were successfully performed at a subset of locations enabling direct measurements of fuel-specific BC yields from flares under field conditions. Quantified BC emission rates from individual flares spanned more than 4 orders of magnitude (up to 53.7 g/s). In addition, emissions during one notable ∼24-h flaring event (during which the plume transmissivity dropped to zero) would have been even larger than this maximum rate, which was measured as this event was ending. This highlights the likely importance of superemitters to global emission inventories. Flare gas volume-specific BC yields were shown to be strongly correlated with flare gas heating value. A newly derived correlation fitting current field data and previous lab data suggests that, in the context of recent studies investigating transport of flare-generated BC in the Arctic and globally, impacts of flaring in the energy industry may in fact be underestimated.

  17. Characteristics and source of black carbon aerosol over Taklimakan Desert

    Institute of Scientific and Technical Information of China (English)

    FU; S.Joshua

    2010-01-01

    Black carbon(BC) and PM10 in the center of the Taklimakan Desert were online monitored in the whole year of 2007.In addi-tion,TSP samples were also synchronously daily collected by medium-volume samplers with Whatman41 filters in the spring of 2007.BC in the dust aerosol was up to 1.14%of the total mass of PM10.A remarkable seasonal variation of BC in the aerosol was observed in the order of winter>spring>autumn>summer.The peak value of BC appeared at midnight while the lowest one in the evening each day,which was just the reverse of that in the urban area.The contribution of BC to the total mass of PM10 on non-dust storm days was~11 times of that in dust storm.Through back trajectory and principal component analysis,it was found that BC in the dust aerosol over Taklimakan Desert might be attributed to the emission from the anthropogenic activities,including domestic heating,cooking,combustion of oil and natural gas,and the medium-range transport from those oases located in the margins of the desert.The total BC aerosol from the Taklimakan Desert to be transported to the eastward downstream was estimated to be 6.3×104 ton yr-1.

  18. Black carbon aerosols and the third polar ice cap

    Energy Technology Data Exchange (ETDEWEB)

    Menon, Surabi; Koch, Dorothy; Beig, Gufran; Sahu, Saroj; Fasullo, John; Orlikowski, Daniel

    2010-04-15

    Recent thinning of glaciers over the Himalayas (sometimes referred to as the third polar region) have raised concern on future water supplies since these glaciers supply water to large river systems that support millions of people inhabiting the surrounding areas. Black carbon (BC) aerosols, released from incomplete combustion, have been increasingly implicated as causing large changes in the hydrology and radiative forcing over Asia and its deposition on snow is thought to increase snow melt. In India BC emissions from biofuel combustion is highly prevalent and compared to other regions, BC aerosol amounts are high. Here, we quantify the impact of BC aerosols on snow cover and precipitation from 1990 to 2010 over the Indian subcontinental region using two different BC emission inventories. New estimates indicate that Indian BC emissions from coal and biofuel are large and transport is expected to expand rapidly in coming years. We show that over the Himalayas, from 1990 to 2000, simulated snow/ice cover decreases by {approx}0.9% due to aerosols. The contribution of the enhanced Indian BC to this decline is {approx}36%, similar to that simulated for 2000 to 2010. Spatial patterns of modeled changes in snow cover and precipitation are similar to observations (from 1990 to 2000), and are mainly obtained with the newer BC estimates.

  19. Black carbon aerosols and the third polar ice cap

    Directory of Open Access Journals (Sweden)

    S. Menon

    2009-12-01

    Full Text Available Recent thinning of glaciers over the Himalayas (sometimes referred to as the third polar region have raised concern on future water supplies since these glaciers supply water to large river systems that support millions of people inhabiting the surrounding areas. Black carbon (BC aerosols, released from incomplete combustion, have been increasingly implicated as causing large changes in the hydrology and radiative forcing over Asia and its deposition on snow is thought to increase snow melt. In India BC from biofuel combustion is highly prevalent and compared to other regions, BC aerosol amounts are high. Here, we quantify the impact of BC aerosols on snow cover and precipitation from 1990 to 2010 over the Indian subcontinental region using two different BC emission inventories. New estimates indicate that Indian BC from coal and biofuel are large and transport is expected to expand rapidly in coming years. We show that over the Himalayas, from 1990 to 2000, simulated snow/ice cover decreases by ~0.9% due to aerosols. The contribution of the enhanced Indian BC to this decline is ~30%, similar to that simulated for 2000 to 2010. Spatial patterns of modeled changes in snow cover and precipitation are similar to observations (from 1990 to 2000, and are mainly obtained with the newer BC estimates.

  20. Black carbon aerosols and the third polar ice cap

    Directory of Open Access Journals (Sweden)

    S. Menon

    2010-05-01

    Full Text Available Recent thinning of glaciers over the Himalayas (sometimes referred to as the third polar region have raised concern on future water supplies since these glaciers supply water to large river systems that support millions of people inhabiting the surrounding areas. Black carbon (BC aerosols, released from incomplete combustion, have been increasingly implicated as causing large changes in the hydrology and radiative forcing over Asia and its deposition on snow is thought to increase snow melt. In India BC emissions from biofuel combustion is highly prevalent and compared to other regions, BC aerosol amounts are high. Here, we quantify the impact of BC aerosols on snow cover and precipitation from 1990 to 2010 over the Indian subcontinental region using two different BC emission inventories. New estimates indicate that Indian BC emissions from coal and biofuel are large and transport is expected to expand rapidly in coming years. We show that over the Himalayas, from 1990 to 2000, simulated snow/ice cover decreases by ~0.9% due to aerosols. The contribution of the enhanced Indian BC to this decline is ~36%, similar to that simulated for 2000 to 2010. Spatial patterns of modeled changes in snow cover and precipitation are similar to observations (from 1990 to 2000, and are mainly obtained with the newer BC estimates.

  1. Siberian Arctic black carbon sources constrained by model and observation

    Science.gov (United States)

    Winiger, Patrik; Andersson, August; Eckhardt, Sabine; Stohl, Andreas; Semiletov, Igor P.; Dudarev, Oleg V.; Charkin, Alexander; Shakhova, Natalia; Klimont, Zbigniew; Heyes, Chris; Gustafsson, Örjan

    2017-02-01

    Black carbon (BC) in haze and deposited on snow and ice can have strong effects on the radiative balance of the Arctic. There is a geographic bias in Arctic BC studies toward the Atlantic sector, with lack of observational constraints for the extensive Russian Siberian Arctic, spanning nearly half of the circum-Arctic. Here, 2 y of observations at Tiksi (East Siberian Arctic) establish a strong seasonality in both BC concentrations (8 ngṡm‑3 to 302 ngṡm‑3) and dual-isotope–constrained sources (19 to 73% contribution from biomass burning). Comparisons between observations and a dispersion model, coupled to an anthropogenic emissions inventory and a fire emissions inventory, give mixed results. In the European Arctic, this model has proven to simulate BC concentrations and source contributions well. However, the model is less successful in reproducing BC concentrations and sources for the Russian Arctic. Using a Bayesian approach, we show that, in contrast to earlier studies, contributions from gas flaring (6%), power plants (9%), and open fires (12%) are relatively small, with the major sources instead being domestic (35%) and transport (38%). The observation-based evaluation of reported emissions identifies errors in spatial allocation of BC sources in the inventory and highlights the importance of improving emission distribution and source attribution, to develop reliable mitigation strategies for efficient reduction of BC impact on the Russian Arctic, one of the fastest-warming regions on Earth.

  2. [Size distributions of organic carbon (OC) and elemental carbon (EC) in Shanghai atmospheric particles].

    Science.gov (United States)

    Wang, Guang-Hua; Wei, Nan-Nan; Liu, Wei; Lin, Jun; Fan, Xue-Bo; Yao, Jian; Geng, Yan-Hong; Li, Yu-Lan; Li, Yan

    2010-09-01

    Size distributions of organic carbon (OC), elemental carbon (EC) and secondary organic carbon (SOC) in atmospheric particles with size range from 7.20 microm, collected in Jiading District, Shanghai were determined. For estimating size distribution of SOC in these atmospheric particles, a method of determining (OC/EC)(pri) in atmospheric particles with different sizes was discussed and developed, with which SOC was estimated. According to the correlation between OC and EC, main sources of the particles were also estimated roughly. The size distributions of OC and SOC showed a bi-modal with peaks in the particles with size of 3.0 microm, respectively. EC showed both of a bi-modal and tri-modal. Compared with OC, EC was preferably enriched in particles with size of particles (particles. OC and EC were preferably enriched in fine particles (particles with different sizes accounted for 15.7%-79.1% of OC in the particles with corresponding size. Concentrations of SOC in fine aerosols ( 3.00 microm) accounted for 41.4% and 43.5% of corresponding OC. Size distributions of OC, EC and SOC showed time-dependence. The correlation between OC and EC showed that the main contribution to atmospheric particles in Jiading District derived from light petrol vehicles exhaust.

  3. Sources of uncertainties in modelling black carbon at the global scale

    OpenAIRE

    2010-01-01

    Our understanding of the global black carbon (BC) cycle is essentially qualitative due to uncertainties in our knowledge of its properties. This work investigates two source of uncertainties in modelling black carbon: those due to the use of different schemes for BC ageing and its removal rate in the global Transport-Chemistry model TM5 and those due to the uncertainties in the definition and quantification of the observations, which propagate through to both the emission inventories, and the...

  4. The Influence of Unidirectional Pressure on Electrical Conductivity of Carbon Black Filled Polyethylene

    Institute of Scientific and Technical Information of China (English)

    WANG Ke; ZHANG Guo; ZHAO Zhudi; PENG Yi; DI Weihua; DU Chuang

    2006-01-01

    High density polyethylene filled with conductive carbon black was prepared by conventional melt-mixing method. The effect of unidirectional pressure on the conductivity was studied. Wide angle X-ray diffraction (WAXD) was used to show the influence of pressure on the aggregate structure of the polymer filled with carbon black (CB) fillers. A model on the basis of the formation and destruction of conductive networks was proposed to explain the change in the conductivity with the application of pressure.

  5. Factorial Based Response Surface Modeling with Confidence Intervals for Optimizing Thermal Optical Transmission Analysis of Atmospheric Black Carbon

    Science.gov (United States)

    We demonstrate how thermal-optical transmission analysis (TOT) for refractory light-absorbing carbon in atmospheric particulate matter was optimized with empirical response surface modeling. TOT employs pyrolysis to distinguish the mass of black carbon (BC) from organic carbon (...

  6. The Hawking radiation of the charged particle via tunnelling from the axisymmetric Sen black hole

    Institute of Scientific and Technical Information of China (English)

    Jiang Qing-Quan; Yang Shu-Zheng; Chen De-You

    2006-01-01

    Extending Parikh's semi-classical quantum tunnelling model, this paper has studied the Hawking radiation of the charged particle via tunnelling from the horizon of the axisymmetric Sen black hole. Different from the uncharged massless particle, the geodesies of the charged massive particle tunnelling from the horizon is not light-like. The derived result supports Parikh's opinion and provides a correct modification to Hawking strictly thermal spectrum developed by the fixed background space-time and not considering the energy conservation and the self-gravitation interaction.

  7. A Numerical Study on Electrical Percolation of Polymer-Matrix Composites with Hybrid Fillers of Carbon Nanotubes and Carbon Black

    Directory of Open Access Journals (Sweden)

    Yuli Chen

    2014-01-01

    Full Text Available The electrical percolation of polymer-matrix composites (PMCs containing hybrid fillers of carbon nanotubes (CNTs and carbon black (CB is estimated by studying the connection possibility of the fillers using Monte Carlo simulation. The 3D simulation model of CB-CNT hybrid filler is established, in which CNTs are modeled by slender capped cylinders and CB groups are modeled by hypothetical spheres with interspaces because CB particles are always agglomerated. The observation on the effects of CB and CNT volume fractions and dimensions on the electrical percolation threshold of hybrid filled composites is then carried out. It is found that the composite electrical percolation threshold can be reduced by increasing CNT aspect ratio, as well as increasing the diameter ratio of CB groups to CNTs. And adding CB into CNT composites can decrease the CNT volume needed to convert the composite conductivity, especially when the CNT volume fraction is close to the threshold of PMCs with only CNT filler. Different from previous linear assumption, the nonlinear relation between CB and CNT volume fractions at composite percolation threshold is revealed, which is consistent with the synergistic effect observed in experiments. Based on the nonlinear relation, the estimating equation for the electrical percolation threshold of the PMCs containing CB-CNT hybrid fillers is established.

  8. Ultraviolet Spectroscopy of Matrix-isolated Amorphous Carbon Particles

    Science.gov (United States)

    Schnaiter, M.; Mutschke, H.; Henning, Th.; Lindackers, D.; Strecker, M.; Roth, P.

    1996-06-01

    In view of the interstellar 217.5 nm and the circumstellar 230--250 nm extinction features, the UV extinction behavior of small matrix-isolated amorphous carbon grains is investigated experimentally. The particles were produced in a flame by burning acetylene with oxygen at low pressure. To prevent coagulation, the condensing primary soot grains (average diameter ~6 nm) were extracted by a molecular beam technique into a high-vacuum chamber. There they were deposited into a layer of solid argon, isolated from each other. The particle mass and size were controlled using a particle mass spectrometer. The measured UV extinction of the matrix-isolated particles is compared with measurements on samples produced in the conventional way by collecting carbon smoke on substrate as well as with scattering calculations for small spheres and ellipsoides. The laboratory data give a good representation of the circumstellar extinction feature observed in the spectrum of V348 Sgr.

  9. Particle transport in magnetized media around black holes and associated radiation

    CERN Document Server

    Vieyro, Florencia L

    2012-01-01

    Galactic black hole coronae are composed of a hot, magnetized plasma. The spectral energy distribution produced in this component of X-ray binaries can be strongly affected by different interactions between locally injected relativistic particles and the matter, radiation and magnetic fields in the source. We study the non-thermal processes driven by the injection of relativistic particles into a strongly magnetized corona around an accreting black hole. We compute in a self-consistent way the effects of relativistic bremsstrahlung, inverse Compton scattering, synchrotron radiation, and the pair-production/annihilation of leptons, as well as hadronic interactions. Our goal is to determine the non-thermal broadband radiative output of the corona. The set of coupled kinetic equations for electrons, positrons, protons, and photons are solved and the resulting particle distributions are computed self-consistently. The spectral energy distributions of transient events in X-ray binaries are calculated, as well as t...

  10. Scavenging of biomass burning refractory black carbon and ice nuclei in a Western Pacific extratropical storm

    Directory of Open Access Journals (Sweden)

    J. L. Stith

    2011-01-01

    Full Text Available In situ airborne sampling of refractory black carbon (rBC particles and Ice Nuclei (IN was conducted in and near an extratropical cyclonic storm in the Western Pacific Ocean during the Pacific Dust Experiment, PACDEX, in the spring of 2007. Airmass origins were from Eastern Asia. Cloud hydrometeors were evaporated by a counterflow virtual impactor and the residue was sampled by a single particle soot photometer (SP2 instrument and a continuous flow diffusion chamber ice nucleus detector. Clouds associated primarily with the warm sector of the storm were sampled at various locations and altitudes. In storm midlevels at temperatures where heterogeneous freezing is expected to be significant (here −24 to −29 °C, IN measurements from ice particle residues generally agreed well with simultaneous measurements of total ice concentrations provided that the measurements were made at ambient temperatures similar to those in the CFDC chamber, suggesting heterogeneous freezing as the dominant ice formation process in the mid levels of these warm sector clouds. Lower in the storm, at warmer temperatures (−22 to −6.4 °C, ice particle concentrations were similar to IN concentrations at CFDC chamber temperatures representative of colder temperatures. This is consistent with ice particles forming at storm mid-levels by heterogeneous freezing on IN, followed by sedimentation to lower altitudes. Homogeneous freezing did not appear to contribute significantly to midlevel ice concentrations and rime-splintering was also unlikely due to the absence of significant supercooled liquid water in the warm sector clouds. IN number concentrations were typically about a~factor of five to ten lower than simultaneous measurements of rBC concentrations in cloud.

  11. Black carbon aerosol over the Los Angeles Basin during CalNex

    Science.gov (United States)

    Metcalf, A. R.; Craven, J. S.; Ensberg, J. J.; Brioude, J.; Angevine, W.; Sorooshian, A.; Duong, H. T.; Jonsson, H. H.; Flagan, R. C.; Seinfeld, J. H.

    2012-04-01

    Refractory black carbon (rBC) mass and number concentrations were quantified by a Single Particle Soot Photometer (SP2) in the CalNex 2010 field study on board the Center for Interdisciplinary Remotely-Piloted Aircraft Studies (CIRPAS) Twin Otter in the Los Angeles (LA) Basin in May, 2010. The mass concentrations of rBC in the LA Basin ranged from 0.002-0.530μg m-3, with an average of 0.172 μg m-3. Lower concentrations were measured in the Basin outflow regions and above the inversion layer. The SP2 afforded a quantification of the mixing state of rBC aerosols through modeling the scattering cross-section with a core-and-shell Mie model to determine coating thickness. The rBC particles above the inversion layer were more thickly coated by a light-scattering substance than those below, indicating a more aged aerosol in the free troposphere. Near the surface, as the LA plume is advected from west to east with the sea breeze, a coating of scattering material grows on rBC particles, coincident with a clear growth of ammonium nitrate within the LA Basin and the persistence of water-soluble organic compounds as the plume travels through the outflow regions. Detailed analysis of the rBC mixing state reveals two modes of coated rBC particles; a mode with smaller rBC core diameters (˜90 nm) but thick (>200 nm) coating diameters and a mode with larger rBC cores (˜145 nm) with a thin (<75 nm) coating. The "weekend effect" in the LA Basin results in more thickly coated rBC particles, coinciding with more secondary formation of aerosol.

  12. The influence of different black carbon and sulfate mixing methods on their optical and radiative properties

    Science.gov (United States)

    Zhang, Hua; Zhou, Chen; Wang, Zhili; Zhao, Shuyun; Li, Jiangnan

    2015-08-01

    Three different internal mixing methods (Core-Shell, Maxwell-Garnett, and Bruggeman) and one external mixing method are used to study the impact of mixing methods of black carbon (BC) with sulfate aerosol on their optical properties, radiative flux, and heating rate. The optical properties of a mixture of BC and sulfate aerosol particles are considered for three typical bands. The results show that mixing methods, the volume ratio of BC to sulfate, and relative humidity have a strong influence on the optical properties of mixed aerosols. Compared to internal mixing, external mixing underestimates the particle mass absorption coefficient by 20-70% and the particle mass scattering coefficient by up to 50%, whereas it overestimates the particle single scattering albedo by 20-50% in most cases. However, the asymmetry parameter is strongly sensitive to the equivalent particle radius, but is only weakly sensitive to the different mixing methods. Of the internal methods, there is less than 2% difference in all optical properties between the Maxwell-Garnett and Bruggeman methods in all bands; however, the differences between the Core-Shell and Maxwell-Garnett/Bruggeman methods are usually larger than 15% in the ultraviolet and visible bands. A sensitivity test is conducted with the Beijing Climate Center Radiation transfer model (BCC-RAD) using a simulated BC concentration that is typical of east-central China and a sulfate volume ratio of 75%. The results show that the internal mixing methods could reduce the radiative flux more effectively because they produce a higher absorption. The annual mean instantaneous radiative force due to BC-sulfate aerosol is about -3.18 W/m2 for the external method and -6.91 W/m2 for the internal methods at the surface, and -3.03/-1.56/-1.85 W/m2 for the external/Core-Shell/(Maxwell-Garnett/Bruggeman) methods, respectively, at the tropopause.

  13. Evaluating the climate impacts of stratospheric Sulphate, Titania and Black-Carbon injection scenarios using HadGEM2-CCS

    Science.gov (United States)

    Jones, Anthony; Haywood, James; Jones, Andy; Hardimann, Steven

    2015-04-01

    Stratospheric Aerosol Injection (SAI) has emerged as a possible method for ameliorating future global warming. Although most SAI modelling studies have simulated Sulphate injection scenarios (in-line with the natural analogue of volcanic eruptions), various research has identified advantages of using alternative aerosols to sulphate (e.g. Tang et al 2014). In particular, minerals with optimal refractive indices (such as Titania) and sunlight-absorbing aerosols (such as Black-Carbon) have been identified as candidate particles. In this talk, I will present the results of 80-year integrations of HadGEM2-CCS (N96L60) with injection of either sulphate, titania or black-carbon initiated in 2020 and continued until 2100. Aerosol is injected at such a rate as to balance top of the atmosphere (TOA) radiative fluxes in the RCP8.5 scenario, akin to the G3 design of the GeoMIP project. I will compare the climate changes in the baseline scenario (RCP8.5) with the geoengineering scenarios for the 2090s period, and attribute these changes to optical properties of the aerosol species used. Stratospheric dynamical and radiative changes impact the underlying tropical overturning circulation, affecting precipitation, with the magnitude and distribution of impacts dependent on the aerosol species used. Black carbon in particular causes stratospheric heating of >40K, impacting the hydrological cycle and reducing global mean annual precipitation by ~0.25mm/day compared to a historical period. The efficiency of solar-absorption by black carbon means that the injection-rate required to balance TOA fluxes in RCP8.5 is shown to be approximately 1/20th of the mass needed of sulphate and 1/5th of the mass needed of titania. Despite similar global-mean temperature evolution in the geoengineering scenarios (a relative stabilisation), the distribution of high-latitude residual warming and tropical cooling in the sulphate and titania simulations is opposite to the high-latitude cooling and low

  14. The Effectiveness of the Regulatory Regime for Black Carbon Mitigation in the Arctic

    Directory of Open Access Journals (Sweden)

    Daria Shapovalova

    2016-11-01

    Full Text Available In addition to being a hazardous air pollutant, Black Carbon is the second-largest contributor to Arctic warming. Its mitigation is being addressed at the international regulatory level by the Arctic Council and the Convention on Long-Range Transboundary Air Pollution (CLRTAP. Whilst the Convention and its protocols are binding documents, the Black Carbon regulation under their framework appears to have ‘soft law’ characteristics. At the same time, the voluntary Black Carbon and Methane Framework, adopted by the Arctic Council, demonstrates positive compliance and follow-up dynamics compared to earlier norm-creating attempts. This paper argues that the nature of the norm (binding or non-binding is not the decisive factor regarding effective implementation in the Arctic region. Current efforts to mitigate Black Carbon by means of a non-binding Arctic Council Black Carbon and Methane Framework represent an improvement in the Council's normative function and may have more effect on the behaviour of Arctic States than relevant provisions under the Gothenburg Protocol to the CLRTAP. To support this argument, the first section presents an overview of the Arctic Council as an actor in Arctic policy-making. It then provides an assessment of current efforts to combat Black Carbon carried out by the Arctic Council and the CLRTAP.

  15. Global emission inventory and atmospheric transport of black carbon. Evaluation of the associated exposure

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Rong

    2015-06-01

    This thesis presents research focusing on the improvement of high-resolution global black carbon (BC) emission inventory and application in assessing the population exposure to ambient BC. A particular focus of the thesis is on the construction of a high-resolution (both spatial and sectorial) fuel consumption database, which is used to develop the emission inventory of black carbon. Above all, the author updates the global emission inventory of black carbon, a resource subsequently used to study the atmospheric transport of black carbon over Asia with the help of a high-resolution nested model. The thesis demonstrates that spatial bias in fuel consumption and BC emissions can be reduced by means of the sub-national disaggregation approach. Using the inventory and nested model, ambient BC concentrations can be better validated against observations. Lastly, it provides a complete uncertainty analysis of global black carbon emissions, and this uncertainty is taken into account in the atmospheric modeling, helping to better understand the role of black carbon in regional and global air pollution.

  16. The nature of carbon material in the black shale rock mass of Kazakhstan

    Energy Technology Data Exchange (ETDEWEB)

    Marchenko, L.G.

    1981-01-01

    Carbon material is closely tied to ores of various origin lying in the carbon (black shale) rock masses of Kazakhastan. The nature of the carbon material in several gold fields is closely examined. Shungite, its paragenesis with ore materials and its role in the carbon and ore material processes, is described. The accumulation of shungite in zones determined to consist of ores, is looked at in terms of prospecting criteria.

  17. On the partner particles for moving mirror radiation and black hole evaporation

    CERN Document Server

    Hotta, M; Unruh, W G

    2015-01-01

    The partner mode with respect to a vacuum state for a given mode (like that corresponding to one of the thermal particles emitted by a black hole) is defined and calculated. The partner modes are explicitly calculated for a number of cases, in particular for the modes corresponding to a particle detector being excited by turn-on/turn-off transients, or with the thermal particles emitted by the accelerated mirror model for black hole evaporation. One of the key results is that the partner mode in general is just a vacuum fluctuation, and one can have the partner mode be located in a region where the state cannot be distinguished from the vacuum state by any series of local measurements, including the energy density. I.e., "information" (the correlations with the thermal emissions) need not be associated with any energy transport. The idea that black holes emit huge amounts of energy in their last stages because of all the information which must be emitted under the assumption of black-hole unitarity is found n...

  18. Carbon particle induced foaming of molten sucrose for the preparation of carbon foams

    Energy Technology Data Exchange (ETDEWEB)

    Narasimman, R.; Vijayan, Sujith; Prabhakaran, K., E-mail: kp2952002@gmail.com

    2014-11-15

    Graphical abstract: - Highlights: • An easy method for the preparation of carbon foam from sucrose is presented. • Wood derived activated carbon particles are used to stabilize the molten sucrose foam. • The carbon foams show relatively good mechanical strength. • The carbon foams show excellent CO{sub 2} adsorption and oil absorption properties. • The process could be scaled up for the preparation of large foam bodies. - Abstract: Activated carbon powder was used as a foaming and foam setting agent for the preparation of carbon foams with a hierarchical pore structure from molten sucrose. The rheological measurements revealed the interruption of intermolecular hydrogen bonding in molten sucrose by the carbon particles. The carbon particles stabilized the bubbles in molten sucrose by adsorbing on the molten sucrose–gas interface. The carbon foams obtained at the activated carbon powder to sucrose weight ratios in the range of 0–0.25 had a compressive strength in the range of 1.35–0.31 MPa. The produced carbon foams adsorb 2.59–3.04 mmol/g of CO{sub 2} at 760 mmHg at 273 K and absorb oil from oil–water mixtures and surfactant stabilized oil-in-water emulsions with very good selectivity and recyclability.

  19. Quantification and radiocarbon source apportionment of black carbon in atmospheric aerosols using the CTO-375 method

    Science.gov (United States)

    Zencak, Zdenek; Elmquist, Marie; Gustafsson, Örjan

    To make progress towards linking the atmosphere and biogeosphere parts of the black carbon (BC) cycle, a chemothermal oxidation method (CTO-375), commonly applied for isolating BC from complex geomatrices such as soils, sediments and aquatic particles, was applied to investigate the BC also in atmospheric particles. Concentrations and 14C-based source apportionment of CTO-375 based BC was established for a reference aerosol (NIST RM-8785) and for wintertime aerosols collected in Stockholm and in a Swedish background area. The results were compared with thermal-optical (OC/EC) measurements. For NIST RM-8785, a good agreement was found between the BC CTO-375 concentration and the reported elemental carbon (EC) concentration measured by the "Speciation Trends Network—National Institute of Occupational Safety and Health" method (EC NIOSH) with BC CTO-375 of 0.054±0.002 g g -1 and EC NIOSH of 0.067±0.008 g g -1. In contrast, there was an average factor of ca. 20 difference between BC CTO-375 and EC NIOSH for the ambient Scandinavian wintertime aerosols, presumably reflecting a combination of BC CTO-375 isolating only the recalcitrant soot-BC portion of the BC continuum and the EC NIOSH metric inadvertently including some intrinsically non-pyrogenic organic matter. Isolation of BC CTO-375 with subsequent off-line radiocarbon analysis yielded fraction modern values (fM) for total organic carbon (TOC) of 0.93 (aerosols from a Swedish background area), and 0.58 (aerosols collected in Stockholm); whereas the fM for BC CTO-375 isolates were 1.08 (aerosols from a Swedish background area), and 0.87 (aerosols collected in Stockholm). This radiocarbon-based source apportionment suggests that contribution from biomass combustion to cold-season atmospheric BC CTO-375 in Stockholm was 70% and in the background area 88%.

  20. Spinor Particle Creation in Near Extremal Reissner-Nordstrom Black Holes

    CERN Document Server

    Chen, Chiang-Mei; Tang, Fu-Yi; Tsai, Ping-Yen

    2014-01-01

    The pair production of spinor particles, which is captured by the solution of the Dirac equation with an appropriate boundary condition, in charged black holes is investigated. We obtain the closed form of the production rate in the near extremal limit of the Reissner-Nordstrom black holes. The cosmic censorship conjecture is guaranteed by the pair production process. Moreover, the absorption cross section ratio and retarded Green's functions of the spinor fields calculated from the gravity side match well with those of spinor operators in the dual CFT side.

  1. Newtonian black holes: Particle production, "Hawking" temperature, entropies and entropy field equations

    CERN Document Server

    Martínez-Merino, Aldo; Ryan, Michael P

    2016-01-01

    Newtonian gravitation with some slight modifications, along with some highly simplified ideas from quantum field theory allow us to reproduce, at least at the level of back-of-the-envelope calculations, many results of black hole physics. We consider particle production by a black hole, the Newtonian equivalent of the Hawking temperature, and the Bekenstein entropy. Also, we are able to deduce Newtonian field equations from entropy. We finally study higher-order Newtonian theories under the same assumptions used for ordinary Newtonian theory. In a companion article we will look at entropic forces for various entropies and make contact with our analysis of higher-order Newtonian theories.

  2. A New Method to Study Hawking Radiation of Charged Particle from Stationary Axisymmetric Sen Black Hole

    Institute of Scientific and Technical Information of China (English)

    YANG Shu-Zheng; CHEN De-You

    2007-01-01

    @@ Taking the self-gravitation interaction and energy conservation, charge conservation and angular momentum conservation into account, we discuss the tunnelling characteristics of the charged particle from Sen black hole by the Hamilton-Jacobi method. The result shows that the tunnelling probability is related to the change of Bekenstein-Hawking entropy, and the actual radiation spectrum deviates from the pure thermal one, which is consistent with the result of Parikh and Wilczek and gives a new method to correct the Hawking pure thermal spectrum of Sen black hole.

  3. Perturbative evolution of particle orbits around Kerr black holes time domain calculation

    CERN Document Server

    López-Aleman, R; Pullin, J; Lopez-Aleman, Ramon; Khanna, Gaurav; Pullin, Jorge

    2003-01-01

    Treating the Teukolsky perturbation equation numerically as a 2+1 PDE and smearing the singularities in the particle source term by the use of narrow Gaussian distributions, we have been able to reproduce earlier results for equatorial circular orbits that were computed using the frequency domain formalism. A time domain prescription for a more general evolution of nearly geodesic orbits under the effects of radiation reaction is presented. This approach can be useful when tackling the more realistic problem of a stellar-mass black hole moving on a generic orbit around a supermassive black hole under the influence of radiation reaction forces.

  4. Are emissions of black carbon from gasoline vehicles overestimated? Real-time, in situ measurement of black carbon emission factors.

    Science.gov (United States)

    Wang, Yang; Xing, Zhenyu; Zhao, Shuhui; Zheng, Mei; Mu, Chao; Du, Ke

    2016-03-15

    Accurately quantifying black carbon (BC) emission factors (EFs) is a prerequisite for estimation of BC emission inventory. BC EFs determined by measuring BC at the roadside or chasing a vehicle on-road may introduce large uncertainty for low emission vehicles. In this study, BC concentrations were measured inside the tailpipe of gasoline vehicles with different engine sizes under different driving modes to determine the respective EFs. BC EFs ranged from 0.005-7.14 mg/kg-fuel under the speeds of 20-70 km/h, 0.05-28.95 mg/kg-fuel under the accelerations of 0.5-1.5m/s(2). Although the water vapor in the sampling stream could result in an average of 12% negative bias, the BC EFs are significantly lower than the published results obtained with roadside or chasing vehicle measurement. It is suggested to conduct measurement at the tailpipe of gasoline vehicles instead of in the atmosphere behind the vehicles to reduce the uncertainty from fluctuation in ambient BC concentration.

  5. Rotating Black Hole, Twistor-String and Spinning Particle

    CERN Document Server

    Burinskii, A

    2005-01-01

    We discuss basic features of the model of spinning particle based on the Kerr solution. It contains a very nontrivial {\\it real} stringy structure consisting of the Kerr circular string and an axial stringy system. We consider also the complex and twistorial structures of the Kerr geometry and show that there is a {\\it complex} twistor-string built of the complex N=2 chiral string with a twistorial $(x,\\theta)$ structure. By imbedding into the real Minkowski $\\bf M^4$, the N=2 supersymmetry is partially broken and string acquires the open ends. Orientifolding this string, we identify the chiral and antichiral structures. Target space of this string is equivalent to the Witten's `diagonal' of the $\\bf CP^3\\times CP^{*3}.$

  6. Impacts of black carbon and co-pollutant emissions from transportation sector in Mexico City

    Science.gov (United States)

    Zavala, Miguel; Almanza, Victor; Garcia, Agustin; Jazcilevich, Aron; Lei, Wenfang; Molina, Luisa

    2016-04-01

    Black carbon is one of the most important short-lived climate-forcing agents, which is harmful to human health and also contributes significantly to climate change. Transportation is one of the largest sources of black carbon emissions in many megacities and urban complexes, with diesel vehicles leading the way. Both on-road and off-road vehicles can emit substantial amounts of harmful BC-containing particulate matter (PM) and are also responsible for large emissions of carbon dioxide (CO2), carbon monoxide (CO), nitrogen oxides (NOx), and many other co-emitted volatile organic compounds (VOCs). Regionally, black carbon emissions contributions from mobile sources may vary widely depending on the technical characteristics of the vehicle fleet, the quality and chemical properties of the fuels consumed, and the degree of local development and economic activities that foster wider and more frequent or intensive use of vehicles. This presentation will review and assess the emissions of black carbon from the on-road and off-road transportation sector in the Mexico City Metropolitan Area. Viable mitigation strategies, including innovative technological alternatives to reduce black carbon and co-pollutants in diesel vehicles and their impacts on climate, human health and ecosystems will be described.

  7. Modeling the impact of black carbon on snowpack properties at an high altitude site in the Himalayas

    Science.gov (United States)

    Jacobi, Hans-Werner; Ménégoz, Martin; Gallée, Hubert; Lim, Saehee; Zanatta, Marco; Jaffrezo, Jean-Luc; Cozic, Julie; Laj, Paolo; Bonasoni, Paolo; Cristofanelli, Paolo; Stocchi, Paolo; Marinoni, Angela; Verza, Gianpietro; Vuillermoz, Elisa

    2013-04-01

    Light absorbing aerosols in the snow can modify the snow albedo. As a result, the seasonal snowpack can melt earlier compared to the unaffected snow leading to a warming effect on the atmosphere. Several global model studies have indicated that the long-range transport of light absorbing aerosols into the Himalayas and the subsequent deposition to the snow have contributed to a temperature rise in these regions. Due to its strong light absorbing properties, black carbon (BC) may play an important role in this process. To evaluate the possible impact of BC on snow albedo we determined BC concentrations in a range of fresh and older snow samples collected between 2009 and 2012 in the vicinity of the Pyramid station, Nepal at an altitude of more than 5000 m. BC concentrations in the snow were obtained after nebulizing the melted samples using a single particle soot photometer. The observed seasonal cycle in BC concentrations in the snow corresponds to observed seasonal cycles in atmospheric BC detected at the Pyramid station. Older snow showed somewhat higher concentrations compared to fresh snow samples indicating the influence of dry deposition of BC. In order to study in detail the impact of black carbon on snow properties, we upgraded the existing one-dimensional physical snowpack model CROCUS to account for the influence of black carbon on the absorption of radiation by the snow. A radiative transfer scheme was implemented into the snowpack model taking into account the solar zenith angle, the snow water equivalent and grain size, the soil albedo, and the concentration of black carbon in the snow. The upgraded model was applied to a high altitude site in the Himalayas using observed BC concentrations and meteorological data recorded at Pyramid station. First results of the simulations will be presented.

  8. Characteristics of Black Carbon Aerosol during the Chinese Lunar Year and Weekdays in Xi’an, China

    Directory of Open Access Journals (Sweden)

    Qiyuan Wang

    2015-02-01

    Full Text Available Black carbon (BC aerosol plays an important role in climate forcing. The net radiative effect is strongly dependent on the physical properties of BC particles. A single particle soot photometer and a carbon monoxide analyser were deployed during the Chinese Lunar Year (CLY and on weekdays at Xi’an, China, to investigate the characteristics of refractory black carbon aerosol (rBC. The rBC mass on weekdays (8.4 μg·m−3 exceeds that during the CLY (1.9 μg·m−3, presumably due to the lower anthropogenic emissions during the latter. The mass size distribution of rBC shows a primary mode peak at ~205 nm and a small secondary mode peak at ~102-nm volume-equivalent diameter assuming 2 g·cm−3 in void-free density in both sets of samples. More than half of the rBC cores are thickly coated during the CLY (fBC = 57.5%; the percentage is slightly lower (fBC = 48.3% on weekdays. Diurnal patterns in rBC mass and mixing state differ for the two sampling periods, which are attributed to the distinct anthropogenic activities. The rBC mass and CO mixing ratios are strongly correlated with slopes of 0.0070 and 0.0016 μg·m−3·ppbv−1 for weekdays and the CLY, respectively.

  9. 20 years of Black Carbon measurements in Germany

    Science.gov (United States)

    Kutzner, Rebecca; Quedenau, Jörn; Kuik, Friderike; von Schneidemesser, Erika; Schmale, Julia

    2016-04-01

    Black Carbon (BC) is an important short-lived climate-forcing pollutant contributing to global warming through absorption of sunlight. At the same time, BC, as a component of particulate matter (PM) exerts adverse health effects, like decreased lung function and exacerbated asthma. Globally, anthropogenic emission sources of BC include residential heating, transport, and agricultural fires, while the dominant natural emission sources are wildfires. Despite the various adverse effects of BC, legislation that requires mandatory monitoring of BC concentrations does not currently exist in the European Union. Instead, BC is only indirectly monitored as component of PM10 and PM2.5 (particulate matter with a diameter smaller 10 μm and 2.5 μm). Before the introduction of mandatory PM10 and PM2.5 monitoring in the European Union in 2005 and 2015, respectively, 'black smoke', a surrogate for BC, was a required measurement in Germany from the early 1990s. The annual mean limit value was 14 μg m-3 from 1995 and 8 μg m-3 from 1998 onwards. Many 'black smoke' measurements were stopped in 2004, with the repeal of the regulations obtaining at the time. However, in most German federal states a limited number BC monitoring stations continued to operate. Here we present a synthesis of BC data from 213 stations across Germany covering the period between 1994 and 2014. Due to the lack of a standardized method and respective legislation, the data set is very heterogeneous relying on twelve different measurement methods including chemical, optical, and thermal-optical methods. Stations include locations classified as background, urban-background, industrial and traffic among other types. Raw data in many different formats has been modelled and integrated in a relational database, allowing various options for further data analysis. We highlight results from the year 2009, as it is the year with the largest measurement coverage based on the same measurement method, with 30 stations. In

  10. Sources of uncertainties in modelling black carbon at the global scale

    Directory of Open Access Journals (Sweden)

    E. Vignati

    2010-03-01

    Full Text Available Our understanding of the global black carbon (BC cycle is essentially qualitative due to uncertainties in our knowledge of its properties. This work investigates two source of uncertainties in modelling black carbon: those due to the use of different schemes for BC ageing and its removal rate in the global Transport-Chemistry model TM5 and those due to the uncertainties in the definition and quantification of the observations, which propagate through to both the emission inventories, and the measurements used for the model evaluation.

    The schemes for the atmospheric processing of black carbon that have been tested with the model are (i a simple approach considering BC as bulk aerosol and a simple treatment of the removal with fixed 70% of in-cloud black carbon concentrations scavenged by clouds and removed when rain is present and (ii a more complete description of microphysical ageing within an aerosol dynamics model, where removal is coupled to the microphysical properties of the aerosol, which results in a global average of 40% in-cloud black carbon that is scavenged in clouds and subsequently removed by rain, thus resulting in a longer atmospheric lifetime. This difference is reflected in comparisons between both sets of modelled results and the measurements. Close to the sources, both anthropogenic and vegetation fire source regions, the model results do not differ significantly, indicating that the emissions are the prevailing mechanism determining the concentrations and the choice of the aerosol scheme does not influence the levels. In more remote areas such as oceanic and polar regions the differences can be orders of magnitude, due to the differences between the two schemes. The more complete description reproduces the seasonal trend of the black carbon observations in those areas, although not always the magnitude of the signal, while the more simplified approach underestimates black carbon concentrations by orders of

  11. Sources of uncertainties in modelling black carbon at the global scale

    Science.gov (United States)

    Vignati, E.; Karl, M.; Krol, M.; Wilson, J.; Stier, P.; Cavalli, F.

    2010-03-01

    Our understanding of the global black carbon (BC) cycle is essentially qualitative due to uncertainties in our knowledge of its properties. This work investigates two source of uncertainties in modelling black carbon: those due to the use of different schemes for BC ageing and its removal rate in the global Transport-Chemistry model TM5 and those due to the uncertainties in the definition and quantification of the observations, which propagate through to both the emission inventories, and the measurements used for the model evaluation. The schemes for the atmospheric processing of black carbon that have been tested with the model are (i) a simple approach considering BC as bulk aerosol and a simple treatment of the removal with fixed 70% of in-cloud black carbon concentrations scavenged by clouds and removed when rain is present and (ii) a more complete description of microphysical ageing within an aerosol dynamics model, where removal is coupled to the microphysical properties of the aerosol, which results in a global average of 40% in-cloud black carbon that is scavenged in clouds and subsequently removed by rain, thus resulting in a longer atmospheric lifetime. This difference is reflected in comparisons between both sets of modelled results and the measurements. Close to the sources, both anthropogenic and vegetation fire source regions, the model results do not differ significantly, indicating that the emissions are the prevailing mechanism determining the concentrations and the choice of the aerosol scheme does not influence the levels. In more remote areas such as oceanic and polar regions the differences can be orders of magnitude, due to the differences between the two schemes. The more complete description reproduces the seasonal trend of the black carbon observations in those areas, although not always the magnitude of the signal, while the more simplified approach underestimates black carbon concentrations by orders of magnitude. The sensitivity to wet

  12. Nanoporous carbon supported metal particles: their synthesis and characterisation

    Energy Technology Data Exchange (ETDEWEB)

    Yang Yunxia, E-mail: yunxia.yang@csiro.au; Tang Liangguang; Burke, Nick; Chiang, Ken [CSIRO Earth Science and Resource Engineering (Australia)

    2012-08-15

    In the current work, a simplified hard templating approach is used to synthesise metal (Ag, Rh, Ir and Pt) containing structured carbon. The target metals are first introduced into the NaY zeolite template by wetness impregnation. The metals are carried in the super cages of the zeolite and subsequently embedded in the final structures after the steps of carbonisation and the template removal. Scanning electron microscopy images have confirmed that the carbon structures produced by this method retain the morphology of the original template. Transmission electron microscopy reveals the presence of dispersed metal particles in all the carbon structures produced. The metal loadings in these templated structures can reach 35 wt% without significant losses of surface areas and pore volumes. Selected carbon supported metals are tested for their catalytic activity for the methanation of carbon monoxide. The finding suggested that this method is effective in preparing metal nanoparticles for use as catalysts.

  13. Cellphones as a Distributed Platform for Black Carbon Data Collection

    Science.gov (United States)

    Ramanathan, N.; Ramana, M.; Lukac, M. L.; Siva, P.; Ahmed, T.; Kar, A.; Rehman, I.; Ramanathan, V.

    2010-12-01

    Black carbon (BC), the visible component of soot that gives emissions such as diesel engine exhaust their dark color, has come to be recognized as a major contributor to global warming, and a frontline concern for climate change strategies (Ramanathan 2001, Jacobson 2010). We have developed a new low-cost instrument for gathering and measuring atmospheric BC concentrations that leverages cellphones to transmit data from an air filtration unit to a centralized database for analysis. Our new system relies on image processing techniques, as opposed to other more expensive optical methods, to interpret images of filters captured with a cellphone camera. As a result, the entire system costs less than $500 (and is orders of magnitude cheaper than an Aethalometer, the prevailing method for measuring atmospheric BC). We are working with three community groups in Los Angeles, and will recruit three groups in the San Francisco Bay Area, to enable 40 citizens to be actively engaged in monitoring BC across California. We are working with The Energy Resources Institute, an international NGO based in India, to deploy this instrument with 60 people in conjunction with Project Surya, which aims to deploy clean cookstoves and rigorously evaluate their impact on BC emissions. Field tests of this new instrument performed in California report an average error of 0.28 µg/m3 when compared with an Aethelometer. These excellent results hold the promise of making large-scale data collection of BC feasible and relatively easy to reproduce (Ramanathan et al., forthcoming). The use of cellphones for data collection permits monitoring of BC to occur on a greater, more comprehensive scale not previously possible, and serves as a means of instituting more precise, variation-sensitive evaluations of emissions. By storing the data in a publicly available repository, our system will provide real-time access to mass-scale BC measurements to researchers and the public. Through our pilot

  14. Mechanical History Dependence in Carbon Black Suspensions for Flow Batteries: A Rheo-Impedance Study

    Science.gov (United States)

    2017-01-01

    We studied the effects of shear and its history on suspensions of carbon black (CB) in lithium ion battery electrolyte via simultaneous rheometry and electrical impedance spectroscopy. Ketjen black (KB) suspensions showed shear thinning and rheopexy and exhibited a yield stress. Shear step experiments revealed a two time scale response. The immediate effect of decreasing the shear rate is an increase in both viscosity and electronic conductivity. In a much slower secondary response, both quantities change in the opposite direction, leading to a reversal of the initial change in the conductivity. Stepwise increases in the shear rate lead to similar responses in the opposite direction. This remarkable behavior is consistent with a picture in which agglomerating KB particles can stick directly on contact, forming open structures, and then slowly interpenetrate and densify. The fact that spherical CB particles show the opposite slow response suggests that the fractal structure of the KB primary units plays an important role. A theoretical scheme was used to analyze the shear and time-dependent viscosity and conductivity. Describing the agglomerates as effective hard spheres with a fractal architecture and using an effective medium approximation for the conductivity, we found the changes in the derived suspension structure to be in agreement with our qualitative mechanistic picture. This behavior of KB in flow has consequences for the properties of the gel network that is formed immediately after the cessation of shear: both the yield stress and the electronic conductivity increase with the previously applied shear rate. Our findings thus have clear implications for the operation and filling strategies of semisolid flow batteries. PMID:28122184

  15. Climate Response of Direct Radiative Forcing of Anthropogenic Black Carbon

    Science.gov (United States)

    Chung, Serena H.; Seinfeld,John H.

    2008-01-01

    The equilibrium climate effect of direct radiative forcing of anthropogenic black carbon (BC) is examined by 100-year simulations in the Goddard Institute for Space Studies General Circulation Model II-prime coupled to a mixed-layer ocean model. Anthropogenic BC is predicted to raise globally and annually averaged equilibrium surface air temperature by 0.20 K if BC is assumed to be externally mixed. The predicted increase is significantly greater in the Northern Hemisphere (0.29 K) than in the Southern Hemisphere (0.11 K). If BC is assumed to be internally mixed with the present day level of sulfate aerosol, the predicted annual mean surface temperature increase rises to 0.37 K globally, 0.54 K for the Northern Hemisphere, and 0.20 K for the Southern Hemisphere. The climate sensitivity of BC direct radiative forcing is calculated to be 0.6 K W (sup -1) square meters, which is about 70% of that of CO2, independent of the assumption of BC mixing state. The largest surface temperature response occurs over the northern high latitudes during winter and early spring. In the tropics and midlatitudes, the largest temperature increase is predicted to occur in the upper troposphere. Direct radiative forcing of anthropogenic BC is also predicted to lead to a change of precipitation patterns in the tropics; precipitation is predicted to increase between 0 and 20 N and decrease between 0 and 20 S, shifting the intertropical convergence zone northward. If BC is assumed to be internally mixed with sulfate instead of externally mixed, the change in precipitation pattern is enhanced. The change in precipitation pattern is not predicted to alter the global burden of BC significantly because the change occurs predominantly in regions removed from BC sources.

  16. Radiative absorption enhancement from coatings on black carbon aerosols

    Energy Technology Data Exchange (ETDEWEB)

    Cui, Xinjuan; Wang, Xinfeng; Yang, Lingxiao [Environmental Research Institute, School of Environmental Science and Engineering, Shandong University, Jinan 250100 (China); Chen, Bing, E-mail: bingchen@sdu.edu.cn [Environmental Research Institute, School of Environmental Science and Engineering, Shandong University, Jinan 250100 (China); Chen, Jianmin, E-mail: jmchen@sdu.edu.cn [Environmental Research Institute, School of Environmental Science and Engineering, Shandong University, Jinan 250100 (China); Andersson, August; Gustafsson, Örjan [Department of Environmental Science and Analytical Chemistry (ACES) and the Bolin Centre for Climate Research, Stockholm University, SE-10691 Stockholm (Sweden)

    2016-05-01

    The radiative absorption enhancement of ambient black carbon (BC), by light-refractive coatings of atmospheric aerosols, constitutes a large uncertainty in estimates of climate forcing. The direct measurements of radiative absorption enhancement require the experimentally-removing the coating materials in ambient BC-containing aerosols, which remains a challenge. Here, the absorption enhancement of the BC core by non-absorbing aerosol coatings was quantified using a two-step removal of both inorganic and organic matter coatings of ambient aerosols. The mass absorption cross-section (MAC) of decoated/pure atmospheric BC aerosols of 4.4 ± 0.8 m{sup 2}g{sup −1} was enhanced to 9.6 ± 1.8 m{sup 2}g{sup −1} at 678-nm wavelength for ambiently-coated BC aerosols at a rural Northern China site. The enhancement of MAC (E{sub MAC}) rises from 1.4 ± 0.3 in fresh combustion emissions to ~ 3 for aged ambient China aerosols. The three-week high-intensity campaign observed an average E{sub MAC} of 2.25 ± 0.55, and sulfates were primary drivers of the enhanced BC absorption. - Highlights: • A method was developed to remove coatings surrounding BC in ambient aerosols. • The MAC of decoated BC of 4.4 was enhanced to 9.6 m{sup 2}g{sup −1} for ambient BC aerosols. • BC radiative forcing in the ambient atmosphere was enhanced by a factor of ~ 2. • BC absorption enhancement peaked in day time driven by secondary sulfate.

  17. Engineering a novel material: Nanometric titanium carbide particles in a matrix of carbon nanotubes

    CERN Document Server

    BADIE, Sylvain

    2015-01-01

    New physics studies at ISOLDE are motivated by new beams available, especially beams of exotic nuclei located at the frontier of the nuclear chart. Such beams are often short lived (in the order of milliseconds) and decay before they can be extracted from the target material, where typical diffusion times are in the order of seconds or more. Novel nanostructured and nanocomposite target materials have been developed to increase the release efficiency by reducing the diffusion paths and so the diffusion times, allowing ISOLDE to deliver new and more intense beams of exotic nuclei. 35Ca (25 ms half-life) was attempted by developing a titanium carbide and carbon black nanocomposite, but such isotope could not be extracted. A different production method with different precursors - titanium oxide and multiwall carbon nanotubes - is here proposed and expected to yield a target material which will increase the release rates of such isotope. A novel material, very porous, consisting of titanium carbide particles disp...

  18. Relationship between Black Carbon and heavy traffic in São Paulo, Brazil

    Science.gov (United States)

    Miranda, R. M.; Perez-Martinez, P.; Ribeiro, F. N. D.; Andrade, M. D. F.

    2015-12-01

    Carbonaceous aerosols play an important role in air quality, human health and global climate change. Black Carbon (BC) can be considered the most efficient light absorber in the visible spectrum and is mainly found in the fine fraction of aerosol. Typically is emitted by incomplete combustion of fossil fuels related to traffic, industrial processes and biomass burning. São Paulo Metropolitan Area (SPMA) with more than 19 million inhabitants, 7 million vehicles, as well as the major industrial and technological park of the country, has high concentrations of air pollutants, especially in the winter and vehicles are considered the principal source of particles emitted to the atmosphere. Since November 2014, Black Carbon and PM2.5 are being monitored using a MAAP (Multi Angle Absorption Photometer) Thermo 5012 and a Dust Trak DRX-8533 TSI in the East Campus of University of São Paulo, close to important highways and also to the largest airport of Brazil (Guarulhos Airport). Average BC concentration was 1.7 μg/m3 with some peaks above 17.0 μg/m3 and for PM2.5 average was 10.2 μg/m3. Particle concentrations reached values greater than the air quality standard (60 μg/m3) in the winter months. Winds coming from the East direction predominate. Traffic restrictions to heavy duty vehicles in the road-rings next to the sampling site during some hours of the day are the responsible for the daily BC and PM2.5 behavior (figure below), where high concentrations occur early in the morning and late at night, when heavy diesel vehicles are released for transit. Seasonal variations are different for BC and PM2.5 due to local sources of BC and meteorological conditions that have more influence on the particles. The weekly variation indicates that concentrations are lower on Sundays and higher from Tuesday to Thursday. Emission factors for BC were calculated based on traffic information.

  19. Hawking Radiation of Mass Generating Particles from Dyonic Reissner–Nordström Black Hole

    Indian Academy of Sciences (India)

    I. Sakalli; A Ovgun

    2016-09-01

    The Hawking radiation is considered as a quantum tunneling process, which can be studied in the framework of the Hamilton--Jacobi method. In this study, we present the wave equation for a mass generating massive and charged scalar particle (boson). In sequel, we analyse the quantum tunneling of these bosons from a generic 4-dimensional spherically symmetric black hole. We apply the Hamilton--Jacobi formalism to derive the radial integral solution for the classically forbidden action which leads to the tunneling probability. To support our arguments, we take the dyonic Reissner--Nordström black hole as a test background. Comparing the tunneling probability obtained with the Boltzmann formula, we succeed in reading the standard Hawking temperature of the dyonic Reissner–Nordström black hole.

  20. Acceleration of charged particles due to chaotic scattering in the combined black hole gravitational field and asymptotically uniform magnetic field

    CERN Document Server

    Stuchlík, Zdeněk

    2015-01-01

    To test the role of large-scale magnetic fields in accretion processes, we study dynamics of charged test particles in vicinity of a black hole immersed into an asymptotically uniform magnetic field. Using the Hamiltonian formalism of charged particle dynamics, we examine chaotic scattering in the effective potential related to the black hole gravitational field combined with the uniform magnetic field. Energy interchange between the translational and oscillatory modes od the charged particle dynamics provides mechanism for charged particle acceleration along the magnetic field lines. This energy transmutation is an attribute of the chaotic charged particle dynamics in the combined gravitational and magnetic fields only, the black hole rotation is not necessary for such charged particle acceleration. The chaotic scatter can cause transition to the motion along the magnetic field lines with small radius of the Larmor motion or vanishing Larmor radius, when the speed of the particle translational motion is larg...

  1. Carbon dust particles in a beam-plasma discharge

    Science.gov (United States)

    Koval, O. A.; Vizgalov, V.; Shalpegin, A. V.

    2016-09-01

    This paper focuses on dynamics of micro-sized carbon dust grains in beam-plasma discharge (BPD) plasmas. It was demonstrated that injected dust particles can be captured and transported along the discharge. Longitudinal average velocity of the particles in the central area of the plasma column was 17 m/sec, and 2 m/sec in the periphery. Dust injection caused a decrease of emission intensity of metastable nitrogen molecular ion. This effect is suggested for a spectroscopy method for particles’ potential measurements. Five-micron radius carbon dust grains obtained potential above 500 V in the experiments on PR-2 installation, proving the feasibility of BPDs for the charging of fine dust particles up to high potential values, unattainable in similar plasma conditions.

  2. Black carbon in seasonal snow across northern Xinjiang in northwestern China

    Science.gov (United States)

    Ye, Hao; Zhang, Rudong; Shi, Jinsen; Huang, Jianping; Warren, Stephen G.; Fu, Qiang

    2012-12-01

    Black carbon (BC) particles in snow can significantly reduce the snow albedo and enhance the absorption of solar radiation, with important impacts on climate and the hydrological cycle. A field campaign was carried out to measure the BC content in seasonal snow in Qinghai and Xinjiang provinces of western China, in January and February 2012. 284 snow samples were collected at 38 sites, 6 in Qinghai and 32 in Xinjiang. The observational results at the sites in Xinjiang, where the absorbing impurities in snow are dominated by BC particles, are reported in this work. The BC mass fractions in seasonal snow across northern Xinjiang have a median value of ˜70 ng g-1, much lower than those in northeast China. The estimated concentration of BC at the cleanest site in Xinjiang is 20 ng g-1, which is similar to that found along the coast of the Arctic Ocean. It is found that the BC content of snow decreases with altitude. Taking into account this altitude dependence, our measured BC contents in snow are consistent with a recent measurement of BC in winter snow on Tianshan glacier. The data from this field campaign should be useful for testing transport models and climate models for the simulated BC in snow.

  3. Regenerated cellulose fibers spun-dyed with carbon black/latex composite dispersion.

    Science.gov (United States)

    Wang, Chunxia; Du, Changsen; Tian, Anli; Fu, Shaohai; Xu, Changhai

    2014-01-30

    A carbon black (CB)/latex composite was prepared by the method of miniemulsion polymerization for use as a colorant for spun dyeing of regenerated cellulose fibers. Analysis of experimental results revealed that the CB/latex composite had a small particle size and a narrow particle size distribution which were important to ensure a stable dispersion being later added to spinning solution. A good stability of the prepared CB/latex composite dispersion in the spinning solution indicated that it was highly possible to use the CB/latex composite as a colorant for spun dyeing of regenerated cellulose fibers. When a 3.5% mass ratio of CB/latex composite to cellulose was used for spun dyeing, the spun-dyed fibers had the highest tensile strength, breaking elongation and color strength. The rubbing and washing color fastnesses of spun-dyed regenerated cellulose fibers could satisfy requirements of most textiles. This study provided a new insight into producing spun-dyed regenerated cellulose with a novel colorant.

  4. Fluvial organic carbon losses from a Bornean black water river

    OpenAIRE

    2010-01-01

    The transport of carbon from terrestrial ecosystems such as peatlands into rivers and out to the oceans plays an important role in the carbon cycle because it provides a link between the terrestrial and marine carbon cycles. Concentrations of dissolved organic carbon (DOC) and particulate organic carbon (POC) were analysed from the source to the mouth of the River Sebangau in Central Kalimantan, Indonesia during the dry and wet seasons in 2008/2009 and an annual total organic carbon (TOC) flu...

  5. Sedimentary records of black carbon in the sea area of the Nansha Islands since the last glaciation

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Core 17962 taken from the sea area of the Nansha Islands recorded a sedimentary history of more than 30 000 years. The black carbon data from the core, which can inform us of the history of vegetation fires, show that during the last glaciation, especially during the last glacial maximum at about 18 kaBP, the fluctuation of the concentration and accumulation rate of the black carbon was relatively great, whereas it was small during the Holocene. The isotope composition of the black carbon indicates that the precursors of black carbon were mainly grasses from the last glaciation to the Holocene. The sub-alpine and alpine vegetation zones covered mainly with grass and bush on the lands around the southern South China Sea were probably the sources of black carbon. The altitudinal vegetation changes from the last glaciation to the Holocene gave rise to the changes of the sedimentary characteristics of black carbon.

  6. Black hole emission of vector particles in (1+1) dimensions

    CERN Document Server

    Kruglov, S I

    2014-01-01

    We investigate the radiation of spin-1 particles by black holes in (1+1) dimensions within the Proca equation. The process is considered as quantum tunnelling of bosons through an event horizon. It is shown that the emission temperature for the Schwarzschild background geometry is the same as the Hawking temperature corresponding to scalar particles emission. We also obtain the radiation temperatures for the de Sitter, Rindler and Schwarzschild-de Sitter space-times. In a particular case when two horizons in Schwarzschild-de Sitter space-time coincides the Nariai temperature is recovered. The thermodynamical entropy of a black hole is calculated for Schwarzschild-de Sitter space-time having two horizons.

  7. Model for Quasinormal Mode Excitation by a Particle Plunging into a Black Hole

    Science.gov (United States)

    Mark, Zachary; Zimmerman, Aaron; Yang, Huan; Chen, Yanbei

    2016-03-01

    It is known that the late time gravitational waveform produced by a particle plunging into a Kerr black hole is well described by a sum of quasinormal modes. However it is not yet understood how the early part of the waveform gives way to the quasinormal mode description, which diverges at early times, nor how the inhomogenous part of the waveform contributes. Motivated by, we offer a model for quasinormal mode excitation by a particle plunging into a Schwarzschild black hole. To develop our model we study approximations to the Regge-Wheeler equation that allow for a closed-form expression for the frequency-domain Green's function, which we use to isolate the component of the waveform that should be identified with quasinormal ringing. Our description of quasinormal ringing does not diverge at early times and reveals that quasinormal ringing should be understood in analogy with a damped harmonic oscillator experiencing a transient driving source.

  8. Quantification of extraneous carbon during compound specific radiocarbon analysis of black carbon.

    Science.gov (United States)

    Ziolkowski, Lori A; Druffel, Ellen R M

    2009-12-15

    Radiocarbon ((14)C) is a radioactive isotope that is useful for determining the age and cycling of carbon-based materials in the Earth system. Compound specific radiocarbon analysis (CSRA) provides powerful insight into the turnover of individual components that make up the carbon cycle. Extraneous or nonspecific background carbon (C(ex)) is added during sample processing and subsequent isolation of CSRA samples. Here, we evaluate the quantity and radiocarbon signature of C(ex) added from two sources: preparative capillary gas chromatography (PCGC, C(PCGC)) and chemical preparation of CSRA of black carbon samples (C(chemistry)). We evaluated the blank directly using process blanks and indirectly by quantifying the difference in the isotopic composition between processed and unprocessed samples for a range of sample sizes. The direct and indirect assessment of C(chemistry+PCGC) agree, both in magnitude and radiocarbon value (1.1 +/- 0.5 microg of C, fraction modern = 0.2). Half of the C(ex) is introduced before PCGC isolation, likely from coeluting compounds in solvents used in the extraction method. The magnitude of propagated uncertainties of CSRA samples are a function of sample size and collection duration. Small samples collected for a brief amount of time have a smaller propagated (14)C uncertainty than larger samples collected for a longer period of time. CSRA users are cautioned to consider the magnitude of uncertainty they require for their system of interest, to frequently evaluate the magnitude of C(ex) added during sampling processing, and to avoid isolating samples < or = 5 microg of carbon.

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

    Science.gov (United States)

    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.

  10. Central Asian supra-glacier snow melt enhanced by anthropogenic black carbon

    Science.gov (United States)

    Schmale, Julia; Flanner, Mark; Kang, Shichang; Sprenger, Michael; Farinotti, Daniel; Zhang, Qianggong; Guo, Junming; Li, Yang; Lawrence, Mark; Schwikowski, Margit

    2016-04-01

    In Central Asia, more than 60 % of the population depends on water stored in glaciers and mountain snow. Densely populated areas near lower-lying mountain ranges are particularly vulnerable and a recent study showed that the region might lose 50 % of its glacier mass by 2050. While temperature, precipitation and dynamic processes are key drivers of glacial change, deposition of light absorbing impurities such as mineral dust and black carbon can lead to accelerated melting through surface albedo reduction. Here, we discuss the origin of deposited mineral dust and black carbon and their impacts on albedo change and snow melt. 218 snow samples were taken on 4 glaciers, Abramov (Pamir), Suek, Glacier No. 354 and Golubin (Tien Shan), representing deposition between summer 2012 and 2014. They were analyzed for elemental carbon, mineral dust and iron among other parameters. We find the elemental carbon concentration to be at the higher end of the range reported for neighboring mountain ranges between 70 and 502 ng g-1 (interquartile range). To investigate the origin of the snow impurities, we used a Lagrangian particle dispersion model, LAGRANTO. Back trajectory ensembles of 40 members with varied starting points to capture the meteorological spread were released every 6 hours for the covered period at all sites. "Footprints" were calculated and combined with emission inventories to estimate the relative contribution of anthropogenic and natural BC to deposited aerosol on the glaciers. We find that more than 94 % of BC is of anthropogenic origin and the major source region is Central Asia followed by the Middle East. Further exploring the implications of mineral dust and BC deposition, we calculate the snow albedo reduction with the Snow-Ice-Aerosol-Radiative model (SNICAR). Even though mineral dust concentrations were up to a factor of 50 higher than BC concentrations, BC dominates the albedo reduction. Using these results we calculate the snow melt induced by

  11. Angular profile of Particle Emission from a Higher-dimensional Black Hole: Analytic Results

    CERN Document Server

    Kanti, Panagiota

    2012-01-01

    During the spin-down phase of the life of a higher-dimensional black hole, the emission of particles on the brane exhibits a strong angular variation with respect to the rotation axis of the black hole. It has been suggested that this angular variation is the observable that could disentangle the dependence of the radiation spectra on the number of extra dimensions and angular momentum of the black hole. Working in the low-energy regime, we have employed analytical formulae for the greybody factors, angular eigenvalues and eigenfunctions of fermions and gauge bosons, and studied the characteristics of the corresponding angular profiles of emission spectra in terms of only a few dominant partial modes. We have confirmed that, in the low-energy channel, the emitted gauge bosons become aligned to the rotation axis of the produced black hole while fermions form an angle with the rotation axis whose exact value depends on the angular-momentum of the black hole. In the case of scalar fields, we demonstrated the exi...

  12. Horizon structure of Kerr-Bardeen black hole and particle acceleration

    CERN Document Server

    Ghosh, Sushant G

    2015-01-01

    We investigate the horizon structure and ergoregion in a Kerr-Bardeen regular black hole, a rotating generalization of the well known regular black hole due to Bardeen \\cite{Bardeen:1968}, which has an additional parameter ($g$) due to magnetic charge, apart from mass ($M$) and rotation parameter ($a$). Interestingly, for each value of parameter $g$, there exist a critical rotation parameter ($a=a_{E}$), which corresponds to an extremal black hole with degenerate horizons, while for $aa_{E}$. We find that the extremal value $a_E$ is also influenced by the parameter $g$ and so is the ergoregion. While the value of $a_E$ remarkably decreases when compared with the Kerr black hole, the ergoregion becomes more thick with increase in $g$. We also study collision of two equal mass particle near the horizon of this black hole, and explicitly bring out the effect of parameter $g$. The center-of-mass energy ($E_{CM}$) not only depends on rotation parameter $a$, but also on parameter $g$. It is demonstrated that the ce...

  13. Hawking Radiation of Scalar and Vector Particles From 5D Myers-Perry Black Holes

    CERN Document Server

    Jusufi, Kimet

    2016-01-01

    In the present paper we explore the Hawking radiation as a quantum tunneling effect from a rotating 5 dimensional Myers-Perry (5D-MPBH) black hole with two independent angular momentum componentes. First, we investigate the Hawking temperature by considering the tunneling of massive scalar particles and spin-1 vector particles from the 5D-MPBH in the Painlev\\'e coordinates and then in the corotating frames. More specifically, we solve the Klein-Gordon and Proca equation by applying the WKB method and Hamilton-Jacobi equation in both cases. Finally, we recover the Hawking temperature and show that coordinates systems do not affect the Hawking temperature.

  14. Particles motion on topological Lifshitz black holes in 3+1 dimensions

    CERN Document Server

    Olivares, Marco; Vásquez, Yerko; Villanueva, J R

    2013-01-01

    In the present paper we study the causal structure of a topological black hole presented by Mann R. B. JHEP 06, 075 (2009) by mean the standard Lagrangian procedure, which allow us analyze qualitatively the behavior of test particles using the effective potential. Then, the geodesic motion of massive and massless particles is obtained analytically. We find that confined orbits are forbidden on this spacetime, however radial photons can escape to infinity in an infinite proper time but in a finite coordinate time, this correspond to an interesting and novel result.

  15. Hawking Radiation of Scalar and Vector Particles from 5D Myers-Perry Black Holes

    Science.gov (United States)

    Jusufi, Kimet; Övgün, Ali

    2017-02-01

    In the present paper we explore the Hawking radiation as a quantum tunneling effect from a rotating 5 dimensional Myers-Perry black hole (5D-MPBH) with two independent angular momentum components. First, we investigate the Hawking temperature by considering the tunneling of massive scalar particles and spin-1 vector particles from the 5D-MPBH in the Painlevé coordinates and then in the corotating frames. More specifically, we solve the Klein-Gordon and Proca equations by applying the WKB method and Hamilton-Jacobi equation in both cases. Finally, we recover the Hawking temperature and show that coordinates systems do not affect the Hawking temperature.

  16. Scattering and absorption of particles by a black hole involving a global monopole

    Institute of Scientific and Technical Information of China (English)

    Shao Jian Zhou; Wang Yong Jiu

    2012-01-01

    Under the conditions that the wavelength of a particle is much larger than its radius of central mass,and the Schwarzschild field is weak,the scattering of a particle has been studied by many researchers.They obtained that scalar and vector particles abide by Rutherford's angle distribution by using the low level perturbation method and the scattered field's approximation in a weak field.The scattering cross section of a photon coincides with the section in Newton's field of point mass.We can obtain the photon's polarization effect by calculating the second-order perturbation in the linear Schwarzschild field.This article discusses the scattering and absorption of a particle by a black hole involving a global monopole by using the aforesaid method.

  17. Gravitational waves from a particle scattered by a Schwarzchild black hole

    Energy Technology Data Exchange (ETDEWEB)

    Oohara, Ken-ichi; Nakamura, Takashi (Kyoto Univ. (Japan). Dept. of Physics)

    1984-01-01

    Using the generalized Regge-Wheeler equation, we have computed the gravitational radiation emitted by a particle of mass ..mu.. with orbital angular momentum ..mu..Lsub(z)(Lsub(z)>4(GM/c/sup 2/)c) and the total energy ..mu..c/sup 2/ scattered by a Schwarzschild black hole of mass M(>>..mu..). It is found that contrary to plunging cases (Lsub(z)<4(GM/c/sup 2/)c), the quasi-normal mode is not excited even when the periastron approaches the limiting value 4(GM/c/sup 2/). The total energy for Lsub(z) = 4.1(GM/c/sup 2/)c is 1.24 x 10/sup -1/ (..mu../M)..mu..c/sup 2/ which is smaller than that for Lsub(z) = 3.9(GM/c/sup 2/)c, 5.49 x 10/sup -1/ (..mu../M)..mu..c/sup 2/. The peak of the energy spectrum is not determined by the quasi-normal mode but by the angular velocity of the particle at the periastron. We have also calculated the energy from a rotating ring scattered by the black hole. In this case, the energy does not diverge in the limit Lsub(z) ..-->.. 4(GM/c/sup 2/)c. However, it has discontinuity at Lsub(z) = 4(GM/c/sup 2/)c, which is due to the frigidity of a black hole to a scattered particle.

  18. 西安郊区泾河秋、冬季大气黑碳变化及粒径特征%Analysis of Variation and Particle Size Characteristics of Black Carbon at Jinghe, Suburban of Xi'an in Autumn and Winter

    Institute of Scientific and Technical Information of China (English)

    杜川利; 余兴; 李星敏; 陈闯; 王繁强; 彭艳; 董妍; 董自鹏

    2013-01-01

    Black carbon (BC) is one of the most important research fields in aerosol climate effect studies due to its strong absorption effect.Compared to early international efforts,systematic BC observations were started late since 1990s' in several cities of China.The variation and particle size characteristics and their causing factors of BC concentration were analyzed based on data collected at Jinghe station,suburban of Xi' an,during autumn and winter (October 1st,2008-February 28,2009).The station is suitable for BC characteristics study since it is far from downtown area without main BC source nearby.The observational data included BC and particle concentration data collected by atmospheric elements station,meteorological variables collected by automatic meteorological station and sounding station.Results showed that:1) suburban has lower BC concentration than urban area; Contrast to tri-peak diurnal cycle at urban area,suburban showed double-peak characteristic with maximum values of 5.5 μg/m3 (09:00 o'clock) and 6.1 μg/m3 (23:00 o'clock).The two corresponding trough values were 4.9 μg/m3 (06:00 o'clock) and 2.6 μg/m3 (16:00 o'clock),respectively; 2)Relationship between BC concentration and particle size varied with particle sizes.The BC concentration was directly proportional to ultrafine particles and inversely proportional to big particles (e.g.dust).Dust affects measurement of BC concentration; 3) BC concentration was significantly related with temperature inversion near the ground (correlation coefficient).Wind speed had different effects in the processes of transport and diffusion of BC.Continuous precipitation had remarkable removal effects to BC.The increasing BC concentration during autumn could be contributed by the burning of crop stalks during the harvest seasons.In December and January,residential heating through burning coal and firewood by simple equipment caused relative high BC concentration.The reasons for lowest BC concentration in February

  19. Magnetic properties of iron particles embedded in multiwall carbon nanotubes.

    Science.gov (United States)

    Arya, Ved Prakash; Prasad, V; Kumar, P S Anil

    2009-09-01

    Iron nanoparticles are embedded in multiwall carbon nanotubes by the chemical vapor deposition, where benzene and ferrocene are taken as precursor materials. Varying quantity of iron particles are embedded in these tubes by taking different amount of ferrocene. These particles exhibit a magnetic moment up to 98 emu/g and an enhanced coercivity in the range of 500-2000 Oe. Negative magnetoresistance approximately 10% is observed in the presence of magnetic field up to 11 T applied at various temperatures in the range of 1.3 K-300 K. It is argued that the enhanced coercivity is due to the shape anisotropy. The negative magnetoresistance is believed to be due to the weak localization and spin dependent scattering of electrons by the ferromagnetic particles. In addition we also observe a dependence of the magnetoresistance on the direction of applied field and this is correlated with the shape anisotropy of the Fe particles.

  20. Oxidation of carbon by CeO{sub 2}: Effect of the contact between carbon and catalyst particles

    Energy Technology Data Exchange (ETDEWEB)

    May Issa; Corinne Petit; Alain Brillard; Jean-Francois Brilhac [Universite de Haute-Alsace, Mulhouse (France). Laboratoire Gestion des Risques et Environnement

    2008-05-15

    The oxidation of carbon black, CB, in presence of CeO{sub 2} is investigated to gain a better understanding of the effect of the contact between the two solids during this reaction. Different CB/CeO{sub 2} mixtures are tested in a fixed bed reactor. The experimental data are used to propose a model for CB oxidation in presence of CeO{sub 2}. It accounts for the size distribution of CeO{sub 2} particles, the contact area between CB and CeO{sub 2}, the mass of CB in the sample and the initial ratio CB/CeO{sub 2}. Corresponding kinetic parameters are determined. 35 refs., 10 figs., 3 tabs.

  1. 1 Mixing state and absorbing properties of black carbon during Arctic haze

    Science.gov (United States)

    Zanatta, Marco; Gysel, Martin; Eleftheriadis, Kosas; Laj, Paolo; Hans-Werner, Jacobi

    2016-04-01

    The Arctic atmosphere is periodically affected by the Arctic haze occurring in spring. One of its particulate components is the black carbon (BC), which is considered to be an important contributor to climate change in the Arctic region. Beside BC-cloud interaction and albedo reduction of snow, BC may influence Arctic climate interacting directly with the solar radiation, warming the corresponding aerosol layer (Flanner, 2013). Such warming depends on BC atmospheric burden and also on the efficiency of BC to absorb light, in fact the light absorption is enhanced by mixing of BC with other atmospheric non-absorbing materials (lensing effect) (Bond et al., 2013). The BC reaching the Arctic is evilly processed, due to long range transport. Aging promote internal mixing and thus absorption enhancement. Such modification of mixing and is quantification after long range transport have been observed in the Atlantic ocean (China et al., 2015) but never investigated in the Arctic. During field experiments conducted at the Zeppelin research site in Svalbard during the 2012 Arctic spring, we investigated the relative precision of different BC measuring techniques; a single particle soot photometer was then used to assess the coating of Arctic black carbon. This allowed quantifying the absorption enhancement induced by internal mixing via optical modelling; the optical assessment of aged black carbon in the arctic will be of major interest for future radiative forcing assessment.Optical characterization of the total aerosol indicated that in 2012 no extreme smoke events took place and that the aerosol population was dominated by fine and non-absorbing particles. Low mean concentration of rBC was found (30 ng m-3), with a mean mass equivalent diameter above 200 nm. rBC concentration detected with the continuous soot monitoring system and the single particle soot photometer was agreeing within 15%. Combining absorption coefficient observed with an aethalometer and rBC mass

  2. 废旧橡胶热裂解炭黑的制备及应用进展%Progress in preparation and application of pyrolysis carbon black from waste tire

    Institute of Scientific and Technical Information of China (English)

    李硕; 吴晓羽; 王仕峰

    2016-01-01

    Effect factors of preparation technology of pyrolysis carbon black from waste tire were re-viewed with 36 references, including temperature, pressure, particle size of waste rubber, heating rate, et al. The structural features, properties and appli-cations of pyrolysis carbon black were introduced. The pyrolysis carbon black was compared with the commercial carbon black in properties, and the re-search direction was put forward.%综述了废旧橡胶热裂解炭黑制备工艺的影响因素,包括温度、压力、废旧橡胶的粒径及加热速率等,介绍了热裂解炭黑的结构特点、性能及其应用,并对比了热裂解炭黑和商业炭黑的性能差距,指出其研究方向。

  3. Sources and mixing state of size-resolved elemental carbon particles in a European megacity: Paris

    Directory of Open Access Journals (Sweden)

    R. M. Healy

    2012-02-01

    Full Text Available An Aerosol Time-Of-Flight Mass Spectrometer (ATOFMS was deployed to investigate the size-resolved chemical composition of single particles at an urban background site in Paris, France, as part of the MEGAPOLI winter campaign in January/February 2010. ATOFMS particle counts were scaled to match coincident Twin Differential Mobility Particle Sizer (TDMPS data in order to generate hourly size-resolved mass concentrations for the single particle classes observed. The total scaled ATOFMS particle mass concentration in the size range 150–1067 nm was found to agree very well with the sum of concurrent High-Resolution Time-of-Flight Aerosol Mass Spectrometer (HR-ToF-AMS and Multi-Angle Absorption Photometer (MAAP mass concentration measurements of organic carbon (OC, inorganic ions and black carbon (BC (R2 = 0.91. Clustering analysis of the ATOFMS single particle mass spectra allowed the separation of elemental carbon (EC particles into four classes: (i EC attributed to biomass burning (ECbiomass, (ii EC attributed to traffic (ECtraffic, (iii EC internally mixed with OC and ammonium sulfate (ECOCSOx, and (iv EC internally mixed with OC and ammonium nitrate (ECOCNOx. Average hourly mass concentrations for EC-containing particles detected by the ATOFMS were found to agree reasonably well with semi-continuous quantitative thermal/optical EC and optical BC measurements (r2 = 0.61 and 0.65–0.68 respectively, n = 552. The EC particle mass assigned to fossil fuel and biomass burning sources also agreed reasonably well with BC mass fractions assigned to the same sources using seven-wavelength aethalometer data (r2 = 0.60 and 0.48, respectively, n = 568. Agreement between the ATOFMS and other instrumentation improved noticeably when a period influenced by significantly aged, internally mixed EC particles was removed from the intercomparison. 88% and 12% of EC particle

  4. Sources and mixing state of size-resolved elemental carbon particles in a European megacity: Paris

    Science.gov (United States)

    Healy, R. M.; Sciare, J.; Poulain, L.; Kamili, K.; Merkel, M.; Müller, T.; Wiedensohler, A.; Eckhardt, S.; Stohl, A.; Sarda-Estève, R.; McGillicuddy, E.; O'Connor, I. P.; Sodeau, J. R.; Wenger, J. C.

    2012-02-01

    An Aerosol Time-Of-Flight Mass Spectrometer (ATOFMS) was deployed to investigate the size-resolved chemical composition of single particles at an urban background site in Paris, France, as part of the MEGAPOLI winter campaign in January/February 2010. ATOFMS particle counts were scaled to match coincident Twin Differential Mobility Particle Sizer (TDMPS) data in order to generate hourly size-resolved mass concentrations for the single particle classes observed. The total scaled ATOFMS particle mass concentration in the size range 150-1067 nm was found to agree very well with the sum of concurrent High-Resolution Time-of-Flight Aerosol Mass Spectrometer (HR-ToF-AMS) and Multi-Angle Absorption Photometer (MAAP) mass concentration measurements of organic carbon (OC), inorganic ions and black carbon (BC) (R2 = 0.91). Clustering analysis of the ATOFMS single particle mass spectra allowed the separation of elemental carbon (EC) particles into four classes: (i) EC attributed to biomass burning (ECbiomass), (ii) EC attributed to traffic (ECtraffic), (iii) EC internally mixed with OC and ammonium sulfate (ECOCSOx), and (iv) EC internally mixed with OC and ammonium nitrate (ECOCNOx). Average hourly mass concentrations for EC-containing particles detected by the ATOFMS were found to agree reasonably well with semi-continuous quantitative thermal/optical EC and optical BC measurements (r2 = 0.61 and 0.65-0.68 respectively, n = 552). The EC particle mass assigned to fossil fuel and biomass burning sources also agreed reasonably well with BC mass fractions assigned to the same sources using seven-wavelength aethalometer data (r2 = 0.60 and 0.48, respectively, n = 568). Agreement between the ATOFMS and other instrumentation improved noticeably when a period influenced by significantly aged, internally mixed EC particles was removed from the intercomparison. 88% and 12% of EC particle mass was apportioned to fossil fuel and biomass burning respectively using the ATOFMS data

  5. Sources and mixing state of size-resolved elemental carbon particles in a European megacity: Paris

    Directory of Open Access Journals (Sweden)

    R. M. Healy

    2011-11-01

    Full Text Available An Aerosol Time-Of-Flight Mass Spectrometer (ATOFMS was deployed to investigate the size-resolved chemical composition of single particles at an urban background site in Paris, France, as part of the MEGAPOLI winter campaign in January/February 2010. ATOFMS particle counts were scaled to match coincident Twin Differential Mobility Particle Sizer (TDMPS data in order to generate hourly size-resolved mass concentrations for the single particle classes observed. The total scaled ATOFMS particle mass concentration in the size range 150–1067 nm was found to agree very well with the sum of concurrent High-Resolution Time-of-Flight Aerosol Mass Spectrometer (HR-ToF-AMS and Multi-Angle Absorption Photometer (MAAP mass concentration measurements of organic carbon (OC, inorganic ions and black carbon (BC (R2 = 0.91. Clustering analysis of the ATOFMS single particle mass spectra allowed the separation of elemental carbon (EC particles into four classes: (i EC attributed to biomass burning (ECbiomass, (ii EC attributed to traffic (ECtraffic, (iii EC internally mixed with OC and ammonium sulfate (ECOCSOx, and (iv EC internally mixed with OC and ammonium nitrate (ECOCNOx. Average hourly mass concentrations for EC-containing particles detected by the ATOFMS were found to agree reasonably well with semi-continuous quantitative thermal/optical EC and optical BC measurements (r2 = 0.61 and 0.65–0.68, respectively, n = 552. The EC particle mass assigned to fossil fuel and biomass burning sources also agreed reasonably well with BC mass fractions assigned to the same sources using seven-wavelength aethalometer data (r2 = 0.60 and 0.48, respectively, n = 568. Agreement between the ATOFMS and other instrumentation improved noticeably when a period influenced by significantly aged, internally mixed EC particles was removed from the intercomparison. 88 % and 12 % of EC

  6. Fine Particulate Matter in São Paulo During the Winter Months: Concentrations and Black Carbon Comparison Between Techniques and Equipments

    Science.gov (United States)

    Miranda, R. M.; Andrade, M. D. F.

    2014-12-01

    During the winter months in São Paulo, Brazil, particulate matter and black carbon were monitored using a Dust Trak (TSI model 8533), a Black Carbon monitor (MAAP-Thermo) and a PM2.5 sampler (Partisol-Thermo). The concentrations were obtained every 5 minutes, from June to August 2014, for the first and second and every 12 hours for the third. The experiment took place in a site at the University of São Paulo which is located in the Southeast part of the Metropolitan Area of São Paulo (MASP). MASP is one of the biggest urban centers of the world, with more than 20 million inhabitants, 10 million vehicles and high values of some regulated pollutants, as particulate matter, especially in winter. Ambient fine particles associated with vehicle emissions have been linked to adverse health effects. Black carbon has a significant share of particulate mass concentrations. Previous studies showed a contribution of more than 30% for São Paulo. This year the climate was atypical in São Paulo. The summer was the driest of the last 30 years. The winter was hot and also dry. Dust trak monitor showed peaks of more than 120 μg/m3 for PM2.5. For a specific period, black carbon concentrations from the MAAP monitor were compared to black carbon measured by optical reflectance on teflon filters collected by the Partisol sampler. Monitor values were around 30% higher, but specific characteristics can influence this value. In the past, optical reflectance and thermal techniques for black carbon were compared. The reflectance technique showed higher results for the fine fraction than the thermal method. Now, reflectance is being compared to instrument measurements and results are also satisfactory.

  7. Erosion of carbon/carbon by solar wind charged particle radiation during a solar probe mission

    Science.gov (United States)

    Sokolowski, Witold; O'Donnell, Tim; Millard, Jerry

    1991-01-01

    The possible erosion of a carbon/carbon thermal shield by solar wind-charged particle radiation is reviewed. The present knowledge of erosion data for carbon and/or graphite is surveyed, and an explanation of erosion mechanisms under different charged particle environments is discussed. The highest erosion is expected at four solar radii. Erosion rates are analytically estimated under several conservative assumptions for a normal quiet and worst case solar wind storm conditions. Mass loss analyses and comparison studies surprisingly indicate that the predicted erosion rate by solar wind could be greater than by nominal free sublimation during solar wind storm conditions at four solar radii. The predicted overall mass loss of a carbon/carbon shield material during the critical four solar radii flyby can still meet the mass loss mission requirement of less than 0.0025 g/sec.

  8. Migration of nanoparticles from plastic packaging materials containing carbon black into foodstuffs.

    Science.gov (United States)

    Bott, Johannes; Störmer, Angela; Franz, Roland

    2014-01-01

    Carbon black was investigated to assess and quantify the possibility that nanoparticles might migrate out of plastic materials used in the food packaging industry. Two types of carbon black were incorporated in low-density polyethylene (LDPE) and polystyrene (PS) at 2.5% and 5.0% loading (w/w), and then subjected to migration studies. The samples were exposed to different food simulants according to European Union Plastics Regulation 10/2011, simulating long-term storage with aqueous and fatty foodstuffs. Asymmetric flow field-flow fractionation (AF4) coupled to a multi-angle laser light-scattering (MALLS) detector was used to separate, characterise and quantify the potential release of nanoparticles. The AF4 method was successful in differentiating carbon black from other matrix components, such as extracted polymer chains, in the migration solution. At a detection limit of 12 µg kg⁻¹, carbon black did not migrate from the packaging material into food simulants. The experimental findings are in agreement with theoretical considerations based on migration modelling. From both the experimental findings and theoretical considerations, it can be concluded that carbon black does not migrate into food once it is incorporated into a plastics food contact material.

  9. Estimate the influence of snow grain size and black carbon on albedo

    Institute of Scientific and Technical Information of China (English)

    ZhongMing Guo; NingLian Wang; XiaoBo Wu; HongBo Wu; YuWei Wu

    2015-01-01

    Estimation of the influence of snow grain size and black carbon on albedo is essential in obtaining the accurate albedo. In this paper, field measurement data, including snow grain size, snow depth and density was obtained. Black carbon samples were collected from the snow surface. A simultaneous observation using Analytical Spectral Devices was employed in the Qiyi Glacier located in the Qilian Mountain. Analytical Spectral Devices spectrum data were used to analyze spectral re-flectance of snow for different grain size and black carbon content. The measurements were compared with the results obtained from the Snow, Ice, and Aerosol Radiation model, and the simulation was found to correlate well with the ob-served data. However, the simulated albedo was near to 0.98 times of the measured albedo, so the other factors were as-sumed to be constant using the corrected Snow, Ice, and Aerosol Radiation model to estimate the influence of measured snow grain size and black carbon on albedo. Field measurements were controlled to fit the relationship between the snow grain size and black carbon in order to estimate the influence of these factors on the snow albedo.

  10. Estimation of Black Carbon Emissions from Dry Dipterocarp Forest Fires in Thailand

    Directory of Open Access Journals (Sweden)

    Ubonwan Chaiyo

    2014-12-01

    Full Text Available This study focused on the estimation of black carbon emissions from dry dipterocarp forest fires in Thailand. Field experiments were set up at the natural forest, Mae Nam Phachi wildlife sanctuary, Ratchaburi Province, Thailand. The dead leaves were the main component consumed of the surface biomass with coverage higher than 90% in volume and mass. The dead leaves load was 342 ± 190 g∙m−2 and followed by a little mass load of twig, 100 g∙m−2. The chemical analysis of the dead leaves showed that the carbon content in the experimental biomass fuel was 45.81 ± 0.04%. From the field experiments, it was found that 88.38 ± 2.02% of the carbon input was converted to carbon released to the atmosphere, while less than 10% were left in the form of residues, and returned to soil. The quantity of dead leaves consumed to produce each gram of carbon released was 2.40 ± 0.02 gdry biomass burned. From the study, the emissions factor of carbon dioxide, carbon monoxide, particulate matter (PM2.5 and black carbon amounted 1329, 90, 26.19 and 2.83 g∙kg−1dry biomass burned, respectively. In Thailand, the amount of black carbon emissions from dry dipterocarp forest fires amounted 17.43 tonnes∙y−1.

  11. Correct statement of a scattering problem for quantum charged scalar particles on the Reissner-Nordström black holes

    CERN Document Server

    Firsova, N E

    1998-01-01

    We study a correct statement of the scattering problem arising for quantum charged scalar particles on the Reissner-Nordström black holes when taking into account the own electric field of black hole. The elements of the corresponding S-matrix are explored in the form convenient to physical applications and for applying numerical methods. Some further possible issues are outlined.

  12. Binder-Free and Carbon-Free Nanoparticle Batteries: A Method for Nanoparticle Electrodes without Polymeric Binders or Carbon Black

    KAUST Repository

    Ha, Don-Hyung

    2012-10-10

    In this work, we have developed a new fabrication method for nanoparticle (NP) assemblies for Li-ion battery electrodes that require no additional support or conductive materials such as polymeric binders or carbon black. By eliminating these additives, we are able to improve the battery capacity/weight ratio. The NP film is formed by using electrophoretic deposition (EPD) of colloidally synthesized, monodisperse cobalt NPs that are transformed through the nanoscale Kirkendall effect into hollow Co 3O 4. EPD forms a network of NPs that are mechanically very robust and electrically connected, enabling them to act as the Li-ion battery anode. The morphology change through cycles indicates stable 5-10 nm NPs form after the first lithiation remained throughout the cycling process. This NP-film battery made without binders and conductive additives shows high gravimetric (>830 mAh/g) and volumetric capacities (>2100 mAh/cm 3) even after 50 cycles. Because similar films made from drop-casting do not perform well under equal conditions, EPD is seen as the critical step to create good contacts between the particles and electrodes resulting in this significant improvement in battery electrode assembly. This is a promising system for colloidal nanoparticles and a template for investigating the mechanism of lithiation and delithiation of NPs. © 2012 American Chemical Society.

  13. Inventory and burial fluxes of Black Carbon in the Swedish continental shelf sediments

    Science.gov (United States)

    Sánchez-García, L.; Cato, I.; Gustafsson, Ö.

    2009-04-01

    Highly condensed black carbon (BC) particles, mainly derived from incomplete combustion of biomass and fossil fuel, are involved in several important processes in the biogeosphere [1], including sedimentary carbon burial, sequestration of organic pollutants in soils and sediments, affecting Earth's radiative heat balance and even human respiratory health. BC is commonly found to constitute several to 20% of total sedimentary carbon, and thus plays an important but poorly constrained role in the global biogeospheric carbon cycle. Sequestration of biogenic carbon as BC is a direct sink of the element from the rapidly cycling atmosphere-biosphere reservoirs, whereas burial of petrogenic/fossil BC is simply a conversion of one form of geological carbon to another [2]. Considerable emphasis has been made on the relevant role this recalcitrant form of organic matter (OM) may play on the global C cycle and yet large uncertainty exists around BC detection and quantification. This work seeks to provide a large-scale estimate of the reservoir and burial sink flux of BC in sediments from the extensive Swedish continental shelf (SCS), as a first approach to global inventories. To this end, a total of 120 sediment samples were collected from the Exclusive Economic Zone (EEZ) along the ?2000 km SCS stretch. The most recalcitrant fraction of the sedimentary OM was isolated and determined by means of a commonly applied method in biogeochemical studies of soils and sediments: chemo-thermal oxidation at 375˚ C in air (CTO-375). The obtained BC concentration was used to estimate the inventory and burial flux of BC in the SCS surface sediments, following [3], which takes into account key geophysical and geochemical properties of the nine distinct sedimentary regimes of the SCS that was separately assessed. Globally representative values of the sediment properties (e.g. density of dried sediments, bioturbated mixing depth, sedimentation rate or porosity over the mixed depth) were

  14. Simulating the global atmospheric black carbon cycle: a revisit to the contribution of aircraft emissions

    Directory of Open Access Journals (Sweden)

    J. Hendricks

    2004-06-01

    Full Text Available The black carbon (BC burden of the upper troposphere and lowermost stratosphere (UTLS is investigated with the general circulation model (GCM ECHAM4. The special focus is the contribution of aircraft emissions to the UTLS BC loading. Previous studies on the role of aircraft emissions in the global BC cycle either neglect BC sources located at the Earth's surface or simplify the BC cycle by assuming pre-defined BC residence times. Here, the global BC cycle including emissions, transport, and removal is explicitly simulated. The BC emissions considered include surface sources as well as BC from aviation. This enables a consistent calculation of the relative contribution of aviation to the global atmospheric BC cycle. As a further extension to the previous studies, the aviation-induced perturbation of the UTLS BC particle number concentration is investigated. Several sensitivity studies were performed to evaluate the uncertainties associated with the model predictions. The simulated UTLS BC concentrations are compared to in-situ observations. The simulations suggest that the large-scale contribution of aviation to the UTLS BC mass budget typically amounts to only a few percent, even in the most frequented flight regions. The aviation impact far away from these regions is negligible. The simulated aircraft contributions to the UTLS BC particle number concentration are much larger compared to the corresponding mass perturbations. The simulations suggest that aviation can cause large-scale increases in the UTLS BC particle number concentration of more than 30% in regions highly frequented by aircraft. The relative effect shows a pronounced annual variation with the largest relative aviation impact occurring during winter.

  15. Simulating the global atmospheric black carbon cycle: a revisit to the contribution of aircraft emissions

    Directory of Open Access Journals (Sweden)

    J. Hendricks

    2004-01-01

    Full Text Available The black carbon (BC burden of the upper troposphere and lowermost stratosphere (UTLS is investigated with the general circulation model (GCM ECHAM4. The special focus is the contribution of aircraft emissions to the UTLS BC loading. Previous studies on the role of aircraft emissions in the global BC cycle either neglect BC sources located at the Earth's surface or simplify the BC cycle by assuming pre-defined BC residence times. Here, the global BC cycle including emissions, transport, and removal is explicitly simulated. The BC emissions considered include surface sources as well as BC from aviation. This enables a consistent calculation of the relative contribution of aviation to the global atmospheric BC cycle. As a further extension to the previous studies, the aviation-induced perturbation of the UTLS BC particle number concentration is investigated. The uncertainties associated with the model predictions are evaluated by means of several sensitivity studies. Especially, the sensitivity of the results to different assumptions on the BC hygroscopic properties is analysed. The simulated UTLS BC concentrations are compared to in-situ observations. The simulations suggest that the large-scale contribution of aviation to the UTLS BC mass budget typically amounts to only a few percent, even in the most frequented flight regions. The aviation impact far away from these regions is negligible. The simulated aircraft contributions to the UTLS BC particle number concentration are much larger compared to the corresponding mass perturbations. The simulations suggest that aviation can cause large-scale increases in the UTLS BC particle number concentration of more than 30% in regions highly frequented by aircraft. The relative effect shows a pronounced annual variation with the largest relative aviation impact occurring during winter.

  16. Hawking Tunneling Radiation of a Particle with Electric and Magnetic Charge from Kerr-Newman-Kasuya Black Hole

    Institute of Scientific and Technical Information of China (English)

    ZHAO Wei-Qin; LEI Jie-Hong; LIU Zhi-Xiang; YANG Shu-Zheng

    2008-01-01

    Extending the Parikh's quantum tunneling method of an uncharged particle, we investigate the quantum radiation characteristics of a particle with electric and magnetic charge via tunneling from the event horizon of theKerr-Newman-Kasuya black hole. The derived result supports the Parikh's opinion and the correction to the thermal spectrum is of precisely the form that satisfies the underlying unitary quantum theory, and finally provides a might explanation to the black hole information puzzle.

  17. Absorbing Aerosols: Field and Laboratory Studies of Black Carbon and Dust

    Science.gov (United States)

    Aiken, A. C.; Flowers, B. A.; Dubey, M. K.

    2011-12-01

    Currently, absorbing aerosols are thought to be the most uncertain factor in atmospheric climate models (~0.4-1.2 W/m2), and the 2nd most important factor after CO2 in global warming (1.6 W/m2; Ramanathan and Carmichael, Nature Geoscience, 2008; Myhre, Science, 2009). While most well-recognized atmospheric aerosols, e.g., sulfate from power-plants, have a cooling effect on the atmosphere by scattering solar radiation, black carbon (BC or soot) absorbs sunlight strongly which results in a warming of the atmosphere. Dust particles are also present globally and can absorb radiation, contributing to a warmer and drier atmosphere. Direct on-line measurements of BC and hematite, an absorbing dust aerosol, can be made with the Single Particle Soot Photometer (SP2), which measures the mass of the particles by incandescence on an individual particle basis. Measurements from the SP2 are combined with absorption measurements from the three-wavelength photoacoustic soot spectrometer (PASS-3) at 405, 532, and 781 nm and the ultraviolet photoacoustic soot spectrometer (PASS-UV) at 375 nm to determine wavelength-dependent mass absorption coefficients (MACs). Laboratory aerosol samples include flame-generated soot, fullerene soot, Aquadag, hematite, and hematite-containing dusts. Measured BC MAC's compare well with published values, and hematite MAC's are an order of magnitude less than BC. Absorbing aerosols measured in the laboratory are compared with those from ambient aerosols measured during the Las Conchas fire and BEACHON-RoMBAS. The Las Conchas fire was a wildfire in the Jemez Mountains of New Mexico that burned over 100,000 acres during the Summer of 2011, and BEACHON-RoMBAS (Bio-hydro-atmosphere interactions of Energy, Aerosols, Carbon, H2O, Organics & Nitrogen - Rocky Mountain Biogenic Aerosol Study) is a field campaign focusing on biogenic aerosols at the Manitou Forest Observatory near Colorado Springs, CO in Summer 2011. Optical properties and size

  18. Role of black carbon in the distribution of polychlorinated dibenzo-p-dioxins/dibenzofurans in aged field-contaminated soils

    Energy Technology Data Exchange (ETDEWEB)

    Chai, Y.Z.; Davis, J.W.; Wilken, M.; Martin, G.D.; Mowery, D.M.; Ghosh, U. [Dow Chemical Co USA, Midland, MI (United States). Toxicology & Environmental Research & Consulting

    2011-01-15

    Floodplain soils containing elevated levels of polychlorinated dibenzo-p-dioxins/dibenzofurans (PCDD/Fs) were collected from several locations along the Tittabawassee River (Michigan, USA). The PCDD/F profiles of these soils exhibited distinct congener patterns consistent with byproducts from either chloralkali manufacturing or chlorophenols productions. Black carbon (BC) particles were isolated for the first time from floodplain soil impacted by PCDD/Fs. Petrographic analysis showed that BC particles, including coal, oxidized coal, metallurgical coke, depositional carbon, coal tar/pitch, cenosphere, and charcoal, comprised approximately 30% by volume of the organic fraction with size range of 250 {mu} m-2000 {mu} m from a typical floodplain soil. The BC particles with anthropogenic origin such as pitch and coke associated with the chloralkali production process served as both the source and subsequent transporter for the highly hydrophobic PCDD/Fs. These anthropogenic BC particles were enriched with high levels of PCDFs, containing approximately 1000-fold the concentration found in the bulk soil. The strong association of PCDD/Fs with anthropogenic BC directly impacts the physicochemical and biological availability thus the risk associated with these hydrophobic organochlorines in soils and sediments.

  19. Role of black carbon in the distribution of polychlorinated dibenzo-p-dioxins/dibenzofurans in aged field-contaminated soils.

    Science.gov (United States)

    Chai, Yunzhou; Davis, John W; Wilken, Michael; Martin, Greg D; Mowery, Daniel M; Ghosh, Upal

    2011-01-01

    Floodplain soils containing elevated levels of polychlorinated dibenzo-p-dioxins/dibenzofurans (PCDD/Fs) were collected from several locations along the Tittabawassee River (Michigan, USA). The PCDD/F profiles of these soils exhibited distinct congener patterns consistent with byproducts from either chloralkali manufacturing or chlorophenols productions. Black carbon (BC) particles were isolated for the first time from floodplain soil impacted by PCDD/Fs. Petrographic analysis showed that BC particles, including coal, oxidized coal, metallurgical coke, depositional carbon, coal tar/pitch, cenosphere, and charcoal, comprised approximately 30% by volume of the organic fraction with size range of 250μm-2000μm from a typical floodplain soil. The BC particles with anthropogenic origin such as pitch and coke associated with the chloralkali production process served as both the source and subsequent transporter for the highly hydrophobic PCDD/Fs. These anthropogenic BC particles were enriched with high levels of PCDFs, containing approximately 1000-fold the concentration found in the bulk soil. The strong association of PCDD/Fs with anthropogenic BC directly impacts the physicochemical and biological availability thus the risk associated with these hydrophobic organochlorines in soils and sediments.

  20. Black carbon measurements during winter 2013-2014 in Athens and intercomparison between different techniques

    Science.gov (United States)

    Liakakou, Eleni; Stravroulas, Jason; Roukounakis, Nikolaos; Paraskevopoulou, Despina; Fourtziou, Luciana; Psiloglou, Vassilis; Gerasopoulos, Evangelos; Sciare, Jean; Mihalopoulos, Nikolaos

    2014-05-01

    Black carbon (BC) is a particulate pollutant species emitted from the combustion of fuels, biomass burning for agricultural purposes and forest fires, with the first two anthropogenic sources being the major contributors to the atmospheric burden of BC. The presence of BC is important due to its direct and indirect physicochemical effects and its use as a tracer of burning and subsequent transport processes. Black carbon measurements took place during winter 2013 -2014 in the frame of a pollution monitoring experiment conducted at the urban site of Thissio, Athens (city center) at the premises of the National Observatory of Athens. The economic crisis in Greece and the resulting turn of Athens inhabitants to wood burning for domestic heating, has led to increased daily concentrations of BC in the range of 2-6 μg m-3, peaking at night time (15-20 μg m-3). Three different optical methods were used for the determination of BC. A Particle Soot Absorption Photometer (PSAP; Radiance Research) commercial instrument was used to monitor the light absorption coefficient (σap) at 565 nm of ambient aerosols, with 1 minute resolution. During parts of the campaign, a portable Aethalometer (AE-42; Magee Scientific) was also used to provide measurement of the aerosol BC content at 7 wavelengths over 5 minutes intervals. Exploiting the measurements at different wavelengths is was feasible to separate wood burning BC from BC related to fossil fuel. Two Multi Angle Absorption Photometers (MAAP; Thermo) were also operated as reference. Finally, aerosol samples were collected on 12-hour basis using a sequential dichotomous sampler for the sampling of PM2.5, PM2.5-10and PM10 fractions of aerosols on quartz filters, and the filters were analyzed for elemental carbon (EC) by a thermal - optical transmission technique. The main objective of the study is the intercomparison of the different BC monitoring techniques under a large range of ambient concentrations achieved due to the special

  1. Attribution of aerosol light absorption to black carbon, brown carbon, and dust in China – interpretations of atmospheric measurements during EAST-AIRE

    Directory of Open Access Journals (Sweden)

    B. J. Huebert

    2008-06-01

    Full Text Available Black carbon, brown carbon, and mineral dust are three of the most important light absorbing aerosols. Their optical properties differ greatly and are distinctive functions of the wavelength of light. Most optical instruments that quantify light absorption, however, are unable to distinguish one type of absorbing aerosol from another. It is thus instructive to separate total absorption from these different light absorbers to gain a better understanding of the optical characteristics of each aerosol type. During the EAST-AIRE (East Asian Study of Tropospheric Aerosols: an International Regional Experiment campaign near Beijing, we measured light scattering using a nephelometer, and light absorption using an aethalometer and a particulate soot absorption photometer. We also measured the total mass concentrations of carbonaceous (elemental and organic carbon and inorganic particulates, as well as aerosol number and mass distributions. We were able to identify periods during the campaign that were dominated by dust, biomass burning, fresh (industrial chimney plumes, other coal burning pollution, and relatively clean (background air for Northern China. Each of these air masses possessed distinct intensive optical properties, including the single scatter albedo and Ångstrom exponents. Based on the wavelength-dependence and particle size distribution, we apportioned total light absorption to black carbon, brown carbon, and dust; their mass absorption efficiencies at 550 nm were estimated to be 9.5, 0.5, and 0.03 m2/g, respectively. While agreeing with the common consensus that BC is the most important light absorber in the mid-visible, we demonstrated that brown carbon and dust could also cause significant absorption, especially at shorter wavelengths.

  2. Aerosol organic carbon to black carbon ratios: Analysis ofpublished data and implications for climate forcing

    Energy Technology Data Exchange (ETDEWEB)

    Novakov, T.; Menon, S.; Kirchstetter, T.W.; Koch, D.; Hansen, J.E.

    2005-07-11

    Measurements of organic carbon (OC) and black carbon (BC)concentrations over a variety of locations worldwide, have been analyzed to infer the spatial distributions of the ratios of OC to BC. Since these ratios determine the relative amounts of scattering and absorption, they are often used to estimate the radiative forcing due to aerosols. An artifact in the protocol for filter measurements of OC has led to widespread overestimates of the ratio of OC to BC in atmospheric aerosols. We developed a criterion to correct for this artifact and analyze corrected OC to BC ratios. The OC to BC ratios, ranging from 1.3to 2.4, appear relatively constant and are generally unaffected by seasonality, sources or technology changes, at the locations considered here. The ratios compare well with emission inventories over Europe and China but are a factor of two lower in other regions. The reduced estimate for OC/BC in aerosols strengthens the argument that reduction of soot emissions maybe a useful approach to slow global warming.

  3. Influence of γ-ray Irradiation on the PTC Effect of EPDM/Carbon Black Composite

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    @@ Introduction The positive temperature coefficient(PTC) effect is characterized by an increase of resistivity with an elevated temperature.The PTC effect of carbon black(CB) filled polymers is useful for self-regulation heaters,over-current protectors,sensors,etc.Much work has been done on the PTC effect of the carbon black filled crystalline polymer composite[1-4],whereas carbon black filled amorphous polymers have not drawn researchers much attention because the PTC effect in these composites is small or cannot be detected[5-7].In this work,the influence of γ-ray irradiation on the PTC effect of CB filled amorphous ethylene-propylene-diene terpolymer(EPDM) composites was studied.

  4. The effects of additional black carbon on Arctic sea ice surface albedo: variation with sea ice type and snow cover

    Directory of Open Access Journals (Sweden)

    A. A. Marks

    2013-03-01

    Full Text Available Black carbon in sea ice will decrease sea ice surface albedo through increased absorption of incident solar radiation, exacerbating sea ice melting. Previous literature has reported different albedo responses to additions of black carbon in sea ice and has not considered how a snow cover may mitigate the effect of black carbon in sea ice. Sea ice is predominately snow covered. Visible light absorption and light scattering coefficients are calculated for a typical first year and multi-year sea ice and "dry" and "wet" snow types that suggest black carbon is the dominating absorbing impurity. The albedo response of first year and multi-year sea ice to increasing black carbon, from 1–1024 ng g−1, in a top 5 cm layer of a 155 cm thick sea ice was calculated using the radiative transfer model: TUV-snow. Sea ice albedo is surprisingly unresponsive to black carbon additions up to 100 ng g−1 with a decrease in albedo to 98.7% of the original albedo value due to an addition of 8 ng g−1 of black carbon in first year sea ice compared to an albedo decrease to 99.6% for the same black carbon mass ratio increase in multi-year sea ice. The first year sea ice proved more responsive to black carbon additions than the multi-year ice. Comparison with previous modelling of black carbon in sea ice suggests a more scattering sea ice environment will be less responsive to black carbon additions. Snow layers on sea ice may mitigate the effects of black carbon in sea ice. "Wet" and "dry" snow layers of 0.5, 1, 2, 5 and 10 cm were added onto the sea ice surface and the snow surface albedo calculated with the same increase in black carbon in the underlying sea ice. Just a 0.5 cm layer of snow greatly diminishes the effect of black carbon on surface albedo, and a 2–5 cm layer (less than half the e-folding depth of snow is enough to "mask" any change in surface albedo owing to additional black carbon in sea ice, but not thick enough to ignore the underlying sea ice.

  5. Characteristics of Nonafluorobutyl Methyl Ether (NFE) Adsorption onto Activated Carbon Fibers and Different-Size-Activated Carbon Particles.

    Science.gov (United States)

    Tanada; Kawasaki; Nakamura; Araki; Tachibana

    2000-08-15

    The characteristics of adsorption of 1,1,1,2,2,3,3,4,4-nonafluorobutyl methyl ether (NFE), a chlorofluorocarbon (CFC) replacement, onto six different activated carbon; preparations (three activated carbon fibers and three different-sized activated carbon particles) were investigated to evaluate the interaction between activated carbon surfaces and NFE. The amount of NFE adsorbed onto the three activated carbon fibers increased with increasing specific surface area and pore volume. The amount of NFE adsorbed onto the three different-sized-activated carbon particles increased with an increase in the particle diameter of the granular activated carbon. The differential heat of the NFE adsorption onto three activated carbon fibers depended on the porosity structure of the activated carbon fibers. The adsorption rate of NFE was also investigated in order to evaluate the efficiency of NFE recovery by the activated carbon surface. The Sameshima equation was used to obtain the isotherms of NFE adsorption onto the activated carbon fibers and different-sized-activated carbon particles. The rate constant k for NFE adsorption onto activated carbon fibers was larger for increased specific surface area and pore volume. The rate of NFE adsorption on activated carbons of three different particle sizes decreased with increasing particle diameter at a low initial pressure. The adsorption isotherms of NFE for the six activated carbons conformed to the Dubinin-Radushkevich equation; the constants BE(0) (the affinity between adsorbate and adsorbent) and W(0) (the adsorption capacity) were calculated. These results indicated that the interaction between the activated carbon and NFE was larger with the smaller specific surface area of the activated carbon fibers and with the smaller particle diameter of the different-sized-activated carbon particles. The degree of packing of NFE in the pores of the activated carbon fibers was greater than that in the pores of the granular activated

  6. Gravitational Radiation from the radial infall of highly relativistic point particles into Kerr black holes

    CERN Document Server

    Cardoso, V; Cardoso, Vitor; Lemos, Jos\\'e P. S.

    2003-01-01

    In this paper, we consider the gravitational radiation generated by the collision of highly relativistic particles with rotating Kerr black holes. We use the Sasaki-Nakamura formalism to compute the waveform, energy spectra and total energy radiated during this process. We show that the gravitational spectrum for high-energy collisions has definite characteristic universal features, which are independent of the spin of the colliding objects. We also discuss possible connections between these results and the black hole-black hole collision at the speed of light process. With these results at hand, we predict that during the high speed collision of a non-rotating hole with a rotating one, about 35% of the total energy gets converted into gravitational waves. Thus, if one is able to produce black holes at the Large Hadron Collider, 35% of the partons' energy should be emitted during the so called balding phase. This energy will be missing, since we don't have gravitational wave detectors able to measure such amp...

  7. Evidence of old soil carbon in grass biosilica particles

    Directory of Open Access Journals (Sweden)

    P. E. Reyerson

    2015-09-01

    Full Text Available Plant biosilica particles (phytoliths contain small amounts of carbon called phytC. Based on the assumptions that phytC is of photosynthetic origin and a closed system, claims were recently made that phytoliths from grasslands play a significant role in atmospheric CO2 sequestration. However, anomalous phytC radiocarbon (14C dates suggested contributions from a non-photosynthetic source to phytC. Here we address this non-photosynthetic source hypothesis using comparative isotopic measurements (14C and δ13C of phytC, plant tissues, atmospheric CO2, and soil organic matter. State-of-the-art methods assured phytolith purity, while sequential stepwise-combustion revealed complex chemical–thermal decomposability properties of phytC. Although photosynthesis is the main source of carbon in plant tissue, it is found that phytC is partially derived from soil carbon that can be several thousand years old. The accumulation of old soil organic matter derived carbon in plant biosilica suggests that Si absorption and phytolith production promote old soil organic carbon mobilization. Although the magnitude of this mechanism still needs to be properly assessed at plant and ecosystem scales, its confirmation alone argues against attempts to use phytC as a proxy of plant carbon and call for the reexamination of phytolith atmospheric CO2 biosequestration estimates.

  8. Dynamics of particles around a pseudo-Newtonian Kerr black hole with halos

    Institute of Scientific and Technical Information of China (English)

    Wang Ying; Wu Xin

    2012-01-01

    The regular and chaotic dynamics of test particles in a superposed field between a pseudo-Newtonian Kerr black hole and quadrupolar halos is detailed.In particular,the dependence of dynamics on the quadrupolar parameter of the halos and the spin angular momentum of the rotating black hole is studied.It is found that the small quadrupolar moment,in contrast with the spin angular momentum,does not have a great effect on the stability and radii of the innermost stable circular orbits of these test particles.In addition,chaos mainly occurs for small absolute values of the rotating parameters,and does not exist for the maximum counter-rotating case under some certain initial conditions and parameters.This means that the rotating parameters of the black hole weaken the chaotic properties.It is also found that the counter-rotating system is more unstable than the co-rotating one.Furthermore,chaos is absent for small absolute values of the quadrupoles,and the onset of chaos is easier for the prolate halos than for the oblate ones.

  9. Offsetting features of climate responses to anthropogenic sulfate and black carbon direct radiative forcings

    Science.gov (United States)

    Ocko, I.; Ramaswamy, V.

    2012-12-01

    The two most prominent anthropogenic aerosols—sulfate and black carbon—affect Earth's radiation budget in opposing ways. Here we examine how these aerosols independently impact the climate, by simulating climate responses from pre-industrial times (1860) to present-day (2000) for isolated sulfate and black carbon direct radiative forcings. The NOAA Geophysical Fluid Dynamics Laboratory CM2.1 global climate model is employed with prescribed distributions of externally mixed aerosols. We find that sulfate and black carbon induce opposite effects for a myriad of climate variables. Sulfate (black carbon) is generally cooling (warming), shifts the ITCZ southward (northward), reduces (enhances) the SH Hadley Cell, enhances (reduces) the NH Hadley Cell, and increases (decreases) total sea ice volume. Individually, sulfate and black carbon affect Hadley Cell circulation more than long-lived greenhouse gases, but the net aerosol effect is a weakened response due to opposite behaviors somewhat canceling out the individual effects. Because anthropogenic aerosols are a critical contributor to Earth's climate conditions, this study has implications for future climate changes as well.

  10. Commuter exposure to black carbon, carbon monoxide, and noise in the mass transport khlong boats of Bangkok, Thailand

    Science.gov (United States)

    Ziegler, A. D.; Velasco, E.; Ho, K. J.

    2013-12-01

    Khlong (canal) boats are a unique mass transport alternative in the congested city of Bangkok. Canals and rivers provide exclusive transit-ways for reducing the commuting time of thousands of city residents daily. However, as a consequence of the service characteristics and boats design and state of repair, they can represent a potential public health risk and an important source of black carbon and greenhouse gases. This work quantifies commuter exposure to black carbon, CO and noise when waiting for and travelling in these diesel fueled boats. Exposure to toxic pollutants and acute noise is similar or worse than for other transportation modes. Mean black carbon concentrations observed at one busy pier and along the main canal were much higher than ambient concentrations at sites impacted by vehicular traffic. Concentrations of CO were similar to those reported for roadside areas of Bangkok. The equivalent continuous sound levels registered at the landing pier were similar to those reported for roadsides, but values recorded inside the boats were significantly higher. We believe that the boat service is a viable alternative mode of mass transport, but public safety could be improved to provide a high quality service, comparable to modern rail systems or emerging bus rapid transit systems. These investments would also contribute to reduce the emission of black carbon and other greenhouse and toxic pollutants.

  11. Transparent exopolymer particles: Effects on carbon cycling in the ocean

    Science.gov (United States)

    Mari, Xavier; Passow, Uta; Migon, Christophe; Burd, Adrian B.; Legendre, Louis

    2017-02-01

    Transparent Exopolymer Particles (TEP) have received considerable attention since they were first described in the ocean more than 20 years ago. This is because of their carbon-rich composition, their high concentrations in ocean's surface waters, and especially because of their ability to promote aggregation due to their high stickiness (i.e. biological glue). As large aggregates contribute significantly to vertical carbon flux, TEP are commonly seen as a key factor that drives the downward flux of particulate organic carbon (POC). However, the density of TEP is lower than that of seawater, which causes them to remain in surface waters and even move upwards if not ballasted by other particles, which often leads to their accumulation in the sea surface microlayer. Hence we question here the generally accepted view that TEP always increase the downward flux of POC via gravitational settling. In the present reassessment of the role of TEP, we examine how the presence of a pool of non-sinking carbon-rich particulate organic matter in surface waters influences the cycling of organic carbon in the upper ocean at daily to decadal time scales. In particular, we focus on the role of TEP in the retention of organic carbon in surface waters versus downward export, and discuss the potential consequences of climate change on this process and on the efficiency of the biological carbon pump. We show that TEP sink only when ballasted with enough high-density particles to compensate their low density, and hence that their role in vertical POC export is not solely linked to their ability to promote aggregation, but also to their contribution to the buoyancy of POC. It follows that the TEP fraction of POC determines the degree of retention and remineralization of POC in surface waters versus its downward export. A high TEP concentration may temporally decouple primary production and downward export. We identify two main parameters that affect the contribution of TEP to POC cycling

  12. Black carbon fractal morphology and short-wave radiative impact: a modelling study

    Directory of Open Access Journals (Sweden)

    M. Kahnert

    2011-11-01

    Full Text Available We investigate the impact of the morphological properties of freshly emitted black carbon aerosols on optical properties and on radiative forcing. To this end, we model the optical properties of fractal black carbon aggregates by use of numerically exact solutions to Maxwell's equations within a spectral range from the UVC to the mid-IR. The results are coupled to radiative transfer computations, in which we consider six realistic case studies representing different atmospheric pollution conditions and surface albedos. The spectrally integrated radiative impacts of black carbon are compared for two different fractal morphologies, which brace the range of recently reported experimental observations of black carbon fractal structures. We also gauge our results by performing corresponding calculations based on the homogeneous sphere approximation, which is commonly employed in climate models. We find that at top of atmosphere the aggregate models yield radiative impacts that can be as much as 2 times higher than those based on the homogeneous sphere approximation. An aggregate model with a low fractal dimension can predict a radiative impact that is higher than that obtained with a high fractal dimension by a factor ranging between 1.1–1.6. Although the lower end of this scale seems like a rather small effect, a closer analysis reveals that the single scattering optical properties of more compact and more lacy aggregates differ considerably. In radiative flux computations there can be a partial cancellation due to the opposing effects of different error sources. However, this cancellation effect can strongly depend on atmospheric conditions and is therefore quite unpredictable. We conclude that the fractal morphology of black carbon aerosols and their fractal parameters can have a profound impact on their radiative forcing effect, and that the use of the homogeneous sphere model introduces unacceptably high biases in radiative impact studies. We

  13. Aerosol Absorption by Black Carbon and Dust: Implications of Climate Change and Air Quality in Asia

    Science.gov (United States)

    Chin, Mian

    2010-01-01

    Atmospheric aerosol distributions from 2000 to 2007 are simulated with the global model GOCART to attribute light absorption by aerosol to its composition and sources. We show the seasonal and interannual variations of absorbing aerosols in the atmosphere over Asia, mainly black carbon and dust. and their linkage to the changes of anthropogenic and dust emissions in the region. We compare our results with observations from satellite and ground-based networks, and estimate the importance of black carbon and dust on regional climate forcing and air quality.

  14. Polymer-carbon black composite sensors in an electronic nose for air-quality monitoring

    Science.gov (United States)

    Ryan, M. A.; Shevade, A. V.; Zhou, H.; Homer, M. L.

    2004-01-01

    An electronic nose that uses an array of 32 polymer-carbon black composite sensors has been developed, trained, and tested. By selecting a variety of chemical functionalities in the polymers used to make sensors, it is possible to construct an array capable of identifying and quantifying a broad range of target compounds, such as alcohols and aromatics, and distinguishing isomers and enantiomers (mirror-image isomers). A model of the interaction between target molecules and the polymer-carbon black composite sensors is under development to aid in selecting the array members and to enable identification of compounds with responses not stored in the analysis library.

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

    Science.gov (United States)

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

    2012-02-07

    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) 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.

  16. Spinning Particle as a Non-trivial Rotating Super Black Hole with Broken N=2 Supersymmetry

    CERN Document Server

    Burinskii, A

    1999-01-01

    A non-trivial super black hole solution is considered as representing a combined model of the Kerr spinning particle and superparticle. Treatment is based on the broken N=2 supersymmetry in supergravity in analogue with Deser-Zumino model of broken supersymmetry in N=1 supergravity. There appears a non-linear realization of broken supersymmetry, which is very specific for the Kerr geometry and which leads to a family of the exact non-trivial rotating and charged super black hole solutions (super-Kerr-Newman solutions). Peculiarities of the super-Kerr-Newman solutions and in particular the appearance of the short ranging traveling waves of torsion and other fields, build of the nilpotent Grassmann variables, on the pure bosonic Kerr-Newman background are discussed.

  17. Characterization of long-term and seasonal variations of black carbon (BC concentrations at Neumayer, Antarctica

    Directory of Open Access Journals (Sweden)

    R. Weller

    2012-09-01

    Full Text Available Continuous black carbon (BC observations were conducted from 1999 through 2009 by an Aethalometer (AE10 and from 2006 through 2011 by a Multi-Angle Absorption Photometer (MAAP at Neumayer Station (NM under stringent contamination control. Considering the respective observation period, BC concentrations measured by the MAAP were somewhat higher (median ± standard deviation: 2.1 ± 2.0 ng m−3 compared to the AE10 results (1.6 ± 2.1 ng m−3. Neither for the AE10 nor for the MAAP data set a significant long-term trend could be detected. Consistently a pronounced seasonality was observed with both instruments showing a primary annual maximum between October and November and a minimum in April with a maximum/minimum ratio of 4.5/1.6 = 3.8 and 2.7/0.64 = 4.2 for the MAAP and AE10 data, respectively. Occasionally a secondary summer maximum in January/February was visible. With the aim to assess the impact of BC on optical properties of the aerosol at NM, we evaluated the BC data along with particle scattering coefficients measured by an integrating nephelometer. We found the mean single scattering albedo of ω550 = 0.992 ± 0.0090 (median: 0.994 at a wavelength of 550 nm with a range of values from 0.95 to 1.0.

  18. Characterization of long-term and seasonal variations of black carbon (BC) concentrations at Neumayer, Antarctica

    Science.gov (United States)

    Weller, R.; Minikin, A.; Petzold, A.; Wagenbach, D.; König-Langlo, G.

    2013-02-01

    Continuous black carbon (BC) observations were conducted from 1999 through 2009 by an Aethalometer (AE10) and from 2006 through 2011 by a Multi-Angle Absorption Photometer (MAAP) at Neumayer Station (NM) under stringent contamination control. Considering the respective observation period, BC concentrations measured by the MAAP were somewhat higher (median ± standard deviation: 2.1 ± 2.0 ng m-3) compared to the AE10 results (1.6 ± 2.1 ng m-3). Neither for the AE10 nor for the MAAP data set a significant long-term trend could be detected. Consistently a pronounced seasonality was observed with both instruments showing a primary annual maximum between October and November and a minimum in April with a maximum/minimum ratio of 4.5/1.6 = 3.8 and 2.7/0.64 = 4.2 for the MAAP and AE10 data, respectively. Occasionally a secondary summer maximum in January/February was visible. With the aim to assess the impact of BC on optical properties of the aerosol at NM, we evaluated the BC data along with particle scattering coefficients measured by an integrating nephelometer. We found the mean single scattering albedo of ω550 = 0.992 ± 0.0090 (median: 0.994) at a wavelength of 550 nm with a range of values from 0.95 to 1.0.

  19. Characterization of long-term and seasonal variations of black carbon (BC concentrations at Neumayer, Antarctica

    Directory of Open Access Journals (Sweden)

    R. Weller

    2013-02-01

    Full Text Available Continuous black carbon (BC observations were conducted from 1999 through 2009 by an Aethalometer (AE10 and from 2006 through 2011 by a Multi-Angle Absorption Photometer (MAAP at Neumayer Station (NM under stringent contamination control. Considering the respective observation period, BC concentrations measured by the MAAP were somewhat higher (median ± standard deviation: 2.1 ± 2.0 ng m−3 compared to the AE10 results (1.6 ± 2.1 ng m−3. Neither for the AE10 nor for the MAAP data set a significant long-term trend could be detected. Consistently a pronounced seasonality was observed with both instruments showing a primary annual maximum between October and November and a minimum in April with a maximum/minimum ratio of 4.5/1.6 = 3.8 and 2.7/0.64 = 4.2 for the MAAP and AE10 data, respectively. Occasionally a secondary summer maximum in January/February was visible. With the aim to assess the impact of BC on optical properties of the aerosol at NM, we evaluated the BC data along with particle scattering coefficients measured by an integrating nephelometer. We found the mean single scattering albedo of ω550 = 0.992 ± 0.0090 (median: 0.994 at a wavelength of 550 nm with a range of values from 0.95 to 1.0.

  20. Black carbon sources constrained by observations in the Russian high Arctic.

    Science.gov (United States)

    Popovicheva, Olga Borsovna; Evangeliou, Nikolaos; Eleftheriadis, Konstantinos; Kalogridis, Athina Cerise; Movchan, Vadim Vadimovich; Sitnikov, Nikolay; Eckhardt, Sabine; Makshtas, Alexander; Stohl, Andreas

    2017-02-24

    Understanding the role of short-lived climate forcers like black carbon (BC) at high northern latitudes in climate change is hampered by the scarcity of surface observations in the Russian Arctic. In this study, highly time resolved Equivalent BC (EBC) measurements during a ship campaign in the White, Barents and Kara Seas in October 2015 are presented. The measured EBC concentrations are compared with BC concentrations simulated with a Lagrangian particle dispersion model coupled with a recently completed global emission inventory to quantify the origin of the Arctic BC. EBC showed increased values (100-400 ng m-3) in the Kara Strait, Kara Sea, and Kola Peninsula, and an extremely high concentration (1000 ng m-3) in the White Sea. Assessment of BC origin throughout the expedition showed that gas flaring emissions from the Yamal/Khanty-Mansiysk and Nenets/Komi regions contributed the most when the ship was close to the Kara Strait, north of 70˚N. Near Arkhangelsk (White Sea), biomass burning in mid-latitudes, surface transportation, and residential and commercial combustion from Central and Eastern Europe were found to be important BC sources. The model reproduced observed EBC concentrations efficiently, building credibility in the emission inventory for BC emissions at high northern latitudes.

  1. Climatic impacts of stratospheric geoengineering with sulfate, black carbon and titania injection

    Science.gov (United States)

    Jones, Anthony C.; Haywood, James M.; Jones, Andy

    2016-03-01

    In this paper, we examine the potential climatic effects of geoengineering by sulfate, black carbon and titania injection against a baseline RCP8.5 scenario. We use the HadGEM2-CCS model to simulate scenarios in which the top-of-the-atmosphere radiative imbalance due to rising greenhouse gas concentrations is offset by sufficient aerosol injection throughout the 2020-2100 period. We find that the global-mean temperature is effectively maintained at historical levels for the entirety of the period for all three aerosol-injection scenarios, though there is a wide range of side-effects which are discussed in detail. The most prominent conclusion is that although the BC injection rate necessary to produce an equivalent global mean temperature response is much lower, the severity of stratospheric temperature changes (> +70 °C) and precipitation impacts effectively exclude BC from being a viable option for geoengineering. Additionally, while it has been suggested that titania would be an effective particle because of its high scattering efficiency, it also efficiently absorbs solar ultraviolet radiation producing a significant stratospheric warming (> +20 °C). As injection rates and climatic impacts for titania are close to those for sulfate, there appears to be little benefit in terms of climatic influence of using titania when compared to the injection of sulfur dioxide, which has the added benefit of being well-modeled through extensive research that has been carried out on naturally occurring explosive volcanic eruptions.

  2. Climatic impacts of stratospheric geoengineering with sulfate, black carbon and titania injection

    Directory of Open Access Journals (Sweden)

    A. C. Jones

    2015-11-01

    Full Text Available In this paper, we examine the potential climatic effects of geoengineering by sulfate, black carbon and titania injection against a baseline RCP8.5 scenario. We use the HadGEM2-CCS model to simulate scenarios in which the top-of-the-atmosphere radiative imbalance due to rising greenhouse gas concentrations is offset by sufficient aerosol injection throughout the 2020–2100 period. We find that the global-mean temperature is effectively maintained at historical levels for the entirety of the period for all 3 aerosol-injection scenarios, though there are a wide range of side-effects which are discussed in detail. The most prominent conclusion is that although the BC injection rate necessary to produce an equivalent global mean temperature-response is much lower, the severity of stratospheric temperature changes (> +70 °C and precipitation impacts effectively exclude BC from being a viable option for geoengineering. Additionally, while it has been suggested that titania would be an effective particle because of its high scattering efficiency, it also efficiently absorbs solar ultraviolet radiation producing a significant stratospheric warming (> +20 °C. As injection rates for titania are close to those for sulfate, there appears little benefit of using titania when compared to injection of sulfur dioxide, which has the added benefit of being well modelled through extensive research that has been carried out on naturally occurring explosive volcanic eruptions.

  3. A characterization of Arctic aerosols on the basis of aerosol optical depth and black carbon measurements

    Directory of Open Access Journals (Sweden)

    R. S. Stone

    2014-06-01

    Full Text Available Abstract Aerosols, transported from distant source regions, influence the Arctic surface radiation budget. When deposited on snow and ice, carbonaceous particles can reduce the surface albedo, which accelerates melting, leading to a temperature-albedo feedback that amplifies Arctic warming. Black carbon (BC, in particular, has been implicated as a major warming agent at high latitudes. BC and co-emitted aerosols in the atmosphere, however, attenuate sunlight and radiatively cool the surface. Warming by soot deposition and cooling by atmospheric aerosols are referred to as “darkening” and “dimming” effects, respectively. In this study, climatologies of spectral aerosol optical depth AOD (2001–2011 and Equivalent BC (EBC (1989–2011 from three Arctic observatories and from a number of aircraft campaigns are used to characterize Arctic aerosols. Since the 1980s, concentrations of BC in the Arctic have decreased by more than 50% at ground stations where in situ observations are made. AOD has increased slightly during the past decade, with variations attributed to changing emission inventories and source strengths of natural aerosols, including biomass smoke and volcanic aerosol, further influenced by deposition rates and airflow patterns.

  4. Assessing recent measurement techniques for quantifying black carbon concentration in snow

    Directory of Open Access Journals (Sweden)

    J. P. Schwarz

    2012-05-01

    Full Text Available We evaluate the performance of the Single Particle Soot Photometer (SP2 and the Integrating Sphere/Integrating Sandwich Spectrophotometer (ISSW in quantifying the concentration of refractory black carbon (BC in snow samples. We find that the SP2 can be used to measure BC mass concentration in snow with substantially larger uncertainty (60% than for atmospheric sampling (<30%. Achieving this level of accuracy requires careful assessment of nebulizer performance and SP2 calibration with consideration of the fact that BC in snow tends to larger sizes than typically observed in the atmosphere. Once these issues are addressed, the SP2 is able to measure the size distribution and mass concentration of BC in the snow. Laboratory comparison of the SP2 and the Integrating Sphere/Integrating Sandwich Spectrophotometer (ISSW revealed significant biases in the estimate of BC concentration from the ISSW when test samples contained dust or non-absorbing particulates. These results suggest that current estimates of BC mass concentration in snow and ice using either the SP2 or the ISSW may be associated with significant underestimates of uncertainty.

  5. Automatic Method for Controlling the Iodine Adsorption Number in Carbon Black Oil Furnaces

    Directory of Open Access Journals (Sweden)

    Zečević, N.

    2008-12-01

    Full Text Available There are numerous of different inlet process factors in carbon black oil furnaces which must be continuously and automatically adjusted, due to stable quality of final product. The most important six inlet process factors in carbon black oil-furnaces are:1. volume flow of process air for combustion2. temperature of process air for combustion3. volume flow of natural gas for insurance the necessary heat for thermal reaction of conversionthe hydrocarbon oil feedstock in oil-furnace carbon black4. mass flow rate of hydrocarbon oil feedstock5. type and quantity of additive for adjustment the structure of oil-furnace carbon black6. quantity and position of the quench water for cooling the reaction of oil-furnace carbon black.The control of oil-furnace carbon black adsorption capacity is made with mass flow rate of hydrocarbon feedstock, which is the most important inlet process factor. Oil-furnace carbon black adsorption capacity in industrial process is determined with laboratory analyze of iodine adsorption number. It is shown continuously and automatically method for controlling iodine adsorption number in carbon black oil-furnaces to get as much as possible efficient control of adsorption capacity. In the proposed method it can be seen the correlation between qualitatively-quantitatively composition of the process tail gasses in the production of oil-furnace carbon black and relationship between air for combustion and hydrocarbon feedstock. It is shown that the ratio between air for combustion and hydrocarbon oil feedstock is depended of adsorption capacity summarized by iodine adsorption number, regarding to BMCI index of hydrocarbon oil feedstock.The mentioned correlation can be seen through the figures from 1. to 4. From the whole composition of the process tail gasses the best correlation for continuously and automatically control of iodine adsorption number is show the volume fraction of methane. The volume fraction of methane in the

  6. Bounding the role of black carbon in the climate system: A scientific assessment

    Science.gov (United States)

    Bond, T. C.; Doherty, S. J.; Fahey, D. W.; Forster, P. M.; Berntsen, T.; Deangelo, B. J.; Flanner, M. G.; Ghan, S.; KäRcher, B.; Koch, D.; Kinne, S.; Kondo, Y.; Quinn, P. K.; Sarofim, M. C.; Schultz, M. G.; Schulz, M.; Venkataraman, C.; Zhang, H.; Zhang, S.; Bellouin, N.; Guttikunda, S. K.; Hopke, P. K.; Jacobson, M. Z.; Kaiser, J. W.; Klimont, Z.; Lohmann, U.; Schwarz, J. P.; Shindell, D.; Storelvmo, T.; Warren, S. G.; Zender, C. S.

    2013-06-01

    carbon aerosol plays a unique and important role in Earth's climate system. Black carbon is a type of carbonaceous material with a unique combination of physical properties. This assessment provides an evaluation of black-carbon climate forcing that is comprehensive in its inclusion of all known and relevant processes and that is quantitative in providing best estimates and uncertainties of the main forcing terms: direct solar absorption; influence on liquid, mixed phase, and ice clouds; and deposition on snow and ice. These effects are calculated with climate models, but when possible, they are evaluated with both microphysical measurements and field observations. Predominant sources are combustion related, namely, fossil fuels for transportation, solid fuels for industrial and residential uses, and open burning of biomass. Total global emissions of black carbon using bottom-up inventory methods are 7500 Gg yr-1 in the year 2000 with an uncertainty range of 2000 to 29000. However, global atmospheric absorption attributable to black carbon is too low in many models and should be increased by a factor of almost 3. After this scaling, the best estimate for the industrial-era (1750 to 2005) direct radiative forcing of atmospheric black carbon is +0.71 W m-2 with 90% uncertainty bounds of (+0.08, +1.27) W m-2. Total direct forcing by all black carbon sources, without subtracting the preindustrial background, is estimated as +0.88 (+0.17, +1.48) W m-2. Direct radiative forcing alone does not capture important rapid adjustment mechanisms. A framework is described and used for quantifying climate forcings, including rapid adjustments. The best estimate of industrial-era climate forcing of black carbon through all forcing mechanisms, including clouds and cryosphere forcing, is +1.1 W m-2 with 90% uncertainty bounds of +0.17 to +2.1 W m-2. Thus, there is a very high probability that black carbon emissions, independent of co-emitted species, have a positive forcing and warm

  7. Black Ink of Activated Carbon Derived From Palm Kernel Cake (PKC)

    Science.gov (United States)

    Selamat, M. H.; Ahmad, A. H.

    2009-06-01

    Recycling the waste from natural plant to produce useful end products will benefit many industries and help preserve the environment. The research reported in this paper is an investigation on the use of the natural waste of palm kernel cake (PKC) to produce carbon residue as a black carbon for pigment source by using pyrolysis process. The activated carbons (AC) is produced in powder form using ball milling process. Rheological spectra in ink is one of quality control process in determining its performance properties. Findings from this study will help expand the scientific knowledge-base for black ink production and formulation base on PKC. Various inks with different weight percentage compositions of AC will be made and tested against its respective rheological properties in order to determine ideal ink printing system. The items in the formulation used comprised of organic and bio-waste materials with added additive to improve the quality of the black ink. Modified Polyurethane was used as binder. The binder's properties highlighted an ideal vehicle to be applied for good black ink opacity performance. The rheological behaviour is a general foundation for ink characterization where the wt% of AC-PKC resulted in different pseudoplastic behaviors, including the Newtonian behavior. The result found that Newtonian field was located in between 2 wt% and 10 wt% of AC-PKC composition with binder. Mass spectroscopy results shown that the carbon content in PKC is high and very suitable for black performance. In the ageing test, the pigment of PKC perform fairly according to the standard pigment of Black carbon (CB) of ferum oxide pigment. The contact angle for substrate's wettability of the ink system shown a good angle proven to be a water resistive coating on paper subtrates; an advantage of the PKC ink pigment performance.

  8. Solid phase extraction method for the study of black carbon cycling in dissolved organic carbon using radiocarbon

    OpenAIRE

    2015-01-01

    © 2015 Elsevier B.V.. Radiocarbon analysis is a powerful tool for understanding the cycling of individual components within carbon pools, such as black carbon (BC) in dissolved organic carbon (DOC). Radiocarbon (δ14C) measurements of BC in DOC provide insight into one source of aged, recalcitrant DOC. We report a modified solid phase extraction (SPE) method to concentrate 43±6% of DOC (SPE-DOC) from seawater. We used the Benzene Polycarboxylic Acid (BPCA) method to isolate BC from SPE-DOC (SP...

  9. A new algorithm for brown and black carbon identification and organic carbon detection in fine atmospheric aerosols by a multi-wavelength Aethalometer

    Directory of Open Access Journals (Sweden)

    F. Esposito

    2012-02-01

    Full Text Available A novel approach for the analysis of aerosol absorption coefficient measurements is presented. A 7-wavelenghts aethalometer has been employed to identify brown carbon (BrC and black carbon (BC and to detect organic carbon (OC in fine atmospheric aerosols (PM2.5. The Magee Aethalometer estimates the BC content in atmospheric particulate by measuring the light attenuation in the aerosols accumulated on a quartz filter, at the standard wavelength λ = 0.88 μm. The known Magee algorithm is based on the hypothesis of a mass absorption coefficient inversely proportional to the wavelength. The new algorithm has been developed and applied to the whole spectral range; it verifies the spectral absorption behavior and, thus, it distinguishes between black and brown carbon. Moreover, it allows also to correct the absorption estimation at the UV wavelength commonly used to qualitatively detect the presence of mixed hydrocarbons. The algorithm has been applied to data collected in Agri Valley, located in Southern Italy, where torched crude oil undergoes a pre-treatment process.

    The Magee Aethalometer has been set to measure Aerosol absorption coefficients τaer (λ, t every 5 min. Wavelength dependence of τaer (λ, t has been analyzed by a best-fit technique and, excluding UV-wavelengths, both the absorption Angstrom coefficient α and the BC (or BrC concentration have been determined. Finally, daily histograms of α provide information on optical properties of carbonaceous aerosol, while the extrapolation at UV-wavelengths gives information on the presence of semivolatile organic carbon (OC particles.

  10. Characterization of calcium carbonate sorbent particle in furnace environment

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Kang Soo [Aerosol and Particle Technology Laboratory, Department of Mechanical Engineering, KAIST 291 Daehak-ro, Yuseong-gu, Daejeon, 305-701 (Korea, Republic of); Jung, Jae Hee [Environment Sensor System Research Center, KIST 39-1 Hawolgok-dong, Seongbuk-gu, Seoul, 136-791 (Korea, Republic of); Keel, Sang In; Yun, Jin Han; Min, Tai Jin [Environmental Systems Research Division, KIMM 104 Sinseongno, Yuseong-gu, Daejeon, 305-343 (Korea, Republic of); Kim, Sang Soo, E-mail: sskim@kaist.ac.kr [Aerosol and Particle Technology Laboratory, Department of Mechanical Engineering, KAIST 291 Daehak-ro, Yuseong-gu, Daejeon, 305-701 (Korea, Republic of)

    2012-07-01

    The oxy-fuel combustion system is a promising technology to control CO{sub 2} and NO{sub X} emissions. Furthermore, sulfation reaction mechanism under CO{sub 2}-rich atmospheric condition in a furnace may lead to in-furnace desulfurization. In the present study, we evaluated characteristics of calcium carbonate (CaCO{sub 3}) sorbent particles under different atmospheric conditions. To examine the physical/chemical characteristics of CaCO{sub 3}, which is used as a sorbent particle for in-furnace desulfurization in the oxy-fuel combustion system, they were injected into high temperature drop tube furnace (DTF). Experiments were conducted at varying temperatures, residence times, and atmospheric conditions in a reactor. To evaluate the aerosolizing characteristics of the CaCO{sub 3} sorbent particle, changes in the size distribution and total particle concentration between the DTF inlet and outlet were measured. Structural changes (e.g., porosity, grain size, and morphology) of the calcined sorbent particles were estimated by BET/BJH, XRD, and SEM analyses. It was shown that sorbent particles rapidly calcined and sintered in the air atmosphere, whereas calcination was delayed in the CO{sub 2} atmosphere due to the higher CO{sub 2} partial pressure. Instead, the sintering effect was dominant in the CO{sub 2} atmosphere early in the reaction. Based on the SEM images, it was shown that the reactions of sorbent particles could be explained as a grain-subgrain structure model in both the air and CO{sub 2} atmospheres.

  11. Improvement of the Rotary Dryers of Wet Pelletized Oil-Furnace Carbon Blacks

    Directory of Open Access Journals (Sweden)

    Zečević, M

    2010-05-01

    Full Text Available Due to the demand for higher production capacity and natural-gas energy savings, improvements were made to the rotary dryers in the drying process of wet pelletized oil-furnace carbon blacks. Since the rotary dryers were originally designed for drying semi-wet pelletized oil-furnace carbon blacks, they did not entirely satisfy optimal conditions for drying wet pelletized oil-furnace carbon blacks. Figure 1 shows the drying principle with key dimensions. The energy for drying the wet pelletized oil-furnace carbon blacks was provided by natural gas combustion in an open-furnace system with an uncontrolled feed of combustion air. Improvements on the rotary dryers were carried out by adjusting the excess oxygen in the gases passing through the butterfly valve on the dryer exhaust stack. By regulating the butterfly valve on the dryer exhaust stack, and applying the prescribed operations for drying wet pelletized oil furnace carbon blacks, the excess oxygen in the tail gases was adjusted in the range of φ = 3.0 % and 5.0 %, depending on the type of oil-furnace carbon blacks. Suggested also is installation of a direct-reverse automatic butterfly valve on the dryer exhaust stack to automatically determine the volume fraction of oxygen in the tail gas, and the volume flow rate of natural gas for combustion. The results the improvements carried out are shown in Tables 3 to 5. Table 2 shows the thermal calculations for the hood of the rotary dryer. Preheating of the process water in the temperature range of 70 °C and 80 °C is also recommended using the net heat from the oil-furnace process for wet pelletization. The results of preheating the process water are shown in Table 1. Depending on the type of oil-furnace carbon black, the aforementioned improvements resulted in natural gas energy savings ranging from 25 % to 35 % in relation to the average natural gas requirement in the drying process, and thus a reduction in carbon emissions of up to 40

  12. Black carbon measurements in the Pearl River Delta region of China

    Science.gov (United States)

    Huang, X.; Gao, R.; Schwarz, J. P.; Ling-Yan, H.; Fahey, D. W.; Laurel A, W.; Zeng, L.

    2009-12-01

    The Pearl River Delta (PRD) region in southeastern China is one of the most polluted industrial/metropolitan areas in the world. The 3C-STAR campaign (Synthesized Prevention Techniques for Air Pollution Complex and Integrated Demonstration in Key City-Cluster Region), carried out in October-November, 2008, was aimed at improving the understanding and quantification of air pollution in the region, while developing technical capacity for regional air quality monitoring and modeling. We report single-particle soot photometer (SP2) measurements and analyses of refractory black carbon (rBC) at Kaiping, a rural site downwind of the major pollution sources in the PRD area. The rBC mass loadings varied between 0.5 and 10 µg-rBC kg-air-1, and averaged 2.8 µg-rBC kg-air-1. These values are roughly an order of magnitude higher than those measured in the Houston, Texas, a major US metropolitan area. The rBC mass distributions show a primary lognormal peak with a median mass diameter of 0.22 µm volume-equivalent diameter (VED), which is similar to those observed in Houston and other regions with the SP2 instrument. A second mode with a mass median diameter of 0.69 µm VED, has not been observed before. Coatings are found on over 50% of rBC particles, suggesting that they are aged and/or of biomass-burning origin. The high rBC loadings cause significant heating of the atmosphere due to direct solar absorption. A diurnal heating rate of over 0.5 K day-1. is estimated for the average of entire dataset with a maximum heating rate near 3 K day-1.

  13. Tunnelling Radiation of Charged and Magnetized Massive Particles from BTZ Black Holes

    Institute of Scientific and Technical Information of China (English)

    HE Tang-Mei; ZHANG Jing-Yi

    2007-01-01

    We investigate the tunnelling radiation of charged and magnetized massive particles from a Ba(n)ados-TeitelboimZanelli (BTZ) black hole by extending the Parikh-Wilczek tunnelling framework. In order to calculate the emission rate,we reconstruct the electromagnetic field tensor and the Lagrangian of the field corresponding to the source with electric and magnetic charges,and treat the charges as an equivalent electric charge for simplicity in the later calculation.The result supports Parikh-Wilczek's conclusion,that is,the Hawking thermal radiation actually deviates from perfect thermality and agrees with an underlying unitary theory.

  14. Scalar field self-force effects on a particle orbiting a Reissner-Nordstrom black hole

    CERN Document Server

    Bini, Donato; Geralico, Andrea

    2016-01-01

    Scalar field self-force effects on a scalar charge orbiting a Reissner-Nordstr\\"om black hole are investigated. The scalar wave equation is solved analytically in a post-Newtonian framework, and the solution is used to compute the self-field as well as the components of the self-force at the particle's location up to 7.5 post-Newtonian order. The energy fluxes radiated to infinity and down the hole are also evaluated. Comparison with previous numerical results in the Schwarzschild case shows a good agreement in both strong-field and weak-field regimes.

  15. Black Carbon Flux Across the Himalaya through the Kali Gandaki Valley in Nepal

    Science.gov (United States)

    Dhungel, S.; Panday, A. K.; Mahata, K. S.

    2013-12-01

    Significant increases in black carbon concentration have been observed in the recent years over the Indo-Gangetic plain, the foothills of the Himalaya, as well as the high Himalaya and the Tibetan Plateau. The concentration of increased black carbon can be significantly correlated to the albedo effect and the warming of atmosphere at high altitudes due to the deposition of black carbon in the snow clad mountains. It is hypothesized that this deposition contributes to increased melting of Himalayan glaciers and snowfields. Satellite images show increasing amounts of aerosol haze over the Indo-Gangetic plains which penetrate into the Himalayan valleys. But how does it reach the high altitude of the Himalayan cryosphere? To date, mechanisms of transport upwind of the valley from the Indo-Gangetic plains up to the Himalaya have not been thoroughly investigated. We hypothesize that wind systems in the deep river valleys that cut across the Himalaya, such as the Arun valley and Kali Gandaki valley, serve as important pathways for pollutant transport. In 2010 the University of Virginia, in collaboration with ICIMOD and Nepal Wireless, established an atmospheric research station in Jomsom, Nepal (28.78N, 83.42E, 2900 m.a.s.l.). The station is equipped to measure black carbon (BC), carbon monoxide (CO), and ozone concentrations. It also has an automated weather station, a filter sampler, and a NASA Aeronet Sunphotometer. Here we use our observations in Jomsom to present an estimate of the annual flux of black carbon from the Indo-Gangetic plains to the Tibetan Plateau through the Kali Gandaki valley. In this way, we gain insight into the significance of deep valleys and their role as pathways for pollutant transport.

  16. Preparation of calcium carbonate particles coated with titanium dioxide

    Institute of Scientific and Technical Information of China (English)

    Hai Lin; Ying-bo Dong; Le-yong Jiang

    2009-01-01

    The preparation of a new mineral composite material, calcium carbonate particles coated with titanium dioxide, was stud-ied. The mechanism of the preparation process was proposed. The new mineral composite material was made by the mechanochemi-eal method under the optimum condition that the mass ratio of calcium carbonate particles to titanium dioxide was 6.5:3.5. The mass ratios of two different types of titanium dioxide (anatase to rutile) and grinding media to grinded materials were 8:2 and 4:1 respec-tively, and the modified density was 60%. Under this condition, the new material was capable of forming after 120-min modification.The hiding power and oil absorption of this new material were 29.12 g/m~2 and 23.30%, respectively. The results show that the modi-fication is based on surface hydroxylation. After coating with titanium dioxide, the hiding power of calcium carbonate can be im-proved greatly. The new mineral composite materials can be used as the substitute for titanium dioxide.

  17. Critical review of black carbon and elemental carbon source apportionment in Europe and the United States

    Science.gov (United States)

    Briggs, Nicole L.; Long, Christopher M.

    2016-11-01

    An increasing number of air pollution source apportionment studies in Europe and the United States have focused on the black carbon (BC) fraction of ambient particulate matter (PM) given its linkage with adverse public health and climate impacts. We conducted a critical review of European and US BC source apportionment studies published since 2003. Since elemental carbon (EC) has been used as a surrogate measure of BC, we also considered source apportionment studies of EC measurements. This review extends the knowledge presented in previous ambient PM source apportionment reviews because we focus on BC and EC and critically examine the differences between source apportionment results for different methods and source categories. We identified about 50 BC and EC source apportionment studies that have been conducted in either Europe or the US since 2003, finding a striking difference in the commonly used source apportionment methods between the two regions and variations in the assigned source categories. Using three dominant methodologies (radiocarbon, aethalometer, and macro-tracer methods) that only allow for BC to be broadly apportioned into either fossil fuel combustion or biomass burning source categories, European studies generally support fossil fuel combustion as the dominant ambient BC source, but also show significant biomass burning contributions, in particular in wintertime at non-urban locations. Among US studies where prevailing methods such as chemical mass balance (CMB) and positive matrix factorization (PMF) models have allowed for estimation of more refined source contributions, there are fewer findings showing the significance of biomass burning and variable findings on the relative proportion of BC attributed to diesel versus gasoline emissions. Overall, the available BC source apportionment studies provide useful information demonstrating the significance of both fossil fuel combustion and biomass burning BC emission sources in Europe and the US

  18. Seasonal and diurnal variations of black carbon and organic carbon aerosols in Bangkok

    Science.gov (United States)

    Sahu, L. K.; Kondo, Y.; Miyazaki, Y.; Pongkiatkul, Prapat; Kim Oanh, N. T.

    2011-08-01

    Measurements of black carbon (BC) and organic carbon (OC) were conducted in Bangkok during 2007-2008. Annual trends of BC and OC show strong seasonality with lower and higher concentrations during wet and dry seasons, respectively. Flow of cleaner air, wet removal, and negligible biomass burning resulted in the lowest concentrations of aerosols in the wet season. In addition to anthropogenic sources, long-range transport and biomass burning caused higher concentrations in the dry and hot seasons, respectively. Despite extensive biomass burning in the hot season, moderate levels of aerosols were due to the mixing with air masses from the Pacific Ocean. Diurnal distributions exhibit peaks during rush hour marked by minima in the OC/BC ratio and stagnant wind flow. The lowest concentrations in the afternoon hours could be due to deeper planetary boundary layer and reduced traffic. Overall, the concentrations of both BC and OC decrease with the increase in wind speed. The weekend effects, due to reduced emission during weekends, in the concentrations of both BC and OC were significant. Therefore, stricter abatement in vehicular emissions could substantially reduce pollution. A slope of ΔBC/ΔCO of 9.8 ngm-3 ppbv-1 for the wet season represents the emission ratio from vehicular sources. The highest of ΔOC/ΔBC (3 μg μg-1) in the hot season was due to the predominant influence of biomass burning and significant formation of secondary OC. The levels of BC and OC in Bangkok fall within the ranges of their concentrations measured in the major cities of East Asia.

  19. Black carbon and carbon monoxide over Bay of Bengal during W_ICARB: Source characteristics

    Science.gov (United States)

    Girach, I. A.; Nair, Vijayakumar S.; Babu, S. Suresh; Nair, Prabha R.

    2014-09-01

    The ship borne measurements of near-surface black carbon (BC) and carbon monoxide (CO) were carried out over Bay of Bengal (BoB) during the winter period of 2009 under W_ICARB, the second phase of ‘Integrated Campaign for Aerosols, gases and Radiation Budget (ICARB)'. The CO mixing ratio and BC mass concentration varied in the ranges of 80-480 ppbv and 75-10,000 ng m-3, respectively over this marine region. The BC and CO showed similar variations over northern BoB where airmass from Indo-Gangetic Plain (IGP) region prevailed during the observations period leading to a very strong positive correlation. The association of BC and CO was poor over the eastern and southern part of BoB could be due to the removal of BC aerosols by rain and/or processes of dilution and mixing while transported over to BoB. The highest value of CO observed over eastern BoB was partially due to biomass burning over East Asia. The BC/CO ratio for IGP airmass found to be 20.3 ng m-3 ppb-1 and ∼16 ng m-3 ppb-1 during winter and pre-monsoon, respectively which indicate the role of biomass burning as the source of BC over the region. Based on the emission flux of CO from various inventories and observed BC/CO ratios during pre-monsoon and winter, the BC emission for India is estimated to be in the range of 0.78-1.23 Tg year-1. The analysis of scavenging of BC revealed the loss rate of BC due to relative humidity 0.39 ± 0.08 ng m-3 ppb-1 RH (%)-1 over northern BoB and 0.53 ± 0.04 ng m-3 ppb-1 RH (%)-1 over the southern-BoB during winter.

  20. Enhanced Activated Carbon Cathode Performance for Microbial Fuel Cell by Blending Carbon Black

    KAUST Repository

    Zhang, Xiaoyuan

    2014-02-04

    Activated carbon (AC) is a useful and environmentally sustainable catalyst for oxygen reduction in air-cathode microbial fuel cells (MFCs), but there is great interest in improving its performance and longevity. To enhance the performance of AC cathodes, carbon black (CB) was added into AC at CB:AC ratios of 0, 2, 5, 10, and 15 wt % to increase electrical conductivity and facilitate electron transfer. AC cathodes were then evaluated in both MFCs and electrochemical cells and compared to reactors with cathodes made with Pt. Maximum power densities of MFCs were increased by 9-16% with CB compared to the plain AC in the first week. The optimal CB:AC ratio was 10% based on both MFC polarization tests and three electrode electrochemical tests. The maximum power density of the 10% CB cathode was initially 1560 ± 40 mW/m2 and decreased by only 7% after 5 months of operation compared to a 61% decrease for the control (Pt catalyst, 570 ± 30 mW/m2 after 5 months). The catalytic activities of Pt and AC (plain or with 10% CB) were further examined in rotating disk electrode (RDE) tests that minimized mass transfer limitations. The RDE tests showed that the limiting current of the AC with 10% CB was improved by up to 21% primarily due to a decrease in charge transfer resistance (25%). These results show that blending CB in AC is a simple and effective strategy to enhance AC cathode performance in MFCs and that further improvement in performance could be obtained by reducing mass transfer limitations. © 2014 American Chemical Society.

  1. Collisions of massive particles, timelike thin shells and formation of black holes in three dimensions

    Science.gov (United States)

    Lindgren, Jonathan

    2016-12-01

    We study collisions of massive pointlike particles in three dimensional anti-de Sitter space, generalizing the work on massless particles in [1]. We show how to construct exact solutions corresponding to the formation of either a black hole or a conical singularity from the collision of an arbitrary number of massive particles that fall in radially and collide at the origin of AdS. No restrictions on the masses or the angular and radial positions from where the particles are released, are imposed. We also consider the limit of an infinite number of particles, obtaining novel timelike thin shell spacetimes. These thin shells have an arbitrary mass distribution as well as a non-trivial embedding where the radial location of the shell depends on the angular coordinate, and we analyze these shells using the junction formalism of general relativity. We also consider the massless limit and find consistency with earlier results, as well as comment on the stress-energy tensor modes of the dual CFT.

  2. Collisions of massive particles, timelike thin shells and formation of black holes in three dimensions

    CERN Document Server

    Lindgren, Jonathan

    2016-01-01

    We study collisions of massive pointlike particles in three dimensional anti-de Sitter space, generalizing the work on massless particles in [1]. We show how to construct exact solutions corresponding to the formation of either a black hole or a conical singularity from the collision of an arbitrary number of massive particles that fall in radially and collide at the origin of AdS. No restrictions on the masses or the angular and radial positions from where the particles are released, are imposed. We also consider the limit of an infinite number of particles, obtaining novel timelike thin shell spacetimes. These thin shells have an arbitrary