WorldWideScience

Sample records for carbon black comparison

  1. Reinforcement of Multiwalled Carbon Nanotube in Nitrile Rubber: In Comparison with Carbon Black, Conductive Carbon Black, and Precipitated Silica

    OpenAIRE

    Atip Boonbumrung; Pongdhorn Sae-oui; Chakrit Sirisinha

    2016-01-01

    The properties of nitrile rubber (NBR) reinforced by multiwalled carbon nanotube (MWCNT), conductive carbon black (CCB), carbon black (CB), and precipitated silica (PSi) were investigated via viscoelastic behavior, bound rubber content, electrical properties, cross-link density, and mechanical properties. The filler content was varied from 0 to 15 phr. MWCNT shows the greatest magnitude of reinforcement considered in terms of tensile strength, modulus, hardness, and abrasion resistance follow...

  2. Reinforcement of Multiwalled Carbon Nanotube in Nitrile Rubber: In Comparison with Carbon Black, Conductive Carbon Black, and Precipitated Silica

    Directory of Open Access Journals (Sweden)

    Atip Boonbumrung

    2016-01-01

    Full Text Available The properties of nitrile rubber (NBR reinforced by multiwalled carbon nanotube (MWCNT, conductive carbon black (CCB, carbon black (CB, and precipitated silica (PSi were investigated via viscoelastic behavior, bound rubber content, electrical properties, cross-link density, and mechanical properties. The filler content was varied from 0 to 15 phr. MWCNT shows the greatest magnitude of reinforcement considered in terms of tensile strength, modulus, hardness, and abrasion resistance followed by CCB, CB, and PSi. The MWCNT filled system also exhibits extremely high levels of filler network and trapped rubber even at relatively low loading (5 phr leading to high electrical properties and poor dynamic mechanical properties. Although CCB possesses the highest specific surface area, it gives lower level of filler network than MWCNT and also gives the highest elongation at break among all fillers. Both CB and PSi show comparable degree of reinforcement which is considerably lower than CCB and MWCNT.

  3. Black carbon in marine sediments

    NARCIS (Netherlands)

    Middelburg, J.J.; Nieuwenhuize, J.; Van Breugel, P.

    1999-01-01

    Concentrations of black carbon were determined for a number of marine sediments. A comparison of black carbon based on thermal oxidation and hot concentrated nitric acid pretreatments revealed that the latter significantly overestimates combustion derived carbon phases. Black carbon accounts for abo

  4. Comparison of manufactured and black carbon nanoparticle concentrations in aquatic sediments

    NARCIS (Netherlands)

    Koelmans, A.A.; Nowack, B.; Wiesner, M.

    2009-01-01

    In this paper, we show that concentrations of manufactured carbon-based nanoparticles (MCNPs) in aquatic sediments will be negligible compared to levels of black carbon nanoparticles (BCNPs). This is concluded from model calculations accounting for MCNP sedimentation fluxes, removal rates due to agg

  5. Carbon black recovery

    International Nuclear Information System (INIS)

    A process and apparatus for recovering carbon black from hot smoke which comprises passing the smoke through a cyclone separation zone following cooling, then through aggregate filter beds and regeneration of filter beds with clean off-gas which is recycled to the carbon black reaction zone as quench

  6. Comparison of structural health assessment capabilities in epoxy – carbon black and epoxy – carbon nanotube nanocomposites

    OpenAIRE

    F. Inam; B. R. Bhat; N. Luhyna; Vo, T.

    2014-01-01

    A novel method for comparing structural health of different types of brittle epoxy nanocomposites filled with carbon nanostructured fillers is presented. Epoxy – 0.2 vol% carbon black (CB) and epoxy – 0.2 vol% carbon nanotube (CNT) nanocomposite bars were prepared by calendering and thermal curing. Nanocomposite bars were subjected to Vickers diamond indentation to produce sub-surface damage. Electrical conductivities were analysed by 4-point method to estimate the structural damage caused by...

  7. Pyrolytic carbon coated black silicon

    OpenAIRE

    Shah, Ali; Stenberg, Petri; Karvonen, Lasse; Ali, Rizwan; Honkanen, Seppo; Lipsanen, Harri; Peyghambarian, N.; Kuittinen, Markku; Svirko, Yuri; Kaplas, Tommi

    2016-01-01

    Carbon is the most well-known black material in the history of man. Throughout the centuries, carbon has been used as a black material for paintings, camouflage, and optics. Although, the techniques to make other black surfaces have evolved and become more sophisticated with time, carbon still remains one of the best black materials. Another well-known black surface is black silicon, reflecting less than 0.5% of incident light in visible spectral range but becomes a highly reflecting surface ...

  8. Scattering directionality parameters of fractal black carbon aerosols and comparison with the Henyey-Greenstein approximation.

    Science.gov (United States)

    Pandey, Apoorva; Chakrabarty, Rajan K

    2016-07-15

    Current radiation transfer schemes employ the Henyey-Greenstein (HG) phase function to connect three single parameter representations of aerosol scattering directionality-the hemispherical upscatter fraction (β), the backscatter fraction (b), and the asymmetry parameter (g). The HG phase function does not account for particle morphology, which could lead to significant errors. In this Letter, we compute these single parameters for fractal black carbon (BC) aerosols using the numerically exact superposition T-matrix method. The variations in β, g, and b as a function of aerosol morphology are examined. Corrected empirical relationships connecting these parameters are proposed. We find that the HG phase function could introduce up to a 35% error in β and g estimates. Interestingly, these errors are suppressed by the large mass absorption cross-sections of BC aerosols in radiative transfer calculations and contribute to ≤8% error in direct forcing efficiencies. PMID:27420533

  9. Comparison of Toxicity and Deposition of Nano-Sized Carbon Black Aerosol Prepared With or Without Dispersing Sonication

    Science.gov (United States)

    Kang, Mingu; Han, Jeong-Hee

    2013-01-01

    Nanotoxicological research has shown toxicity of nanomaterials to be inversely related to particle size. However, the contribution of agglomeration to the toxicity of nanomaterials has not been sufficiently studied, although it is known that agglomeration is associated with increased nanomaterial size. In this study, we prepared aerosols of nano-sized carbon black by 2 different ways to verify the effects of agglomeration on the toxicity and deposition of nano-sized carbon black. The 2 methods of preparation included the carbon black dispersion method that facilitated clustering without sonication and the carbon black dispersion method involving sonication to achieve scattering and deagglomeration. Male Sprague-Dawley rats were exposed to carbon black aerosols 6 hr a day for 3 days or for 2 weeks. The median mass aerodynamic diameter of carbon black aerosols averaged 2.08 μm (for aerosol prepared without sonication; group N) and 1.79 μm (for aerosol prepared without sonication; group S). The average concentration of carbon black during the exposure period for group N and group S was 13.08 ± 3.18 mg/m3 and 13.67 ± 3.54 mg/ m3, respectively, in the 3-day experiment. The average concentration during the 2-week experiment was 9.83 ± 3.42 mg/m3 and 9.08 ± 4.49 mg/m3 for group N and group S, respectively. The amount of carbon black deposition in the lungs was significantly higher in group S than in group N in both 3-day and 2-week experiments. The number of total cells, macrophages and polymorphonuclear leukocytes in the bronchoalveolar lavage (BAL) fluid, and the number of total white blood cells and neutrophils in the blood in the 2- week experiment were significantly higher in group S than in normal control. However, differences were not found in the inflammatory cytokine levels (IL-1β, TNF-α, IL-6, etc.) and protein indicators of cell damage (albumin and lactate dehydrogenase) in the BAL fluid of both group N and group S as compared to the normal control. In

  10. Comparison Between Elemental Carbon Measured Using Thermal-Optical Analysis and Black Carbon Measurements Using A Novel Cellphone-Based System

    Science.gov (United States)

    Ramanathan, N.; Khan, B.; Leong, I.; Lukac, M.

    2011-12-01

    Black carbon (BC) is produced through the incomplete combustion of fossil and solid fuels. Current BC emissions inventories have large uncertainties of factors of 2 or more due to sparse measurements and because BC is often emitted by local sources that vary over time and space (Bond et al, 2004). Those uncertainties are major sources of error in air pollution models. Emissions from a variety of improved cookstove/fuel/combustion conditions were collected on pre-conditioned 47 mm quartz-fiber filters and analyzed for organic carbon (OC) and elemental carbon (EC) using thermal-optical analysis (TOA). The samples were then analyzed for BC concentration by using cellphone-based instrumentation developed by Ramanathan et al., 2011. The cellphone-based monitoring system (CBMS) is a wireless, low-cost, low-power system that monitors BC emissions. The CBMS is comprised of an aerosol filter sampler containing a battery-powered air pump and a 25mm filter holder that draws air in through a quartz-fiber filter. As black carbon deposits increase, the filter darkens--the darkest color representing the highest loading. A cellphone photograph of the filter with the black carbon deposit is taken and relayed to an analytics unit for comparison to a reference scale to estimate airborne BC concentration. The BC concentration can then be compared to the thermally derived EC concentration. TOA was conducted on a Sunset Laboratory Dual Optics Carbon Analyzer using a modified version of the Birch and Cary (1996) NIOSH 5040 protocol. The dual-optical instrument permitted simultaneous monitoring of the transmission (TOT) and reflectance (TOR). 619 samples were collected; EC was obtained using NIOSH TOT and NIOSH TOR methods, and BC was obtained using the CBMS analytics unit. The mean BC value reported by the CBMS agrees within 20% of the reference values for EC, confirming the findings in Ramanathan et al. (2011) based on samples from India. Given this accuracy, we conclude that the CBMS

  11. Pyrolytic carbon coated black silicon.

    Science.gov (United States)

    Shah, Ali; Stenberg, Petri; Karvonen, Lasse; Ali, Rizwan; Honkanen, Seppo; Lipsanen, Harri; Peyghambarian, N; Kuittinen, Markku; Svirko, Yuri; Kaplas, Tommi

    2016-01-01

    Carbon is the most well-known black material in the history of man. Throughout the centuries, carbon has been used as a black material for paintings, camouflage, and optics. Although, the techniques to make other black surfaces have evolved and become more sophisticated with time, carbon still remains one of the best black materials. Another well-known black surface is black silicon, reflecting less than 0.5% of incident light in visible spectral range but becomes a highly reflecting surface in wavelengths above 1000 nm. On the other hand, carbon absorbs at those and longer wavelengths. Thus, it is possible to combine black silicon with carbon to create an artificial material with very low reflectivity over a wide spectral range. Here we report our results on coating conformally black silicon substrate with amorphous pyrolytic carbon. We present a superior black surface with reflectance of light less than 0.5% in the spectral range of 350 nm to 2000 nm. PMID:27174890

  12. Carbon black vs. black carbon and other airborne materials containing elemental carbon: Physical and chemical distinctions

    International Nuclear Information System (INIS)

    Airborne particles containing elemental carbon (EC) are currently at the forefront of scientific and regulatory scrutiny, including black carbon, carbon black, and engineered carbon-based nanomaterials, e.g., carbon nanotubes, fullerenes, and graphene. Scientists and regulators sometimes group these EC-containing particles together, for example, interchangeably using the terms carbon black and black carbon despite one being a manufactured product with well-controlled properties and the other being an undesired, incomplete-combustion byproduct with diverse properties. In this critical review, we synthesize information on the contrasting properties of EC-containing particles in order to highlight significant differences that can affect hazard potential. We demonstrate why carbon black should not be considered a model particle representative of either combustion soots or engineered carbon-based nanomaterials. Overall, scientific studies need to distinguish these highly different EC-containing particles with care and precision so as to forestall unwarranted extrapolation of properties, hazard potential, and study conclusions from one material to another. -- Highlights: •Major classes of elemental carbon-containing particles have distinct properties. •Despite similar names, carbon black should not be confused with black carbon. •Carbon black is distinguished by a high EC content and well-controlled properties. •Black carbon particles are characterized by their heterogenous properties. •Carbon black is not a model particle representative of engineered nanomaterials. -- This review demonstrates the significant physical and chemical distinctions between elemental carbon-containing particles e.g., carbon black, black carbon, and engineered nanomaterials

  13. Novel Conductive Carbon Black and Polydimethlysiloxane ECG Electrode: A Comparison with Commercial Electrodes in Fresh, Chlorinated, and Salt Water.

    Science.gov (United States)

    Noh, Yeonsik; Bales, Justin R; Reyes, Bersain A; Molignano, Jennifer; Clement, Amanda L; Pins, George D; Florian, John P; Chon, Ki H

    2016-08-01

    In this study, we evaluated the performance of two novel conductive carbon black (CB) and polydimethlysiloxane (PDMS) bio-potential electrodes, with and without an integrated flexible copper mesh, against commercially available electrodes (Polar(®) textile, Silver-coated textile, and carbon rubber). The electrodes were tested in three types of water (fresh/unfiltered, chlorinated, and salt water). Our testing revealed that our CB/PDMS electrode with integrated copper mesh provided a high-fidelity ECG signal morphologies without any amplitude degradation in all of the types of water tested (N = 10). The non-meshed CB/PDMS electrodes were also subjected to a long-term durability test by the US Navy SCUBA divers during which the electrodes maintained ECG signal quality for a 6 h period of continuous use. The results of a material degradation analysis revealed the CB/PDMS composite material does not exhibit significant changes in physical integrity after prolonged exposure to the test conditions. The newly developed meshed CB/PDMS electrodes have the potential to be used in a wide variety of both dry and wet environments including the challenge of obtaining ECG signals in salt water environments. PMID:26769718

  14. Surface area of particle administered versus mass in determining the pulmonary toxicity of ultrafine and fine carbon black: comparison to ultrafine titanium dioxide

    Directory of Open Access Journals (Sweden)

    Sager Tina M

    2009-05-01

    Full Text Available Abstract Background Nanoparticles are characterized by having a high surface area per mass. Particulate surface area has been reported to play an important role in determining the biological activity of nanoparticles. However, recent reports have questioned this relationship. This study was conducted to determine whether mass of particles or surface area of particles is the more appropriate dose metric for pulmonary toxicity studies. In this study, rats were exposed by intratracheal instillation to various doses of ultrafine and fine carbon black. At 1, 7, or 42 days post-exposure, inflammatory and cytotoxic potential of each particle type was compared on both a mass dosage (mg/rat as well as an equal surface area dosage (cm2 of particles per cm2 of alveolar epithelium. In an additional study, the pulmonary responses to instillation of ultrafine carbon black were compared to equivalent particle surface area doses of ultrafine titanium dioxide. Results Ultrafine carbon black particles caused a dose dependent but transient inflammatory and cytotoxic response. On a mass basis, these responses were significantly (65 fold greater than those for fine sized carbon black. However, when doses were equalized based on surface area of particles given, the ultrafine carbon black particles were only slightly (non-significantly more inflammogenic and cytotoxic compared to the fine sized carbon black. At one day post-exposure, inflammatory potencies of the ultrafine carbon black and ultrafine titanium dioxide particles were similar. However, while the pulmonary reaction to ultrafine carbon black resolved with time, the inflammatory effects of ultrafine titanium dioxide were more persistent over a 42 day post-exposure period. Conclusion These results indicate that for low toxicity low solubility materials, surface area of particles administered rather than mass burden of particles may be a more appropriate dose metric for pulmonary toxicity studies. In addition

  15. Atmospheric black carbon in the Russian Arctic: anthropogenic inputs in comparison with average or extremal wood fires' ones

    Science.gov (United States)

    Vinogradova, Anna A.; Smirnov, Nikolay S.; Korotkov, Vladimir N.

    2016-04-01

    Model estimates of atmospheric black carbon concentrations were made for different points of the Russian Arctic. Anthropogenic BC emissions and wood fires' ones were calculated from Russian official statistics for the 2000s. We used the data of Ministry of Natural Resources and Environment of RF on anthropogenic air emissions of pollution in Russian cities and regions [1], as well as the data of Federal Forestry Agency of RF (Rosleshoz) [2] on wood fires. We considered the area within (50-72)N and (20-180)E, which covers about 94% of the Russian territory, where both anthropogenic and fire BC emissions have been arranged through grid cells (1×1) deg. Anthropogenic BC emissions are estimated as annual values based on the data for 54 regions and more than 100 cities. Total emission is estimated as (220 ± 30) Gg BC in 2010 [3], including emissions from open flares associated with gas/oil extractive industry which are about (25 ± 8) Gg/yr. We analyzed the data on wood fires (detailing crown, ground and underground fires in forests and fires on non-forest lands) with their spatial and seasonal variations during 15 years (2000-2014). Different combustion factors [4] and BC emission coefficients [5] were used in calculations for different types of burning. Russian total average annual BC emission from fires, occurring mainly in summertime, was estimated as 30 Gg with large variations (4-100 Gg/yr) from year to year. Asian territory emits about 90% of this value. We estimated anthropogenic (BC_A) and fires' (BC_F) contributions to BC air concentrations at different Russian Arctic points using the approach [6] - decadal back-trajectory analysis combined with spatial distribution of sensitivity pollution emission function (SPEF). Extraordinary atmospheric circulation causing, to a great extent, abnormally intensive fires in the middle latitudes often leads to a decrease in SPEF values for these territories. As a result, fires are not so dangerous for the whole Arctic, as

  16. 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.

  17. Microwave effective permittivity of carbon black filled polymers: Comparison of mixing law and effective medium equation predictions

    Science.gov (United States)

    El Bouazzaoui, S.; Achour, M. E.; Brosseau, C.

    2011-10-01

    Carbon black (CB) filled polymers have become the platform to study a number of interesting properties including percolation mechanisms, localization effects, and multiscale modeling of interface and interphase regions surrounding filler particles. A systematic microwave study of the effective complex permittivity of CB filled diglycidylic ether of bisphenol A based epoxy samples, determined by the impedance bridge (35 GHz) and the cavity perturbation (2.4 and 9.5 GHz) techniques, is reported. A series of composite materials was fabricated by mechanical mixing with three types of CB (Monarch and Sterling) particles differing with their average particle size and surface area. On the basis of the limited experimental evidence presented here, our distinctive features are seen in the data: (i) We found no enhancement of the effective permittivity near the dc percolation threshold; (ii) the calculation of the effective permittivity based on Lichteneker and Rother's mixing law with constant k close to zero reproduces the measured CB volume fraction dependence of the effective permittivity very well for the series of samples containing Monarch particles, (iii) the data are not well fit with the Bruggeman equation for supercolative samples. This is an indication that a mean field model is not strictly applicable because this simple model assumes a given microstructure for the composite material; and (iv) the two exponent phenomenological percolation equation (TEPPE) can yield good predictive values of the imaginary part of the effective complex permittivity over the range of frequencies and CB volume fractions with non-universal values of the percolation exponents. It is concluded that fitting the experimental data with mixing law and effective medium equation predictions has limited applicability because these models assume a given microstructure for the composite material.

  18. Dissolved black carbon in Antarctic lakes: Chemical signatures of past and present sources

    Science.gov (United States)

    Khan, Alia L.; Jaffé, Rudolf; Ding, Yan; McKnight, Diane M.

    2016-06-01

    The perennially ice-covered, closed-basin lakes in the McMurdo Dry Valleys, Antarctica, serve as sentinels for understanding the fate of dissolved black carbon from glacial sources in aquatic ecosystems. Here we show that dissolved black carbon can persist in freshwater and saline surface waters for thousands of years, while preserving the chemical signature of the original source materials. The ancient brines of the lake bottom waters have retained dissolved black carbon with a woody chemical signature, representing long-range transport of black carbon from wildfires. In contrast, the surface waters are enriched in contemporary black carbon from fossil fuel combustion. Comparison of samples collected 25 years apart from the same lake suggests that the enrichment in anthropogenic black carbon is recent. Differences in the chemical composition of dissolved black carbon among the lakes are likely due to biogeochemical processing such as photochemical degradation and sorption on metal oxides.

  19. Immersion microcalorimetry of a carbon black

    International Nuclear Information System (INIS)

    This research thesis first reports a detailed bibliographical study on various topics (fabrication of carbon black, oxidation, immersion heat, adsorptions, main existing theories, and thermodynamics) and then the development of immersion and adsorption microcalorimetry apparatuses aimed at studying the surface of a carbon black and the influence of the oxidation of this carbon black on the adsorption of polar and non-polar solvents. Immersion heats of a raw or oxidised carbon black have been measured in water, in cyclohexane and in methanol. The adsorption of methanol at 20 C and that of nitrogen at -196 C have also been measured. The author outlines that degassing conditions had to be taken into account before performing measurements

  20. Graft-copolymerization onto carbon black

    International Nuclear Information System (INIS)

    Radiation-induced graft copolymerization of vinyl monomer onto carbon black was performed. During the γ-ray- and electron beam-induced polymerization (In-source), or the electron beam post-polymerization, the graft-copolymerization behavior was affected by the kinds of both carbon blacks and monomers, i.e. the smaller the size of carbon black particles, the higher the apparent grafted fraction. Homopolymer in the grafted carbon black samples was washed out by the solvent of the polymer, and the extracted polymer seemed to be dimer or trimer of the used monomer. In the case of the post-polymerization with the pre-irradiation doses of 50 Mrad, homopolymer was hardly observed. The polymer sheets of plastics or rubbers with grafted carbon black had an electrical conductivity unalterable considerably by the heating cycles. The particles of grafted carbon black in the sheet might be kept much more at the surface layer within 100 nm depth than at the inner layer. (author)

  1. Influence of public transport in black carbon

    Science.gov (United States)

    Vasquez, Y.; Oyola, P.; Gramsch, E. V.; Moreno, F.; Rubio, M.

    2013-05-01

    As a consequence of poor air quality in Santiago de Chile, several measures were taken by the local authorities to improve the environmental conditions and protect the public health. In year 2005 the Chilean government implemented a project called "Transantiago" aimed to introduce major modifications in the public transportation system. The primary objectives of this project were to: provide an economically, socially and environmentally sustainable service and improve the quality of service without increasing fares. In this work we evaluate the impact of the Transantiago system on the black carbon pollution along four roads directly affected by the modification to the transport system. The black carbon has been used to evaluate changes in air quality due to changes in traffic. The assessment was done using measurements of black carbon before Transantiago (June-July 2005) and after its implementation (June-July 2007). Four sites were selected to monitor black carbon at street levels, one site (Alameda) that represents trunk-bus streets, i.e., buses crossing the city through main avenues. Buses using these streets had an important technological update with respect to 2005. Two streets (Usach and Departamental) show a mixed condition, i.e., they combine feeder and trunk buses. These streets combine new EURO III buses with old buses with more than 3 years of service. The last street (Eliodoro Yañez) represent private cars road without public transportation and did not experience change. Hence, the results from the years 2005 and 2007 can be directly compared using an appropriate methodology. To ensure that it was not the meteorological conditions that drive the trends, the comparison between year 2005 and 2007 was done using Wilcoxon test and a regression model. A first assessment at the four sites suggested a non decrease in black carbon concentration from 2005 to 2007, except for Alameda. A first statistical approach confirmed small increases in BC in Usach and E

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

    OpenAIRE

    Meri Ruppel; Lund, Marianne T.; Henrik Grythe; Rose, Neil L.; Jan Weckström; Atte Korhola

    2013-01-01

    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 evaluat...

  3. Black carbon, a short lived climate forcer

    International Nuclear Information System (INIS)

    Black carbon, an indicator of urban pollution health effects, is at the heart of adaptation issues as benefits of its control can be felt both at the scale of climate phenomenon and air quality. This element has to do with several notions whose definitions need to be stated again. It sets urban policies at the crossing of climate, air pollution, population health and sustainable development stakes. The CITEPA has made available Mark Tuddenham's literature monitoring concerning black carbon, and, more widely, SLFC (Short lived climate forcers). (authors)

  4. Comparisons of Black Hole Entropy

    CERN Document Server

    Kupferman, Judy

    2016-01-01

    In this thesis I examine several different concepts of black hole entropy in order to understand whether they describe the same quantity. I look at statistical and entanglement entropies, Wald entropy and Carlip's entropy from conformal field theory, and compare their behavior in a few specific aspects: divergence at the BH horizon, dependence on space time curvature and behavior under a geometric variation. I find that statistical and entanglement entropy may be similar but they seem to differ from the entropy of Wald and Carlip. Chapters 2 and 3 overlap with 1010.4157 and 1310.3938. Chapter 4 does not appear elsewhere.

  5. 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.

  6. Black carbon in deep-sea sediments

    OpenAIRE

    Masiello, CA; Druffel, ERM

    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 ...

  7. Modified carbon black materials for lithium-ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    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.

  8. Comparison of measurement of aerosol black carbon at Barrow, Alaska, and Wrangel Island, USSR: An approach to estimating the deposition of soot to snow and ice surfaces

    International Nuclear Information System (INIS)

    During late spring 1989 (and 1990, in planning), measurements of aerosol black carbon were, made on Wrangel Island in the Soviet Arctic to complement the routine measurements at the NOAA/GMCC Barrow Observatory of this combustion-derived pollutant. The results are compared during time intervals in which trajectories led from Barrow to Wrangel Island, with typical transit times of one day. The intervening surface is entirely frozen ocean, without land masses' topography to complicate air flow, nor any human habitation combustion sources. Aerosol black carbon is chemically unreactive, and so any losses in transit will be due to deposition onto the frozen ocean surface. This species is strongly optically absorbing, and a small aerosol deposition from the Arctic haze may reduce the surface albedo sufficiently to increase the absorption of solar radiation in spring and lead to premature, thawing. The authors discuss the possible effects of the deposition of soot from the Arctic haze onto high latitude snow and ice cover in terms of climate change

  9. 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...

  10. 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.

  11. Cycling of black carbon in the ocean

    OpenAIRE

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

    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 ...

  12. Black carbon characterization in Quebec black spruce forests

    Science.gov (United States)

    Soucemarianadin, Laure; Quideau, Sylvie; Wasylishen, Roderick; MacKenzie, M. Derek

    2014-05-01

    Black carbon (BC), an important component of the global soil carbon pool, is a major by-product of wildfires in Quebec black spruce forests. However, BC characteristics vary depending on the environmental conditions under which it is formed and this may further affect its resistance to degradation. The objective of this study was to characterize the chemical and physical properties of BC formed under variable fire severity to assess its potential for recalcitrance as a passive carbon pool. Samples (n = 267) of BC produced by early season wildfires in 2005-2007 were collected from the surface of black spruce forest floors to cover the range of severity encountered in these fire-affected forests. Representative samples (n = 33) were then analyzed using elemental analysis, solid-state 13C nuclear magnetic resonance (NMR) spectroscopy, scanning electron microscopy and surface area analysis (BET method). Properties of BC sampled in the field were compared with those of samples produced under a range of controlled formation conditions in the laboratory. The NMR spectra of the BC collected on sites affected by low fire severity showed a distribution of total intensity between the different spectral regions very similar to those of unburned fuels, and were dominated by peaks indicative of cellulose, while spectra for BC from higher fire severity sites were dominated by a broad peak assigned to aromatic carbons. Atomic H/C and O/C ratios decreased along the fire severity gradient, confirming that increasing severity was associated with an increase in condensation. By comparing field- to laboratory-produced samples, we concluded that the temperature of formation in the field ranged between 75 and 250 ° C. In all analyzed BC samples, the fraction of aromatic carbon:total carbon was low, suggesting that the freshly produced BC in this boreal forest environment may be susceptible to rapid physical alteration and chemical degradation. Nevertheless, it is important to highlight

  13. Comparative analysis of black carbon in soils

    OpenAIRE

    Schmidt, Michael W I; Skjemstad, Jan O.; Czimczik, Claudia I.; Glaser, Bruno; Prentice, Ken M; Gelinas, Yves; Thomas A.J. Kuhlbusch

    2001-01-01

    Black carbon (BC), produced by incomplete combustion of fossil fuels and vegetation, occurs ubiquitously in soils and sediments. BC exists as a continuum from partly charred material to highly graphitized soot particles, with no general agreement on clear-cut boundaries of definition or analysis. In a comparative analysis, we measured BC forms in eight soil samples by six established methods. All methods involved removal of the non-BC components from the sample by thermal or chemical means or...

  14. Kinetics and mechanism of nitric oxidation of carbon black

    International Nuclear Information System (INIS)

    After some generalities about carbon blacks (preparation by various processes, structure, industrial use), the author notices that carbon black is often dispersed in aqueous solutions and, as it is hydrophobic, must therefore be submitted to treatment to become hydrophilic. Oxidation in liquid phase suits perfectly, and oxidation by nitric acid gives good results. Thus, this research thesis reports the study of the oxidation reaction mechanism in the case of oxidation of carbon black by nitric acid in aqueous solution. After having defined the different types of carbon blacks used in this study, and given an overview of the oxidation process (methods, purification and purity control of the obtained blacks, determination of the efficiency in terms of oxidised or purified black, difficulties faced during the elemental analysis of oxidised blacks), the author discusses the mechanism of formation of carbon dioxide during the oxidation of Philblack 0 carbon black by nitric acid. He reports the study of the oxidation kinetics, and the study of a thermal treatment of oxidised carbon blacks. The last part reports the study of the evolution of various properties of carbon blacks during oxidation: specific surface (BET method), density, examination by electronic microscopy and X-rays, magnetic susceptibility

  15. Reinforcing Effects of Carbon Black on Asphalt Binder for Pavement

    OpenAIRE

    Yamaguchi, Katsuyuki; Sasaki, Iwao; Nishizaki, Itaru; Meiarashi, Seishi; Moriyoshi, Akihiro

    2005-01-01

    Carbon black, used as a reinforcing filler for rubber materials, was evaluated for asphalt binders in pavements. Carbon black added to straight asphalt within 20 wt% caused an increase in the elastic modulus and a decrease in the viscosity of the asphalt, especially at temperatures higher than room temperature. Addition of carbon black raised the maximum service temperature of asphalt in the category of the binder performance grade according to the SHRP (Strategic Highway Research Program) sp...

  16. 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.

  17. Respiratory health effects of carbon black: a survey of European carbon black workers.

    OpenAIRE

    Gardiner, K; Trethowan, N W; Harrington, J M; Rossiter, C E; Calvert, I A

    1993-01-01

    A study population of 3086 employees was identified in 18 carbon black production plants in seven European countries. Respiratory health questionnaires, spirometry, and chest radiographs were used to estimate effects on health and personal monitoring procedures were employed to measure current exposure to inspirable and respirable dust along with sulphur and carbon monoxide. The low concentrations of gaseous contaminants made the generation of their current and cumulative exposure indices imp...

  18. Qualitative determination of carbon black in food products.

    Science.gov (United States)

    Miranda-Bermudez, E; Belai, N; Harp, B Petigara; Yakes, B J; Barrows, J N

    2012-01-01

    Carbon black (C.I. 77266) is an insoluble pigment produced by the partial combustion of hydrocarbons. The pigment is known by several synonyms, including vegetable carbon, lamp black and carbon ash, that correspond to the raw materials and methods used for its production. Vegetable carbon (E153) is permitted for use in colouring food in the European Union. The US Food and Drug Administration (USFDA) has not approved the use of any type of carbon black for colouring food, although the agency batch certifies the pigment as D&C Black No. 2 for use in colouring certain cosmetics. Since carbon black (as vegetable carbon) may be present in food products offered for import into the United States, the USFDA's district laboratories need a qualitative analytical method for determining its presence. We have developed an extraction method for this purpose. A sample is broken down and dissolved with nitric acid. The resulting solution is filtered and treated with hydrochloric acid to dissolve any black iron oxide also present as a colour additive. A black residue remaining on the filter paper indicates the presence of carbon black in the food. We confirmed the presence of carbon black in residues from several standards and food products using Raman spectroscopy. The limit of detection for this method is 0.0001%. PMID:22035229

  19. 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...... 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....

  20. Longitudinal variability of black carbon vertical profiles

    Science.gov (United States)

    Schwarz, J. P.; Weinzierl, B.; Samset, B. H.; Perring, A. E.; Dollner, M.; Heimerl, K.; Markovic, M. Z.; Ziemba, L. D.

    2015-12-01

    Black carbon (BC) aerosol contributes substantially to both climate forcing and climate forcing uncertainty. An important source of this uncertainty derives from the difficulty in predicting BC's global abundance and vertical distribution. Here we present a multi-year record of black carbon (BC) vertical concentration profiles from both sides of the Atlantic, obtained from airborne Single Particle Soot Photometers (SP2s) flown on the NASA DC-8, and the DLR Falcon research aircraft from the CONCERT, ACCESS, DC3, SEAC4RS, and SALTRACE campaigns. The measurements constrain the relative rates of BC transport/removal from, and zonal mixing in, the upper troposphere, as well as the range of BC loadings in these regions. They also constrain the time-rates of change of BC loads in altitudes at which it is a highly efficient (although sparse) climate forcer, and a relatively long-lived aerosol tracer. We find that concentration of BC in the upper troposphere can vary by a factor 10. Over the Northern mid-latitudes concentrations are however consistent to a fraction of this range over wide longitudinal ranges, over month-long timescales. The data show that BC becomes zonally mixed here starting at 500 hPa and extending to near the tropopause. These results imply broader value than previously associated with measured vertical profiles in constraining global scale BC loadings aloft.

  1. Double-walled carbon nanotubes synthesized using carbon black as the dot carbon source

    Science.gov (United States)

    Chen, Zhi-Gang; Li, Feng; Ren, Wen-Cai; Cong, Hongtao; Liu, Chang; Qing Lu, Gao; Cheng, Hui-Ming

    2006-07-01

    Double-walled carbon nanotubes (DWNTs) were synthesized used carbon black as the dot carbon source by a semi-continuous hydrogen arc discharge process. High-resolution transmission electron microscopy (HRTEM) observations revealed that most of the tubes were DWNTs with outer and inner diameters in the range of 2.67-4 nm and 1.96-3.21 nm, respectively. Most of the DWNTs were in a bundle form of about 10-30 nm in diameter with high purity (about 70%) from thermal gravimetric analysis (TGA), resonant laser Raman spectroscopy, scanning electron microscopy (SEM) and TEM characterizations. It was found that carbon black as the dot carbon source could be easy controlled to synthesize one type of nanotube. A simple process combining oxidation and acid treatment to purify the DWNT bundles was used without damaging the bundles. The structure of carbon black, as the key element for influencing purity, bundle formation and purification of DWNTs, is discussed.

  2. 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.

  3. Are black carbon and soot the same?

    Directory of Open Access Journals (Sweden)

    P. R. Buseck

    2012-09-01

    Full Text Available The climate change and environmental literature, including that on aerosols, is replete with mention of black carbon (BC, but neither reliable samples nor standards exist. Thus, there is uncertainty about its exact nature. That confusion can be avoided if terms are defined and widely understood. Here we discuss an ambiguity between BC and soot and propose a more precise definition for soot as a specific material, which we call ns-soot, where "ns" refers to carbon nanospheres. We define ns-soot as particles that consist of nanospheres, typically with diameters < 100 nm, that possess distinct structures of concentrically wrapped, graphene-like layers of carbon and with grape-like (acinoform morphologies. We additionally propose that, because of their importance for climate modeling and health issues, distinctions are made among bare, coated, and embedded ns-soot. BC, on the other hand, is not a well-defined material. We propose that the term should be restricted to light-absorbing refractory carbonaceous matter of uncertain character and that the uncertainty is stated explicitly.

  4. 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.

  5. 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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Y.; Shao, M. [Peking University, Beijing (China)

    2007-05-15

    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.

  7. Occupational exposure to carbon black in its manufacture.

    Science.gov (United States)

    Gardiner, K; Trethowan, W N; Harrington, J M; Calvert, I A; Glass, D C

    1992-10-01

    Carbon black is manufactured by the vapour phase pyrolysis of heavy aromatic hydrocarbon feedstocks. Its manufacture is worldwide and the majority of its production is for use in the rubber industry especially tyre manufacture. Its carbonaceous nature has led many to investigate the occurrence of exposure-related medical conditions. To quantify any such relationships, it is necessary to assess exposure accurately. As part of such an epidemiological investigation survey involving the measurement both of respirable and of total inhalable carbon black was undertaken in 18 plants in seven European countries between mid-1987 and mid-1989. A total of 1298 respirable samples (SIMPEDS cyclone) and 1317 total inhalable samples (IOM head) were taken and deemed of sufficient quality for inclusion in the study. The distributions of the time-weighted average values were assessed and found to be best described by a log-normal distribution, and so exposure is characterized by geometric means and standard deviations. The data are presented in terms of 13 separate job titles for both dust fractions and shows a wide variation between job titles, with the highest mean exposure experienced by the site cleaners, and 30% of the samples taken from the warehouse packers being in excess of the relevant countries' occupational exposure limits for total inhalable dust. The quality and extent of this data allows both for comparison with exposure standards and for generation of occupational exposure indices, which will be presented in another paper (Gardiner et al., in preparation). PMID:1444068

  8. A comparison of carbon calculators

    International Nuclear Information System (INIS)

    International attention to carbon dioxide emissions is turning to an individual's contribution, or 'carbon footprint.' Calculators that estimate an individual's CO2 emissions have become more prevalent on the internet. Even with similar inputs, however, these calculators can generate varying results, often by as much as several metric tons per annum per individual activity. This paper examines the similarities and differences among ten US-based calculators. Overall, the calculators lack consistency, especially for estimates of CO2 emissions from household electricity consumption. In addition, most calculators lack information about their methods and estimates, which impedes comparison and validation. Although carbon calculators can promote public awareness of carbon emissions from individual behavior, this paper reveals the need for improved consistency and transparency in the calculators

  9. Comparative studies of industrial grade carbon black powders

    Science.gov (United States)

    Chawla, Komal; Chauhan, Alok P. S.

    2016-05-01

    Comparative studies of two dissimilar industrial grade Carbon Black (CB) powders (N375 and N405) were conducted. The structure, surface area and particle size are the three important characteristics of CB powder that determine their processability and application as filler in preparing rubber compounds. The powders were characterized for their structure using dibutyl phthalate absorption (DBPA), particle size via laser particle size analyzer and surface area by nitrogen adsorption method. The structural characterization showed that N405 had lower DBPA in comparison to N375, confirming low structure of N405 grade CB powder. It was observed from the particle size analysis that N375 was coarser than N405 grade CB. The total surface area values were determined by the BET method based on the cross sectional area of the nitrogen molecule. N375, a coarse grade CB powder with high structure, depicted less surface area as compared to N405.

  10. 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. PMID:26114917

  11. Preparation of Zircon Whisker Using Carbon Black as Reducing Agent

    Directory of Open Access Journals (Sweden)

    WANG San-Hai, JIANG Wei-Hui, FENG Guo, LIU Jian-Min, MIAO Li-Feng, WANG Hong-Da

    2014-08-01

    Full Text Available Zircon whisker was synthesized at 700°C via non-hydrolytic Sol-Gel method using anhydrous zirconium tetrachloride (ZrCl4 as zirconium source, tetraethylorthosilicate (TEOS as silicon source, lithium fluoride (LiF as mineralizer, ethanol as solvent and carbon black as reducing agent. Thermogravimetric analysis and differential thermal analysis (TG-DTA, X-ray diffraction analysis (XRD and transmission electron microscope (TEM were employed to characterize the influences of adding ways and amount of carbon black on the synthesis and morphology of zircon whisker. The results show that the carbon black added in form of suspension is favorable to the one-dimension growth of zircon. When 6wt% carbon black is added, optimized zircon whiskers are achieved along the growth direction of [001], which diameter and aspect ratio are in the range of 30­90 nm and 6­15, respectively. Because of carbon black reacting with oxygen to form carbon dioxide and monoxide, the adding way and amount of carbon black efficiently regulate the oxygen partial pressure in the reaction system. Reducing oxygen partial pressure can form more SiF4 gas, which is the basis of one-dimensional direction growth of zircon. However, excessively low oxygen partial pressure is against the ZrSiO4 formation. Therefore, appropriate oxygen partial pressure can promote the growth of zircon whisker.

  12. 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

  13. The relationship between black carbon concentration and black smoke: A more general approach

    OpenAIRE

    Heal, Mathew R.; Quincey, Paul

    2012-01-01

    The black carbon (BC) component of ambient particulate matter is an important marker for combustion sources and for its impact on human health and radiative forcing. Extensive data archives exist for the black smoke metric, the historic measure of ambient particle darkness. An expression presented in earlier publications (Quincey, 2007; Quincey et al., 2011) for estimating BC concentrations from traditional black smoke measurements is shown to have limitations that can be addressed by using a...

  14. A New Grade Carbon Black Produced by Thermal Plasma Process

    Institute of Scientific and Technical Information of China (English)

    李娟; 何方方; 罗义文; 印永祥; 戴晓雁; 廖旭

    2003-01-01

    This paper presents a new route about producing carbon black, by which the naturalgas cracking is carried out in the absence of oxygen thanks to an electric energy supply externallygiven by a plasma jet. The carbon black produced by this process has a narrow size distributionand a small average diameter of 38 nm as well as a highly branched aggregate. The higher DBPvalue of 1.40 ml/g shows it should be a high structure carbon black. The FTIR spectra shows thatthere are lots of aromatic c-c bonds and a large amount of nitrogen-containing functional groupson the carbon blacks surface, such as -NH, -CN as well as -CH, -OH, -COOH groups.

  15. 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. PMID:19569324

  16. Comparative analysis of black carbon in soils

    Science.gov (United States)

    Schmidt, Michael W. I.; Skjemstad, Jan O.; Czimczik, Claudia I.; Glaser, Bruno; Prentice, Ken M.; Gelinas, Yves; Kuhlbusch, Thomas A. J.

    2001-03-01

    Black carbon (BC), produced by incomplete combustion of fossil fuels and vegetation, occurs ubiquitously in soils and sediments. BC exists as a continuum from partly charred material to highly graphitized soot particles, with no general agreement on clear-cut boundaries of definition or analysis. In a comparative analysis, we measured BC forms in eight soil samples by six established methods. All methods involved removal of the non-BC components from the sample by thermal or chemical means or a combination of both. The remaining carbon, operationally defined as BC, was quantified via mass balance, elemental composition or by exploiting benzenecarboxylic acids as molecular markers or applying 13C MAS NMR (magic angle spinning nuclear magnetic resonance) spectroscopy. BC concentrations measured for individual samples vary over 2 orders of magnitude (up to a factor of 571). One possible explanation for this wide range of results is that the individual BC methods rely on operational definitions with clear-cut but different boundaries and developed for specific scientific questions, whereas BC represents a continuum of materials with widely contrasting physicochemical properties. Thus the methods are inherently designed to analytically determine different parts of the continuum, and it is crucial to know how measurements made by different techniques relate to each other. It is clear from this preliminary comparative analysis that a collection of BC reference materials should be established as soon as possible 1 ) to ensure long-term intralaboratory and interlaboratory data quality and 2) to facilitate comparative analyses between different analytical techniques and scientific approaches

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

    International Nuclear Information System (INIS)

    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

  18. 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.

  19. Synthesis of multiwalled carbon nanotube from different grades of carbon black using arc discharge method

    Science.gov (United States)

    Arora, Neha; Sharma, N. N.

    2016-04-01

    This paper describes the synthesis of nanotube from different grades (Tread * A(non-ASTM), N134,N121,N660 and N330)of carbon black using DC arc discharge method at 40A current for 60sec. Carbon black samples of different grades were procured from industry (Aditya Birla Science and Technology Limited, India). Scanning Electron Micrographs (SEM) of the deposited carbon nanostructures suggests that MWCNTs are formed at 40A and for a minimal exposure time of 60sec.The result formed indicates the N330 grade of carbon black gets converted to MWCNTs (Multiwall Carbon nanotube) as compared to other grades.

  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. Thermal Oxidation of Tail Gases from the Production of Oil-furnace Carbon Black

    OpenAIRE

    Bosak, Z.; Barta, D; Zečević, N.; Šiklušić, S.

    2009-01-01

    This paper describes the production technology of oil-furnace carbon black, as well as the selected solution for preventing the emissions of this process from contaminating the environment.The products of industrial oil-furnace carbon black production are different grades of carbon black and process tail gases. The qualitative composition of these tail gases during the production of oil-furnace carbon black are: carbon(IV) oxide, carbon(II) oxide, hydrogen, methane, hydrogen sulfide, nitrogen...

  2. 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

    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...

  3. Russian anthropogenic black carbon: Emission reconstruction and Arctic black carbon simulation

    Science.gov (United States)

    Huang, Kan; Fu, Joshua S.; Prikhodko, Vitaly Y.; Storey, John M.; Romanov, Alexander; Hodson, Elke L.; Cresko, Joe; Morozova, Irina; Ignatieva, Yulia; Cabaniss, John

    2015-11-01

    Development of reliable source emission inventories is particularly needed to advance the understanding of the origin of Arctic haze using chemical transport modeling. This study develops a regional anthropogenic black carbon (BC) emission inventory for the Russian Federation, the largest country by land area in the Arctic Council. Activity data from combination of local Russia information and international resources, emission factors based on either Russian documents or adjusted values for local conditions, and other emission source data are used to approximate the BC emissions. Emissions are gridded at a resolution of 0.1° × 0.1° and developed into a monthly temporal profile. Total anthropogenic BC emission of Russia in 2010 is estimated to be around 224 Gg. Gas flaring, a commonly ignored black carbon source, contributes a significant fraction of 36.2% to Russia's total anthropogenic BC emissions. Other sectors, i.e., residential, transportation, industry, and power plants, contribute 25.0%, 20.3%, 13.1%, and 5.4%, respectively. Three major BC hot spot regions are identified: the European part of Russia, the southern central part of Russia where human population densities are relatively high, and the Urals Federal District where Russia's major oil and gas fields are located but with sparse human population. BC simulations are conducted using the hemispheric version of Community Multi-scale Air Quality Model with emission inputs from a global emission database EDGAR (Emissions Database for Global Atmospheric Research)-HTAPv2 (Hemispheric Transport of Air Pollution) and EDGAR-HTAPv2 with its Russian part replaced by the newly developed Russian BC emissions, respectively. The simulation using the new Russian BC emission inventory could improve 30-65% of absorption aerosol optical depth measured at the AERONET sites in Russia throughout the whole year as compared to that using the default HTAPv2 emissions. At the four ground monitoring sites (Zeppelin, Barrow

  4. Formation mechanism of diamond nanocrystal from catalysed carbon black

    International Nuclear Information System (INIS)

    Recently, our group has synthesized nanocrystal n-diamond and diamond-like carbon (DLC) from catalysed carbon black. Based on the results of XRD, TGA and DTA, a formation mechanism has been proposed to explain the phase transformation from carbon black to diamond nanocrystal. With the increase of temperature and hence the carbon diffusion in iron, the phase sequence is from Fe(OH)3 into Fe2O3, α-Fe, γ-Fe, then liquid iron. When the carbon in the liquid iron is saturated, DLC or graphite separates out of the liquid iron. With decrease of temperature, the carbon in γ-Fe is separated out, and n-diamond nuclei form and grow

  5. Formation mechanism of diamond nanocrystal from catalysed carbon black

    Science.gov (United States)

    Wen, Bin; Li, Tingju; Dong, Chuang; Zhang, Xingguo; Yao, Shan; Cao, Zhiqiang; Wang, Dehe; Ji, Shouhua; Jin, Junze

    2004-10-01

    Recently, our group has synthesized nanocrystal n-diamond and diamond-like carbon (DLC) from catalysed carbon black. Based on the results of XRD, TGA and DTA, a formation mechanism has been proposed to explain the phase transformation from carbon black to diamond nanocrystal. With the increase of temperature and hence the carbon diffusion in iron, the phase sequence is from Fe(OH)3 into Fe2O3, agr-Fe, ggr-Fe, then liquid iron. When the carbon in the liquid iron is saturated, DLC or graphite separates out of the liquid iron. With decrease of temperature, the carbon in ggr-Fe is separated out, and n-diamond nuclei form and grow.

  6. Formation mechanism of diamond nanocrystal from catalysed carbon black

    Energy Technology Data Exchange (ETDEWEB)

    Wen Bin [Department of Materials Engineering, Dalian University of Technology, Dalian 116023 (China); Li Tingju [Laboratory of Special Processing of Raw Materials, Dalian University of Technology, Dalian 116023 (China); Dong Chuang [Department of Materials Engineering, Dalian University of Technology, Dalian 116023 (China); Zhang Xingguo [Laboratory of Special Processing of Raw Materials, Dalian University of Technology, Dalian 116023 (China); Yao Shan [Laboratory of Special Processing of Raw Materials, Dalian University of Technology, Dalian 116023 (China); Cao Zhiqiang [Laboratory of Special Processing of Raw Materials, Dalian University of Technology, Dalian 116023 (China); Wang Dehe [Department of Materials Engineering, Dalian University of Technology, Dalian 116023 (China); Ji Shouhua [Department of Materials Engineering, Dalian University of Technology, Dalian 116023 (China); Jin Junze [Laboratory of Special Processing of Raw Materials, Dalian University of Technology, Dalian 116023 (China)

    2004-10-06

    Recently, our group has synthesized nanocrystal n-diamond and diamond-like carbon (DLC) from catalysed carbon black. Based on the results of XRD, TGA and DTA, a formation mechanism has been proposed to explain the phase transformation from carbon black to diamond nanocrystal. With the increase of temperature and hence the carbon diffusion in iron, the phase sequence is from Fe(OH){sub 3} into Fe{sub 2}O{sub 3}, {alpha}-Fe, {gamma}-Fe, then liquid iron. When the carbon in the liquid iron is saturated, DLC or graphite separates out of the liquid iron. With decrease of temperature, the carbon in {gamma}-Fe is separated out, and n-diamond nuclei form and grow.

  7. 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).

  8. Automatic grading of carbon blacks from transmission electron microscopy

    Science.gov (United States)

    Luengo, L.; Treuillet, S.; Gomez, E.

    2015-04-01

    Carbon blacks are widely used as filler in industrial products to modify their mechanical, electrical and optical properties. For rubber products, they are the subject of a standard classification system relative to their surface area, particle size and structure. The electron microscope remains the most accurate means of measuring these characteristics on condition that boundaries of aggregates and particles are correctly detected. In this paper, we propose an image processing chain allowing subsequent characterization for automatic grading of the carbon black aggregates. Based on literature review, 31 features are extracted from TEM images to obtain reliable information on the particle size, the shape and microstructure of the carbon black aggregates. Then, they are used for training several classifiers to compare their results for automatic grading. To obtain better results, we suggest to use a cluster identification of aggregates in place of the individual characterization of aggregates.

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

    OpenAIRE

    Donnaperna Lucio; Duclaux Laurent; Gadiou Roger

    2008-01-01

    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 explai...

  10. 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...... resistance of BC to microbial degradation. The difference between soil respiration in sterilized and non-sterilized soil with plant material was visible from the beginning of the experiment, unlike with BC amendments where differences only occurred after some days. In addition, the CO evolution from...

  11. Electrical conductivity of short carbon fibers and carbon black-reinforced chloroprene rubber

    International Nuclear Information System (INIS)

    Elastomers and plastics are intrinsically insulating materials, but by addition of some conductive particles such as conductive carbon black, carbon fibers and metals, they can change to conductive form. Conductivity of these composites are due to formation of the lattices of conductive filler particles in polymer chains. In this report, conductivity of chloroprene rubber filled with carbon black and carbon fibers as a function of temperature and pressure are studied. Electrical conductivity of chloroprene in a function of temperature and pressure are studied. Electrical conductivity of chloroprene in the presence of carbon black with proper mixing conditions increases to the conductivity level of semiconductors and even in the presence of carbon fibers it increases to the level of a conductor material. Meanwhile, the sensitivity of this compound to heat and pressure rises. Thus these composites have found various applications in the manufacture of heat and pressure sensitive sensors

  12. Costs and global impacts of black carbon abatement strategies

    OpenAIRE

    Rypdal, Kristin; Rive, Nathan; Berntsen, Terje K.; Klimont, Zbigniew; Mideksa, Torben K.; Myhre, Gunnar; Skeie, Ragnhild B.

    2011-01-01

    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 and...

  13. Sediment pore water distribution coefficients of PCB congeners in enriched black carbon sediment

    International Nuclear Information System (INIS)

    More than 2300 sediment pore water distribution coefficients (KPCBids) of 93 polychlorinated biphenyls (PCBs) were measured and modeled from sediments from Indiana Harbor and Ship Canal. KPCBids were calculated from previously reported bulk sediment values and newly analyzed pore water. PCBs in pore waters were measured using SPME PDMS-fiber and ∑PCB ranged from 41 to 1500 ng L−1. The resulting KPCBids were ∼1 log unit lower in comparison to other reported values. A simple model for the KPCBid consisted of the product of the organic carbon fraction and the octanol–water partition coefficient and provided an excellent prediction for the measured values, with a mean square error of 0.09 ± 0.06. Although black carbon content is very high in these sediments and was expected to play an important role in the distribution of PCBs, no improvement was obtained when a two-carbon model was used. -- Highlights: •PCB sediment-pore water distribution coefficients were measured and modeled. •Distribution coefficients were lower in comparison to other reported values. •Organic carbon fraction times the KOW yielded the best prediction model. •The incorporation of black carbon into a model did not improve the results. -- The organic carbon fraction times the octanol–water partition coefficient yielded the best prediction model for the sediment pore water distribution coefficient of PCBs

  14. Occupational exposure to carbon black: a particulate sampling study.

    Science.gov (United States)

    Smith, R G; Musch, D C

    1982-12-01

    In order to determine the particulate exposure levels within carbon black production plants, a sampling survey involving workers from seven carbon black producers was initiated in late 1979. A total of 1,951 acceptable samples (1,564 total dust and 387 respirable dust) were collected from closed-face filter cassettes worn by carbon black workers performing normal work operations. A one-centimeter cyclone separator was employed for respirable dust sampling. Overall sampling distributions of the time-weighted average values generated from the survey were best described by the log-normal distribution. Characterization of the particulate exposures to workers is provided for the various areas of employment and specific jobs within these areas. Summary geometric mean time-weighted average values by area of employment and by job category are well within the carbon black permissible exposure limit (PEL) of 3.5 mg/m3. Identification of those job categories subject to relatively higher particulate exposures, and quantification of these exposures, is essential to the effective industrial hygiene monitoring and control of worker exposures. PMID:7158607

  15. Highly Loaded Carbon Black Supported Pt Catalysts for Fuel Cells

    Czech Academy of Sciences Publication Activity Database

    Kaluža, Luděk; Larsen, M.J.; Zdražil, Miroslav; Gulková, Daniela; Vít, Zdeněk; Šolcová, Olga; Soukup, Karel; Koštejn, Martin; Bonde, J.L.; Maixnerová, Lucie; Odgaard, M.

    2015-01-01

    Roč. 256, NOV 1 (2015), s. 375-383. ISSN 0920-5861 R&D Projects: GA MŠk(CZ) 7HX13003 EU Projects: European Commission(XE) 303466 - IMMEDIATE Institutional support: RVO:67985858 Keywords : carbon black * fuell cell * electrocatalyst Subject RIV: CI - Industrial Chemistry, Chemical Engineering Impact factor: 3.893, year: 2014

  16. Carbon dioxide gasification of carbon black: isotope study of carbonate catalysis

    International Nuclear Information System (INIS)

    Temperature-programmed reaction was used with labeled isotopes (13C and 18O) to study interactions between carbon black and potassium carbonate in pure He and 10% CO2/90% He atmospheres. Catalytic gasification precursor complexes were observed. Carbon and oxygen-bearing carbon surface groups interacted with the carbonate above 500 K to form surface complexes. Between 500 and 950 K, and in the presence of gaseous CO2, the complexes participated in C and O exchange with the gas phase while oxygen atoms within the complexes also exchanged with those on the carbon surface. As the temperature rose, the complexes decomposed, with CO2 the initial product. Decomposition started around 500 K in pure He, and around 950 K in CO2/He. Catalytic gasification began only after decomposition of significant portions of the complexes. Elemental potassium formed, and the active catalyst appears to alternate between being potassium metal and a potassium-oxygen-carbon complex. Potassium carbonate is not part of the catalytic cycle. 20 references, 10 figures

  17. Study by electronic microscopy of the structure of oxidised carbon blacks

    International Nuclear Information System (INIS)

    After an overview of some generalities about the preparation of carbon blacks (preparation by tunnel-based, oven-based, heat-based or other processes), about the process of growth of particles of carbon black, and about the inner crystal structure of carbon black, this research thesis reports a study which comprised the oxidation of a carbon black followed by an examination by electronic microscopy in order to determine the inner structure. After a presentation of the characteristics of the carbon blacks used in this study, the author reports the study of nitric oxidation: study by electronic microscopy of the variation of particle diameter and of the obtained oxidation features, study of the variation of the specific surface, study by X-ray and variation of carbon black density during oxidation. The next parts report the study of the behaviour of a thermal black at temperatures below 1.000 C, and the study of air oxidation of various carbon blacks

  18. Retention and clearance of inhaled submicron carbon black particles.

    Science.gov (United States)

    Strom, K A; Johnson, J T; Chan, T L

    1989-01-01

    Carbon black aerosols were used as a probe of the pulmonary retention and clearance of submicron particles. Male Fischer rats (COBS CD) were exposed for 20 h/d, 7 d/wk for 1, 3, or 6 wk to either 7 +/- 2 mg/m3 carbon black or filtered air. The submicron aerosol (mass median aerodynamic diameter, MMAD, 0.24 microns) was generated with a Wright dust feed-cyclone system. Lung and hilar lymph node particle burdens were determined immediately following the exposure and at preselected intervals up to 1 yr postexposure. After 1-, 3-, and 6-wk exposures, the lung burdens were 1.1 +/- 0.1, 3.5 +/- 0.2, and 5.9 +/- 0.1 mg, respectively. One year after a 1-, 3-, or 6-wk exposure, 8%, 46%, and 61% of the initial lung burden remained in the lungs. Initially, the hilar lymph nodes contained 0.2%, 0.9%, and 2.0% of the lung burdens in the 3 exposure groups, respectively. At 1 yr postexposure, particle translocation from the lungs led to a rise in lymph node burdens to 1%, 21%, and 27% of the initial lung burden. The retention of carbon black in both the lungs and lymph nodes combined was 9%, 67%, and 89% for the 1-, 3-, and 6-wk exposed animals. Lung clearance was modeled as a compartmental system consisting of four lung compartments and a regional lymph node compartment. The results from the model are similar for carbon black and diesel engine exhaust particles. However, the compartmental kinetics of carbon black differed in two ways: the deposition efficiency in the alveolar region was lower than that for diesel exhaust particles, and there was earlier transport of particles to the regional lymph nodes. These results showed that when lung burdens reached 0.8 mg, lung clearance was decreased by 50% and lymphatic transport of insoluble particles was increased. PMID:2466129

  19. 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 method...... allows maskless definition of carbon nanotube forests with control of their density, nanotube diameter and height. Four nanograss reactive ion etching recipes are investigated and their wafer-to-wafer repeatability, wafer uniformity, and density control is discussed. Evaluation of carbon nanotube forests...

  20. Black carbon concentration and deposition estimations in Finland by the regional aerosol-climate model REMO-HAM

    Directory of Open Access Journals (Sweden)

    A. I. Hienola

    2012-09-01

    Full Text Available The prediction skill of the regional aerosol-climate model REMO-HAM was assessed against the black carbon (BC concentration measurements from five locations in Finland, with focus on Hyytiälä station for the year 2005. We examined to what extent the model is able to reproduce the measurements using several statistical tools: median comparison, overlap coefficient OVL (the common area under two probability distributions curves and Z-score (a measure of standard deviation, shape and spread of the distributions. The results of the statistics showed that the model is biased low, suggesting either an excessive loss of black carbon in the model, or missing emissions. A further examination of the precipitation data from both measurements and model showed that there is no correlation between REMO's excessive precipitation and BC underestimation. This suggests that the excessive wet removal is not the main cause for the low black carbon concentration output. In addition, a comparison of wind directions in relation with high black carbon concentrations shows that REMO-HAM is able to predict the BC source directions relatively well. Cumulative black carbon deposition fluxes over Finland were estimated, including the deposition on snow.

  1. 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)

  2. 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.

  3. Carbon black directed synthesis of ultrahigh mesoporous carbon aerogels

    OpenAIRE

    Macías, Carlos; Haro Remón, Marta; Rasines, Gloria; Parra Soto, José Bernardo; Ovín Ania, María Concepción

    2013-01-01

    [EN] A simple modification of the conventional sol–gel polymerization of resorcinol–formaldehyde mixtures allowed a facile preparation of ultrahigh mesoporous carbon gels. In the conventional synthesis the growth of the cluster polymer particles leading to the development of the porosity is controlled by the R/C ratio. In the presence of a carbon conductive additive, the polymerization of the reactants proceeded through the formation of less-branched polymer clusters resulting in carbon gels ...

  4. Method of comparison equations for Schwarzschild black holes

    International Nuclear Information System (INIS)

    We employ the method of comparison equations to study the propagation of a massless minimally coupled scalar field on the Schwarzschild background. In particular, we show that this method allows us to obtain explicit approximate expressions for the radial modes with energy below the peak of the effective potential which are fairly accurate over the whole region outside the horizon. This case can be of particular interest, for example, for the problem of black hole evaporation

  5. 黑箱法与二氧化碳诱捕法蚊虫监测结果比较%Comparison of mosquito surveillance efficiency between the black box method and carbon dioxide method

    Institute of Scientific and Technical Information of China (English)

    冷培恩; 刘洪霞; 唐毅; 曹辉; 束惠慧; 徐仁权

    2011-01-01

    Objective To compare mosquito densities using the black box method and the carbon dioxide method and explore the application of the black box approach. Methods The black box method and the carbon dioxide method were used to measure mosquito density and composition at seven locations in two districts of Shanghai. Correlations between species composition, sex ratios and seasonal variation were compared using the two methods. Results The average mosquito density using the black box method (25.63 mosquitoes/box) was 3.50 times higher than the carbon dioxide method (7.32 mosquitoes/ device), and the average density of female mosquitoes using the black box method (14.65 mosquitoes/box) was 2.35 times higher than the carbon dioxide method (6.23 mosquitoes/device), densities were significantly different. The density indices of the two approaches were not correlated. The species composition recorded by the black box method was: Cvlex pipiens pollens (94.97%), Aedes albopictus (4.97%), Cx. Tritaeriorhynchus (0.03%), and Anopheles sinensis (0.03%). The species composition recorded by the carbon dioxide method was: Cx. Pipiens pollens (79.26%), Ae. Albopictus (18.27%), Cx. Trilaeriorhynchus (2.10%) and An. Sinensis (0.37%). The differences in composition were also statistically significant. Conclusion As compared to the carbon dioxide method, the black box method is readily applicable, simple, affordable and can be used in most locations, particularly habitats dominated by Cx. Pipiens pollens. The carbon dioxide method can be used for the monitoring of both Cx. Pipiens pollens and Ae. Albopictus.%目的 比较黑箱法和二氧化碳(CO2)诱捕法监测蚊虫密度的差异,探讨黑箱法在蚊虫密度监测中的作用.方法 在2个区7个点比较黑箱法和CO2诱捕法监测蚊虫密度、种类的差异,比较2种方法监测蚊种构成比、性别比和季节消长趋势的相关性.结果 黑箱法监测蚊虫平均密度为25.63只,箱,是CO2诱捕法平均密度(7

  6. Personal exposure to Black Carbon in transport microenvironments

    Science.gov (United States)

    Dons, Evi; Int Panis, Luc; Van Poppel, Martine; Theunis, Jan; Wets, Geert

    2012-08-01

    We evaluated personal exposure of 62 individuals to the air pollutant Black Carbon, using 13 portable aethalometers while keeping detailed records of their time-activity pattern and whereabouts. Concentrations encountered in transport are studied in depth and related to trip motives. The evaluation comprises more than 1500 trips with different transport modes. Measurements were spread over two seasons. Results show that 6% of the time is spent in transport, but it accounts for 21% of personal exposure to Black Carbon and approximately 30% of inhaled dose. Concentrations in transport were 2-5 times higher compared to concentrations encountered at home. Exposure was highest for car drivers, and car and bus passengers. Concentrations of Black Carbon were only half as much when traveling by bike or on foot; when incorporating breathing rates, dose was found to be twice as high for active modes. Lowest 'in transport' concentrations were measured in trains, but nevertheless these concentrations are double the concentrations measured at home. Two thirds of the trips are car trips, and those trips showed a large spread in concentrations. In-car concentrations are higher during peak hours compared to off-peak, and are elevated on weekdays compared to Saturdays and even more so on Sundays. These findings result in significantly higher exposure during car commute trips (motive 'Work'), and lower concentrations for trips with motive 'Social and leisure'. Because of the many factors influencing exposure in transport, travel time is not a good predictor of integrated personal exposure or inhaled dose.

  7. Measuring black carbon spectral extinction in the visible and infrared

    Science.gov (United States)

    Smith, A. J. A.; Peters, D. M.; McPheat, R.; Lukanihins, S.; Grainger, R. G.

    2015-09-01

    This work presents measurements of the spectral extinction of black carbon aerosol from 400 nm to 15 μm. The aerosol was generated using a Miniature Combustion Aerosol Standard soot generator and then allowed to circulate in an aerosol cell where its extinction was measured using a grating spectrometer in the visible and a Fourier transform spectrometer in the infrared. Size distribution, number concentration, and mass extinction cross sections have also been obtained using single-particle aerosol samplers. A mean mass extinction cross section at 550 nm of 8.3 ± 1.6 m2 g-1 is found which, assuming a reasonable single scatter albedo of 0.2, corresponds to a mass absorption cross section of 6.6 ± 1.3 m2 g-1. This compares well with previously reported literature values. Computer analysis of electron microscope images of the particles provides independent confirmation of the size distribution as well as fractal parameters of the black carbon aerosol. The aerosol properties presented in this work are representative of very fresh, uncoated black carbon aerosol. After atmospheric processing of such aerosols (which could include mixing with other constituents and structural changes), different optical properties would be expected.

  8. 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.

  9. 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

  10. 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

  11. Arctic Black Carbon Initiative: Reducing Emissions of Black Carbon from Power & Industry in Russia

    Science.gov (United States)

    Cresko, J.; Hodson, E. L.; Cheng, M.; Fu, J. S.; Huang, K.; Storey, J.

    2012-12-01

    Deposition of black carbon (BC) on snow and ice is widely considered to have a climate warming effect by reducing the surface albedo and promoting snowmelt. Such positive climate feedbacks in the Arctic are especially problematic because rising surface temperatures may trigger the release of large Arctic stores of terrestrial carbon, further amplifying current warming trends. Recognizing the Arctic as a vulnerable region, the U.S. government committed funds in Copenhagen in 2009 for international cooperation targeting Arctic BC emissions reductions. As a result, the U.S. Department of State has funded three research and demonstration projects with the goal to better understand and mitigate BC deposition in the Russian Arctic from a range of sources. The U.S. Department of Energy's (DOE) Arctic BC initiative presented here is focused on mitigating BC emissions resulting from heat and power generation as well as industrial applications. A detailed understanding of BC sources and its transport and fate is required to prioritize efforts to reduce BC emissions from sources that deposit in the Russian Arctic. Sources of BC include the combustion of fossil fuels (e.g. coal, fuel oil, diesel) and the combustion of biomass (e.g. wildfires, agricultural burning, residential heating and cooking). Information on fuel use and associated emissions from the industrial and heat & power sectors in Russia is scarce and difficult to obtain from the open literature. Hence, our project includes a research component designed to locate Arctic BC emissions sources in Russia and determine associated BC transport patterns. We use results from the research phase to inform a subsequent assessment/demonstration phase. We use a back-trajectory modeling method (potential source contribution function - PSCF), which combines multi-year, high-frequency measurements with knowledge about atmospheric transport patterns. The PSCF modeling allows us to map the probability (by season and year) at course

  12. Black Carbon Deposition on Glaciers and in the Seasonal Snowpack in Western Washington's Mountainous Regions

    Science.gov (United States)

    Delaney, I.; Kaspari, S.; Larrabee, M.

    2012-12-01

    Black carbon deposition on snow and ice darkens the surface of glaciers and snowpack, reducing albedo. Radiation absorbed by black carbon in snow can accelerate snowmelt and change the timing of runoff. This is particularly important in Washington State, as glaciers and seasonal snowpack have shrunk considerably in recent years and are integral to the region's water resources. However, little data exists regarding the concentration of black carbon in Washington snow, which is necessary to determine if enough black carbon is present to substantially accelerate snowmelt. From the winter through the summer of 2012, we collected snow samples from the snow surface, snow pits and snow cores (glaciers on Mt. Rainier, Blewett Pass in the central Cascades, N. Klawatti, Noisy and Sandalee glaciers in the North Cascades and Blue Glacier on Mt. Olympus. Samples were analyzed for black carbon using a Single Particle Soot Photometer (SP2), and select samples were also analyzed for black carbon using a Sunset Lab OC-EC Aerosol Analyzer to compare with the SP2 method. We use the resultant data set to examine how snow accumulation, dry deposition, and proximity to emission sources (such as the Puget Sound metropolitan area) affect black carbon concentration in snow and ice. The results of this research provide insight in to 1) regional scale variation in black carbon deposition, 2) temporal trends in black carbon deposition, and 3) the persistence of black carbon in the snowpack throughout the season.

  13. Adsorption Behavior of Black Carbon for Radioactive Iodine Species in Subsurface Environments

    Science.gov (United States)

    Choung, S.; Kim, M.; Um, W.

    2012-12-01

    Releases of radioactive iodines (125/129/131I) into subsurface environments occur during nuclear power plant operations, nuclear weapons tests, and nuclear accidents such as Chernobyl and Fukushima. Environmental concern is mostly for 129I due to high toxicity and long-half life, t1/2=1,600,000 years. The fate and transport of radioactive iodines depend on the speciation in the environments. Sorption of iodate (IO3-) is strongly affected by natural organic matter (NOM) in soil/sediments, while iodide (I-) sorption is less. Although there are numerous forms and compositions of NOM in soil/sediments, previous studies were mostly focused on general organic matter such as humic and fulvic acids. The objective of this study is addressed to evaluate the impact of black carbon as different NOM forms in subsurface environments. Laboratory-produced wood char was used as a representative of black carbon for sorption batch experiments. Commercial humic acid was added to experiments for comparison of iodine sorption behavior to black carbon material. Stable iodine isotope, 127I, was used as a surrogate of radioactive iodine. The 13C-NMR analyses indicated that the wood char consisted of dominantly aromatic chemical structures, while the humic acid exhibited relatively more aliphatic structures than aromaticity. The char and humic acid significantly increased iodide and iodate sorption, respectively. However, iodate sorption on char and iodide sorption on humic acid were negligible in this study. These observations implied different sorption mechanisms between black carbon and humic acid due to different pore structures and chemical compositions. Both of sorption isotherms are dependent on aqueous concentrations, following Freundlich isotherm with n~0.7. The sorption behavior and mechanism of iodine is significantly influenced by the NOM types in soils and sediments, which can enhance iodine retardation in the subsurface environment.

  14. Intercontinental transport of black carbon to the Arctic free troposphere

    Science.gov (United States)

    Liu, Dantong; Quennehen, Boris; Allan, James; Darbyshire, Eoghan; Williams, Paul; Taylor, Jonathan; Flynn, Michael; Bower, Keith; Coe, Hugh

    2015-04-01

    Black carbon has a large radiative forcing potential in the Arctic, through altering the atmosphere's radiative balance and also initiating ice melt after deposition. Here we present an analysis of aerosol data collected aboard the UK Facility for Airborne Atmospheric Measurements (FAAM) BAe-146 research aircraft during five flights in the free troposphere in the region of Svalbard in March 2013 as part of the Natural Environment Research Council (NERC) Aerosol-Cloud Coupling and Climate Interaction in the Arctic (ACCACIA) project. A number of discrete layers of pollution typical of continental emissions were detected, evidenced by black carbon (measured using a single particle soot photometer), carbon monoxide, organic matter and sulphate (measured using an aerosol mass spectrometer). These were detected at all altitudes within the free troposphere (up to 8 km) and potential source regions were investigated on a plume-by-plume basis using FLEXPART and HYSPLIT. Continental areas were identified as separate potential sources for the different plumes, with transit times of up to 12 days. East Asia showed the strongest influence, being responsible for high concentration plumes at all layers and Europe was found to be responsible for plumes in the lower to mid troposphere. North America had a somewhat weaker influence and no significant influence from Northern Russia was found. Emissions inventory data was used in conjunction with the FLEXPART potential source footprints to try to estimate the relative significance of different sources and it was found that direct emissions from human activities (e.g. transport, industry) were more prevalent than open biomass burning. Significant loadings were detected (of the order of 100 ng sm-3 black carbon relative to CO concentrations of around 50 ppbv) even when instrumental data and model outputs suggest that significant precipitation occurred during uplift, indicating that inefficient scavenging is taking place.

  15. Black carbon concentration and deposition estimations in Finland by the regional aerosol–climate model REMO-HAM

    Directory of Open Access Journals (Sweden)

    A. I. Hienola

    2013-04-01

    Full Text Available The prediction skill of the regional aerosol–climate model REMO-HAM was assessed against the black carbon (BC concentration measurements from five locations in Finland, with focus on Hyytiälä station for the year 2005. We examined to what extent the model is able to reproduce the measurements using several statistical tools: median comparison, overlap coefficient (OVL; the common area under two probability distributions curves and Z score (a measure of standard deviation, shape and spread of the distributions. The results of the statistics showed that the model is biased low. The local and regional emissions of BC have a significant contribution, and the model tendency to flatten the observed BC is most likely dominated by the lack of domestic burning of biofuel in the emission inventories. A further examination of the precipitation data from both measurements and model showed that there is no correlation between REMO's excessive precipitation and BC underestimation. This suggests that the excessive wet removal is not the main cause of the low black carbon concentration output. In addition, a comparison of wind directions in relation with high black carbon concentrations shows that REMO-HAM is able to predict the BC source directions relatively well. Cumulative black carbon deposition fluxes over Finland were estimated, including the deposition on snow.

  16. Effects of carbon black distribution on the electrical properties of Br/Epdm compounds

    International Nuclear Information System (INIS)

    The correlations between mechanical and electrical properties of butadiene/ethylene propylene diene terpolymer (BR/EPDM) and the distribution of carbon black levels are studied. It was found that the BR phase in the blends, compared to the EPDM phase, is more preferential for the used type of carbon black, probably because the lower viscosity and lower polarity of the BR phase. Tensile strength increases with an increase of carbon black. Possible reasons for these results are discussed

  17. 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.

  18. 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.

  19. Black Carbon Emissions from Associated Natural Gas Flaring.

    Science.gov (United States)

    Weyant, Cheryl L; Shepson, Paul B; Subramanian, R; Cambaliza, Maria O L; Heimburger, Alexie; McCabe, David; Baum, Ellen; Stirm, Brian H; Bond, Tami C

    2016-02-16

    Approximately 150 billion cubic meters (BCM) of natural gas is flared and vented in the world annually, emitting greenhouse gases and other pollutants with no energy benefit. About 7 BCM per year is flared in the United States, and half is from North Dakota alone. There are few emission measurements from associated gas flares and limited black carbon (BC) emission factors have been previously reported from the field. Emission plumes from 26 individual flares in the Bakken formation in North Dakota were sampled. Methane, carbon dioxide, and BC were measured simultaneously, allowing the calculation of BC mass emission factors using the carbon balance method. Particle optical absorption was measured using a three-wavelength particle soot absorption photometer (PSAP) and BC particle number and mass concentrations were measured with a single particle soot photometer. The BC emission factors varied over 2 orders of magnitude, with an average and uncertainty range of 0.14 ± 0.12 g/kg hydrocarbons in associated gas and a median of 0.07 g/kg which represents a lower bound on these measurements. An estimation of the BC emission factor derived from PSAP absorption provides an upper bound at 3.1 g/kg. These results are lower than previous estimations and laboratory measurements. The BC mass absorption cross section was 16 ± 12 m(2)/g BC at 530 nm. The average absorption Ångström exponent was 1.2 ± 0.8, suggesting that most of the light absorbing aerosol measured was black carbon and the contribution of light absorbing organic carbon was small. PMID:26764563

  20. 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.

  1. 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).

  2. Highly Loaded Carbon Black Supported Pt Catalysts for Fuel Cells

    Czech Academy of Sciences Publication Activity Database

    Kaluža, Luděk; Zdražil, Miroslav; Gulková, Daniela; Vít, Zdeněk; Šolcová, Olga; Soukup, Karel; Maixnerová, Lucie

    Prague: Orgit, 2014, s. 35. ISBN 978-80-02-02555-9. [International Congress of Chemical and Process Engineering /21./ - CHISA 2014 and Conference on Process Integration, Modelling and Optimisation for Energy Saving and Pollution Reduction /17./ - PRES 2014. Prague (CZ), 23.08.2014-27.08.2014] R&D Projects: GA MŠk(CZ) 7HX13003 EU Projects: European Commission(XE) 303466 - IMMEDIATE Institutional support: RVO:67985858 Keywords : pt catalysts * fuel cells * carbon black Subject RIV: CI - Industrial Chemistry, Chemical Engineering

  3. Highly Loaded Carbon Black Supported Platinum Catalysts for Fuel Batteries

    Czech Academy of Sciences Publication Activity Database

    Kaluža, Luděk; Zdražil, Miroslav; Gulková, Daniela

    Prague: J. Heyrovský Institute of Physical Chemistry of ASCR, v.v.i, 2014 - (Žilková, N.; Horáček, M.), Po10 ISBN 978-80-87351-34-5. [Symposium on Catalysis /46./. Prague (CZ), 03.11.2014-05.11.2014] R&D Projects: GA MŠk(CZ) 7HX13003 EU Projects: European Commission(XE) 303466 - IMMEDIATE Institutional support: RVO:67985858 Keywords : Carbon Black * Platinum * fuel cell Subject RIV: CF - Physical ; Theoretical Chemistry

  4. Dielectric study of Poly(styrene- co -butadiene) Composites with Carbon Black, Silica, and Nanoclay

    KAUST Repository

    Vo, Loan T.

    2011-08-09

    Dielectric spectroscopy is used to measure polymer relaxation in styrene-butadiene rubber (SBR) composites. In addition to the bulk polymer relaxation, the SBR nanocomposites also exhibit a slower relaxation attributed to polymer relaxation at the polymer-nanoparticle interface. The glass transition temperature associated with the slower relaxation is used as a way to quantify the interaction strength between the polymer and the surface. Comparisons were made among composites containing nanoclay, silica, and carbon black. The interfacial relaxation glass transition temperature of SBR-clay nanocomposites is more than 80 °C higher than the SBR bulk glass transition temperature. An interfacial mode was also observed for SBR-silica nanocomposites, but the interfacial glass transition temperature of SBR-silica nanocomposite is somewhat lower than that of clay nanocomposites. An interfacial mode is also seen in the carbon black filled system, but the signal is too weak to analyze quantitatively. The interfacial polymer relaxation in SBR-clay nanocomposites is stronger compared to both SBR-carbon black and SBR-silica composites indicating a stronger interfacial interaction in the nanocomposites containing clay. These results are consistent with dynamic shear rheology and dynamic mechanical analysis measurements showing a more pronounced reinforcement for the clay nanocomposites. Comparisons were also made among clay nanocomposites using different SBRs of varying styrene concentration and architecture. The interfacial glass transition temperature of SBR-clay nanocomposites increases as the amount of styrene in SBR increases indicating that styrene interacts more strongly than butadiene with clay. © 2011 American Chemical Society.

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

    Energy Technology Data Exchange (ETDEWEB)

    Cruz-Núñez, Xochitl, E-mail: xcruz@unam.mx

    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 53–473 Gg 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. - Highlights: • Black carbon emissions are estimated between 53 and 473 Gg/year on a fuel consumption method. • Black carbon emissions are estimated between 62 and 89 Gg/year on a sector method.

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

    International Nuclear Information System (INIS)

    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 53–473 Gg 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. - Highlights: • Black carbon emissions are estimated between 53 and 473 Gg/year on a fuel consumption method. • Black carbon emissions are estimated between 62 and 89 Gg/year on a sector method

  7. Sensitive method for dosing carboxylic functions of carbons and its application to the study of thermally processed carbon blacks

    International Nuclear Information System (INIS)

    This research thesis reports the development of a sensitive method for the dosing of carboxylic functions present at the surface of carbon blacks, and the use of this method to study the evolution of a carbon black during heat treatments. After a brief description of modes of fabrication of carbon blacks and of their structure, the author proposes an overview of knowledge on their oxidation and functional analysis. After having outlined that existing methods do not allow the measurement of function quantities less than ten micro-equivalent per gram of carbon, the author reports the development of a method which allows such measurements. By using this method, the author shows that carboxylic groups of a carbon black, oxidized by air or not, decompose during degassing by forming carbon dioxide, and that, reciprocally, the released carbon dioxide is exclusively produced by the decomposition of carboxylic groups

  8. 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.

  9. Characteristic of black carbon in fine particulate matter at Bandung and Lembang sites 2004 - 2005

    International Nuclear Information System (INIS)

    Black carbons (BC) are impure forms of carbon produced by incomplete combustion of fossils fuels or biomass. It has a significant influence in climate forcing due to its light absorption capabilities. In the atmosphere main source of BC are anthropogenic include biomass burning, motor vehicles and industrial sources such as coal combustion. Black carbon typically 10-40% of the fine particulate matter size less than 2.5 µm, therefore it is important to measure the BC correctly. In this study, the measurement of black carbon in fine fractions PM2.5 was done based on reflectance method using EEL Smoke Stain Reflectometer. The sampling was carried out using Gent Stacked Filter Unit twice a week in two locations (BATAN Bandung and Bureau of Meteorological and Geophysics Station Lembang). The results showed there was a significant increasing in both sampling sites in 2005 compared to previous year. The annual average of BC in 2004 at sampling site Bandung and Lembang were 3.16 and 2.42 µg/m3 respectively; in 2005 similarly BC levels at Bandung were higher than that of Lembang with annual average of 3.90 and 2.61 µg/m3 respectively. These concentrations contribute around 18 - 25 % of the fine particulate matter. Comparison the BC concentration with other countries in Asia that used the same method and formula is also presented to show the distribution of BC in Asia. The results showed that BC concentration in Indonesia was lower compared to other countries in Asia. (author)

  10. 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.

  11. 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.

  12. PTCR effect in carbon black/copolymer composites

    International Nuclear Information System (INIS)

    Some materials show an abrupt increase in resistivity when the temperature changes only over a few degrees. This phenomenon, known as PTCR effect (positive temperature coefficient of resistivity), has been largely studied in the last few years, due to its potential applications in industry. Particularly, it can be used in auto controlled heaters, temperature sensors, protection circuits and in security systems for power electronic circuits. In this work we present the study of the electrical properties of the percolating system carbon black particles filled with ethylene butylacrylate copolymer composite (EBA), in the temperature range from -100 to 100 oC and in frequencies between 10 Hz and 100 kHz. The PTCR effect was observed at temperatures slightly above the room temperature, for concentrations higher than that of the percolation critical concentration. The mechanism responsible for the change in resistivity, at this stage, is predominantly tunnelling, wherein the conductive filler particles are not in physical contact, and the electrons tunnel through the insulating gap between them. At low temperatures, such as below and close to the glass transition temperature, the DC conductivity obeys the Arrhenius law. The calculated activation energy values are independent of carbon black contents inside the copolymer matrix, suggesting that these particles do not interact significantly with the chain segments of the macromolecules in the EBA copolymer.

  13. In Brief: Reducing black carbon emissions could immediately reduce global temperature increases

    Science.gov (United States)

    Tretkoff, Ernie

    2011-03-01

    A new assessment by the United Nations Environment Programme (UNEP) shows that measures to reduce emissions of black carbon, or soot, which is produced through burning of wood and other biofuels as well as by some industrial processes, could improve public health and help to significantly reduce projected global temperature increases. The Integrated Assessment of Black Carbon and Tropospheric Ozone highlights how specific measures targeting black carbon and other emissions from fossil fuel extraction, residential wood-burning cooking, diesel vehicles, waste management, agriculture, and small industries could affect climate. Full implementation of a variety of measures to reduce black carbon and methane emissions could reduce future global warming by about 0.5°C, the assessment found. Reducing black carbon could have substantial benefits in the Arctic, the Himalayas, and other snow-covered regions because black carbon that settles on top of snow absorbs heat, speeding melting of snow and ice. Black carbon emission reductions would affect global temperatures more quickly than carbon dioxide emission reductions. Furthermore, reducing black carbon emissions would improve public health in the regions that emit large amounts of the harmful air pollutant.

  14. 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

  15. 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.

  16. Highly crystalline graphene/carbon black composite counter electrodes with controllable content: Synthesis, characterization and application in dye-sensitized solar cells

    International Nuclear Information System (INIS)

    Highlights: ► Certain graphene in composite counter electrode (CE) boosted the efficiency of DSSCs. ► Composite CE combined the merits of graphene and carbon black. ► Systematic research showed the importance of the amount of graphene in composite CE. ► Composite counter electrode had excellent electrochemical stability. -- Abstract: Highly crystalline graphene/carbon black composite counter electrodes, possessing advantages of both rapid electron transport of graphene and high surface area of carbon black, have been prepared using a facile approach. Tuning composite content allows for the fabrication of high-efficiency dye-sensitized solar cells (DSSCs) in this work. The ratio of graphene and carbon black at ca. 1:3 in weight has been confirmed optimum for synthesizing the composite counter electrode. By comparison with those made of either highly crystalline graphene or carbon black, the DSSC based on composite counter electrode has higher conversion efficiency. Moreover, not only does our DSSCs have comparable performance to that of the Pt-based DSSC, but is more cost-effective. Additionally, the chemical catalysis and stability of composite counter electrodes toward I3− reduction, and the interfacial charge transfer have been quantitatively investigated by cyclic voltammetry and electrochemical impedance spectra. The results have revealed that the content of graphene and carbon black in composite counter electrodes is very important for fabricating the DSSCs with high catalytic performance and fast interfacial electron transfer

  17. Enhanced haze pollution by black carbon in megacities in China

    Science.gov (United States)

    Ding, A. J.; Huang, X.; Nie, W.; Sun, J. N.; Kerminen, V.-M.; Petäjä, T.; Su, H.; Cheng, Y. F.; Yang, X.-Q.; Wang, M. H.; Chi, X. G.; Wang, J. P.; Virkkula, A.; Guo, W. D.; Yuan, J.; Wang, S. Y.; Zhang, R. J.; Wu, Y. F.; Song, Y.; Zhu, T.; Zilitinkevich, S.; Kulmala, M.; Fu, C. B.

    2016-03-01

    Aerosol-planetary boundary layer (PBL) interactions have been found to enhance air pollution in megacities in China. We show that black carbon (BC) aerosols play the key role in modifying the PBL meteorology and hence enhancing the haze pollution. With model simulations and data analysis from various field observations in December 2013, we demonstrate that BC induces heating in the PBL, particularly in the upper PBL, and the resulting decreased surface heat flux substantially depresses the development of PBL and consequently enhances the occurrences of extreme haze pollution episodes. We define this process as the "dome effect" of BC and suggest an urgent need for reducing BC emissions as an efficient way to mitigate the extreme haze pollution in megacities of China.

  18. 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.

  19. Black Carbon Vertical Profiles Strongly Affect its Radiative Forcing Uncertainty

    Energy Technology Data Exchange (ETDEWEB)

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

    2013-03-01

    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.

  20. 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.

  1. Enhancement of micropore filling of water on carbon black by platinum loading

    International Nuclear Information System (INIS)

    Two kinds of typical carbons, carbon black and activated carbon fibers, were modified with platinum nanoparticles without changing their original pore structures. The surface properties of the modified carbons were investigated by measuring of water adsorption isotherms. Micropore filling of water was facilitated by the presence of platinum nanoparticles on the surface of the carbon black. On the other hand, such a filling effect was not observed in the case of the activated carbon fibers. A critical content and/or size of platinum nanoparticles could be required to promote efficiently the water adsorption.

  2. Continuous flux of dissolved black carbon from a vanished tropical forest biome

    Science.gov (United States)

    Dittmar, Thorsten; de Rezende, Carlos Eduardo; Manecki, Marcus; Niggemann, Jutta; Coelho Ovalle, Alvaro Ramon; Stubbins, Aron; Bernardes, Marcelo Correa

    2012-09-01

    Humans have used fire extensively as a tool to shape Earth's vegetation. The slash-and-burn destruction of Brazil's Atlantic forest, which once covered over 1.3millionkm2 of present-day Brazil and was one of the largest tropical forest biomes on Earth, is a prime example. Here, we estimate the amount of black carbon generated by the burning of the Atlantic forest, using historical records of land cover, satellite data and black carbon conversion ratios. We estimate that before 1973, destruction of the Atlantic forest generated 200-500 million tons of black carbon. We then estimate the amount of black carbon exported from this relict forest between 1997 and 2008, using measurements of polycyclic aromatic black carbon collected from a large river draining the region, and a continuous record of river discharge. We show that dissolved black carbon (DBC) continues to be mobilized from the watershed each year in the rainy season, despite the fact that widespread forest burning ceased in 1973. We estimate that the river exports 2,700 tons of DBC to the ocean each year. Scaling our findings up, we estimate that 50,000-70,000 tons of DBC are exported from the former forest each year. We suggest that an increase in black carbon production on land could increase the size of the refractory pool of dissolved organic carbon in the deep ocean.

  3. Emissions of black carbon and co-pollutants emitted from diesel vehicles in the Mexico City Metropolitan Area

    Science.gov (United States)

    Zavala, Miguel; Molina, Luisa T.; Fortner, Edward; Knighton, Berk; Herndon, Scott; Yacovitch, Tara; Floerchinger, Cody; Roscioli, Joseph; Kolb, Charles; Mejia, Jose Antonio; Sarmiento, Jorge; Paramo, Victor Hugo; Zirath, Sergio; Jazcilevich, Aron

    2014-05-01

    Black carbon emitted from freight, public transport, and heavy duty trucks sources is linked with adverse effects on human health. In addition, the control of emissions of black carbon, an important short-lived climate forcing agent (SLCF), has recently been considered as one of the key strategies for mitigating regional near-term climate change. Despite the availability of new emissions control technologies for reducing emissions from diesel-powered mobile sources, their introduction is still not widespread in many urban areas and there is a need to characterize real-world emission rates of black carbon from this key source. The emissions of black carbon, organic carbon, and other gaseous and particle pollutants from diesel-powered mobile sources in Mexico were characterized by deploying a mobile laboratory equipped with real-time instrumentation in Mexico City as part of the SLCFs-Mexico 2013 project. From February 25-28 of 2013 the emissions from selected diesel-powered vehicles were measured in both controlled experiments and real-world on-road driving conditions. Sampled vehicles had several emissions levels technologies, including: EPA98, EPA03, EPA04, EURO3-5, and Hybrid. All vehicles were sampled using diesel fuel and several vehicles were measured using both diesel and biodiesel fuels. Additional measurements included the use of a remote sensing unit for the co-sampling of all tested vehicles, and the installation and operation of a Portable Emissions Measurements System (PEMS) for the measurement of emissions from a test vehicle. We will present inter-comparisons of the emission factors obtained among the various vehicle technologies that were sampled during the experiment as well as the inter-comparison of results from the various sampling platforms. The results can be used to

  4. Automatic Method for Controlling the Iodine Adsorption Number in Carbon Black Oil Furnaces

    OpenAIRE

    Zečević, N.

    2008-01-01

    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 blac...

  5. Measured Black Carbon Deposition on the Sierra Nevada Snow Pack and Implication for Snow Pack Retreat

    Energy Technology Data Exchange (ETDEWEB)

    Hadley, O.L.; Corrigan, C.E.; Kirchstetter, T.W.; Cliff, S.S.; Ramanathan, V.

    2010-01-12

    Modeling studies show that the darkening of snow and ice by black carbon deposition is a major factor for the rapid disappearance of arctic sea ice, mountain glaciers and snow packs. This study provides one of the first direct measurements for the efficient removal of black carbon from the atmosphere by snow and its subsequent deposition to the snow packs of California. The early melting of the snow packs in the Sierras is one of the contributing factors to the severe water problems in California. BC concentrations in falling snow were measured at two mountain locations and in rain at a coastal site. All three stations reveal large BC concentrations in precipitation, ranging from 1.7 ng/g to 12.9 ng/g. The BC concentrations in the air after the snow fall were negligible suggesting an extremely efficient removal of BC by snow. The data suggest that below cloud scavenging, rather than ice nuclei, was the dominant source of BC in the snow. A five-year comparison of BC, dust, and total fine aerosol mass concentrations at multiple sites reveals that the measurements made at the sampling sites were representative of large scale deposition in the Sierra Nevada. The relative concentration of iron and calcium in the mountain aerosol indicates that one-quarter to one-third of the BC may have been transported from Asia.

  6. Structure aggregation of carbon black in ethylene-propylene diene polymer

    Directory of Open Access Journals (Sweden)

    2009-03-01

    Full Text Available The modulus of filled and unfilled Ethylene-propylene diene rubber (EPDM vulcanizates was used to predict the shape-factor of carbon black aggregation in the polymer. Four types of carbon black that vary in particle size and structure were used in this study. Quadratic curves relating the carbon black volume concentration and the modulus ratio of filled and unfilled rubber vulcanizates were used to adopt the shape factor of certain carbon black type. The shape factor of MT, HAF, SRF and Lampblack were 3, 3.75, 4 and 4.25 respectively. X-ray diffraction technique (XRD was also used to evaluate the relative size of crystallite on the filler surface to that of the rubber and correlating it to the shape factor of carbon black aggregation in the polymer. Effect of the pH values and structure of carbon blacks used on the shape factor of filler aggregates were also studied. It was found that the shape factor is independent on the particle size while it is dependent on the pH value and structure of carbon black. Also the crystallites size of the filler is proportional to the shape factor.

  7. 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

  8. 黑土团聚体与颗粒中碳、氮含量及腐殖质组成的比较%Comparison of Carbon, Nitrogen Contents and Humus Compositions in the Aggregates and Particles of Black Soil

    Institute of Scientific and Technical Information of China (English)

    窦森; 郝翔翔

    2013-01-01

    [目的]研究黑土不同粒级团聚体和颗粒中的碳、氮及腐殖质组分含量,并分析、比较土壤团聚体与土壤颗粒中腐殖质相互关系.[方法]以黑土区连续9年的耕作试验为平台,采用湿筛法分离土壤团聚体,超声波方法分离土壤颗粒,分别测定不同粒级团聚体和土壤颗粒中的碳、氮、胡敏酸(HA)、富里酸(FA)、铁结合胡敏素(Hi)、黏粒结合胡敏素(Hc)和不溶性胡敏素(Hr)的含量.[结果]>53μm粒级颗粒中的碳、氮以及HA、FA、Hi和Hc的含量明显低于<53 μm粒级颗粒,而>53 μm和<53 μm粒级团聚体中的碳、氮以及HA、FA、Hi和Hc的含量则基本处于同一水平.因此,形成团聚体的过程,弱化了粒级之间有机质的差异.相同粒级比较,在>53 μm粒级中,团聚体比颗粒含有更多的腐殖质,且PQ值和腐殖质化程度大于颗粒;但在<53 μm粒级中,团聚体和颗粒中腐殖质的含量和PQ值则处于同一水平,说明在较大粒级中,由于同样也包含了小颗粒的作用,强化了团聚体与颗粒中有机质的差异.[结论]土壤团聚体与土壤颗粒中碳、氮以及腐殖质各组分含量随粒级变化的规律存在着明显差异.不同粒级土壤颗粒中有机质的含量差异及其腐殖化程度差异会随着团聚化作用减弱.%[Objective] The objective of this study was to research the contents of carbon,nitrogen and humus composition in different aggregates and particle-size fractions of black soil,to analyze and compare the relationship of humus in the soil aggregate and particle-size fractions.[Method] The research platform was an 9-years field experiment carried out in black soil region,and soil aggregates and particles were separated by wet sieving and ultrasonic method,respectively.The contents of total C,N,the composition of humic substance (HS) in soil aggregates and particle-size fractions,were investigated respectively.[Result] The contents of C,N,humic acid (HA

  9. 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.

  10. 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)

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

    International Nuclear Information System (INIS)

    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

  12. 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.

  13. 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

  14. Black carbon estimation in French calcareous soils using chemo-thermal oxidation method

    OpenAIRE

    Caria, G.; Arrouays, D.; Dubromel, E.; Jolivet, C.; Ratié, C.; Bernoux, MARTIAL,; Barthès, Bernard; Brunet, Didier; Grinand, Clovis

    2011-01-01

    We studied the black carbon (BC) content of ca. 405 samples from French topsoil and artificial soil and carbonate mixtures. Our protocol involved three main steps: (i) decarbonation by HCl, (ii) elimination of non-pyrogenic organic carbon in a furnace at 375 degrees C, and (iii) quantification of residual carbon by CHN analysis. BC content increased for calcareous soils according to their carbonates content. Subsequent analyses confirmed the existence of a methodological artefact for BC deter...

  15. 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.

  16. 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

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

    Directory of Open Access Journals (Sweden)

    M. O. Andreae

    2006-05-01

    Full Text Available Although the definition and measurement methods of atmospheric ''black carbon'' (''BC'' 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 directly from aerosol absorption measurements near specific combustion sources, from observations of spectral properties of water extracts of continental aerosol, from laboratory studies indicating the formation of light-absorbing organic matter in the atmosphere, and indirectly from the chemical analogy of aerosol species to colored natural humic substances. We show that these species may severely bias measurements of ''BC'' and ''EC'' over vast parts of the troposphere, where mass concentration of Cbrown is high relative to that of combustion soot. We also imply that due to the strongly skewed 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. The possible consequences of these effects on our understanding of tropospheric processes are discussed.

  18. Mass spectrometry of refractory black carbon particles from six sources: carbon-cluster and oxygenated ions

    Directory of Open Access Journals (Sweden)

    J. C. Corbin

    2013-10-01

    Full Text Available We discuss the major mass spectral features of different types of refractory carbonaceous particles, ionized after laser vapourization with an Aerodyne High-Resolution Soot-Particle Aerosol Mass Spectrometer (SP-AMS. The SP-AMS was operated with a switchable 1064 nm laser and a 600 °C thermal vapourizer, yielding respective measurements of the refractory and non-refractory particle components. Six samples were investigated, all of which were composed primarily of refractory material: fuel-rich and fuel-lean propane/air diffusion-flame combustion particles; graphite-spark-generated particles; a commercial Fullerene-enriched Soot; Regal Black, a commercial carbon black; and nascent aircraft-turbine combustion particles. All samples exhibited a spectrum of carbon-cluster ions Cxn+ in their refractory mass spectrum. Smaller clusters (xxn+ distribution. For Fullerene Soot, fuel-rich-flame particles and spark-generated particles, significant Cxn+ clusters at x≫6 were present, with significant contributions from multiply-charged ions (n>1. In all six cases, the ions C1+ and C3+ contributed over 60% to the total C1x+ intensity. Furthermore, the ratio of these major ions C1+/C3+ could be used to predict whether significant Cxn+ signals with x>5 were present. When such signals were present, C1+/C3+ was close to 1. When absent, C1+/C3+ was Significant refractory oxygenated ions such as CO+ and CO2+ were also observed for all samples. We discuss these signals in detail for Regal Black, and describe their formation via decomposition of oxygenated moieties incorporated into the refractory carbon structure. These species may be of importance in atmospheric processes such as water uptake, aging and heterogeneous chemistry.

  19. Assessing the Extent of Black Carbon Absorption Enhancements from Field Observations

    Science.gov (United States)

    Cappa, C. D.; Zhang, X.; Metcalf, A. R.; Kim, H.; Zhang, Q.; Zimmermann, K.; Bertram, T. H.; Corrigan, A. L.; Russell, L. M.

    2013-12-01

    Black carbon (BC) and brown carbon (BrC) play important roles as short-lived climate forcers (SLCFs) as a result of their short atmospheric lifetimes and ability to absorb solar radiation. The direct impacts of BC on climate depend on just how efficiently a given BC particle absorbs solar radiation, while the impacts of BrC depend on the specific properties of the BrC. The addition of 'coatings' to BC particles can theoretically increase the absorption by a given particle, and this theoretical 'lensing' enhancement has been confirmed through laboratory experiments. However, recent field observations (from the CalNex and CARES studies; Cappa et al. 2012), using a novel thermodenuder-absorption method, have suggested that the actual enhancement for ambient particles is substantially less than theoretically expected. Here, we will discuss results from similar measurements made during two recent field studies, the 2013 DISCOVER-AQ Fresno study and the 2013 SOAS Look Rock study. DISCOVER-AQ took place in Jan/Feb 2013 in Fresno, CA. This region is severely impacted by particulate matter from local and regional residential biomass burning, and thus provides a sharp contrast to the previous CalNex and CARES studies. SOAS took place during June/July 2013 at Look Rock National Park, TN, a relatively remote region strongly impacted by biogenic emissions (predominately isoprene) and located approximately 30 miles away from Knoxville, TN. The difference in absorption for dry, ambient particles will be compared with absorption measured for particles that have been passed through a thermodenuder. Additionally, variations in the mass absorption coefficient, determined from comparison of the measured light absorption and refractory black carbon concentrations, will be examined. The relative contributions of BrC and BC to total absorption at 405 nm, 532 nm and 870 nm will be discussed. The overall measurements suggest a relatively small role for lensing-induced absorption

  20. Black Carbon Inclusive Multichemical Modeling of PBDE and PCB Biomagnification and -Transformation in Estuarine Food Webs

    NARCIS (Netherlands)

    Paolo, C.; Gandhi, N.; Bhavsar, S.; Heuvel-Greve, van den M.J.; Koelmans, A.A.

    2010-01-01

    Bioavailability and bioaccumulation of polybrominated diphenylethers (PBDEs) are affected by adsorption on black carbon (BC) and metabolism in biota, respectively. Recent studies have addressed these two processes separately, illustrating their importance in assessing contaminant dynamics. In order

  1. Modern biofuels life-cycle effects on black carbon emissions and impacts

    Science.gov (United States)

    Campbell, J.; Spak, S.; Mena-Carrasco, M.; Carmichael, G. R.; Chen, Y.; Tsao, C.

    2010-12-01

    The rapid growth of modern biofuels production (primarily ethanol) contributes to increased black carbon and co-pollutant emissions, particularly due to the field burning of agriculture wastes and the indirect land use impacts of forest clearing. U.S. bioenergy policy has already mandated life-cycle emissions thresholds for greenhouse gases from biofuels but there is still a need to incorporate black carbon and other short-lived climate forcers into these metrics. Thus, an understanding of the biofuels sector for black carbon and co-pollutant emissions and impacts remains a critical knowledge gap. Here we combine high-resolution agronomic data and regional chemical transport modeling to consider the life-cycle emissions of black carbon from sugarcane ethanol production in Brazil. Furthermore, we explore the potential for significant radiative forcing from the pre-harvest burning of sugarcane fields and the indirect land use emissions associated with deforestation.

  2. 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.

  3. Daily personal exposure to black carbon: A pilot study

    Science.gov (United States)

    Williams, Ryan D.; Knibbs, Luke D.

    2016-05-01

    Continuous personal monitoring is the benchmark for air pollution exposure assessment. Black carbon (BC) is a strong marker of primary combustion like vehicle and biomass emissions. There have been few studies that quantified daily personal BC exposure and the contribution that different microenvironments make to it. In this pilot study, we used a portable aethalometer to measure BC concentrations in an individual's breathing zone at 30-s intervals while he performed his usual daily activities. We used a GPS and time-activity diary to track where he spent his time. We performed twenty 24-h measurements, and observed an arithmetic mean daily exposure concentration of 603 ng/m3. We estimated that changing commute modes from bus to train reduced the 24-h mean BC exposure concentration by 29%. Switching from open windows to closed windows and recirculated air in a car led to a reduction of 32%. Living in a home without a wood-fired heater caused a reduction of 50% compared with a wood-heated home. Our preliminary findings highlight the potential utility of simple approaches to reduce a person's daily BC exposure.

  4. 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.

  5. Hygroscopicity of Black-Carbon-Containing Aerosol in Wildfire Plumes

    Science.gov (United States)

    Perring, A. E.; Schwarz, J. P.; Markovic, M. Z.; Fahey, D. W.; Yokelson, R. J.; Jimenez, J. L.; Campuzano Jost, P.; Day, D. A.; Palm, B. B.; Wisthaler, A.; Ziemba, L. D.; Anderson, B. E.; Diskin, G. S.; Huey, L. G.; Gao, R. S.

    2015-12-01

    Water uptake by black carbon (BC) containing aerosol has been quantified in wildfire plumes of varying age (from 1 to ~40 hr old) sampled in North America during the NASA SEAC4RS mission of 2013. Measurements were made in flight using parallel single-particle soot photometers (SP2) that simultaneously detected the BC component of the ambient aerosol ensemble under contrasting humidity conditions. The hygroscopicity parameter, κ, of material internally mixed with BC derived from this data set is consistent with previous estimates of bulk aerosol hygroscopicity from biomass burning sources. We explore the temporal evolution of κ during aging of the Yosemite Rim Fire plume to constrain the rate of conversion of BC-containing aerosol from hydrophobic to hydrophilic modes in these emissions. We also investigate the relationship between κ values for BC-containing particles and the oxidation state and hygroscopicity of the bulk aerosol. These observations have implications for BC transport and removal in biomass burning plumes and provide important constraints on model treatment of BC optical and microphysical properties from wildfire sources in ambient conditions.

  6. Preparation and characterization of dopamine-decorated hydrophilic carbon black

    Energy Technology Data Exchange (ETDEWEB)

    Zhu Lijun; Lu Yonglai [State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, Beijing 100029 (China); Key Laboratory of Beijing City on Preparation and Processing of Novel Polymer Materials, Beijing 100029 (China); Wang Yiqing [State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, Beijing 100029 (China); Key Laboratory of Carbon Fiber and Functional Polymers, Ministry of Education, Beijing 100029 (China); Zhang Liqun [State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, Beijing 100029 (China); Key Laboratory of Beijing City on Preparation and Processing of Novel Polymer Materials, Beijing 100029 (China); Wang Wencai, E-mail: wangw@mail.buct.edu.cn [State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, Beijing 100029 (China); Key Laboratory of Carbon Fiber and Functional Polymers, Ministry of Education, Beijing 100029 (China)

    2012-05-01

    Inspired by the bio-adhesive proteins secreted by mussels for attachment to almost all wet substrates, a facile method involving oxidative polymerization of dopamine was proposed to prepare highly hydrophilic carbon black (CB) particles. A self-assembled polydopamine (PDA) ad-layer was formed via the oxidative polymerization of dopamine on the surface of CB simply by dipping the CB into an alkaline dopamine solution and mildly stirring at room temperature. The process is simple, controllable, and environment-friendly. The surface composition and structure of the CB were characterized by X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR). The surface morphology of the CB was observed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results showed that the PDA ad-layer was successfully deposited on the CB surfaces. The PDA-functionalized CB (CB-PDA) gave a stable colloidal dispersion in water. Contact angle measurement results indicated that the hydrophilicity of CB was significantly improved after dopamine modification. TGA results confirmed that the modified CB maintained good heat resistance. The method provided a facile route to prepare hydrophilic CB having terminal hydroxyl groups.

  7. Trend in global black carbon emissions from 1960 to 2007.

    Science.gov (United States)

    Wang, Rong; Tao, Shu; Shen, Huizhong; Huang, Ye; Chen, Han; Balkanski, Yves; Boucher, Olivier; Ciais, Philippe; Shen, Guofeng; Li, Wei; Zhang, Yanyan; Chen, Yuanchen; Lin, Nan; Su, Shu; Li, Bengang; Liu, Junfeng; Liu, Wenxin

    2014-06-17

    Black carbon (BC) plays an important role in both climate change and health impact. Still, BC emissions as well as the historical trends are associated with high uncertainties in existing inventories. In the present study, global BC emissions from 1960 to 2007 were estimated for 64 sources, by using recompiled fuel consumption and emission factor data sets. Annual BC emissions had increased from 5.3 (3.4-8.5 as an interquartile range) to 9.1 (5.6-14.4) teragrams during this period. Our estimations are 11-16% higher than those in previous inventories. Over the period, we found that the BC emission intensity, defined as the amount of BC emitted per unit of energy production, had decreased for all the regions, especially China and India. Improvements in combustion technology and changes in fuel composition had led to an increase in energy use efficiency, and subsequently a decline of BC emission intensities in power plants, the residential sector, and transportation. On the other hand, the BC emission intensities had increased in the industrial and agricultural sectors, mainly due to an expansion of low-efficiency industry (coke and brick production) in developing countries and to an increasing usage of diesel in agriculture in developed countries. PMID:24825392

  8. 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.

  9. Preparation and characterization of dopamine-decorated hydrophilic carbon black

    International Nuclear Information System (INIS)

    Inspired by the bio-adhesive proteins secreted by mussels for attachment to almost all wet substrates, a facile method involving oxidative polymerization of dopamine was proposed to prepare highly hydrophilic carbon black (CB) particles. A self-assembled polydopamine (PDA) ad-layer was formed via the oxidative polymerization of dopamine on the surface of CB simply by dipping the CB into an alkaline dopamine solution and mildly stirring at room temperature. The process is simple, controllable, and environment-friendly. The surface composition and structure of the CB were characterized by X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR). The surface morphology of the CB was observed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results showed that the PDA ad-layer was successfully deposited on the CB surfaces. The PDA-functionalized CB (CB-PDA) gave a stable colloidal dispersion in water. Contact angle measurement results indicated that the hydrophilicity of CB was significantly improved after dopamine modification. TGA results confirmed that the modified CB maintained good heat resistance. The method provided a facile route to prepare hydrophilic CB having terminal hydroxyl groups.

  10. Organic Carbon--water Concentration Quotients (IIsocS and [pi]pocS): Measuring Apparent Chemical Disequilibria and Exploring the Impact of Black Carbon in Lake Michigan

    Science.gov (United States)

    When black carbon (bc) and biologically derived organic carbon (bioc) phases are present in sediments or suspended particulates, both forms of carbon act additively to sorb organic chemicals but the bc phase has more sorption capacity per unit mass. . . .

  11. Black carbon emissions from Russian diesel sources: case study of Murmansk

    OpenAIRE

    Evans, M.; N. Kholod; Malyshev, V.; Tretyakova, S.; Gusev, E.; Yu, S.; Barinov, A.

    2015-01-01

    Black carbon (BC) is a potent pollutant because of its effects on climate change, ecosystems and human health. Black carbon has a particularly pronounced impact as a climate forcer in the Arctic because of its effect on snow albedo and cloud formation. We have estimated BC emissions from diesel sources in Murmansk Region and Murmansk City, the largest city in the world above the Arctic Circle. In this study we developed a detailed inventory of diesel sources including on-road ...

  12. Black carbon emissions from Russian diesel sources: case study of Murmansk

    OpenAIRE

    Evans, M.; N. Kholod; Malyshev, V.; Tretyakova, S.; Gusev, E.; Yu, S.; Barinov, A.

    2015-01-01

    Black carbon (BC) is a potent pollutant because of its effects on climate change, ecosystems and human health. Black carbon has a particularly pronounced impact as a climate forcer in the Arctic because of its effect on snow albedo and cloud formation. We have estimated BC emissions from diesel sources in the Murmansk Region and Murmansk City, the largest city in the world above the Arctic Circle. In this study we developed a detailed inventory of diesel sources including on...

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

    OpenAIRE

    Vignati, E.; Karl, M; M. Krol; Wilson, J.(School of Physics and Astronomy, University of Birmingham, Birmingham, United Kingdom); Stier, P; F. Cavalli

    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...

  14. Using Pyrolized Carbon Black (PCB) from Waste Tires in Asphalt Pavement (Part 2, Asphalt Binder)

    OpenAIRE

    Zeng, Yongdong; Lovell, C. W.

    1996-01-01

    Scrap tires derived from automobiles have become a large environmental problem in the United States. In this study, research is carried out to investigate the potential use of tire-derived pyrolyzed carbon black from scrap tires as an asphalt cement modifier. The asphalt cements used in this research were AC10 and AC20. Penetration and softening point tests were performed to obtain the consistency of the asphalt cements. The pyrolyzed carbon black, as provided by Wolf Industries, was comb...

  15. 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

  16. Challenges for Reducing Emissions of Black Carbon from the Transport Sector in Urban Areas

    Science.gov (United States)

    Zavala, M. A.; Molina, L. T.

    2013-05-01

    The transport sector is a large contributor of harmful gaseous and particulate emissions in many urban areas. Black carbon is a component of short-lived particulate matter emitted predominantly by freight, public transport, and heavy- duty trucks. Controlling the emissions of black carbon from the transport sector is important for mitigating its impacts on climate, ecosystems, and human health. However, reducing the emissions of black carbon from mobile sources may be a challenging task in many developing urban areas due to economic, social, and technical constrains. Several emissions control technologies offer a proven approach for reducing emissions of black carbon from diesel-powered mobile sources, but the accurate quantification of associated emissions benefits in developing urban areas is not well documented. We describe recent advances for the estimation of black carbon emissions from the transport sector in real world driving conditions and present examples of the potential benefits of implementing various emission control technologies in Mexico. The results can help in the identification of key factors that hinder the implementation of control emissions for reducing emissions of black carbon elsewhere.

  17. 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.

  18. Measurement of Black Carbon and Co-pollutants Emitted from Diesel Vehicles in Mexico

    Science.gov (United States)

    Zavala, M. A.; Molina, L. T.; Fortner, E.; Herndon, S.; Knighton, B.; Yacovitch, T. I.; Floerchinger, C. R.; Roscioli, J. R.; Kolb, C. E.; Paramo, V. H.; Zirath, S.; Mejia, J.; Jazcilevich, A. D.

    2013-12-01

    Freight, public transport, and heavy-duty trucks can contribute to harmful emissions of black carbon and other co-pollutants in many urban areas. Controlling the emissions of black carbon from the transport sector is important for the potential of mitigating its impacts on climate, ecosystems, and human health. However, reducing the emissions of black carbon from mobile sources is be a challenging task in many developing urban areas due to economic, social, and technical constrains, as well as the uncertainties surrounding the accurate quantification of the associated benefits. Several emissions control technologies offer a proven approach for reducing emissions of black carbon from diesel-powered mobile sources, but the accurate quantification of associated emissions benefits in developing urban areas is not well documented. We present the results of the measurement of black carbon and co-emitted pollutants of dozens of diesel powered vehicles, including freight trucks, public transport buses, and intra-city metrobuses sampled during a 4-day experiment in Mexico City in February of 2013 as part of the SLCFs-Mexico project. Measurements were obtained with the Aerodyne Mobile Laboratory, remote sensing, and portable emissions measurements, and encompassed the sampling of several vehicle models and technologies in experimental and real-world driving conditions. The results can help in the identification of key factors that hinder the implementation of control emissions for reducing emissions of black carbon elsewhere and the potential benefits of implementing various emission control technologies.

  19. Global emission inventory and atmospheric transport of black carbon. Evaluation of the associated exposure

    International Nuclear Information System (INIS)

    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.

  20. 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.

  1. 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 0.005-7.14mg/kg-fuel under the speeds of 20-70km/h, 0.05-28.95mg/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. PMID:26799329

  2. 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.

  3. 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

  4. 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

  5. Aerosol black carbon over Svalbard regions of Arctic

    Science.gov (United States)

    Gogoi, Mukunda M.; Babu, S. Suresh; Moorthy, K. Krishna; Thakur, Roseline C.; Chaubey, Jai Prakash; Nair, Vijayakumar S.

    2016-03-01

    In view of the climate impact of aerosol Black Carbon (BC) over snow covered regions (through enhanced absorption of radiation as well as snow-albedo forcing), and in view of the increasing anthropogenic presence and influence in the northern polar regions, continuous long term measurements of airborne BC have been undertaken from the Svalbard region of Norwegian Arctic (Ny-Ålesund, 79°N, 12°E, 8 m a.s.l.). This study, employing data over a period of 4-years (2010-2013) have shown a consistent spring-time enhancement in BC concentrations, having a (climatological) seasonal mean value of ∼50.3 ± 19.5 ng m-3, nearly 3-times higher than the lowest BC concentrations in summer (∼19.5 ± 6.5 ng m-3). Spectral variation of absorbance indicates that long-range transported biomass burning aerosols contribute as high as 25% to the high BC concentrations in the Arctic atmosphere in spring. Concurrent estimates of BC concentrations in the Arctic snow (for an ensemble of snow samples collected over a period of time during spring) showed values ranging from 0.6 ppb to 4.1 ppb. These values have been used to estimate the BC scavenging ratio (SR). Our studies revealed a mean value of SR ∼98 ± 46, which varied over wide range from 40 to 184 for individual samples. In a broader perspective, the seasonal variations of atmospheric BC concentrations at the Arctic are similar to those seen at the high altitude Himalayas; even though the concentrations are much lower at Arctic. It is found that synoptic conditions mainly influence the high altitude Himalayas, while the influences of local anthropogenic influences are not negligible at the Arctic in modulating the seasonal variations of absorbing aerosols.

  6. Origin of black carbon concentration peaks in Cairo (Egypt)

    Energy Technology Data Exchange (ETDEWEB)

    Mahmoud, K.F.; Wahab, M.M.A. [Cairo Univ, Fac Sci, Astron and Meteorol Dept, Giza (Egypt); Alfaro, S.C. [Univ Paris 12, LISA, F-94010 Creteil, (France); Alfaro, S.C. [Univ Paris 07, CNRS, F-94010 Creteil (France); Favez, O.; Sciare, J. [CEA Saclay, DSM, LSCE IPSL, Lab mixte CEA-CNRS-UVSQ, F-91191 Gif Sur Yvette (France)

    2008-07-01

    The concentration in black carbon (BC) has been monitored in the mega-city of Cairo (Egypt) during the autumn 2004 and spring 2005 intensive observation periods of the Cairo Aerosol Characterization Experiment (CACHE). As expected for a species released by human activities, hourly mean of this concentration is found to be large at all times. It is also significantly larger in autumn than in spring (9.9 {+-} 6.6 and 6.9 {+-} 4.8 {mu}gC/m{sup 3}, respectively) and quite variable at shorter (diurnal) time scales. Indeed, sharp concentration peaks larger than 25 {mu}gC/m{sup 3} are frequently detected during both observation periods. In order to apportion the roles played by emission intensity and meteorological conditions in the development of these peaks, a simple model is developed that allows derivation of the hourly mean BC emissions by the part of town located upwind of the measurement site. The analysis of the time dependence of these emissions indicates that traffic is by far the major source of BC in Cairo during daytime and this even in autumn when biomass burning takes place in the Nile delta. It is only between 03:00 and 05:00 in the night, at a time when traffic emissions are quite reduced, that the influence of this particular source on BC concentration can become significant. This study also indicates that BC emissions by motorized traffic remain important from the morning rush hour until late in the night. During the day, and particularly in spring, the dilution effect resulting from the development of the planetary boundary layer prevents BC concentrations from becoming very large. This is no longer the case just before sunrise and after sunset, when the combination of dense traffic and low boundary layer is responsible for the observed sharp increase in BC concentration. (authors)

  7. Black carbon concentration trends in Helsinki during 1996–2005

    Directory of Open Access Journals (Sweden)

    T. Pakkanen

    2007-10-01

    Full Text Available The black carbon (BC concentration trends were studied during ten years in Helsinki, Finland. Measurements were made in three campaigns between 1996 and 2005 at an urban area locating two kilometres from the centre of Helsinki. The first campaign was from November 1996 to June 1997, the second from September 2000 to May 2001 and the third from March 2004 to October 2005. In this study, only data from winter and spring months was analysed. The effect of traffic and meteorological variables on the measured BC concentrations was studied by means of a multiple regression analysis, where the meteorological data was obtained from a meteorological pre-processing model (MPP-FMI. During the ten years, the campaign median BC concentrations were found to decrease slightly from 1.11 to 1.00 μg m−3. The lowest campaign median concentration (0.93 μg m−3 was measured during the second campaign in 2000–2001, when also the lowest traffic rates were measured. The strongest decrease between campaigns 1 and 3 was observed during weekday daytimes, when the traffic rates are highest. The variables affecting the measured BC concentrations most were traffic, wind speed and mixing height. On weekdays, traffic had clearly the most important influence and on weekends the effect of wind speed diluted the effect of traffic. The affecting variables and their influence on the BC concentration were similar in winter and spring. The separate examination of the three campaigns showed that the effect of traffic on the BC concentrations had decreased during the studied years. This reduction was caused by cleaner emissions from vehicles, since between years 1996 and 2005 the traffic rates had increased. A rough estimate gave that vehicle number-scaled BC mass concentrations have decreased from 0.0028 to 0.0020 μg m−3 between campaigns 1 and 3.

  8. Black Carbon Increases Cation Exchange Capacity in Soils

    International Nuclear Information System (INIS)

    Black Carbon (BC) may significantly affect nutrient retention and play a key role in a wide range of biogeochemical processes in soils, especially for nutrient cycling. Anthrosols from the Brazilian Amazon (ages between 600 and 8700 yr BP) with high contents of biomass-derived BC had greater potential cation exchange capacity (CEC measured at pH 7) per unit organic C than adjacent soils with low BC contents. Synchrotron-based near edge X-ray absorption fine structure (NEXAFS) spectroscopy coupled with scanning transmission X-ray microscopy (STXM) techniques explained the source of the higher surface charge of BC compared with non-BC by mapping cross-sectional areas of BC particles with diameters of 10 to 50 (micro)m for C forms. The largest cross-sectional areas consisted of highly aromatic or only slightly oxidized organic C most likely originating from the BC itself with a characteristic peak at 286.1 eV, which could not be found in humic substance extracts, bacteria or fungi. Oxidation significantly increased from the core of BC particles to their surfaces as shown by the ratio of carboxyl-C/aromatic-C. Spotted and non-continuous distribution patterns of highly oxidized C functional groups with distinctly different chemical signatures on BC particle surfaces (peak shift at 286.1 eV to a higher energy of 286.7 eV) indicated that non-BC may be adsorbed on the surfaces of BC particles creating highly oxidized surface. As a consequence of both oxidation of the BC particles themselves and adsorption of organic matter to BC surfaces, the charge density (potential CEC per unit surface area) was greater in BC-rich Anthrosols than adjacent soils. Additionally, a high specific surface area was attributable to the presence of BC, which may contribute to the high CEC found in soils that are rich in BC

  9. Speciation of the ionizable antibiotic sulfamethazine on black carbon (biochar).

    Science.gov (United States)

    Teixidó, Marc; Pignatello, Joseph J; Beltrán, José L; Granados, Mercè; Peccia, Jordan

    2011-12-01

    Adsorption of ionizable compounds by black carbon is poorly characterized. Adsorption of the veterinary antibiotic sulfamethazine (SMT; a.k.a., sulfadimidine; pK(a1) = 2.28, pK(a2) = 7.42) on a charcoal was determined as a function of concentration, pH, inorganic ions, and organic ions and molecules. SMT displayed unconventional adsorption behavior. Despite its hydrophilic nature (log K(ow) = 0.27), the distribution ratio K(d) at pH 5, where SMT(0) prevails, was as high as 10(6) L kg(-1), up to 10(4) times greater than literature reported K(oc). The K(d) decreases at high and low pH but not commensurate with the decline in K(ow) of the ionized forms. At pH 1, where SMT(+) is predominant and the surface is positive, a major driving force is π-π electron donor-acceptor interaction of the protonated aniline ring with the π-electron rich graphene surface, referred to as π(+)-π EDA, rather than ordinary electrostatic cation exchange. In the alkaline region, where SMT(-) prevails and the surface is negative, adsorption is accompanied by near-stoichiometric proton exchange with water, leading to the release of OH(-) and formation of an exceptionally strong H-bond between SMT(0) and a surface carboxylate or phenolate, classified as a negative charge-assisted H-bond, (-)CAHB. At pH 5, SMT(0) adsorption is accompanied by partial proton release and is competitive with trimethylphenylammonium ion, signifying contributions from SMT(+) and/or the zwitterion, SMT(±), which take advantage of π(+)-π EDA interaction and Coulombic attraction to deprotonated surface groups. In essence, both pK(a1) and pK(a2) increase, and SMT(±) is stabilized, in the adsorbed relative to the dissolved state. PMID:22026725

  10. A comparison of remnants in noncommutative Bardeen black holes

    OpenAIRE

    Mehdipour, S. Hamid; Ahmadi, M. H.

    2016-01-01

    We derive the mass term of the Bardeen metric in the presence of a noncommutative geometry induced minimal length. In this setup, the proposal of a stable black hole remnant as a candidate to store information is confirmed. We consider the possibility of having an extremal configuration with one degenerate event horizon and compare different sizes of black hole remnants. As a result, once the magnetic charge $g$ of the noncommutative Bardeen solution becomes larger, both the minimal nonzero m...

  11. Long-term Black Carbon Dynamics in Cultivated Soil

    Energy Technology Data Exchange (ETDEWEB)

    Nguyen, Binh T; Lehmann, Johannes C; Kinyangi, James; Smernik, Ron; Riha, Susan J; Engelhard, Mark H

    2008-07-01

    Black carbon (BC) is a quantitatively important C pool in the global carbon cycle due to its relative recalcitrance against decay compared with other C pools. However, how rapidly BC is oxidized and in what way the molecular structure changes during decomposition over decadal time scales, is largely unknown. In the present study, the long-term dynamics in quality and quantity of BC were investigated in cultivated soil using X-ray Photoelectron Spectroscopy (XPS), Fourier-Transform Infrared (FTIR) and Nuclear Magnetic Resonance (NMR) techniques. BC particles, obtained from soil samples at 8 conversion ages stretching over 100 years and from a forest soil sample from Kenya, were manually picked under a light microscope for characterization and quantification. BC contents rapidly decreased from 12.7 to 3.8 mg C g⁻¹ soil during the first 30 years since conversion, after which they slowly decreased to a steady state at 3.51 mg C g ⁻¹soil. BC-derived C losses over 100 years were estimated at 6000 kg C ha⁻¹ to a depth of 0.1 m. The initial rapid changes in BC stocks resulted in a mean residence time of only around 8.3 years, which was likely a function of both decomposition as well as transport processes. The molecular properties of BC changed more rapidly on surfaces than in the interior of BC particles and more rapidly during the first 30 years than during the following 70 years. The Oc/C ratios (Oc is O bound to C) and carbonyl groups (C=O) increased over time by 133 and 192 %, respectively, indicating oxidation was an important degradation process controlling BC quality. Al, Si, polysaccharides, and to a lesser extent Fe were rapidly adsorbed on BC particle surfaces within the first few years after BC deposition to soil. The protection by physical and chemical stabilization was apparently sufficient to not only minimize decomposition below detection between 30 and 100 years after deposition, but also physical export by erosion and vertical transport below 0

  12. Effects of airborne black carbon pollution on maize

    Science.gov (United States)

    Illes, Bernadett; Anda, Angela; Soos, Gabor

    2013-04-01

    The black carbon (BC) changes the radiation balance of the Earth and contributes to global warming. The airborne BC deposited on the surface of plant, changing the radiation balance, water balance and the total dry matter (TDM) content of plant. The objective of our study was to investigate the impact of soot originated from motor vehicle exhaust on maize. The field experiment was carried out in Keszthely Agrometeorological Research Station (Hungary) in three consecutive years (2010, 2011, 2012) of growing season. The test plant was the maize hybrid Sperlona (FAO 340) with short growing season. The BC was chemically "pure", which means that it is free any contaminants (e.g. heavy metals). The BC was coming from the Hankook Tyre Company (Dunaújváros, Hungary), where used that for improve the wear resistance of tires. We used a motorised sprayer of SP 415 type to spray the BC onto the leaf surface. The leaf area index (LAI) was measured each week on the same 12 sample maize in each treatment using an LI 3000A automatic planimeter (LI-COR, Lincoln, NE). Albedo was measured by pyranometers of the CMA-11 type (Kipp & Zonen, Vaisala), what we placed the middle of the plot of 0.3 ha. The effects of BC were studied under two different water supplies: evapotranspirometers of Thornthwaite type were used for "ad libitum" treatment and rainfed treatment in field plots. In 2010 and 2012, a big difference was not observed in the case of LAI in the effects of BC. However, in 2011 there was a significant difference. The LAI of the BC polluted maize was higher (10-15%, P<0.05), than the LAI of the control maize in the rainfed plot and in the ET chambers, respectively. The albedo of the BC contaminated maize decreased (15-30%, P<0.05) in all three years. We also detected that the green plant surface of maize increased on BC contaminated treatment. These results may suggest that the plant is able to absorb the additional carbon source through the leaves. The albedo decreased

  13. On the black carbon problem and its solutions

    Science.gov (United States)

    Jacobson, M. Z.

    2010-12-01

    Black carbon (BC) warms air temperatures in at least seven major ways: (a) directly absorbing downward solar radiation, (b) absorbing upward reflected solar radiation when it is situated above bright surfaces, such as snow, sea ice, and clouds, (c) absorbing some infrared radiation, (d) absorbing additional solar and infrared radiation upon obtaining a coating, (e) absorbing radiation multiply reflected within clouds when situated interstitially between cloud drops, (f) absorbing additional radiation when serving as CCN or scavenged inclusions within cloud drops, and (g) absorbing solar radiation when deposited on snow and sea ice, reducing the albedos of both. Modeling of the climate effects of BC requires treatment of all these processes in detail. In particular, treatment of BC absorption interstitially between cloud drops and from multiply-dispersed cloud drop BC inclusions must be treated simultaneously with treatment of cloud indirect effects to determine the net effects of BC on cloud properties. Here, results from several simulations of the effects of BC from fossil fuel and biofuel sources on global and regional climate and air pollution health are summarized. The simulations account for all the processes mentioned. Results are found to be statistically significant relative to chaotic variability in the climate system. Over time and in steady state, fossil-fuel soot plus biofuel soot are found to enhance warming more than methane. The sum of the soots causes less steady-state warming but more short term warming than does carbon dioxide. Thus eliminating soot emissions from both sources may be the fastest method of reducing rapid climate warming and possibly the only method of saving the Arctic ice. Eliminating such emissions may also reduce over 1.5 million deaths worldwide, particularly in developing countries. Short term mitigation options include the targeting of fossil-fuel and biofuel BC sources with particle traps, new stove technologies, and rural

  14. 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

  15. Imparting improvements in electrochemical sensors: evaluation of different carbon blacks that give rise to significant improvement in the performance of electroanalytical sensing platforms

    International Nuclear Information System (INIS)

    Three different carbon black materials have been evaluated as a potential modifier, however, only one demonstrated an improvement in the electrochemical properties. The carbon black structures were characterised with SEM, XPS and Raman spectroscopy and found to be very similar to that of amorphous graphitic materials. The modifications utilised were constructed by three different strategies (using ultrapure water, chitosan and dihexadecylphosphate). The fabricated sensors are electrochemically characterised using N,N,N',N'-tetramethyl-para-phenylenediamine and both inner-sphere and outer-sphere redox probes, namely potassium ferrocyanide(II) and hexaammineruthenium(III) chloride, in addition to the biologically relevant and electroactive analytes, dopamine (DA) and acetaminophen (AP). Comparisons are made with an edge-plane pyrolytic graphite and glassy-carbon electrode and the benefits of carbon black implemented as a modifier for sensors within electrochemistry are explored, as well as the characterisation of their electroanalytical performances. We reveal significant improvements in the electrochemical performance (excellent sensitivity, faster heterogeneous electron transfer rate (HET)) over that of a bare glassy-carbon and edge-plane pyrolytic graphite electrode and thus suggest that there are substantial advantages of using carbon black as modifier in the fabrication of electrochemical based sensors. Such work is highly important and informative for those working in the field of electroanalysis where electrochemistry can provide portable, rapid, reliable and accurate sensing protocols (bringing the laboratory into the field), with particular relevance to those searching for new electrode materials

  16. Is Carbon Black a Suitable Model Colloidal Substrate for Diesel Soot?

    Science.gov (United States)

    Growney, David J; Mykhaylyk, Oleksandr O; Middlemiss, Laurence; Fielding, Lee A; Derry, Matthew J; Aragrag, Najib; Lamb, Gordon D; Armes, Steven P

    2015-09-29

    Soot formation in diesel engines is known to cause premature engine wear. Unfortunately, genuine diesel soot is expensive to generate, so carbon blacks are often used as diesel soot mimics. Herein, the suitability of a commercial carbon black (Regal 250R) as a surrogate for diesel soot dispersed in engine base oil is examined in the presence of two commonly used polymeric lubricant additives. The particle size, morphology, and surface composition of both substrates are assessed using BET surface area analysis, TEM, and XPS. The extent of adsorption of a poly(ethylene-co-propylene) (dOCP) statistical copolymer or a polystyrene-block-poly(ethylene-co-propylene) (PS-PEP) diblock copolymer onto carbon black or diesel soot from n-dodecane is compared indirectly using a supernatant depletion assay technique via UV spectroscopy. Thermogravimetric analysis is also used to directly determine the extent of copolymer adsorption. Degrees of dispersion are examined using optical microscopy, TEM, and analytical centrifugation. SAXS studies reveal some structural differences between carbon black and diesel soot particles. The mean radius of gyration determined for the latter is significantly smaller than that calculated for the former, and in the absence of any copolymer, diesel soot suspended in n-dodecane forms relatively loose mass fractals compared to carbon black. SAXS provides evidence for copolymer adsorption and indicates that addition of either copolymer transforms the initially compact agglomerates into relatively loose aggregates. Addition of dOCP or PS-PEP does not significantly affect the structure of the carbon black primary particles, with similar results being observed for diesel soot. In favorable cases, remarkably similar data can be obtained for carbon black and diesel soot when using dOCP and PS-PEP as copolymer dispersants. However, it is not difficult to identify simple copolymer-particle-solvent combinations for which substantial differences can be observed

  17. Measurement of black carbon concentration as an indicator of air quality benefits of traffic restriction policies within the ecopass zone in Milan, Italy

    Science.gov (United States)

    Invernizzi, Giovanni; Ruprecht, Ario; Mazza, Roberto; De Marco, Cinzia; Močnik, Griša; Sioutas, Costantinos; Westerdahl, Dane

    2011-07-01

    Traffic restrictions are an unpopular tool to mitigate urban air pollution, and a measurable improvement in air quality is needed to demonstrate the effectiveness of this measure. Previous attempts failed to detect measurable reductions of PM mass pollution within the areas subject to traffic restriction. However black carbon, which is emitted primarily by traffic sources, could be a PM metric more suitable than PM mass to demonstrate pollutant reductions. In this study we report the results of a black carbon monitoring campaign carried out in Milan, Italy, with the aim to detect - and demonstrate more suitably than PM mass - differences in local urban air quality among three zones located very closely with different traffic intensity. The study was carried out in three different days by measuring simultaneously black carbon and PM mass concentrations with fixed monitoring stations located in three main radial roads connecting the outskirts to the city center, each with three segments: 1) an outer one, with no traffic restrictions 2) an intermediate one, subject to the congestion traffic charge called "Ecopass", where a ticket is required to enter for cars equipped with engines prior to Euro 4 standard; 3) the pedestrian zone (no cars admitted) of Duomo Square in the city center, where each of the three main roads ends. The results demonstrated a sharply declining gradient in black carbon levels from the outer zone, without traffic restrictions, to the more central areas, for all of the three radial main roads. The differences in mean black carbon levels in the same day in the different traffic scheme locations were highly significant for each comparison. In contrast to the Black carbon results, mean PM 10, PM 2.5, PM 1 concentrations did not show significant differences among the different traffic zones on the different campaign days. The ratio of black carbon to PM 10 decreased by 47% and 62% in the Ecopass zone and in the pedestrian zone, respectively, as

  18. The role of carbon black/coal-tar pitch interactions in the early stage of carbonization

    Energy Technology Data Exchange (ETDEWEB)

    Menendez, R.; Fernandez, J.J.; Bermejo, J.; Cebolla, V.; Mochida, I.; Korai, Y. [Instituto Nacional del Carbon, Oviedo (Spain)

    1996-09-01

    A study was undertaken of the types of interaction between pitch and carbon black (CB) occurring during thermal treatment in the initial stages of carbonization, and the effects on subsequent coke structures. A commercial coal-tar pitch was blended with CB and thermally treated at temperatures between 400-450{degree}C, for 5 hours - except for 430{degree}C, for 10 hours. The same thermal treatments were applied in the absence of CB to test the effects of temperature alone. Parent and treated pitches were characterized by elemental analysis, optical microscopy, thermomechanical analysis and sequential solvent extraction. Some of the fractions were characterized by FTIR, GC and {sup 1}H-NMR. Cokes obtained at 900{degree}C were characterized by optical microscopy in terms of their porosity and optical texture. Results show that the type of CB/pitch interactions are temperature dependent, the interactions being more significant at lower temperatures. Hydrogenation and polymerization reactions have successively occurred alone the range of temperatures used. CB produced an increase of pitch carbon yield without affecting pitch fluidity at the lower temperatures. The effect on the reduction of coke porosity was pronounced at the initial stages of the treatment. Coke optical texture was affected by the presence of CB showing smaller sizes. 14 refs., 4 figs., 6 tabs.

  19. Evaluating the capabilities of portable black carbon monitors and photometers for measuring airborne carbon nanotubes

    International Nuclear Information System (INIS)

    For daily monitoring of occupational exposure to aerosolized carbon nanotubes (CNTs) where CNTs are manufactured and handled, inexpensive real-time measuring methods are preferable. In this study, we evaluated the capabilities of a portable black carbon monitor (BCM; also called an aethalometer) and a light-scattering aerosol photometer in detecting airborne CNTs. The responses of these instruments to airborne CNTs, aerosolized through vortex shaking, were evaluated by comparing the measurements of CNT mass concentrations made by these instruments to those determined through thermal carbon analysis. Results showed that their raw readings underestimated CNT mass concentrations in most cases. Their sensitivities depended on the type of CNTs and decreased with the particle sizes of aerosolized CNT clumps. We also found that the sensitivity of the BCM tended to substantially decrease with increasing filter load, even before the point at which the filter should be replaced as recommended by the manufacturer, which could be attributed to a clean environmental condition (i.e., the absence of ubiquitous light-scattering material). As an example of the use of these instruments for measuring airborne CNTs in the presence of background aerosols, a CNT-handling simulation was also conducted. Although both the BCM and the photometer could detect CNT emissions, the BCM was more sensitive to the detection of emitted CNTs in the presence of background aerosols. The correction factors obtained from the response evaluations could enhance the measurement accuracy of these instruments, which will be helpful for the daily monitoring of CNTs at workplaces

  20. A comparison of remnants in noncommutative Bardeen black holes

    CERN Document Server

    Mehdipour, S Hamid

    2016-01-01

    We derive the mass term of the Bardeen metric in the presence of a noncommutative geometry induced minimal length. In this setup, the proposal of a stable black hole remnant as a candidate to store information is confirmed. We consider the possibility of having an extremal configuration with one degenerate event horizon and compare different sizes of black hole remnants. As a result, once the magnetic charge $g$ of the noncommutative Bardeen solution becomes larger, both the minimal nonzero mass $M_0$ and the minimal nonzero horizon radius $r_0$ get larger. This means, subsequently, under the condition of an adequate amount of $g$, the three parameters $g$, $M_0$, and $r_0$ are in a connection with each other linearly. According to our results, a noncommutative Bardeen black hole is colder than the noncommutative Schwarzschild black hole and its remnant is bigger, so the minimum required energy for the formation of such a black hole at particle colliders will be larger. We also find a closely similar result f...

  1. A comparison of remnants in noncommutative Bardeen black holes

    Science.gov (United States)

    Mehdipour, S. Hamid; Ahmadi, M. H.

    2016-09-01

    We derive the mass term of the Bardeen metric in the presence of a noncommutative geometry induced minimal length. In this setup, the proposal of a stable black hole remnant as a candidate to store information is confirmed. We consider the possibility of having an extremal configuration with one degenerate event horizon and compare different sizes of black hole remnants. As a result, once the magnetic charge g of the noncommutative Bardeen solution becomes larger, both the minimal nonzero mass M0 and the minimal nonzero horizon radius r0 get larger. This means, subsequently, under the condition of an adequate amount of g, the three parameters g, M0, and r0 are in a connection with each other linearly. According to our results, a noncommutative Bardeen black hole is colder than the noncommutative Schwarzschild black hole and its remnant is bigger, so the minimum required energy for the formation of such a black hole at particle colliders will be larger. We also find a closely similar result for the Hayward solution.

  2. Thermal Oxidation of Tail Gases from the Production of Oil-furnace Carbon Black

    Directory of Open Access Journals (Sweden)

    Bosak, Z.

    2009-01-01

    Full Text Available This paper describes the production technology of oil-furnace carbon black, as well as the selected solution for preventing the emissions of this process from contaminating the environment.The products of industrial oil-furnace carbon black production are different grades of carbon black and process tail gases. The qualitative composition of these tail gases during the production of oil-furnace carbon black are: carbon(IV oxide, carbon(II oxide, hydrogen, methane, hydrogen sulfide, nitrogen, oxygen, and water vapor.The quantitative composition and lower caloric value of process tail gases change depending on the type of feedstock used in the production, as well as the type of process. The lower caloric value of process tail gases is relatively small with values ranging between 1500 and 2300 kJ m–3.In the conventional production of oil-furnace carbon black, process tail gases purified from carbon black dust are freely released into the atmosphere untreated. In this manner, the process tail gases pollute the air in the town of Kutina, because their quantitative values are much higher than the prescribed emissions limits for hydrogen sulfide and carbon(II oxide. A logical solution for the prevention of such air pollution is combustion of the process tail gases, i. e. their thermal oxidation. For this purpose, a specially designed flare system has been developed. Consuming minimum amounts of natural gas needed for oxidation, the flare system is designed to combust low caloric process tail gases with 99 % efficiency. Thus, the toxic and flammable components of the tail gases (hydrogen sulfide, hydrogen, carbon(II oxide, methane and other trace hydrocarbons would be transformed into environmentally acceptable components (sulfur(IV oxide, water, carbon(IV oxide and nitrogen(IV oxide, which are in compliance with the emissions limit values prescribed by law.Proper operation of this flare system in the production of oil-furnace carbon black would solve

  3. Hydropyrolysis: implications for radiocarbon pre-treatment and characterization of Black Carbon

    OpenAIRE

    Ascough, P.; M. I. Bird; Meredith, W.; Wood, R. E.; Snape, C.E.; Brock, F.; Higham, T.F.; Large, D.J.; Apperley, D. C.

    2010-01-01

    Charcoal is the result of natural and anthropogenic burning events, when biomass is exposed to elevated temperatures under conditions of restricted oxygen. This process produces a range of materials, collectively known as pyrogenic carbon, the most inert fraction of which is known as Black Carbon (BC). BC degrades extremely slowly, and is resistant to diagenetic alteration involving the addition of exogenous carbon making it a useful target substance for radiocarbon dating particularly of ...

  4. 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.

  5. 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

  6. 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

  7. Black carbon over the Amazon during SAMBBA: it gets everywhere

    Science.gov (United States)

    Morgan, W.; Allan, J. D.; Flynn, M.; Darbyshire, E.; Liu, D.; Szpek, K.; Langridge, J.; Johnson, B. T.; Haywood, J.; Longo, K.; Artaxo, P.; Coe, H.

    2014-12-01

    Biomass burning represents a major source of Black Carbon (BC) aerosol to the atmosphere, which can result in major perturbations to weather, climate and ecosystem development. Large uncertainties in these impacts prevail, particularly on regional scales. One such region is the Amazon Basin, where large, intense and frequent burning occurs on an annual basis during the dry season. Absorption by atmospheric aerosols is underestimated by models over South America, which points to significant uncertainties relating to BC aerosol properties. Results from the South American Biomass Burning Analysis (SAMBBA) field experiment, which took place during September and October 2012 over Brazil on-board the UK Facility for Airborne Atmospheric Measurement (FAAM) BAe-146 research aircraft, are presented here. Aerosol chemical composition was measured by a DMT Single Particle Soot Photometer (SP2) and an Aerodyne Aerosol Mass Spectrometer (AMS). The physical, chemical and optical properties of BC-containing particles across the region will be characterised, with particular emphasis on the vertical distribution. BC was ubiquitous across the region, with measurements extending from heavily deforested regions in the Western Amazon Basin, through to agricultural fires in the Cerrado (Savannah-like) region and more pristine areas over the Amazon Rainforest. Measurements in the vicinity of Manaus (a city located deep into the jungle) were also conducted. BC concentrations peaked within the boundary layer at a height of around 1.5km. BC-containing particles were found to be rapidly coated in the near-field, with little evidence for additional coating upon advection and dilution. Biomass burning layers within the free troposphere were routinely observed. BC-containing particles within such layers were typically associated with less coating than those within the boundary layer, suggestive of wet removal of more coated BC particles. The importance of such properties in relation to the

  8. 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

  9. Heavy duty piezoresistivity induced strain sensing natural rubber/carbon black nanocomposites reinforced with different carbon nanofillers

    Science.gov (United States)

    He, Qingliang; Yuan, Tingting; Zhang, Xi; Guo, Shimei; Liu, Jingjing; Liu, Jiurong; Liu, Xinyu; Sun, Luyi; Wei, Suying; Guo, Zhanhu

    2014-09-01

    Durable piezoresistive effects of natural rubber nanocomposites have been demonstrated, i.e., with stable and reversible electrical resistance change within the tested 3000 cycles upon applying a small compressive strain (˜16.7%) under a relatively high frequency (0.5 Hz, 2 s/cycle). This unique function was achieved for the first time by combining carbon nanotubes and carbon nanofibers with natural rubber composites pretreated with carbon black. Even though the combination of different carbon nanomaterials, such as graphene nanosheets and carbon nanotubes, can improve the dispersion quality of both the nanostructures in solution or in polymer matrices, this type of synergistic effect between carbon nanotubes and carbon nanofibers in producing stable and reversible piezoresistive effect has been rarely reported. Besides, the strong reinforcement (compressive stress at a maximum strain of 16.7% was increased from 12.6 for untreated to 18.5 MPa for the natural rubber/carbon black composites treated with a combination of 1.0 wt% carbon nanotubes and 1.0 wt% carbon nanofibers) makes the as-prepared composites promising for heavy duty pressure sensors, i.e., healthy motion monitoring of industrial machinery vibrations.

  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. Effect of Thermal Aging on the Viscosity of Suspensions of Carbon Black in Polybutadiene

    Science.gov (United States)

    von Meerwall, E.; Hong, M. P.; Kelley, F. N.

    1998-05-01

    We have studied the effects of aging time and temperature on the viscosity of an hydroxyl-terminated polybutadiene (HTPB) containing suspended carbon black. After surface application such HTPB suspensions are crosslinked to form liners in solid rocket motors. The suspension viscosity decreases with aging time, more rapidly at higher temperatures, and approaches a lower asymptote which depends on filler fraction. Heat-drying the carbon black before incorporation lessens the magnitude of this effect and accelerates the approach to equilibrium; moistening the black enlarges it and delays the approach. We conclude that this effect is related to the moisture adsorbed on the black particles. The water is not completely soluble in the polymer, resulting in reversible emulsification, and is driven off during aging. A variety of secondary experiments performed (use of a wetting agent, centrifugation, dc electrical resistivity, NMR spin-spin relaxation and self-diffusion, optical microscopy) eliminate several other likely explanations.

  12. Comparison of black hole growth in galaxy mergers with gasoline and ramses

    Science.gov (United States)

    Gabor, Jared M.; Capelo, Pedro R.; Volonteri, Marta; Bournaud, Frédéric; Bellovary, Jillian; Governato, Fabio; Quinn, Thomas

    2016-07-01

    Supermassive black hole dynamics during galaxy mergers is crucial in determining the rate of black hole mergers and cosmic black hole growth. As simulations achieve higher resolution, it becomes important to assess whether the black hole dynamics is influenced by the treatment of the interstellar medium in different simulation codes. We compare simulations of black hole growth in galaxy mergers with two codes: the smoothed particle hydrodynamics code gasoline, and the adaptive mesh refinement code ramses. We seek to identify predictions of these models that are robust despite differences in hydrodynamic methods and implementations of subgrid physics. We find that the general behavior is consistent between codes. Black hole accretion is minimal while the galaxies are well-separated (and even as they fly by within 10 kpc at the first pericenter). At late stages, when the galaxies pass within a few kpc, tidal torques drive nuclear gas inflow that triggers bursts of black hole accretion accompanied by star formation. We also note quantitative discrepancies that are model dependent: our ramses simulations show less star formation and black hole growth, and a smoother gas distribution with larger clumps and filaments than our gasoline simulations. We attribute these differences primarily to the subgrid models for black hole fueling, feedback, and gas thermodynamics. The main conclusion is that differences exist quantitatively between codes, and this should be kept in mind when making comparisons with observations. However, both codes capture the same dynamical behaviors in terms of triggering black hole accretion, star formation, and black hole dynamics, which is reassuring.

  13. Nano-carbon black and carbon fiber as conductive materials for the diagnosing of the damage of concrete beam

    OpenAIRE

    Yining Ding; Zhipei Chen; Zhibo Han; Yulin Zhang; Torgal, Fernando Pacheco

    2013-01-01

    The nano-carbon black (NCB) and carbon fiber (CF) as electric conductive materials were added into the concrete. The effect of the NCB and CF on the mechanical properties and on the fractional change in resistance (FCR) of concrete was investigated. The relationships among the FCR, the strain of initial geometrical neutral axis (IGNA) and the beam damage degree were developed. The results showed that the relationship between the FCR and IGNA strain can be described by the First Or...

  14. A soft photo-mask with embedded carbon black and its application in contact photolithography

    International Nuclear Information System (INIS)

    This paper presents a new type of soft photo-mask which can be used in contact photolithography for achieving small line-width, large area, and high throughput ultraviolet (UV) patterning. It starts from a polydimethylsiloxane (PDMS) mold replicated from a silicon master mold. A carbon black photo-resist (PR) is spin-coated on top of the PDMS mold and then thermally cured. After a contact transfer process, the solidified carbon black PR exists only in the concave region of the PDMS mold, which converts the PDMS mold into a carbon-black/PDMS soft photo-mask. Due to its flexibility, this soft photo-mask can be used in contact photolithography on a slightly curved substrate. Experiments on preparing this new soft photo-mask and its application for fabricating patterned sapphire substrates (PSSs) used in the light-emitting-diode (LED) industry are carried out. Successful results are observed. (paper)

  15. 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.

  16. 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.

  17. Exploring biomass based carbon black as filler in epoxy composites: Flexural and thermal properties

    International Nuclear Information System (INIS)

    Carbon blacks (CB), derived from bamboo stem (BS-CB), coconut shells (CNS-CB) and oil palm empty fiber bunch (EFB-CB), were obtained by pyrolysis of fibers at 700 oC, characterized and used as filler in epoxy composites. The results obtained showed that the prepared carbon black possessed well-developed porosities and are predominantly made up of micropores. The BS-CB, CNS-CB and EFB-CB filled composites were prepared and characterized using scanning electron microscope (SEM) and thermogravimetric analyzer (TGA). The SEM showed that the fractured surface of the composite indicates its high resistance to fracture. The CBs-epoxy composites exhibited better flexural properties than the neat epoxy, which was attributed to better adhesion between the CBs and the epoxy resin. TGA showed that there was improvement in thermal stability of the carbon black filled composites compared to the neat epoxy resin.

  18. Effect of part replacement of silica sand with carbon black on composite properties

    International Nuclear Information System (INIS)

    We have reported the properties of natural rubber filled with locally available materials (Adu et al 2000). The effect of local clay, limestone, silica sand and charcoal on the properties of natural rubber has been examined. Results have shown detrimental effects of silica sand on the properties of natural rubber compound. It has been reported that when silica is used as a part for part replacement of carbon black, the heat build up the composite decreased whilst tear resistance improved. Results revealed that within the filler content range used in the present work, the hardness, modulus, and tensile strength of composites loaded with silica sand/carbon black showed enhanced magnitude over the composite loaded singly with silica sand. These parameters generally increased with increasing carbon black content in the composite. New area of use requiring moderate level of tensile strength, hardness and modulus (as in soles of shoes and engine mounts) is therefore opened up for silica sand.(author)

  19. 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.

  20. An Exploratory Study of Socialization Effects on Black Children: Some Black-White Comparisons

    Science.gov (United States)

    Baumrind, Diana

    1972-01-01

    Major conclusion from this exploratory analysis was that if the black families were viewed by white norms they appeared authoritarian, but that, unlike their white counterparts, the most authoritarian of these families produced the most self-assertive and independent girls. (Author)

  1. Key Findings of the AMAP 2015 Assessment on Black Carbon and Tropospheric Ozone as Arctic Climate Forcers

    Science.gov (United States)

    Quinn, P.

    2015-12-01

    The Arctic Monitoring and Assessment Programme (AMAP) established an Expert Group on Short-Lived Climate Forcers (SLCFs) in 2009 with the goal of reviewing the state of science surrounding SLCFs in the Arctic and recommending science tasks to improve the state of knowledge and its application to policy-making. In 2011, the result of the Expert Group's work was published in a technical report entitled The Impact of Black Carbon on Arctic Climate (AMAP, 2011). That report focused entirely on black carbon (BC) and co-emitted organic carbon (OC). The SLCFs Expert Group then expanded its scope to include all species co-emitted with BC as well as tropospheric ozone. An assessment report, entitled Black Carbon and Tropospheric Ozone as Arctic Climate Forcers, was published in 2015. The assessment includes summaries of measurement methods and emissions inventories of SLCFs, atmospheric transport of SLCFs to and within the Arctic, modeling methods for estimating the impact of SLCFs on Arctic climate, model-measurement inter-comparisons, trends in concentrations of SLCFs in the Arctic, and a literature review of Arctic radiative forcing and climate response. In addition, three Chemistry Climate Models and five Chemistry Transport Models were used to calculate Arctic burdens of SLCFs and precursors species, radiative forcing, and Arctic temperature response to the forcing. Radiative forcing was calculated for the direct atmospheric effect of BC, BC-snow/ice effect, and cloud indirect effects. Forcing and temperature response associated with different source sectors (Domestic, Energy+Industry+Waste, Transport, Agricultural waste burning, Forest fires, and Flaring) and source regions (United States, Canada, Russia, Nordic Countries, Rest of Europe, East and South Asia, Arctic, mid-latitudes, tropics, southern hemisphere) were calculated. To enable an evaluation of the cost-effectiveness of regional emission mitigation options, the normalized impacts (i.e., impacts per unit

  2. Seasonal and diurnal trends in black carbon properties and co-pollutants in Mexico City

    Science.gov (United States)

    Retama, A.; Baumgardner, D.; Raga, G. B.; McMeeking, G. R.; Walker, J. W.

    2015-08-01

    The Mexico City metropolitan area (MCMA) is a region that continues to grow in population and vehicular traffic as well as being the largest source of short-lived climate pollutants (SLCP) in Latin America. The local city government has made significant progress in controlling some of these pollutants, i.e., ozone (O3) and carbon monoxide (CO), but particulate matter (PM2.5 and PM10) and black carbon (BC) have shown a less positive response to mitigation strategies that have been in place for almost 3 decades. For the first time, extended measurements of equivalent black carbon (eBC), derived from light absorption measurements, have been made using a Photoacoustic Extinctiometer (PAX) over a 13 month period from March 2013 through March 2014. The daily trends in workdays (Monday through Saturday) and Sunday eBC, PM2.5 and the co-pollutants CO, O3 and NOx are evaluated with respect to the three primary seasons in the MCMA: rainy, cold and dry and warm and dry. The maximum values in all of the particle and gas concentrations were significantly larger (Student's t test, P matter. A significant "weekend effect" was also identified, particularly the decrease in BC due to fewer large transport vehicles that are fueled by diesel, which produces a large fraction of the BC. The other co-pollutant concentrations are also significantly less on weekends except for O3 that shows no change in maximum values from workdays to Sundays. This lack of change is a result of the balancing effects of lower precursor gases, i.e., VOCs, offset by lower concentrations of NOx, that is an O3 inhibitor. A comparison of the average maximum value of eBC measured during the 1 year period of the current study, with maximum values measured in shorter field campaigns in 2000 and 2006, shows no significant change in the eBC emissions over a 14 year period. This suggests that new methods may need to be developed that can decrease potentially toxic levels of this particulate pollutant.

  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. 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.

  5. Impact of time-activity patterns on personal exposure to black carbon

    OpenAIRE

    Dons, Evi; Int Panis, Luc; Van Poppel, Martine; Theunis, Jan; Willems, Hanny; Torfs, Rudi; Wets, Geert

    2011-01-01

    Time-activity patterns are an important determinant of personal exposure to air pollution. This is demonstrated by measuring personal exposure of 16 participants for 7 consecutive days: 8 couples of which one person was a full-time worker and the other was a homemaker; both had a very different time-activity pattern. We used portable aethalometers to measure black carbon levels with a high temporal resolution and a PDA with GPS-logger and electronic diary. The exposure to black carbon differs...

  6. 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.

  7. 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

  8. 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.

  9. Carbon distribution in char residue from gasification of kraft black liquor

    International Nuclear Information System (INIS)

    The char residue yields and the total carbon and carbonate content were measured for dry black liquor solids after pyrolysis or gasification in a laminar entrained-flow reactor. The experimental conditions were 700-1000 deg. C in N2,CO2/N2 or water vapor/N2 at 1 bar total pressure, for residence times from 0.3 to 1.7 s. Fixed carbon yields, when measured at the same particle residence time, decreased with increasing reactor temperature. CO2 and water vapor diminished the char carbon significantly at temperatures above 800 deg. C, compared with pyrolysis in N2. Water vapor oxidized the char carbon more rapidly than did CO2. At 1000 deg. C, the reactions of carbon with sulfate and carbonate became faster, resulting in a smaller difference between carbon conversion rates in the different gas environments. By the end of devolatilization, the amount of carbonate in the char had changed very little at 700-800 deg. C. After devolatilization, carbonate was formed more rapidly at higher temperatures. The presence of CO2 or water vapor increased the formation of carbonate. In the presence of these gases, more carbonate was measured at all temperatures and residence times. The maximum carbonate measured in the char was 16% of the carbon in the black liquor solids, as compared to 4.4% in the original dry liquor solids. Under most conditions, the carbonate, as a fraction of carbon input, first increased to a constant, temperature-independent value and then decreased

  10. 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.; Bernsten, T.; DeAngelo, B. J.; Flanner, M. G.; Ghan, S.; Karcher, 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.

    2013-01-01

    Black 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 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/sq m with 90% uncertainty bounds of (+0.08, +1.27)W/sq m. Total direct forcing by all black carbon sources, without subtracting the preindustrial background, is estimated as +0.88 (+0.17, +1.48) W/sq m. 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/sq m with 90% uncertainty bounds of +0.17 to +2.1 W/sq m. Thus, there is a very high probability that black carbon emissions, independent of co-emitted species, have a positive forcing

  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. 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.

  13. 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

  14. 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.

  15. 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

  16. Contribution of Black Carbon, Brown Carbon and Lensing Effect to Total Aerosol Absorption in Indo-Gangetic Plain

    Science.gov (United States)

    Shamjad, Pm; Tripathi, Sachchida; Bergin, Mike; Vreeland, Heidi

    2016-04-01

    This study reports the optical and physical properties of atmospheric and denuded (heated at 300°C) aerosols from Indo-Gangetic Plain (IGP) during 20 December 2014 to 28 February 2015. A Single Particle Soot Photometer (SP2) and High Resolution Time of Flight Aerosol Mass Spectrometer (HR-ToF-AMS) were used to measure black carbon (BC) and organic carbon (OC) in real time respectively. During experiments large scale carbonaceous aerosol loading is observed in IGP. Multiple biomass burning events are observed with varying intensity and duration. Refractive index of brown carbon (BrC) is derived from filter extracts using Liquid Core Wave Capillary Cell (LWCC). Refractive index of BrC at 405 is 4 times higher in IGP when compared to studies conducted in USA. Through Mie modelling we identified the percentage contribution of black carbon, BrC and lensing effect to total aerosol absorption. On average 75% of absorption is from black carbon alone, while rest is contributed from volatile components. Within the volatile component contribution, at 405 nm BrC contributes around 20% and rest from lensing effect. But at 781 nm lensing contributed more than BrC. Overall results indicate the special characteristics on BrC aerosols in IGP and the importance of considering spectral absorption in global aerosol modelling studies.

  17. 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...... subsequent oxidation; however, CRC samples graphitised =2800 °C did not exhibit this same behaviour. Highlights ¿ We quantitatively determine electrooxidation of carbon support materials. ¿ We can distinguish between the total and partial electrooxidation. ¿ Non or mildly heat treated carbon forms...... passivating layer. ¿ Heat treated carbons are less sensitive to oxidation–reduction cycles....

  18. Scales of variability of black carbon plumes and their dependence on resolution of ECHAM6-HAM

    Science.gov (United States)

    Weigum, Natalie; Stier, Philip; Schutgens, Nick; Kipling, Zak

    2015-04-01

    Prediction of the aerosol effect on climate depends on the ability of three-dimensional numerical models to accurately estimate aerosol properties. However, a limitation of traditional grid-based models is their inability to resolve variability on scales smaller than a grid box. Past research has shown that significant aerosol variability exists on scales smaller than these grid-boxes, which can lead to discrepancies between observations and aerosol models. The aim of this study is to understand how a global climate model's (GCM) inability to resolve sub-grid scale variability affects simulations of important aerosol features. This problem is addressed by comparing observed black carbon (BC) plume scales from the HIPPO aircraft campaign to those simulated by ECHAM-HAM GCM, and testing how model resolution affects these scales. This study additionally investigates how model resolution affects BC variability in remote and near-source regions. These issues are examined using three different approaches: comparison of observed and simulated along-flight-track plume scales, two-dimensional autocorrelation analysis, and 3-dimensional plume analysis. We find that the degree to which GCMs resolve variability can have a significant impact on the scales of BC plumes, and it is important for models to capture the scales of aerosol plume structures, which account for a large degree of aerosol variability. In this presentation, we will provide further results from the three analysis techniques along with a summary of the implication of these results on future aerosol model development.

  19. 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

  20. Seasonal trends in black carbon properties and co-pollutants in Mexico City

    OpenAIRE

    A. Retama; Baumgardner, D; Raga, G. B.; G. R. McMeeking; Walker, J. W.

    2015-01-01

    The Mexico City Metropolitan Area (MCMA) is a region that continues to grow in population and vehicular traffic as well as being the largest source of short lived climate pollutants (SLCP) in Latin America. The local city government has made significant progress in controlling some of these pollutants, i.e. ozone (O3) and carbon monoxide (CO), but particulate matter (PM2.5 and PM10) and black carbon (BC) have shown little response to mitigation strategies th...

  1. Comparison of black, green and rooibos tea on osteoblast activity.

    Science.gov (United States)

    Nash, L A; Ward, W E

    2016-02-17

    Globally, tea is the second most consumed beverage after water. Habitual tea intake has been associated with higher bone mineral density, particularly in postmenopausal women. This association may be due to its polyphenols and resulting protective antioxidant effects. While in vivo studies have shown improved bone outcomes with a consumption of individual purified tea polyphenols, it is unclear if a particular tea - due to its different profiles of polyphenols - is more beneficial than others. Therefore, we compared three different types of commercially available teas on osteoblasts: green, black and rooibos tea. Tea was normalized to 1 or 10 μg per mL gallic acid equivalents to assess differences in outcomes based on tea profiles rather than the quantity of polyphenol naturally present. The lower level of polyphenols (1 μg per mL gallic acid equivalents) - regardless of tea type and thus polyphenol profile - resulted in greater mineral content as well as cellular and alkaline phosphatase activity in Saos2 cells. Moreover, this was associated with higher markers of differentiation (osteopontin, sclerostin) and reduced cellular toxicity and pro-inflammatory markers (IL6, TNFα). Green, black and rooibos tea improved osteoblast activity at the low level and support epidemiological evidence suggesting tea consumption may benefit bone heath. PMID:26885714

  2. 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.

  3. Application of microwave induced combustion in closed vessels for carbon black-containing elastomers decomposition

    International Nuclear Information System (INIS)

    A rapid digestion procedure for the determination of Al, Fe, Mn, Sr and Zn in carbon black-containing elastomers (30%) has been developed using sample combustion in closed quartz vessels. Microwave radiation was used for ignition. Combustion takes place in the presence of oxygen under pressure using ammonium nitrate (50 μl of 6 mol l-1) as aid for ignition. Samples of nitrile-butadiene rubber and ethylenepropylene-diene monomer were decomposed. A quartz device was used simultaneously as a sample holder and for the protection of vessel cap. The influence of the absorption solution (nitric acid or water) and the necessity of an additional reflux step were evaluated. Determination of Al, Fe, Mn, Sr and Zn was performed by inductively coupled plasma optical emission spectrometry. A reference method (ASTM D 4004-06) based on conventional dry ashing and flame atomic absorption spectrometry was used for comparison (Mn and Zn). Results were also compared to those obtained by using wet acid digestion in closed systems. Concentrated and diluted (4 mol l-1) nitric acid, with 5 min of reflux after the combustion, gave best recoveries for all analytes (from 97 to 101%). For dry ashing quantitative recoveries were found only for Zn whereas for Al, Fe, Mn and Sr the recoveries were only 14, 37, 72 and 37%, respectively. With the proposed procedure the residual carbon content was below 0.5% and further determination of analytes was feasible with only the combustion step (for Fe a reflux with diluted HNO3 was necessary). Complete sample digestion is obtained in less time using the proposed procedure than with other procedures and no concentrated acids were necessary

  4. Black carbon aerosols and their radiative properties in the Pearl River Delta region

    Institute of Scientific and Technical Information of China (English)

    WU Dui; MAO JieTai; DENG XueJiao; TIE XueXi; ZHANG YuanHang; ZENG LiMin; LI Fei; TAN HaoBo; BI XueYan; HUANG XiaoYing; CHEN Jing; DENG Tao

    2009-01-01

    The climatic and environmental effects of atmospheric aerosols are a hot topic in global science community, and radiative properties of the aerosols are one of the important parameters in assessing climatic change. Here we studied the black carbon concentration and absorption coefficient measured with aethalometers, scattering coefficient measured with nephelometers, and single scattering albedo derived at an atmospheric composition watch station in Guangzhou from 2004 to 2007. Our main resuits are as follows. The data of black carbon concentration and absorption coefficients measured with instruments cannot be directly used until they are measured in parallel with internationally accepted instruments for comparison, calibration, and reduction. After evaluation of the data, the result shows that the monthly mean of BC concentration varies 3.1-14.8 pg. m-3 and the concentration decreases by about 1 μg. m-3 in average over the four years; It is higher in the dry season with a multi-year mean of monthly mean concentration occurred in December 2004 and extreme minimum in July 2007, end a 4-year mean is 8.4 pg. m-3. It is also shown that monthly mean scattering coefficient derived varies 129 -565 Mm-1, monthly mean absorption coefficient 32-139 Mm-1, and monthly mean single scattering albedo 0.71-0.91, with annual mean values of 0.80, 0.82, 0.79 and 0.84 for 2004, 2005, 2006 and 2007, respectively. Three instruments were used to take simultaneous measurements of BC in PM10, PM2.5, and PM1 and the results showed that PM2.5 took up about 90% of PM10 and PM1 accounted for about 66% of PM2.5, and BC aerosols are mainly present in fine particulates. The variability of BC concentrations is quite consistent between the Nancun station (141 m above sea level) and the Panyu station (13 m above sea level), which are 8 km apart from each other. The concentration in higher altitude station (Panyu) is consistently lower than the lower altitude station (Nancun), and the difference of

  5. Parametric uncertainties in global model simulations of black carbon column mass concentration

    Science.gov (United States)

    Pearce, Hana; Lee, Lindsay; Reddington, Carly; Carslaw, Ken; Mann, Graham

    2016-04-01

    Previous studies have deduced that the annual mean direct radiative forcing from black carbon (BC) aerosol may regionally be up to 5 W m‑2 larger than expected due to underestimation of global atmospheric BC absorption in models. We have identified the magnitude and important sources of parametric uncertainty in simulations of BC column mass concentration from a global aerosol microphysics model (GLOMAP-Mode). A variance-based uncertainty analysis of 28 parameters has been performed, based on statistical emulators trained on model output from GLOMAP-Mode. This is the largest number of uncertain model parameters to be considered in a BC uncertainty analysis to date and covers primary aerosol emissions, microphysical processes and structural parameters related to the aerosol size distribution. We will present several recommendations for further research to improve the fidelity of simulated BC. In brief, we find that the standard deviation around the simulated mean annual BC column mass concentration varies globally between 2.5 x 10‑9 g cm‑2 in remote marine regions and 1.25 x 10‑6 g cm‑2 near emission sources due to parameter uncertainty Between 60 and 90% of the variance over source regions is due to uncertainty associated with primary BC emission fluxes, including biomass burning, fossil fuel and biofuel emissions. While the contributions to BC column uncertainty from microphysical processes, for example those related to dry and wet deposition, are increased over remote regions, we find that emissions still make an important contribution in these areas. It is likely, however, that the importance of structural model error, i.e. differences between models, is greater than parametric uncertainty. We have extended our analysis to emulate vertical BC profiles at several locations in the mid-Pacific Ocean and identify the parameters contributing to uncertainty in the vertical distribution of black carbon at these locations. We will present preliminary

  6. Black carbon aerosols and their radiative properties in the Pearl River Delta region

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    The climatic and environmental effects of atmospheric aerosols are a hot topic in global science community, and radiative properties of the aerosols are one of the important parameters in assessing climatic change. Here we studied the black carbon concentration and absorption coefficient measured with aethalometers, scattering coefficient measured with nephelometers, and single scattering albedo derived at an atmospheric composition watch station in Guangzhou from 2004 to 2007. Our main results are as follows. The data of black carbon concentration and absorption coefficients measured with instruments cannot be directly used until they are measured in parallel with internationally accepted instruments for comparison, calibration, and reduction. After evaluation of the data, the result shows that the monthly mean of BC concentration varies 3.1―14.8 μg·m-3 and the concentration decreases by about 1 μg·m-3 in average over the four years; It is higher in the dry season with a multi-year mean of 8.9 μg/m3 and lower in the rainy season with a multi-year mean of 8.0 μg·m-3; The extreme maximum of monthly mean concentration occurred in December 2004 and extreme minimum in July 2007, and a 4-year mean is 8.4 μg·m-3. It is also shown that monthly mean scattering coefficient derived varies 129 -565 Mm-1, monthly mean absorption coefficient 32-139 Mm-1, and monthly mean single scattering albedo 0.71-0.91, with annual mean values of 0.80, 0.82, 0.79 and 0.84 for 2004, 2005, 2006 and 2007, respectively. Three instruments were used to take simultaneous measurements of BC in PM10, PM2.5, and PM1 and the results showed that PM2.5 took up about 90% of PM10 and PM1 accounted for about 68% of PM2.5, and BC aerosols are mainly present in fine particulates. The variability of BC concentrations is quite consistent between the Nancun station (141 m above sea level) and the Panyu station (13 m above sea level), which are 8 km apart from each other. The concentration in higher

  7. Investigation of reinforcement of the modified carbon black from wasted tires by nuclear magnetic resonance

    Institute of Scientific and Technical Information of China (English)

    ZHOU Jie; YANG Yong-rong; REN Xiao-hong; STAPF Siegfried

    2006-01-01

    Pyrolysis has the potential of transforming waste into recyclable products. Pyrolytic carbon black (PCB) is one of the most important products from the pyrolysis of used tires. Techniques for surface modifications of PCB have been developed. One of the most significant applications for modified PCB is to reinforce the rubber matrix to obtain high added values. The transverse relaxation and the chain dynamics of vulcanized rubber networks with PCB and modified PCB were studied and compared with those of the commercial carbon blacks using selective 1H transverse relaxation (T2) experiments and dipolar correlation effect (DCE) experiments on the stimulated echo. Demineralization and coupling agent modification not only intensified the interactions between the modified PCB and the neighboring polyisoprene chains, but also increased the chemical cross-link density of the vulcanized rubber with modified PCB. The mechanical testing of the rubbers with different kinds of carbon blacks showed that the maximum strain of the rubber with modified PCB was improved greatly. The mechanical testing results confirmed the conclusion obtained by nuclear magnetic resonance (NMR). PCB modified by the demineralization and NDZ-105 titanate coupling agent could be used to replace the commercial semi-reinforcing carbon black.

  8. Nanoscale Interactions between Engineered Nanomaterials and Black Carbon (Biochar) in Soil

    Science.gov (United States)

    An understanding of the interactions between engineered nanomaterials (NMs) and soil constituents, and a comprehension of how these interactions may affect biological uptake and toxicity are currently lacking. Charcoal black carbon is a normal constituent of soils due to fire history, and can be pre...

  9. 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 ...

  10. Black carbon as isolated by chemical oxidation: characterization and contribution in litter and soil

    OpenAIRE

    Alexis, M. A.; Rumpel, C.; Knicker, Heike; Rasse, D.; Péchot, N.; Mariotti, A.

    2007-01-01

    Comunicación oral BG1.05-1WE4O-001, presentada a la sesión BG1.05 Analysis and Characterization of Black Carbon in the Environment (co-listed in AS, HS, OS & SSS).-- Congreso celebrado del 15 -20 de abril, 2007, en Viena, Austria.

  11. Utilization of low-ash biochar to partially replace carbon black in SBR composites

    Science.gov (United States)

    A biochar made from woody waste feedstock with low ash content was blended with carbon black as filler for styrene-butadiene rubber. At 10% total filler concentration (w/w), composites made from 25 or 50% biochar showed improved tensile strength, elongation, and toughness compared to similar composi...

  12. Atmospheric black carbon and warming effects influenced by the source and absorption enhancement in central Europe

    NARCIS (Netherlands)

    Nordmann, S.; Cheng, Y.F.; Carmichael, G.R.; Yu, M.; Denier Van Der Gon, H.A.C.; Zhang, Q.; Saide, P.E.; Pöschl, U.; Su, H.; Birmili, W.; Wiedensohler, A.

    2014-01-01

    Particles containing black carbon (BC), a strong absorbing substance, exert a rather uncertain direct and indirect radiative forcing in the atmosphere. To investigate the mass concentration and absorption properties of BC particles over central Europe, the model WRF-Chem was used at a resolution of

  13. Surface-oxidized carbon black as a catalyst for the water oxidation and alcohol oxidation reactions.

    Science.gov (United States)

    Suryanto, Bryan H R; Zhao, Chuan

    2016-05-11

    Carbon black (CB) is popularly used as a catalyst support for metal/metal oxide nanoparticles due to its large surface area, excellent conductivity and stability. Herein, we show that surface oxidized CB itself, after acidic treatment and electrochemical oxidation, exhibits significant catalytic activity for the electrochemical oxidation of water and alcohols. PMID:27097802

  14. Carbon black nanoparticles and vascular dysfunction in cultured endothelial cells and artery segments

    DEFF Research Database (Denmark)

    Vesterdal, Lise K; Mikkelsen, Lone; Folkmann, Janne K; Sheykhzade, Majid; Cao, Yi; Roursgaard, Martin; Loft, Steffen; Møller, Peter

    2012-01-01

    Exposure to small size particulates is regarded as a risk factor for cardiovascular disease. We investigated effects of exposure to nanosized carbon black (CB) in human umbilical vein endothelial cells (HUVECs) and segments of arteries from rodents. The CB exposure was associated with increased...

  15. Insights from In-situ Measurements of Black Carbon During the Marine Stratus Experiment

    Science.gov (United States)

    Mazzoleni, C.; Dubey, M.; Chylek, P.; Arnott, P. W.; Seinfeld, J. H.; Varutbangkul, V.; Murphy, S. M.; Sorooshian, A.; Rissman, T. A.; Jonsson, H. H.; Buzorius, G.

    2005-12-01

    regarding the mixing state of the aerosol sampled, while functional relations between SSA and absorption can yield information regarding plume dilution and ambient air entrainment. Some of the instruments carried by the aircraft, such as a Particle Soot Absorption Photometer (PSAP), were run downstream of a Counterflow Virtual Impactor (CVI) in cloud. By combining data from PA and PSAP instruments when the CVI was on, we can deduce the distribution (cloud drop and interstitial fraction) and optical properties of black carbon containing particles inside the cloud. In at least one episode the higher absorption and scattering values appeared to be related to aerosols with high levels of inorganic mass, especially sulfate. An on-going comparison with data from an Aerodyne aerosol mass spectrometer and a particle-into-liquid sampler, also onboard the plane, should help us to understand the chemistry and physics of indirect effects of black carbon containing aerosols on marine stratus.

  16. Acute exposure of mice to high-dose ultrafine carbon black decreases susceptibility to pneumococcal pneumonia

    Directory of Open Access Journals (Sweden)

    Gordon Stephen

    2010-10-01

    Full Text Available Abstract Background Epidemiological studies suggest that inhalation of carbonaceous particulate matter from biomass combustion increases susceptibility to bacterial pneumonia. In vitro studies report that phagocytosis of carbon black by alveolar macrophages (AM impairs killing of Streptococcus pneumoniae. We have previously reported high levels of black carbon in AM from biomass smoke-exposed children and adults. We therefore aimed to use a mouse model to test the hypothesis that high levels of carbon loading of AM in vivo increases susceptibility to pneumococcal pneumonia. Methods Female outbred mice were treated with either intranasal phosphate buffered saline (PBS or ultrafine carbon black (UF-CB in PBS; 500 μg on day 1 and day 4, and then infected with S. pneumoniae strain D39 on day 5. Survival was assessed over 72 h. The effect of UF-CB on AM carbon loading, airway inflammation, and a urinary marker of pulmonary oxidative stress was assessed in uninfected animals. Results Instillation of UF-CB in mice resulted a pattern of AM carbon loading similar to that of biomass-smoke exposed humans. In uninfected animals, UF-CB treated animals had increased urinary 8-oxodG (P = 0.055, and an increased airway neutrophil differential count (P . pneumoniae, whereas morbidity and mortality after infection was reduced in UF-CB treated animals (median survival 48 h vs. 30 h, P . pneumoniae colony forming unit counts, and lower airway levels of keratinocyte-derived chemokine/growth-related oncogene (KC/GRO, and interferon gamma. Conclusion Acute high level loading of AM with ultrafine carbon black particles per se does not increase the susceptibility of mice to pneumococcal infection in vivo.

  17. 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.

  18. Characterisation of surface ionisation and adsorption of phenol and 4-nitrophenol on non-porous carbon blacks

    OpenAIRE

    Carrott, Peter; Carrott, Manuela; Vale, Tania; Valente Nabais, Joao; Mourao, Paulo

    2008-01-01

    The adsorption of phenol and 4-nitrophenol from aqueous solutions by carbon blacks was studied. Particular attention was paid to the characterisation of the surface chemistry and ionisation of the carbon blacks by use of a simple carbon surface ionisation model, as well as the use of a normalised form of the Freundlich equation for the analysis of the adsorption isotherms. The results indicated that the solutes interact directly with the graphene layers and that the adsorpti...

  19. Physical and chemical study of the influence of oxidation on the structure of carbon black

    International Nuclear Information System (INIS)

    This research thesis reports the study of the influence of an oxidising attack on carbon black particles by using chemical, physical and electrochemical methods to highlight the oxidation process. The carbon black particle is a spherical set essentially made of amorphous and crystalline carbon. It appears that the oxidising attack mainly occurs against the amorphous parts which surround the crystallites. If the attack is strong enough, crystallites are freed and the particle collapses. This process has been observed by using electronic microscopy, X rays, the BET nitrogen absorption method, and infra-reds. Chemical analysis revealed the presence of carboxyl, hydroxyl and quinone functional groups on the oxidised particle surface. These groups have been dosed by different methods (methylation, calcium acetate dosing, polarography and potassium borohydride reduction)

  20. The chlorination kinetics of zirconium dioxide mixed with carbon black

    International Nuclear Information System (INIS)

    In this research, the effects of chlorine gas at different chlorine partial pressures and carbon concentrations on the carbochlorination of zirconia were studied. It was found that in briquettes containing 18.7 %wt carbon, in a chlorine partial pressure range of 0.25-0.75 atm and for a reacted fraction of less than 0.7, the chemical reaction model was dominant for the carbochlorination process of zirconia. The order of reaction into chlorine gas (n) in this situation was 0.57. Moreover, the best weight ratio of carbon to zirconia was 40/60. In this case, the activation energy of the reaction was 209.9 kJ mol-1 in a temperature range of 1023-1223 K, and the dominant model was the chemical reaction model.

  1. Buried black soils surrounding the white roof of Africa as regional carbon storage hotspot

    Science.gov (United States)

    Zech, M.; Hörold, C.; Leiber-Sauheitl, K.; Hemp, A.; Zech, W.

    2012-04-01

    Mt. Kilimanjaro, the at least still "white roof" of Africa, attracts much attention because of its dramatically shrinking ice caps. By contrast, it was discovered only recently that intriguing paleosol sequences with buried and often strikingly black soils developed along the slopes of Mt. Kilimanjaro during the Late Quaternary. In our study we investigated in detail the soil organic carbon (SOC) contents and SOC stocks of soil profiles which are situated along two altitudinal transects; one along the humid southern slopes and the other one along the more arid northern slopes. We found up to 3 m thick paleosol sequences occurring almost area-wide particularly in the montane forest zone. SOC contents are remarkable high with values of up to more than 10%, indicating high preservation of soil organic matter (SOM). We suggest that the SOM preservation is favoured by several factors, such as (i) the burial by aeolian deposition, (ii) lower temperatures and (iii) more resistant Erica litter during glacial periods, (iv) formation of stable organo-mineral complexes and (v) high black carbon (BC) contents. The SOC-rich buried black soils account for mean SOC stocks of ~82 kg m-2 in the montane rainforest. Extrapolating this SOC storage and comparing it with the SOC storage achieved by the surrounding savannah soils of the Maasai Steppe highlights that the buried black soils are a prominent regional carbon storage hotspot.

  2. Hydrogen production using thermocatalytic decomposition of methane on Ni30/activated carbon and Ni30/carbon black.

    Science.gov (United States)

    Srilatha, K; Viditha, V; Srinivasulu, D; Ramakrishna, S U B; Himabindu, V

    2016-05-01

    Hydrogen is an energy carrier of the future need. It could be produced from different sources and used for power generation or as a transport fuel which mainly in association with fuel cells. The primary challenge for hydrogen production is reducing the cost of production technologies to make the resulting hydrogen cost competitive with conventional fuels. Thermocatalytic decomposition (TCD) of methane is one of the most advantageous processes, which will meet the future demand, hence an attractive route for COx free environment. The present study deals with the production of hydrogen with 30 wt% of Ni impregnated in commercially available activated carbon and carbon black catalysts (samples coded as Ni30/AC and Ni30/CB, respectively). These combined catalysts were not attempted by previous studies. Pure form of hydrogen is produced at 850 °C and volume hourly space velocity (VHSV) of 1.62 L/h g on the activity of both the catalysts. The analysis (X-ray diffraction (XRD)) of the catalysts reveals moderately crystalline peaks of Ni, which might be responsible for the increase in catalytic life along with formation of carbon fibers. The activity of carbon black is sustainable for a longer time compared to that of activated carbon which has been confirmed by life time studies (850 °C and 54 sccm of methane). PMID:26233751

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

    International Nuclear Information System (INIS)

    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 natC(p,x)7Be in the proton energy range 24–38 MeV are reported, with an acceptable agreement. We have demonstrated that sufficient activities of 7Be radioisotope can be produced in carbon black and nanotube that would facilitate studies of their possible impact on human and environment. - Highlights: ► We measured the excitation functions of the reaction natC(p,x)7Be in the energy range 24–38 MeV. ► We calculated the excitation functions of the reaction natC(p,x)7Be in the energy range 24–38 MeV. ► We assessed the thick target yield of the reaction natC(p,x)7Be. ► We reported results on the radiolabeling yields of carbon black and nanotubes with Beryllium 7

  4. Improved electrochemical property of Pb(NO3)2 by carbon black, graphene and carbon nanotube

    International Nuclear Information System (INIS)

    Graphical abstract: - Highlights: • Pb(NO3)2/CB, Pb(NO3)2/GN and Pb(NO3)2/CNT are prepared by a solution route. • The electrochemical property of Pb(NO3)2 is improved by CB, GN and CNT. • Pb(NO3)2/CNT shows the most outstanding cycling and rate properties. • Pb(NO3)2/CNT reveals a reversible capacity of 495.2 mAh g−1 after 45 cycles. - Abstract: As a novel anode material for lithium-ion batteries, Pb(NO3)2 can deliver an initial discharge capacity as high as 1310.8 mAh g−1. However, its capacity retention is poor upon repeated cycles. In this work, carbon black (CB), graphene (GN) and carbon nanotube (CNT) are used as conductive additives to fabricate Pb(NO3)2/CB, Pb(NO3)2/GN and Pb(NO3)2/CNT, respectively. It is observed that CB and GN fail to form uniform three-dimensional conductive network for Pb(NO3)2. As a result, Pb(NO3)2/CB and Pb(NO3)2/GN do not show obviously improved electrochemical properties compared to bare Pb(NO3)2. For comparison, CNTs provide cross-linking conductive cages for Pb(NO3)2 particles. It can be found that CNT coating can significantly enhance the electrochemical property of Pb(NO3)2. Pb(NO3)2/CNT reveals a reversible charge capacity of 495.2 mAh g−1 after 45 cycles at a current density of 50 mA g−1, which is much higher than that of bare Pb(NO3)2 (227.4 mAh g−1), Pb(NO3)2/CB (278.0 mAh g−1), Pb(NO3)2/GN (327.2 mAh g−1). Even cycled at 200 mA g−1, Pb(NO3)2/CNT can maintain a reversible lithium storage capacity of 411.7 mAh g−1. All these results suggest that Pb(NO3)2/CNT is a promising anode material for lithium-ion batteries

  5. Black carbon fractal morphology and short-wave radiative impact: a modelling study

    Directory of Open Access Journals (Sweden)

    M. Kahnert

    2011-08-01

    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 differences in the optical cross sections and asymmetry parameters. 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

  6. Hydrogen and Carbon Black Production from the Degradation of Methane by Thermal Plasma

    Directory of Open Access Journals (Sweden)

    Leila Cottet

    2014-05-01

    Full Text Available Methane gas (CH4 is the main inducer of the so called greenhouse gases effect. Recent scientific research aims to minimize the accumulation of this gas in the atmosphere and to develop processes capable of producing stable materials with added value. Thermal plasma technology is a promising alternative to these applications, since it allows obtaining H2 and solid carbon from CH4, without the parallel formation of byproducts such as CO2 and NOx. In this work, CH4 was degraded by thermal plasma in order to produce hydrogen (H2 and carbon black. The degradation efficiency of CH4, selectivity for H2 production as well as the characterization of carbon black were studied. The best results were obtained in the CH4 flow rate of 5 L min-1 the degradation percentage and the selectivity for H2 production reached 98.8 % and 48.4 %, respectively. At flow rates of less than 5 L min-1 the selectivity for H2 production increases and reaches 91.9 %. The carbon black has obtained amorphous with hydrophobic characteristics and can be marketed to be used in composite material, and can also be activated chemically and/or physically and used as adsorbent material.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2010-11-15

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

  8. Numerical investigation on the Ångström exponent of black carbon aerosol

    Science.gov (United States)

    Li, Ji; Liu, Chao; Yin, Yan; Kumar, K. Raghavendra

    2016-04-01

    Black carbon (BC) plays an important role on the global and regional climate, whereas there are significant uncertainties on its optical properties. Among various optical properties, the Ångström exponent (AE) indicates the spectral variation of the particle-optic interaction and is widely used to understand the aerosol properties. We consider the influence of BC geometry on its optical properties and assess the sensitivity of the AE to particle geometry and size distribution. The fractal aggregates with different fractal dimensions are used to represent realistic BC particles, and popular equivalent volume spherical and spheroidal models are also considered for comparison. Even if the fractal aggregates become highly compact and spherical, their optical properties are still significantly different from those of equivalent volume spheres or spheroids. Meanwhile, the Rayleigh-Debye-Gans approximation can hardly provide accurate results for all optical quantities of aggregates with different dimensions. The extinction Ångström exponent (EAE) and absorption Ångström exponent (AAE) are sensitive to both particle geometry and size distribution. With BC becoming more compact (from fractal aggregate to spheroid and to sphere), the AE becomes more sensitive to particle size distribution. The EAE and AAE of aggregates with different size distributions vary between 1.10-1.63 and 0.87-1.50, respectively, whereas those of the spheres or spheroids have wider ranges. Furthermore, the AE at smaller wavelengths (between 0.35 µm and 0.55 µm) is more sensitive to geometry and size distribution than that given by optical properties at larger wavelengths (between 0.55 µm and 0.88 µm).

  9. 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.

  10. The role of iron and black carbon in aerosol light absorption

    Directory of Open Access Journals (Sweden)

    Y. Derimian

    2008-07-01

    Full Text Available Iron is a major component of atmospheric aerosols, influencing the light absorption ability of mineral dust, and an important micronutrient that affects oceanic biogeochemistry. The regional distribution of the iron concentration in dust is important for climate studies; however, this is difficult to obtain since it requires in-situ aerosol sampling or simulation of complex natural processes. Simultaneous studies of aerosol chemical composition and radiometric measurements of aerosol optical properties, which were performed in the Negev desert of Israel continuously for about eight years, suggest a potential for deriving a relationship between chemical composition and light absorption properties, in particular the spectral single-scattering albedo.

    The two main data sets of the present study were obtained by a sun/sky radiometer and a stacked filter unit sampler that collects particles in coarse and fine size fractions. Analysis of chemical and optical data showed the presence of mixed dust and pollution aerosol in the study area, although their sources appear to be different. Spectral SSA showed an evident response to increased concentrations of iron, black carbon equivalent matter, and their mixing state. A relationship that relates the spectral SSA, the percentage of iron in total particulate mass, and the pollution components was derived. Results calculated, using this relationship, were compared with measurements from dust episodes in several locations around the globe. The comparison showed reasonable agreement between the calculated and the observed iron concentrations, and supported the validity of the suggested approach for the estimation of iron concentrations in mineral dust.

  11. Capturing vertical profiles of aerosols and black carbon over the Indian Ocean using autonomous unmanned aerial vehicles

    Directory of Open Access Journals (Sweden)

    C. E. Corrigan

    2007-08-01

    Full Text Available Measurements of the vertical distribution of aerosol properties provide essential information for generating more accurate model estimates of radiative forcing and atmospheric heating rates compared with employing remotely sensed column averaged properties. A month long campaign over the Indian Ocean during March 2006 investigated the interaction of aerosol, clouds, and radiative effects. Routine vertical profiles of aerosol and water vapor were determined using autonomous unmanned aerial vehicles equipped with miniaturized instruments. Comparisons of these airborne instruments with established ground-based instruments and in aircraft-to-aircraft comparisons demonstrated an agreement within 10%.

    Aerosol absorption optical depths measured directly using the unmanned aircraft differed from columnar AERONET sun-photometer results by only 20%. Measurements of total particle concentration, particle size distributions, aerosol absorption and black carbon concentrations are presented along with the trade wind thermodynamic structure from the surface to 3000 m above sea level. Early March revealed a well-mixed layer up to the cloud base at 500 m above mean seal level (m a.s.l., followed by a decrease of aerosol concentrations with altitude. The second half of March saw the arrival of a high altitude plume existing above the mixed layer that originated from a continental source and increased aerosol concentrations by more than tenfold, yet the surface air mass showed little change in aerosol concentrations and was still predominantly influenced by marine sources. Black carbon concentrations at 1500 m above sea level increased from 70 ng/m³ to more than 800 ng/m³ with the arrival of this polluted plume. The absorption aerosol optical depth increased from as low as 0.005 to as much as 0.035 over the same period. The spectral dependence of the aerosol absorption revealed an absorption Angstrom exponent of 1.0, which is typical of an aerosol with

  12. Seasonal trends in black carbon properties and co-pollutants in Mexico City

    Directory of Open Access Journals (Sweden)

    A. Retama

    2015-04-01

    Full Text Available The Mexico City Metropolitan Area (MCMA is a region that continues to grow in population and vehicular traffic as well as being the largest source of short lived climate pollutants (SLCP in Latin America. The local city government has made significant progress in controlling some of these pollutants, i.e. ozone (O3 and carbon monoxide (CO, but particulate matter (PM2.5 and PM10 and black carbon (BC have shown little response to mitigation strategies that have been in place for more than two decades. For the first time, extended measurements have been made of equivalent black carbon (eBC, derived from light absorption measurements made with a Photoacoustic Extinctiometer (PAX, over a 13 month period from March 2013 through March 2014. The daily trends in workday (Monday through Saturday and Sunday eBC, PM2.5 and the co-pollutants CO, O3 and NOx are evaluated with respect to the three primary seasons in that region: rainy, cold-dry and warm-dry. The maximum values in all of the particle and gas concentrations were significantly larger (Student's t test, P2.5, CO, O3, and NOx were 8.8 to 13.1 μg m-3 (40%, 49 to 73 μg m-3 (40%, 2.5 to 3.8 ppm (40%, 73 to 100 ppb (30% and 144 to 252 ppb (53%, respectively. The primary factors that lead to these large changes between the wet and dry seasons are the accelerated vertical mixing of boundary layer and free tropospheric air by the formation of clouds that dilutes the concentration of the SLCPs and the decreased actinic flux that reduces the production of ozone by photochemical reactions. A significant "weekend effect" was also identified, particularly the decrease in BC due to fewer large transport vehicles that are fueled by diesel that produces a large fraction of the BC emissions. The other co-pollutant concentrations are also significantly less on weekends except for O3 that shows no change in maximum values from workday to Sunday. As has been noted in previous studies, this lack of change is a

  13. Seasonal trends in black carbon properties and co-pollutants in Mexico City

    Science.gov (United States)

    Retama, A.; Baumgardner, D.; Raga, G. B.; McMeeking, G. R.; Walker, J. W.

    2015-04-01

    The Mexico City Metropolitan Area (MCMA) is a region that continues to grow in population and vehicular traffic as well as being the largest source of short lived climate pollutants (SLCP) in Latin America. The local city government has made significant progress in controlling some of these pollutants, i.e. ozone (O3) and carbon monoxide (CO), but particulate matter (PM2.5 and PM10) and black carbon (BC) have shown little response to mitigation strategies that have been in place for more than two decades. For the first time, extended measurements have been made of equivalent black carbon (eBC), derived from light absorption measurements made with a Photoacoustic Extinctiometer (PAX), over a 13 month period from March 2013 through March 2014. The daily trends in workday (Monday through Saturday) and Sunday eBC, PM2.5 and the co-pollutants CO, O3 and NOx are evaluated with respect to the three primary seasons in that region: rainy, cold-dry and warm-dry. The maximum values in all of the particle and gas concentrations were significantly larger (Student's t test, P< 0.05) during the dry periods than in the rainy season. The changes from rainy to dry seasons for eBC, PM2.5, CO, O3, and NOx were 8.8 to 13.1 μg m-3 (40%), 49 to 73 μg m-3 (40%), 2.5 to 3.8 ppm (40%), 73 to 100 ppb (30%) and 144 to 252 ppb (53%), respectively. The primary factors that lead to these large changes between the wet and dry seasons are the accelerated vertical mixing of boundary layer and free tropospheric air by the formation of clouds that dilutes the concentration of the SLCPs and the decreased actinic flux that reduces the production of ozone by photochemical reactions. A significant "weekend effect" was also identified, particularly the decrease in BC due to fewer large transport vehicles that are fueled by diesel that produces a large fraction of the BC emissions. The other co-pollutant concentrations are also significantly less on weekends except for O3 that shows no change in maximum

  14. Black carbon in the Arctic: the underestimated role of gas flaring and residential combustion emissions

    Directory of Open Access Journals (Sweden)

    A. Stohl

    2013-09-01

    annual mean Arctic BC surface concentrations due to residential combustion by 68% when using daily emissions. A large part (93% of this systematic increase can be captured also when using monthly emissions; the increase is compensated by a decreased BC burden at lower latitudes. In a comparison with BC measurements at six Arctic stations, we find that using daily-varying residential combustion emissions and introducing gas flaring emissions leads to large improvements of the simulated Arctic BC, both in terms of mean concentration levels and simulated seasonality. Case studies based on BC and carbon monoxide (CO measurements from the Zeppelin observatory appear to confirm flaring as an important BC source that can produce pollution plumes in the Arctic with a high BC / CO enhancement ratio, as expected for this source type. BC measurements taken during a research ship cruise in the White, Barents and Kara seas north of the region with strong flaring emissions reveal very high concentrations of the order of 200–400 ng m−3. The model underestimates these concentrations substantially, which indicates that the flaring emissions (and probably also other emissions in northern Siberia are rather under- than overestimated in our emission data set. Our results suggest that it may not be "vertical transport that is too strong or scavenging rates that are too low" and "opposite biases in these processes" in the Arctic and elsewhere in current aerosol models, as suggested in a recent review article (Bond et al., Bounding the role of black carbon in the climate system: a scientific assessment, J. Geophys. Res., 2013, but missing emission sources and lacking time resolution of the emission data that are causing opposite model biases in simulated BC concentrations in the Arctic and in the mid-latitudes.

  15. The structure of carbon black-elastomer composites by small-angle neutron scattering and the method of contrast variation

    International Nuclear Information System (INIS)

    We have been exploring the use of small-angle neutron scattering and the method of contrast variation to give a new look at a very old problem: reinforcement of elastomers by carbon black in durable rubber products. Carbon black has a hierarchy of structures consisting of particles covalently bound into aggregates, which in turn associate by weak interactions into agglomerates. We found that in one carbon black, HSA, the aggregates are rodlike, containing an average of 4-6 particles. The aggregates have an outer graphitic shell and an inner core of lower density carbon. The core is continuous throughout the carbon black aggregate. Contrast variation of swollen HSA-polyisoprene gels shows that the HSA is completely embedded in polyisoprene and that the agglomerates are formed predominantly by end on associations of the rodlike aggregates. The surface structure of the carbon black appears smooth over length scales above about 10 angstrom. Further studies using production carbon blacks suggest that these structural characteristics are generally present in commercial rubber composites

  16. NANOMECHANICAL MAPPING OF CARBON BLACK REINFORCED NATURAL RUBBER BY ATOMIC FORCE MICROSCOPY

    Institute of Scientific and Technical Information of China (English)

    Toshio Nishi; Hideyuki Nukaga; So Fujinami; Ken Nakajima

    2007-01-01

    Atomic force microscopy (AFM) has the advantage of obtaining mechanical properties as well as topographic information at the same time. By analyzing force-distance curves measured over two-dimensional area using Hertzian contact mechanics, Young's modulus mapping was obtained with nanometer-scale resolution. Furthermore, the sample deformation by the force exerted was also estimated from the force-distance curve analyses. We could thus reconstruct a real topographic image by incorporating apparent topographic image with deformation image. We applied this method to carbon black reinforced natural rubber to obtain Young's modulus distribution image together with reconstructed real topographic image.Then we were able to recognize three regions; rubber matrix, carbon black (or bound rubber) and intermediate regions.Though the existence of these regions had been investigated by pulsed nuclear magnetic resonance, this paper would be the first to report on the quantitative evaluation of the interfacial region in real space.

  17. Modelling of dielectric relaxation processes of epoxy-resin filled with carbon black particles

    International Nuclear Information System (INIS)

    Composites of an epoxy-resin matrix with randomly dispersed carbon black nanoparticles in various amounts and below the percolation threshold were prepared and their dielectric spectra were measured in the frequency range from 100 Hz to 20 MHz and temperature range from 20 °C to 95 °C. The obtained data were analyzed by means of electric permittivity formalism. Two dielectric relaxation processes were revealed in the frequency range and temperature interval of the measurements. One of these relaxations appearing near the glass transition temperature was associated with the interfacial polarization effect. Whereas the other appearing at lower temperature is consistent with the Havriliak–Negami model. Furthermore, the analysis of the temperature dependence of their relaxation time using the Vogel–Tammam–Fulcher (VTF) model shows the existence of carbon black/matrix interaction

  18. Heat generation of mechanically abused lithium-ion batteries modified by carbon black micro-particulates

    International Nuclear Information System (INIS)

    In the current study, we experimentally investigated the effects of carbon black micro-particulates (CBMP) on the temperature increase of lithium-ion battery coin cells subjected to nail penetration and blunt impact. The major difference between CBMP and regular carbon black additives is in particle size. The testing data showed that addition of 1 wt% of CBMP in the cathode and anode does not influence the cycle life, while can reduce the heat generation rate by nearly 50%, after the peak temperature is reached. Thermal treatment of the modified cells at 100 °C would further reduce the heat generate rate. The initial temperature increase rate, the maximum temperature, as well as the total energy dissipation are not affected. These findings shed light on thermal runaway mitigation of high-energy batteries. (paper)

  19. Effect of irradiation on PTC performances of carbon black filled polymer composites

    International Nuclear Information System (INIS)

    The influences of irradiation on Positive Temperature Coefficient (PTC) functions of polymer-carbon black composites are studied systematically, using HDPE, LDPE, PE/EPDM, PE/EEA as polymer matrixes and carbon black as conductive fillers. The results show that under a certain radiation dose, a remarkable improvement of the PTC intensity and the reproducibility of PTC curves of most polymer blends can be achieved, and Negative Temperature Coefficient (NTC) effects are decreased or eliminated. The mechanism of crosslinking structure on improving and stabilizing the PTC functions of polymer blends is also discussed through modern structural analysis methods. In this paper, an interesting and significant phenomenon is discovered. The PTC curve of PE/EPDM/CB composite presents an obvious NTC phenomenon as the dose exceeding 2 MGy. (author)

  20. AC electrical conductivity of poly(methyl methacrylate)/carbon black composite

    International Nuclear Information System (INIS)

    The study deals with the ac electrical conduction of poly(methyl methacrylate)/carbon black composite of different carbon black (CB) filler concentrations (2, 6, 12 wt%). The ac electrical conductivity was studied as a function of filler concentration, frequency in the range from 100 kHz to 2 MHz, and temperature in the range from 300 to 450 K. It was found that ac electrical conductivity increases by increasing both temperature and CB concentration. The observed overall mechanism of electrical conduction has been related to the transfer of electrons through the CB aggregations distributed in the polymer matrix. The observed increase in conductivity with CB concentration was interpreted through the percolation theory

  1. The measurement of mass and black carbon of fine particles over Klang valley, Kuala Lumpur

    International Nuclear Information System (INIS)

    Fine particles (PM 2.5) of airborne air pollutants samples were collected on weekly basis during the period from 2004-2008 at Klang Valley, Kuala Lumpur. They were analyzed for their mass and black carbon contents. Samples were collected using impactor type air pollutant sampler unit i.e Gent stack sampler capable of collecting of two (2) size groups of air particulate matter, fine (3 and the black carbon was 3.9 - 5.4 μg/m3. The component of BC was about 17% as relative to the gravimetric fine mass. The value for both PM 2.5 and BC were found to be slightly higher during the southwest monsoon May to September due to the haze occasion reported during this season. (Author)

  2. 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. PMID:27508218

  3. 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.

  4. The Arctic response to remote and local forcing of black carbon

    OpenAIRE

    Sand, M.; T. K. Berntsen; Kay, J. E.; J. F. Lamarque; Seland, Ø; Kirkevåg, A.

    2013-01-01

    Recent studies suggest that the Arctic temperature response to black carbon (BC) forcing depend strongly on the location of the forcing. We investigate how atmospheric BC in the mid-latitudes remotely influence the Arctic climate, and compare this with the response to atmospheric BC located in the Arctic itself. In this study, idealized climate simulations are carried out with a fully coupled Earth System Model, which includes a comprehensive treatment of aerosol microphysics. In order to det...

  5. The Arctic response to remote and local forcing of black carbon

    OpenAIRE

    Sand, M.; T. K. Berntsen; Kay, J. E.; J. F. Lamarque; Seland, Ø; Kirkevåg, A.

    2012-01-01

    Recent studies suggest that the Arctic temperature response to black carbon (BC) forcing depend on the location of the forcing. We investigate how BC in the mid-latitudes remotely influence the Arctic climate, and compare this with the response to BC located in the Arctic it self. In this study, idealized climate simulations are carried out with a fully coupled Earth System Model, which includes a comprehensive treatment of aerosol microphysics. In order to determine how BC transported t...

  6. Carbon black and titanium dioxide nanoparticles elicit distinct apoptotic pathways in bronchial epithelial cells

    OpenAIRE

    Baeza-Squiban Armelle; Fleury Jocelyne; Martens Johan A; Andreau Karine; Borot Marie-Caroline; Ferecatu Ioana; Thomassen Leen CJ; Hussain Salik; Marano Francelyne; Boland Sonja

    2010-01-01

    Abstract Background Increasing environmental and occupational exposures to nanoparticles (NPs) warrant deeper insight into the toxicological mechanisms induced by these materials. The present study was designed to characterize the cell death induced by carbon black (CB) and titanium dioxide (TiO2) NPs in bronchial epithelial cells (16HBE14o- cell line and primary cells) and to investigate the implicated molecular pathways. Results Detailed time course studies revealed that both CB (13 nm) and...

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

    OpenAIRE

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

    2016-01-01

    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...

  8. Airborne observations of black carbon aerosol layers at mid-latitudes

    OpenAIRE

    Dahlkötter, Florian

    2014-01-01

    Model studies show that black carbon (BC) is, after CO2, the second strongest component of current global warming. In this study, microphysical and optical properties of BC-containing aerosol layers at mid-latitudes were investigated based on airborne in situ observations during the CONCERT 2011 field experiment. For the first time, the Single Particle Soot Photometer was operated onboard the research aircraft Falcon. Besides comprehensive results to BC in aerosol layers, this study shows the...

  9. Association between Traffic-Related Black Carbon Exposure and Lung Function among Urban Women

    OpenAIRE

    Suglia, Shakira Franco; Gryparis, Alexandros; Schwartz, Joel David; Wright, Rosalind Jo

    2008-01-01

    Background: Although a number of studies have documented the relationship between lung function and traffic-related pollution among children, few have focused on adult lung function or examined community-based populations. Objective: We examined the relationship between black carbon (BC), a surrogate of traffic-related particles, and lung function among women in the Maternal–Infant Smoking Study of East Boston, an urban cohort in Boston, Massachusetts. Methods: We estimated local BC levels us...

  10. Export efficiency of black carbon aerosol in continental outflow: Global implications

    OpenAIRE

    R. J. Park; Jacob, D. J.; Palmer, P. I.; Clarke, A. D.; Weber, R.J.; M. A. Zondlo; Eisele, F. L; Bandy, A. R.; Thornton, D. C.; G. W. Sachse; T. C. Bond

    2005-01-01

    We use aircraft observations of Asian outflow from the NASA Transport and Chemical Evolution over the Pacific (TRACE-P) mission over the NW Pacific in March–April 2001 to estimate the export efficiency of black carbon (BC) aerosol during lifting to the free troposphere, as limited by scavenging from the wet processes (warm conveyor belts and convection) associated with this lifting. Our estimate is based on the enhancement ratio of BC relative to CO in Asian outflow observed at different alti...

  11. Concretionary methane-seep carbonates and associated microbial communities in Black Sea sediments

    OpenAIRE

    Reitner, J.; Peckmann, J.; M. Blumenberg; W. Michaelis; Reimer, A; V. Thiel

    2005-01-01

    Gas seeps in the euxinic northwestern Black Sea provide an excellent opportunity to study anaerobic, methane-based ecosystems with minimum interference from oxygen-dependent processes. An integrated approach using fluorescence- and electron microscopy, fluorescence in situ hybridization, lipid biomarkers, stable isotopes (δ13C), and petrography revealed insight into the anatomy of concretionary methane-derived carbonates currently forming within the sediment around seeps. Some of the carbonat...

  12. Air Quality Responses to Changes in Black Carbon and Nitrogen Oxide Emissions

    OpenAIRE

    Millstein, Dev

    2009-01-01

    Fine particulate matter (PM) affects public health, visibility, climate, and influences ecosystem productivity and species diversity. Diesel engines are an important source of air pollution and will face a variety of new regulations, so emissions from these vehicles are expected to undergo changes over the next decade that will have important effects on primary PM emissions, especially black carbon (BC) emissions, as well as nitrogen oxide (NOx) emissions and therefore secondary pollutants su...

  13. Measurement of black carbon at Syowa station, Antarctica: seasonal variation, transport processes and pathways

    OpenAIRE

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

    2008-01-01

    Measurement of black carbon (BC) was carried out at Syowa station Antarctica (69° S, 39° E) from February 2004 until January 2007. The BC concentration at Syowa ranged from below detection to 176 ng m−3 during the measurements. Higher BC concentrations were observed mostly under strong wind (blizzard) conditions due to the approach of a cyclone and blocking event. The BC-rich air masses traveled from the lower troposphere of the Atlantic and In...

  14. GHG and black carbon emission inventories from Mezquital Valley: The main energy provider for Mexico Megacity

    International Nuclear Information System (INIS)

    The greenhouse gases and black carbon emission inventory from IPCC key category Energy was accomplished for the Mezquital Valley, one of the most polluted regions in Mexico, as the Mexico City wastewater have been continuously used in agricultural irrigation for more than a hundred years. In addition, thermoelectric, refinery, cement and chemistry industries are concentrated in the southern part of the valley, near Mexico City. Several studies have reported air, soil, and water pollution data and its main sources for the region. Paradoxically, these sources contaminate the valley, but boosted its economic development. Nevertheless, no research has been done concerning GHG emissions, or climate change assessment. This paper reports inventories performed by the 1996 IPCC methodology for the baseline year 2005. Fuel consumption data were derived from priority sectors such as electricity generation, refineries, manufacturing & cement industries, transportation, and residential use. The total CO2 emission result was 13,894.9 Gg, which constituted three-quarters of Hidalgo statewide energy category. The principal CO2 sources were energy transformation (69%) and manufacturing (19%). Total black carbon emissions were estimated by a bottom-up method at 0.66 Gg. The principal contributor was on-road transportation (37%), followed by firewood residential consumption (26%) and cocked brick manufactures (22%). Non-CO2 gas emissions were also significant, particularly SO2 (255.9 Gg), which accounts for 80% of the whole Hidalgo State emissions. Results demonstrated the negative environmental impact on Mezquital Valley, caused by its role as a Megacity secondary fuel and electricity provider, as well as by the presence of several cement industries. - Highlights: • First GHG & black carbon inventory for Mezquital Valley: Mexico City energy supplier • Energy industries caused the largest CO2 and SO2 emissions from residual fuel oil. • Diesel transportation was the main black

  15. Surface modification and characterization of carbon black; UV cured colored epoxy composites

    OpenAIRE

    Atif, Muhammad

    2014-01-01

    Carbon Black is inexpensive widely used industrial filler, but its dispersability in solvents/polymeric media has always been a critical point. As a result either surfactants or higher mechanical forces have been utilized to disperse it well in the media. First part of research was aimed at surface modification of CB to increase its dispersability in different solvents and epoxy that directly effects filler-medium interactions. Type and magnitude of this interaction differs with structure and...

  16. Fuel Cell Platinum Catalysts Supported on Mediate Surface Area Carbon Black Supports

    Czech Academy of Sciences Publication Activity Database

    Kaluža, Luděk; Larsen, M.J.; Zdražil, Miroslav; Gulková, Daniela; Odgaard, M.

    2015-01-01

    Roč. 43, č. 2015 (2015), s. 913-918. ISSN 1974-9791. [International Conference on Chemical and Process Engineering - ICheaP12 /12./. Milano, 19.05.2015-22.05.2015] R&D Projects: GA MŠk(CZ) 7HX13003 EU Projects: European Commission(XE) 303466 - IMMEDIATE Institutional support: RVO:67985858 Keywords : carbon black * platinum catalyst * fuel cell Subject RIV: CI - Industrial Chemistry, Chemical Engineering

  17. Determination of Effective Particle Density for Sterically Stabilized Carbon Black Particles: Effect of Diblock Copolymer Stabilizer Composition.

    Science.gov (United States)

    Growney, David J; Fowler, Patrick W; Mykhaylyk, Oleksandr O; Fielding, Lee A; Derry, Matthew J; Aragrag, Najib; Lamb, Gordon D; Armes, Steven P

    2015-08-18

    Two poly(styrene-b-hydrogenated isoprene) (PS-PEP) copolymers and a poly(styrene-b-hydrogenated butadiene) (PS-PB) diblock copolymer of differing polystyrene content (20, 28 or 35 mol %) and molecular weight (117-183 kg mol(-1)) are examined. These copolymers form star-like micelles in n-dodecane, as judged by TEM, DLS, and SAXS studies. At ambient temperature, such micelles are known to adsorb intact onto a model colloidal substrate such as carbon black, conferring a high degree of dispersion (Growney, D. J.; Mykhaylyk, O. O.; Armes, S. P. Langmuir 2014, 30, 6047). Isotherms for micellar adsorption on carbon black at 20 °C are constructed using a supernatant depletion assay based on UV spectroscopy by utilizing the aromatic chromophore in the polystyrene block. Perhaps surprisingly, the diblock copolymer with the lowest polystyrene content has the strongest affinity for the carbon black particles. Assuming that the star-like diblock copolymer micelles adsorb onto carbon black to form hemi-micelles with a stabilizer layer thickness equal to the mean micelle radius, the effective particle density of the resulting sterically stabilized carbon black particles in n-dodecane can be estimated from the SAXS micelle dimensions based on geometric considerations. As an approximation, a spherical core-shell morphology was assumed, and the primary grain size of the carbon black particles was determined to be 74 nm diameter as judged by BET surface area analysis. Using this approach, effective particle densities of 0.90, 0.91, and 0.92 g cm(-3) were calculated for sterically stabilized carbon black particles prepared using the PS-PB20, PS-PEP28, and PS-PEP35 diblock copolymers, respectively. These densities are significantly lower than that of carbon black (1.89 g cm(-3)), which indicates that the sterically stabilized carbon black particles are substantially solvated. Since the rate of sedimentation of the sterically stabilized carbon black particles depends on the density

  18. Seasonal and diurnal trends in black carbon properties and co-pollutants in Mexico City

    OpenAIRE

    A. Retama; Baumgardner, D; Raga, G. B.; G. R. McMeeking; Walker, J. W.

    2015-01-01

    The Mexico City metropolitan area (MCMA) is a region that continues to grow in population and vehicular traffic as well as being the largest source of short-lived climate pollutants (SLCP) in Latin America. The local city government has made significant progress in controlling some of these pollutants, i.e., ozone (O3) and carbon monoxide (CO), but particulate matter (PM2.5 and PM10) and black carbon (BC) have shown a less positive response to mitigation strategies that have...

  19. Preparation of diamond nanocrystals from catalysed carbon black in a high magnetic field

    International Nuclear Information System (INIS)

    Under a static high magnetic field of 10 T, diamond-like carbon (DLC) nanocrystals and graphite-coated n-diamond nanoparticles have been synthesized after a pyrogenation of carbon black and a nanometre-sized iron catalyst at atmospheric pressure and a temperature of 1100 C. The product is analysed by x-ray diffraction, Raman spectroscopy, transmission electron microscopy and electron-probe microanalysis. The average size of the DLC nanopowders is about 20 nm, and that of the graphite-coated n-diamond particles is about 100 nm. The yield of diamond is as high as 30%

  20. 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

  1. The Effects of Silica/Carbon Black Ratio on the Dynamic Properties of the Tread compounds in Truck Tires

    OpenAIRE

    Zafarmehrabian, Ramin; Gangali, Saeed Taghvaei; Ghoreishy, Mir Hamid Reza; Davallu, Mehran

    2012-01-01

    NR is the major constituent in the rubber compound used for the tread on the truck tires. A general compound formulation of the tire tread includes NR and BR as polymer base and carbon black as the reinforcing filler, and curative components. In this paper the effects of dual filler system (carbon black and precipitated silica) on the dynamic properties of tire treat has been studied. The results show by increasing of precipitated silica, significant improvement was observed in fatigue resist...

  2. Black carbon inclusive multichemical modeling of PBDE and PCB biomagnification and -transformation in estuarine food webs.

    Science.gov (United States)

    Di Paolo, Carolina; Gandhi, Nilima; Bhavsar, Satyendra P; Van den Heuvel-Greve, Martine; Koelmans, Albert A

    2010-10-01

    Bioavailability and bioaccumulation of polybrominated diphenylethers (PBDEs) are affected by adsorption on black carbon (BC) and metabolism in biota, respectively. Recent studies have addressed these two processes separately, illustrating their importance in assessing contaminant dynamics. In order to properly examine biomagnification of polychlorinated biphenyls (PCBs) and PBDEs in an estuarine food-web, here we set up a black carbon inclusive multichemical model. A dual domain sorption model, which accounted for sorption to organic matter (OM) and black carbon (BC), was used to estimate aqueous phase concentrations from the measured chemical concentrations in suspended solids. We adapted a previously published multichemical model that tracks the movement of a parent compound and its metabolites in each organism and within its food web. First, the model was calibrated for seven PCB congeners assuming negligible metabolism. Subsequently, PBDE biomagnification was modeled, including biotransformation and bioformation of PBDE congeners, keeping the other model parameters the same. The integrated model was capable of predicting trophic magnification factors (TMF) within error limits. PBDE metabolic half-lives ranged 21-415 days and agreed to literature data. The results showed importance of including BC as an adsorbing phase, and biotransformation and bioformation of PBDEs for a proper assessment of their dynamics in aquatic systems. PMID:20828201

  3. Distinctive sorption mechanisms of 4-chlorophenol with black carbons as elucidated by different pH.

    Science.gov (United States)

    Shih, Yang-hsin; Su, Yuh-fan; Ho, Ren-yu; Su, Po-hsin; Yang, Chien-ying

    2012-09-01

    Black carbon (BC) has been considered as an important sorbent in the environment in recent years due to its high sorption capacity and unique sorption behavior. Sorption characteristics of black carbons from two main sources were investigated to get a better understanding of organic chemical fate in the environment. The present study showed sorption mechanisms of 4-chlorophenol, a common organic contaminant in the surroundings, in two kinds of black carbons, soot surrogate (BC1) and environmental char (BC2) derived from rice straw. Sorption capacity of 4-chlorophenol was much higher in BC1 than on BC2 due to the larger surface area of BC1. However, the surface-area normalized sorption coefficients (sorption capacity per surface area) of BC2 were higher than those of BC1, indicating electrostatic attraction and actions of polar foundational groups on BC2 can react with 4-chlorophenol. With increasing temperature, sorption of BC1 decreased but the sorption of BC2 significantly increased at pH 10 and only slightly increased at pH 4. An exothermic sorption reaction was found for BC1; however, an endothermic reaction of chemical sorption occurred on BC2 at pH 10 due to the electrostatic attraction. At pH4, sorption capacity of BC2 decreased and the small positive sorption enthalpy indicated that less electrostatic attractions occurred because of the neutral form of 4-chlorophenol and the domination of mainly hydrophobic interactions. PMID:22842752

  4. Influence of acid functionalization on the cardiopulmonary toxicity of carbon nanotubes and carbon black particles in mice

    International Nuclear Information System (INIS)

    Engineered carbon nanotubes are being developed for a wide range of industrial and medical applications. Because of their unique properties, nanotubes can impose potentially toxic effects, particularly if they have been modified to express functionally reactive chemical groups on their surface. The present study was designed to evaluate whether acid functionalization (AF) enhanced the cardiopulmonary toxicity of single-walled carbon nanotubes (SWCNT) as well as control carbon black particles. Mice were exposed by oropharyngeal aspiration to 10 or 40 μg of saline-suspended single-walled carbon nanotubes (SWCNTs), acid-functionalized SWCNTs (AF-SWCNTs), ultrafine carbon black (UFCB), AF-UFCB, or 2 μg LPS. 24 hours later, pulmonary inflammatory responses and cardiac effects were assessed by bronchoalveolar lavage and isolated cardiac perfusion respectively, and compared to saline or LPS-instilled animals. Additional mice were assessed for histological changes in lung and heart. Instillation of 40 μg of AF-SWCNTs, UFCB and AF-UFCB increased percentage of pulmonary neutrophils. No significant effects were observed at the lower particle concentration. Sporadic clumps of particles from each treatment group were observed in the small airways and interstitial areas of the lungs according to particle dose. Patches of cellular infiltration and edema in both the small airways and in the interstitium were also observed in the high dose group. Isolated perfused hearts from mice exposed to 40 μg of AF-SWCNTs had significantly lower cardiac functional recovery, greater infarct size, and higher coronary flow rate than other particle-exposed animals and controls, and also exhibited signs of focal cardiac myofiber degeneration. No particles were detected in heart tissue under light microscopy. This study indicates that while acid functionalization increases the pulmonary toxicity of both UFCB and SWCNTs, this treatment caused cardiac effects only with the AF-carbon nanotubes

  5. Effect of ZnO Addition on Structural Properties of ZnO-PANi/ Carbon Black Thin Films

    International Nuclear Information System (INIS)

    The aim of this project was to investigate the effect of ZnO addition on the structural properties of ZnO-PANi/ carbon black thin films. The sol gel method was employed for the preparation of ZnO sol. The sol was dried for 24 h at 100 degree Celsius and then annealed at 600 degree Celsius for 5 h. XRD characterization of the ZnO powder showed the formation of wurtzite type ZnO crystals. The ZnO powder were mixed into PANi/ carbon black solution which was dissolved into M-Pyrol, N-Methyl-2-Pyrrolidinone (NMP) to produce a composite solution of ZnO-PANi/ carbon black. The weight ratio of ZnO were 4 wt %, 6 wt % and 8 wt %. The composite solutions were deposited onto glass substrates using a spin-coating technique to fabricate ZnO-PANi/ carbon black thin films. AFM characterization showed the decreasing of average roughness from 7.98 nm to 2.23 nm with the increment of ZnO addition in PANi/ carbon black films. The thickness of the films also decreased from 59.5 nm to 28.3 nm. FESEM image revealed that ZnO-PANi/ carbon black thin films have changed into agglomerated surface morphology resulting in the increment of porosity of the films. (author)

  6. Historical record of black carbon in urban soils and its environmental implications

    International Nuclear Information System (INIS)

    Energy use in urbanization has fundamentally changed the pattern and fluxes of carbon cycling, which has global and local environmental impacts. Here we have investigated organic carbon (OC) and black carbon (BC) in six soil profiles from two contrast zones in an ancient city (Nanjing) in China. BC in soils was widely variable, from 0.22 to 32.19 g kg-1. Its average concentration in an ancient residential area (Zone 1) was, 0.91 g kg-1, whereas in Zone 2, an industrial and commercial area, the figure was 8.62 g kg-1. The ratio of BC/OC ranged from 0.06 to 1.29 in soil profiles, with an average of 0.29. The vertical distribution of BC in soil is suggested to reflect the history of BC formation from burning of biomass and/or fossil fuel. BC in the surface layer of soils was mainly from traffic emission (especially from diesel vehicles). In contrast, in cultural layers BC was formed from historical coal use. The contents of BC and the ratio of BC/OC may reflect different human activities and pollution sources in the contrasting urban zones. In addition, the significant correlation of heavy metals (Cu, Pb, and Zn) with BC contents in some culture layers suggests the sorption of the metals by BC or their coexistence resulted from the coal-involved smelting. - Soil black carbon can reflect the pollution history of a city during urbanization.

  7. Black and organic carbon emission inventories: review and application to California.

    Science.gov (United States)

    Chow, Judith C; Watson, John G; Lowenthal, Douglas H; Chen, Lung-Wen Antony; Motallebi, Nehzat

    2010-04-01

    Particulate black or elemental carbon (EC) (black carbon [BC]) and organic carbon (OC) affect climate, visibility, and human health. Several "top-down" and "bottom-up" global emission inventories for these components have compiled country-wide emission factors, source profiles, and activity levels that do not necessarily reflect local conditions. Recent estimates of global BC and OC emissions range from 8 to 24 and 33 to 62 Tg (1012 g) per year, respectively. U.S. BC emissions account for 5.6% of the global total emissions. Uncertainties in global BC emission estimates are a factor of 2 or more. The U.S. National Emissions Inventory is well documented, but its major source categories are not easily related to EC- and OC-emitting source subcategories. California's bottom-up emission inventory is easily accessible at many levels of detail and provides an example of how sources can be regrouped for speciated emission rates. PM2.5 (particulate matter with aerodynamic diameters burning. Major discrepancies were found for directly emitted OC, with the global inventory estimating more than twice that of the California inventory. Most of the discrepancy was due to differences in open biomass burning (wildfires and agricultural waste) for which carbon emissions are highly variable. BC and OC emissions are sensitive to the availability and variability of existing source profiles, and profiles more specific to fuels and operating conditions are needed to increase emission accuracy. PMID:20437785

  8. 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.

  9. Influence of black carbon addition on phenanthrene dissipation and microbial community structure in soil

    International Nuclear Information System (INIS)

    Biodegradation processes and changes in microbial community structure were investigated in black carbon (BC) amended soils in a laboratory experiment using two soils (black soil and red soil). We applied different percentages of charcoal as BC (0%, 0.5% and 1% by weight) with 100 mg kg−1 of phenanthrene. Soil samples were collected at different incubation times (0, 7, 15, 30, 60, 120 d). The amendment with BC caused a marked decrease in the dissipation (ascribed to mainly degradation and/or sequestration) of phenanthrene residues from soil. Extracted phenanthrene in black soil with 1% BC were higher, oppositely in red soil, 0.5% BC amendments were higher. There were significant changes in the PLFA pattern in phenanthrene-spiked soils with time but BC had little effect on the microbial community structure of phenanthrene-spiked soils, as indicated by principal component analysis (PCA) of the PLFA signatures. - Highlights: ► Extracted phenanthrene increased substantially as the BC amount increased. ► Extracted phenanthrene in black soil with 1% BC were higher, oppositely in red soil. ► BC caused a marked decrease in the dissipation of phenanthrene from soil. ► PLFA pattern in phenanthrene-spiked soils with time had significant changes. - BC amendments on phenanthrene extraction were different for two soils and time was a more effective factor in microbial community changes.

  10. Co-precipitation Synthesis and Thermal Stability of Zircon Encapsulated Carbon Black

    Directory of Open Access Journals (Sweden)

    PENG Cheng, ZHANG Chu-Xin, L? Ming, LI Zhi-Hong, WU Jian-Qing

    2013-08-01

    Full Text Available Zircon encapsulated carbon black powders were synthesized by a co-precipitation method using TEOS and zirconium oxychloride as starting materials. X-ray diffraction (XRD, scanning electronic microscope (SEM, colorimeter and laser grain size analyzer were used to investigate the phase structure, morphology, thermal stability and size distribution of the prepared composite powders, respectively. The effect of experimental conditions including the pH of the precursor solution, the calcination temperature, the type and amount of mineralizers on their thermal stability was studied by orthogonal test. The optimal conditions were accordingly determined as follows: precursor solution pH=5, calcination temperature 1150¡æ and 5% LiF mineralizer. Under these conditions, zircon encapsulated carbon black with embedded structures can be obtained. The composite powder has high thermal stability and adequate size distribution, and thus it is a good candidate material for black ceramic pigment. When calcined at 1000¡æ in the frit glaze, the powder shows considerable tilting strength.

  11. Physico-mechanical and electrical properties of conductive carbon black reinforced chlorosulfonated polyethylene vulcanizates

    Directory of Open Access Journals (Sweden)

    2008-12-01

    Full Text Available The present work deals with the effect of conductive carbon black (Ensaco 350G on the physico-mechanical and electrical properties of chlorosulfonated polyethylene (CSM rubber vulcanizates. The physico-mechanical properties like tensile strength, tear strength, elongation at break, compression set, hardness and abrasion resistance have been studied before and after heat ageing. Up to 30 parts per hundred rubber (phr filler loading both tensile and tear strength increases beyond which it shows a decreasing trend whereas modulus gradually increases with the filler loading. Incorporation of carbon black increases the hysteresis loss of filled vulcanizates compared to gum vulcanizates. Unlike gum vulcanizate, in filled vulcanizates the rate of relaxation shows increasing trend. The bound rubber content is found to increase with increase in filler loading. Dielectric relaxation spectra were used to study the relaxation behavior as a function of frequency (100 to 106 Hz at room temperature. Variation in real and imaginary parts of electric modulus has been explained on the basis of interfacial polarization of fillers in the polymer medium. The percolation limit of the conductive black as studied by ac conductivity measurements has also been reported.

  12. Black carbon measurements in the boundary layer over western and northern Europe

    Directory of Open Access Journals (Sweden)

    G. R. McMeeking

    2010-06-01

    Full Text Available Europe is a densely populated region that is a significant global source of black carbon (BC aerosol, but there is a lack of information regarding the physical properties and spatial/vertical distribution of BC in the region. We present the first aircraft observations of sub-micron BC aerosol concentrations and physical properties measured by a single particle soot photometer (SP2 in the lower troposphere over Europe. The observations spanned a region roughly bounded by 50° to 60° N and from 15° W to 30° E. The measurements, made between April and September 2008, showed that average BC mass concentrations ranged from about 300 ng m−3 near urban areas to approximately 50 ng m−3 in remote continental regions, lower than previous surface-based measurements. BC represented between 0.5 and 3% of the sub-micron aerosol mass. Black carbon mass size distributions were log-normally distributed and peaked at approximately 180 nm, but shifted to smaller diameters (~160 nm near source regions. Black carbon was correlated with carbon monoxide (CO but had different ratios to CO depending on location and air mass. Light absorption coefficients were measured by particle soot absorption photometers on two separate aircraft and showed similar geographic patterns to BC mass measured by the SP2, but differed by at least a factor of two compared to each other. We summarize the BC and light absorption measurements as a function of longitude and air mass age and also provide profiles of BC mass concentrations and size distribution statistics. Our results will help evaluate model-predicted regional BC concentrations and properties and determine regional and global climate impacts from BC due to atmospheric heating and surface dimming.

  13. Density separation of combustion-derived soot and petrogenic graphitic black carbon: Quantification and isotopic characterization

    International Nuclear Information System (INIS)

    The black carbon continuum is composed of a series of carbon-rich components derived from combustion or metamorphism and characterized by contrasting environmental behavior and susceptibility to oxidation. In this work, we present a micro-scale density fractionation method that allows isolating the small quantities of soot-like and graphitic material usually found in natural samples. Organic carbon and δ13C mass balance calculations were used to quantify the relative contributions of the two fractions to thermally-stable organic matter from a series of aquatic sediments. Varying proportions of soot-like and graphitic material were found in these samples, with large variations in δ13C signatures suggesting important differences in their origin and/or dynamics in the environment.

  14. Effects of Strain-Induced Crystallization on Mechanical Properties of Elastomeric Composites Containing Carbon Nanotubes and Carbon Black

    International Nuclear Information System (INIS)

    The effects of strain-induced crystallization (SIC) on the mechanical properties of elastomeric composites as functions of extension ratio (λ), multi walled carbon nanotube (CNT) content, and carbon black (CB) content are investigated. The differential scanning calorimetry (DSC) analysis shows that the degree of crystallinity increases with the increase in the CB and CNT content. As λ increases, the glass transition temperature (Tg) of the composites increases, and the latent heat of crystallization (LHc) of the composites is maximum at λ=1.5. It is found that the mechanical properties have a linear relation with LHc, depending on the CNT content. According to the TGA (thermogravimetric analysis), the weight loss of the composite matrix is 94.3% and the weight of the composites decreases with the filler content. The ratio of tensile modulus (Ecomp/ Ematrix) is higher than that of tensile strength (σcomp/ σmatrix) because of the CNT orientation inside the elastomeric composites

  15. Black carbon aerosol and carbon monoxide in European regionally polluted air masses at Mace Head, Ireland during 1995-1998

    International Nuclear Information System (INIS)

    Continuous measurements of black carbon aerosol (BCA) at the Mace Head Atmospheric Research Station on the Atlantic Ocean coast of Ireland show the occurrence of dramatically elevated concentrations when regionally polluted air masses are advected to the station. These occurrences correlate well with similar elevations in carbon monoxide and a wide range of other trace gases monitored near-simultaneously with the BCA. Using daily sector allocation and a sophisticated Lagrangian dispersion model, two independent estimates of the European emission source strength of BCA that are required to explain the Mace Head observations have been made. The best estimates of the UK and European emission source strengths of BCA are 46 ± 14 and [(482-511) ± 140] X 103tonnes yr-1, respectively, and these estimates compare favourably with published inventories, at least to within ± 25%, though they are considerably smaller than the emissions employed in some early global climate model studies. (author)

  16. Carbon Dynamics of Forest Floor and Stem in Black Spruce Forest Soils, Interior Alaska

    Science.gov (United States)

    Kim, Yongwon; Kim, Seong-Deog; Kim, Woongji

    2010-05-01

    Our automated open/close chamber system (AOCC) consists of eight chambers, a pump, CO2 gas analyzer, and a datalogger for CO2 data on the lichen, tussock, feather moss, and sphagnum moss of a black spruce forest, Interior Alaska, during the growing seasons of 2007 and 2008. During the observing periods of 2007 and 2008, the seasonal NEE was 0.127±0.049 and -0.039±0.025 mgCO2/m2/s in tussock regime, and 0.006±0.011 and 0.028±0.017 mgCO2/m2/s in sphagnum moss, respectively. Air temperature is a more significant regulator than soil temperature in determining the GPP and Re of forest floor vegetations. Air temperature explained 77-95% of the variability in GPP and Re of the floor vegetations. The contributions (%) of simulated seasonal GPP to the black spruce forest during non-growing periods (DOY 1-120 and 244-365) and during the growing period (DOY 121-243) of 2007 are 63-72%, 20-25%, and 8-18%, respectively. This indicates that the floor CO2 exchange, as well as the contribution of winter carbon emission, is a component of the regional carbon budget that cannot be neglected. As the result of simulated GPP and Re in tussock during 2007, tussocks are found to have on atmospheric CO2 release, similar to results of observation for 63-day of 2007. On the other hand of stem respiration rates of black spruce (Picea Mariana), the continuous measurement of stem respiration was conducted in black spruce stands of different ages (4.3 to 13.5 cm in DBH) in Interior Alaska during the growing seasons of 2007 and 2008, using a pump, CO2 analyzer, chambers, and data-logger. The averaged whole stem respiration rate is 0.011±0.005 mgCO2/m2/s (range 0.005±0.002 to 0.015±0.008 mgCO2/m2/s, CV 45%) in black spruce stands, indicating remarkably diurnal and seasonal variations of stem respiration among the stems during the growing season. It is found that metabolism exhibits 1.5-fold higher in the younger black spruce stand than in the older. Temperatures in the air and stem are

  17. Stakeholder attitudes on carbon capture and storage -- An international comparison

    OpenAIRE

    Johnsson, Filip; Reiner, David; Itaoka, Kenshi; Herzog, Howard J.

    2009-01-01

    This paper presents results from a survey on stakeholder attitudes towards Carbon Capture and Storage (CCS). The survey is the first to make a global comparison across three major regions; USA, Japan, and Europe. The 30-question survey targeted individuals working at stakeholder organizations that seek to shape, and will need to respond to, policy on CCS, including electric utilities, oil & gas companies, CO2-intensive industries and non-governmental organizations (NGOs). The results show ...

  18. Electrochemical evaluation of carbon nanotubes and carbon black for the cathode of Li-air batteries

    Science.gov (United States)

    Fuentes, Roderick E.; Colón-Mercado, Héctor R.; Fox, Elise B.

    2014-06-01

    Cyclic Voltammetry (CV) was used to screen carbon catalysts for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) performance as electrodes for the Li-air battery. Lithium bis(trifluoromethylsulfonyl)imide (LiTF2N) in tetraethylene glycol dimethyl ether (TEGDME) was used as the electrolyte during testing. The effect of manganese/manganese oxide addition on the performance of the carbons was compared to that of the bare carbons in a cycling study. From CV results, it was found that single walled carbon nanotubes (SWCNT) had the highest peak current density per gram for ORR and OER than the other types of carbon studied. The SWCNT ORR peak decreased 49% after 100 cycles and only 36% when manganese/manganese oxide was added. The high activity of SWCNT with manganese/manganese oxide spheres make it a desirable material to use as the cathode for Li-air batteries.

  19. Black Carbon and Dust in Snow and Ice on Snow Dome, Mt. Olympus

    Science.gov (United States)

    Kaspari, S.; Delaney, I.; Skiles, M.; Dixon, D. A.

    2012-12-01

    Deposition of black carbon (BC) and dust on highly reflective snow and glacier ice causes darkening of the surface, resulting in greater absorption of solar energy, heating of the snow/ice, and accelerated snow and glacier melt. The deposition of BC and dust may be affecting the timing and availability of water resources in the Pacific Northwest where the majority of runoff comes from snow and glacier melt, but minimal related research has taken place in this region. A recent modeling study suggested that BC deposition is causing a decrease in spring snow water equivalent and a shift to earlier peak runoff in the spring in the Western United States. Additionally, limited observations made in the early 1980s in Washington State determined that light absorbing impurities (e.g., BC and dust) were reducing the snow albedo. Since 2009, we have collected snow and ice samples from glaciers and the seasonal snowpack from spatially distributed sites in Washington State to determine impurity content, and to assess how impurity concentrations vary in relation to emission source proximity. Here we present results from the summer 2012 fieldwork on Snow Dome, Mt. Olympus in Washington State. Mt. Olympus is located upwind from major regional sources of BC and dust, but may receive BC from ocean shipping and trans-Pacific transport of BC and dust from large Asian sources. We used a field spectrometer to measure spectral albedo on Snow Dome, and analyzed surface snow samples and shallow ice cores to characterize the spatial and temporal variability of impurity deposition. Total impurity load was determined gravimetrically. Dust concentrations are inferred from ICPMS analyses and BC concentrations are determined using a Single Particle Soot Photometer (SP2), with select samples also analyzed for BC using a Sunset EC-OC to facilitate method inter-comparison. We assess the role that absorbing impurities may play in accelerating melt at Snow Dome, and briefly compare our results to

  20. Physical properties of black carbon aerosol emitted by a series of laboratory biomass fires

    Science.gov (United States)

    McMeeking, Gavin; Flynn, Michael; Wold, Cyle; Hao, Wei Min; Fortner, Ed; Onasch, Tim; Carrico, Christian; Kreidenweis, Sonia; Coe, Hugh

    2010-05-01

    Black carbon aerosols have major impacts on the transfer of radiation in the atmosphere and affect climate and air quality on regional and global scales. Globally averaged, biomass burning represents roughly 40% of the total BC emissions to the atmosphere. The amount and physical properties of BC emitted by fires is highly uncertain as is our knowledge regarding the processing/transformation of BC once emitted to the atmosphere. To address these areas, we measured emissions of black carbon (BC) aerosol emitted by a series of controlled laboratory-scale burns involving a range of biomass fuels commonly consumed during prescribed and wildfires in North America. Black carbon aerosol physical properties including size distribution and mixing state were determined using a Droplet Measurement Technologies single particle soot photometer (SP2). The SP2 uses a laser induced incandescence technique to determine the mass of individual BC particles. Unlike filter-based methods previously used to quantify BC emitted from fires, the SP2 does not suffer from artefacts related to the presence of non-BC material co-sampled with BC particles. The SP2 also allows for simultaneous measurement of light scattered by BC particles to diagnose the presence of non-BC material associated with the BC particles (i.e., coatings). We also compare the BC physical property measurements to simultaneous light absorption and scattering measurements made by a DMT photoacoustic spectrometer at multiple wavelengths (405, 532, and 870 nm). Both BC physical and optical properties are linked to fuel properties and combustion conditions. The SP2 and photoacoustic spectrometer sampled downstream of a thermal denuder and three-stage dilution system throughout the study to examine the volatility of aerosol emitted by the fires. This allowed for the examination of the role of non-BC material on aerosol optical properties and BC coatings as measured by the SP2 and has implications for BC atmospheric aging

  1. End of the Little Ice Age in the Alps forced by industrial black carbon.

    Science.gov (United States)

    Painter, Thomas H; Flanner, Mark G; Kaser, Georg; Marzeion, Ben; VanCuren, Richard A; Abdalati, Waleed

    2013-09-17

    Glaciers in the European Alps began to retreat abruptly from their mid-19th century maximum, marking what appeared to be the end of the Little Ice Age. Alpine temperature and precipitation records suggest that glaciers should instead have continued to grow until circa 1910. Radiative forcing by increasing deposition of industrial black carbon to snow may represent the driver of the abrupt glacier retreats in the Alps that began in the mid-19th century. Ice cores indicate that black carbon concentrations increased abruptly in the mid-19th century and largely continued to increase into the 20th century, consistent with known increases in black carbon emissions from the industrialization of Western Europe. Inferred annual surface radiative forcings increased stepwise to 13-17 W⋅m(-2) between 1850 and 1880, and to 9-22 W⋅m(-2) in the early 1900s, with snowmelt season (April/May/June) forcings reaching greater than 35 W⋅m(-2) by the early 1900s. These snowmelt season radiative forcings would have resulted in additional annual snow melting of as much as 0.9 m water equivalent across the melt season. Simulations of glacier mass balances with radiative forcing-equivalent changes in atmospheric temperatures result in conservative estimates of accumulating negative mass balances of magnitude -15 m water equivalent by 1900 and -30 m water equivalent by 1930, magnitudes and timing consistent with the observed retreat. These results suggest a possible physical explanation for the abrupt retreat of glaciers in the Alps in the mid-19th century that is consistent with existing temperature and precipitation records and reconstructions. PMID:24003138

  2. Global mountain snow and ice loss driven by dust and black carbon radiative forcing

    Science.gov (United States)

    Painter, T. H.

    2014-12-01

    Changes in mountain snow and glaciers have been our strongest indicators of the effects of changing climate. Earlier melt of snow and losses of glacier mass have perturbed regional water cycling, regional climate, and ecosystem dynamics, and contributed strongly to sea level rise. Recent studies however have revealed that in some regions, the reduction of albedo by light absorbing impurities in snow and ice such as dust and black carbon can be distinctly more powerful than regional warming at melting snow and ice. In the Rocky Mountains, dust deposition has increased 5 to 7 fold in the last 150 years, leading to ~3 weeks earlier loss of snow cover from forced melt. In absolute terms, in some years dust radiative forcing there can shorten snow cover duration by nearly two months. Remote sensing retrievals are beginning to reveal powerful dust and black carbon radiative forcing in the Hindu Kush through Himalaya. In light of recent ice cores that show pronounced increases in loading of dust and BC during the Anthropocene, these forcings may have contributed far more to glacier retreat than previously thought. For example, we have shown that the paradoxical end of the Little Ice Age in the European Alps beginning around 1850 (when glaciers began to retreat but temperatures continued to decline and precipitation was unchanged) very likely was driven by the massive increases in deposition to snow and ice of black carbon from industrialization in surrounding nations. A more robust understanding of changes in mountain snow and ice during the Anthropocene requires that we move past simplistic treatments (e.g. temperature-index modeling) to energy balance approaches that assess changes in the individual forcings such as the most powerful component for melt - net solar radiation. Remote sensing retrievals from imaging spectrometers and multispectral sensors are giving us more powerful insights into the time-space variation of snow and ice albedo.

  3. Spatio-temporal variations of black carbon concentrations in the Megacity Beijing

    International Nuclear Information System (INIS)

    The spatial and temporal distribution and the flux of black carbon (BC) concentration in Beijing were continuously investigated over a two-year period at five sites to highlight the relative influence of contributing sources. The results demonstrate firstly that there is significant spatio-temporal variability of BC in Beijing. Highest concentrations occurred during winter primarily due to stagnant meteorological conditions, and seasonal BC sources, such as coal combustion for heating purposes. Biomass burning was identified as a minor seasonal source during the summer months. BC also varied spatially with higher concentrations in the SE of Beijing and lower concentrations in the NW, due to the differing emission intensity of various local BC sources such as traffic and industry. Frequently, overnight BC concentrations were higher due to specific meteorological conditions, such as the lower urban mixing layer height and various anthropogenic activities, such as exclusive night-time heavy duty vehicle traffic in the inner-city. -- Highlights: •Black carbon (BC) in PM2.5 was investigated in the megacity Beijing for two years. •BC was measured at five sites and day- and night-time samples were distinguished. •BC was highest in winter due to meteorological conditions and heating activities. •BC was higher during night- than day-time due to a lower MLH and heavy-duty traffic. •Spatial variations were also pronounced due to the influence of local sources. -- Black carbon was investigated for a two-year period in the megacity Beijing to gain detailed knowledge about the seasonal, temporal and spatial patterns of BC particles and their sources

  4. Black and brown carbon fractal aggregates from combustion of two fuels widely used in Asian rituals

    International Nuclear Information System (INIS)

    Incense sticks and mustard oil are the two most popular combustion fuels during rituals and social ceremonies in Asian countries. Given their widespread use in both closed and open burning activities, it is important to quantify the spectral radiative properties of aerosols emitted from the combustion of both fuels. This information is needed by climate models to assess the impact of these aerosols on radiative forcing. In this study, we used a 3-wavelength integrated photoacoustic-nephelometer – operating simultaneously at 405, 532 and 781 nm – to measure the optical coefficients of aerosols emitted from the laboratory combustion of mustard oil lamp and two types of incense sticks. From the measured optical coefficients at three wavelengths, time-varying single scattering albedo (SSA), absorption Ångström exponent (AAE), and scattering Ångström exponent (SAE) were calculated. For incense smoke particles, the time-averaged mean AAE values were found to be as high as 8.32 (between 405 and 532 nm) and 6.48 (between 532 and 781 nm). This spectrally-varying characteristic of AAE indicates that brown carbon – a class of organic carbon which strongly absorbs solar radiation in the blue and near ultraviolet – is the primary component of incense smoke aerosols. For aerosols emitted from the burning of mustard oil lamp, the time-averaged mean AAE values were ∼1.3 (between 405 and 781 nm) indicating that black carbon (BC) is the primary constituent. Scanning electron microscopy combined with image processing revealed the morphology of incense smoke aerosols to be non-coalescing and weakly-bound aggregates with a mean two-dimensional (2-d) fractal dimension (Df)=1.9±0.07, while the mustard oil smoke aerosols had typical fractal-like BC aggregate morphology with a mean 2-d Df=1.85±0.09. -- Highlights: ► Incense and mustard oil burning aerosols characterized by 3-wavelength photoacoustic spectroscopy and nephelometery, and electron microscopy. ► Brown carbon

  5. Associations between Prenatal Exposure to Black Carbon and Memory Domains in Urban Children: Modification by Sex and Prenatal Stress.

    Directory of Open Access Journals (Sweden)

    Whitney J Cowell

    Full Text Available Whether fetal neurodevelopment is disrupted by traffic-related air pollution is uncertain. Animal studies suggest that chemical and non-chemical stressors interact to impact neurodevelopment, and that this association is further modified by sex.To examine associations between prenatal traffic-related black carbon exposure, prenatal stress, and sex with children's memory and learning.Analyses included N = 258 mother-child dyads enrolled in a Boston, Massachusetts pregnancy cohort. Black carbon exposure was estimated using a validated spatiotemporal land-use regression model. Prenatal stress was measured using the Crisis in Family Systems-Revised survey of negative life events. The Wide Range Assessment of Memory and Learning (WRAML2 was administered at age 6 years; outcomes included the General Memory Index and its component indices [Verbal, Visual, and Attention Concentration]. Relationships between black carbon and WRAML2 index scores were examined using multivariable-adjusted linear regression including effect modification by stress and sex.Mothers were primarily minorities (60% Hispanic, 26% Black; 67% had ≤12 years of education. The main effect for black carbon was not significant for any WRAML2 index; however, in stratified analyses, among boys with high exposure to prenatal stress, Attention Concentration Index scores were on average 9.5 points lower for those with high compared to low prenatal black carbon exposure (P3-way interaction = 0.04.The associations between prenatal exposure to black carbon and stress with children's memory scores were stronger in boys than in girls. Studies assessing complex interactions may more fully characterize health risks and, in particular, identify vulnerable subgroups.

  6. Comparison of black-box, glass-box and open-box software for aiding conceptual understanding

    OpenAIRE

    Hosein, Anesa; Aczel, James; Clow, Doug; Richardson, John T. E.

    2008-01-01

    Three mathematical software types: black-box (no steps shown), glass-box (steps shown) and open-box (interactive steps) were used by 32 students to solve conceptual and procedural tasks on the computer via remote observation. Comparison of the three software types suggests that there is no difference in the scores that students receive for conceptual understanding tasks. Students using the black-box are more likely to explore answers than students using the glass and open-box software.

  7. Uptake of Reactive Black 5 by pumice and walnut activated carbon: Chemistry and adsorption mechanisms

    OpenAIRE

    Heibati, B.; Rodriguez-Couto, S.; Amrane, A; M. Rafatullah; Hawari, A.; Al-Ghouti, M. A.

    2014-01-01

    The potential of using pumice and walnut wood activated carbon as low-cost adsorbents for the removal of the diazo dye Reactive Black 5 (RB5) from aqueous solutions was investigated. The Langmuir isotherm fit to the data specified the presence of two different natures of adsorption sites with different binding energies on the AC-W surface. Kinetic modelling showed that the adsorption behaviour and mechanism of RB5 for both adsorbents is believed to happen via surface adsorption followed by di...

  8. Effect of Hydroxyl Concentration on Chemical Sensitivity of Polyvinyl Alcohol/Carbon-Black Composite Chemiresistors

    International Nuclear Information System (INIS)

    The sensitivity and selectivity of polyvinyl alcohol (PVA) / carbon black composite films have been found to vary depending upon the hydroxylation percentage (''-OH'') of the polymer. These chemiresistors made from PVA films whose polymer backbone is 88% hydroxylated (PVA88) have a high sensitivity to water, while chemiresistors made from PVA75 have a higher sensitivity to methanol. The minor differences in polymer composition result in films with different Hildebrand volubility parameters. The relative responses of several different PVA-based chemiresistors to solvents with different volubility parameters are presented. In addition, polyvinyl acetate (PVAC) films with PVA88 are used in an array to distinguish the responses to methanol-water mixtures

  9. Fractal morphology of black carbon aerosol enhances absorption in the thermal infrared wavelengths.

    Science.gov (United States)

    Heinson, William R; Chakrabarty, Rajan K

    2016-02-15

    In this Letter, we numerically calculate the mass absorption cross sections (MACs) of black carbon fractal aggregates in the thermal infrared solar spectrum. Compared to equivalent-size spheres, the MAC values of aggregates show a percent enhancement of ≈150 and 400 at small and large length scales, respectively. The absorption properties of aggregates with size parameters >1 surprisingly continued to remain in the Rayleigh optics regime. We explain this phenomenon using the Maxwell-Garnett effective medium theory and the concept of phase shift parameter. PMID:26872194

  10. GHG and black carbon emission inventories from Mezquital Valley: The main energy provider for Mexico Megacity

    Energy Technology Data Exchange (ETDEWEB)

    Montelongo-Reyes, M.M.; Otazo-Sánchez, E.M.; Romo-Gómez, C.; Gordillo-Martínez, A.J.; Galindo-Castillo, E.

    2015-09-15

    The greenhouse gases and black carbon emission inventory from IPCC key category Energy was accomplished for the Mezquital Valley, one of the most polluted regions in Mexico, as the Mexico City wastewater have been continuously used in agricultural irrigation for more than a hundred years. In addition, thermoelectric, refinery, cement and chemistry industries are concentrated in the southern part of the valley, near Mexico City. Several studies have reported air, soil, and water pollution data and its main sources for the region. Paradoxically, these sources contaminate the valley, but boosted its economic development. Nevertheless, no research has been done concerning GHG emissions, or climate change assessment. This paper reports inventories performed by the 1996 IPCC methodology for the baseline year 2005. Fuel consumption data were derived from priority sectors such as electricity generation, refineries, manufacturing & cement industries, transportation, and residential use. The total CO{sub 2} emission result was 13,894.9 Gg, which constituted three-quarters of Hidalgo statewide energy category. The principal CO{sub 2} sources were energy transformation (69%) and manufacturing (19%). Total black carbon emissions were estimated by a bottom-up method at 0.66 Gg. The principal contributor was on-road transportation (37%), followed by firewood residential consumption (26%) and cocked brick manufactures (22%). Non-CO{sub 2} gas emissions were also significant, particularly SO{sub 2} (255.9 Gg), which accounts for 80% of the whole Hidalgo State emissions. Results demonstrated the negative environmental impact on Mezquital Valley, caused by its role as a Megacity secondary fuel and electricity provider, as well as by the presence of several cement industries. - Highlights: • First GHG & black carbon inventory for Mezquital Valley: Mexico City energy supplier • Energy industries caused the largest CO{sub 2} and SO{sub 2} emissions from residual fuel oil. • Diesel

  11. Carbon black nanoparticles promote endothelial activation and lipid accumulation in macrophages independently of intracellular ROS production

    DEFF Research Database (Denmark)

    Cao, Yi; Roursgaard, Martin; Danielsen, Pernille Høgh; Møller, Peter; Loft, Steffen

    2014-01-01

    Exposure to nanoparticles (NPs) may cause vascular effects including endothelial dysfunction and foam cell formation, with oxidative stress and inflammation as supposed central mechanisms. We investigated oxidative stress, endothelial dysfunction and lipid accumulation caused by nano-sized carbon...... black (CB) exposure in cultured human umbilical vein endothelial cells (HUVECs), THP-1 (monocytes) and THP-1 derived macrophages (THP-1a). The proliferation of HUVECs or co-cultures of HUVECs and THP-1 cells were unaffected by CB exposure, whereas there was increased cytotoxicity, assessed by the LDH...

  12. Effect of Hydroxyl Concentration on Chemical Sensitivity of Polyvinyl Alcohol/Carbon-Black Composite Chemiresistors

    Energy Technology Data Exchange (ETDEWEB)

    Hughes, Robert C.; Patel, Sanjay V.; Yelton, W. Graham

    1999-05-19

    The sensitivity and selectivity of polyvinyl alcohol (PVA) / carbon black composite films have been found to vary depending upon the hydroxylation percentage ("-OH") of the polymer. These chemiresistors made from PVA films whose polymer backbone is 88% hydroxylated (PVA88) have a high sensitivity to water, while chemiresistors made from PVA75 have a higher sensitivity to methanol. The minor differences in polymer composition result in films with different Hildebrand volubility parameters. The relative responses of several different PVA-based chemiresistors to solvents with different volubility parameters are presented. In addition, polyvinyl acetate (PVAC) films with PVA88 are used in an array to distinguish the responses to methanol-water mixtures.

  13. Interaction between carboxyl-functionalized carbon black nanoparticles and porous media

    Science.gov (United States)

    Kim, Song-Bae; Kang, Jin-Kyu; Yi, In-Geol

    2015-04-01

    Carbon nanomaterials, such as carbon nanotubes, fullerene, and graphene, have received considerable attention due to their unique physical and chemical characteristics, leading to mass production and widespread application in industrial, commercial, and environmental fields. During their life cycle from production to disposal, however, carbon nanomaterials are inevitably released into water and soil environments, which have resulted in concern about their health and environmental impacts. Carbon black is a nano-sized amorphous carbon powder that typically contains 90-99% elemental carbon. It can be produced from incomplete combustion of hydrocarbons in petroleum and coal. Carbon black is widely used in chemical and industrial products or applications such as ink pigments, coating plastics, the rubber industry, and composite reinforcements. Even though carbon black is strongly hydrophobic and tends to aggregate in water, it can be dispersed in aqueous media through surface functionalization or surfactant use. The aim of this study was therefore to investigate the transport behavior of carboxyl-functionalized carbon black nanoparticles (CBNPs) in porous media. Column experiments were performed for potassium chloride (KCl), a conservative tracer, and CBNPs under saturated flow conditions. Column experiments was conducted in duplicate using quartz sand, iron oxide-coated sand (IOCS), and aluminum oxide-coated sand (AOCS) to examine the effect of metal (Fe, Al) oxide presence on the transport of CBNPs. Breakthrough curves (BTCs) of CBNPs and chloride were obtained by monitoring effluent, and then mass recovery was quantified from these curves. Additionally, interaction energy profiles for CBNP-porous media were calculated using DLVO theory for sphere-plate geometry. The BTCs of chloride had relative peak concentrations ranging from 0.895 to 0.990. Transport parameters (pore-water velocity v, hydrodynamic dispersion coefficient D) obtained by the model fit from the

  14. Nanosized carbon black combined with Ni2O3 as "universal" catalysts for synergistically catalyzing carbonization of polyolefin wastes to synthesize carbon nanotubes and application for supercapacitors.

    Science.gov (United States)

    Wen, Xin; Chen, Xuecheng; Tian, Nana; Gong, Jiang; Liu, Jie; Rümmeli, Mark H; Chu, Paul K; Mijiwska, Ewa; Tang, Tao

    2014-04-01

    The catalytic carbonization of polyolefin materials to synthesize carbon nanotubes (CNTs) is a promising strategy for the processing and recycling of plastic wastes, but this approach is generally limited due to the selectivity of catalysts and the difficulties in separating the polyolefin mixture. In this study, the influence of nanosized carbon black (CB) and Ni2O3 as a novel combined catalyst system on catalyzing carbonization of polypropylene (PP), polyethylene (PE), polystyrene (PS) and their blends was investigated. We showed that this combination was efficient to promote the carbonization of these polymers to produce CNTs with high yields and of good quality. Catalytic pyrolysis and model carbonization experiments indicated that the carbonization mechanism was attributed to the synergistic effect of the combined catalysts rendered by CB and Ni2O3: CB catalyzed the degradation of PP, PE, and PS to selectively produce more aromatic compounds, which were subsequently dehydrogenated and reassembled into CNTs via the catalytic action of CB together with Ni particles. Moreover, the performance of the synthesized CNTs as the electrode of supercapacitor was investigated. The supercapacitor displayed a high specific capacitance as compared to supercapacitors using commercial CNTs and CB. This difference was attributed to the relatively larger specific surface areas of our synthetic CNTs and their more oxygen-containing groups. PMID:24611910

  15. Preservation of black carbon in the shelf sediments of the East China Sea

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Concentrations and carbon isotopic (14C, 13C) compositions of black carbon (BC) were measured for three sediment cores collected from the Changjiang River estuary and the shelf of the East China Sea. BC concentrations ranged from 0.02 to 0.14 mg/g (dry weight), and accounted for 5% to 26% of the sedimentary total organic carbon (TOC) pool. Among the three sediment cores collected at each site, sediment from the Changjiang River estuary had relatively high BC contents compared with the sediments from the East China Sea shelf, suggesting that the Changjiang River discharge played an important role in the delivery of BC to the coastal region. Radiocarbon measurements indicate that the ages of BC are in the range of 6910 to 12250 years old B.P. (before present), that is in general, 3700 to 9000 years older than the 14C ages of TOC in the sediments. These variable radiocarbon ages suggest that the BC preserved in the sediments was derived from the products of both biomass fire and fossil fuel combustion, as well as from ancient rock weathering. Based on an isotopic mass balance model, we calculated that fossil fuel combustion contributed most (60%―80%) of the BC preserved in these sediments and varied with depth and locations. The deposition and burial of this "slow-cycling" BC in the sediments of the East China Sea shelf represent a significant pool of carbon sink and could greatly in-fluence carbon cycling in the region.

  16. Black carbon contribution to stabilised SOM in soil under slash and burn agriculture

    Science.gov (United States)

    Rumpel, C.; Chaplot, V.; Valentin, C.

    2008-12-01

    Black carbon (BC) produced during slash and burn agriculture on tropical soils may enhance the soils organic matter content and hence their biological properties. However, once deposited on the soil surface, BC may be subject to erosion and/or microbial decomposition and thus not be preserved on site. Up to now, few studies have been carried out to assess the contribution of BC to the soils stable carbon pool on sites under slash and burn agriculture. The aim of the study was to assess the survival potential of BC in sloping tropical soils of clayey texture. The study was carried out in Northern Laos, where the soils are subjected to addition of black carbon produced by burning of agricultural crop residues. Our conceptual approach included the characterisation of (a) morphologically distinct BC forms and (b) chemical soil fractions. The samples were analysed for elemental content, chemical composition by 13C CPMAS NMR spectroscopy, carbon resistant to acid hydrolysis with HCl, carbon resistant to oxidation with acid dichromate solution and 14C activity. Our results indicated that BC produced by slash and burn agriculture was highly aromatic in nature. Its elemental composition as well as its susceptibility to be lost by chemical oxidation was dependent on its morphology. Acid hydrolysis did not lead to carbon loss from any BC form. We thus hypothesised that BC should be present in the hydrolysis resistant fraction isolated from soil. The charactersation of the chemical composition by 13C CPMAS NMR spectroscopy showed that the hydrolysis residue was composed of highly aromatic carbon. Considering the low lignin content of these soils and the good recovery of bulk soil aromatic carbon signal (80-100%) in the hydrolysis residue, we consider that this fraction may be suitable to assess BC contribution to clayey soils. We suggest that BC isolated as hydrolysis resistant C may represent up to 25% of the soils C as compared to 8% as isolated by acid dichromate oxidation

  17. Patterns of methane-related carbonate formation in the black sea

    Science.gov (United States)

    Reitner, J.; Peckmann, J.; Reimer, A.; Thiel, V.

    2003-04-01

    Methane seeps on the northwestern Black Sea shelf were investigated during the GHOSTDABS expedition in 2001. Seep areas close to the Dniepr Canyon are sites of intense carbonate formation. In anoxic waters, at depths between 200 and 400 m, we found three different modes of seepage-induced carbonate precipitation. The most spectacular type comprises up to 4 m high Ca-carbonate towers flushed by methane gas (type 1). These buildups are constructed of cm to dm-scale calcified hollow spheres which are made and later surrounded by microbial mats. At the base of these microbial mats the spheres are stabilized by a continuous rim of carbonate cement. At a later stage, the fragile spheres are entirely cemented by fibrous aragonite and Mg calcite. The towers harbour a highly diverse microbial community, which are, at least in part, based on the anaerobic oxidation of methane (AOM). A second variety of methane-derived carbonates was observed in the vicinity of the large carbonate towers and consists of lenticular concretions growing within the sediment (type 2). The concretions are up to several decimeters in size and consist of Mg calcite crystal aggregates that progressively fuse together, thereby incorporating ambient sedimentary matter. Associated biofilms surrounding the concretions clearly show AOM related populations but exhibit a different community structure and a smaller microbial diversity than type 1 carbonates. Type 3 encompasses background sediments irregularly cemented with microcrystalline Mg-calcite (automicrite). These precipitates may show very thin internal biofilms, and are further characterized by small, “birds eye”-type cavities. These cavities appear to arise from ascending gas bubbles, and are partly cemented by granular to blocky Mg calcites. The internal surfaces are frequently coated by thin biofilms resembling those found associated with type 2 concretions. All studied Ca-carbonates have low d13C values (-25 to -35 permille vs. PDB) and show

  18. 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.

  19. Distribution and preservation of black carbon in the East China Sea sediments: Perspectives on carbon cycling at continental margins

    Science.gov (United States)

    Huang, Liang; Zhang, Jing; Wu, Ying; Wang, Jinlong

    2016-02-01

    We determined the concentrations and radiocarbon (14C) compositions of black carbon (BC) in the sediments of the East China Sea (ECS). The BC concentrations, which were in the range of 0.30-1.52 mg/g, accounted for 12-65% of the total organic carbon (TOC). The distribution of BC in ECS sediments was controlled by factors such as grain size, distance from the coast, and deposition rate. Radiocarbon measurements of BC yielded ages of 6350-10,440 years before present (BP), suggesting that the percentage of BC derived from biomass combustion was in the range of 29-48%. The BC burial flux in sediments of the ECS was estimated to be ∼1.39×106 t/yr, which was similar to burial fluxes reported for shelf sediments in other areas. However, the magnitude of the total BC sink was far greater than that of any other shelf regions studied to date, indicating the global importance of BC accumulation in the ECS, and the magnitude of BC input from large rivers (e.g., the Changjiang). The riverine delivery of BC to the ECS (73%) was far greater than that of atmospheric flux (27%). Further study of the BC cycle and the interactions of BC with other organic compounds in marginal seas was required to better understand the role of BC in the global carbon cycle.

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

    Directory of Open Access Journals (Sweden)

    M. D. Willis

    2015-11-01

    Full Text Available 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 in two distinct particle types: HOA-rich and BC-rich particles. The average mass fraction of black carbon in HOA-rich and BC-rich particles was 0.02–0.08 and 0.72–0.93, 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.

  1. Impact of time-activity patterns on personal exposure to black carbon

    Science.gov (United States)

    Dons, Evi; Int Panis, Luc; Van Poppel, Martine; Theunis, Jan; Willems, Hanny; Torfs, Rudi; Wets, Geert

    2011-07-01

    Time-activity patterns are an important determinant of personal exposure to air pollution. This is demonstrated by measuring personal exposure of 16 participants for 7 consecutive days: 8 couples of which one person was a full-time worker and the other was a homemaker; both had a very different time-activity pattern. We used portable aethalometers to measure black carbon levels with a high temporal resolution and a PDA with GPS-logger and electronic diary. The exposure to black carbon differs between partners by up to 30%, although they live at the same location. The activity contributing most to this difference is transport: Average exposure in transport is 6445 ng m -3, followed by exposure during shopping (2584 ng m -3). Average exposure is lowest while sleeping (1153 ng m -3) and when doing home-based activities (1223 ng m -3). Full-time workers spend almost twice as much time in transport as the homemakers. As a result of the study design we measured in several different homes, shops, cars, etc. enabling a better insight in true overall exposure in those microenvironments. Other factors influencing personal exposure are: background concentrations and location of residence in an urban, suburban or rural environment.

  2. 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.

  3. 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.

  4. Black carbon and elemental concentration of ambient particulate matter in Makassar Indonesia

    International Nuclear Information System (INIS)

    Airborne particulate matter with aerodynamic diameter of less or equal to 10 um or PM10, has been collected on a weekly basis for one year from February 2012 to January 2013 at one site of Makassar, Province of South Sulawesi Indonesia. The samples were collected using a size selective high volume air sampler sited at Daya, a mixed urban, commercial and industrial area in the city of Makassar. The concentration of black carbon (BC) along with a total of 14 elements (i.e Al, Ba, Ca, Cr, Fe, K, Mg, Ba, Na, Ni, Pb, Si, Ti and Zn) were determined from the sample. Results showed that the average particulate mass concentration was 32.9 ± 11.6 μg/m3 with BC and elemental concentration constituted 6.1% and 10.6% of the particulate concentration, respectively. Both BC and elemental constituents contributed 16.7% while 83.3% of the particulate matter remained to be counted for. The black carbon concentration was higher during the dry months which may be attributed to rampant biomass burning during hot and dry weather conditions, apart from other possible sources. Most of the elements were enriched relative to soil origin illustrating of their possible associations with other sources such as marine and anthropogenic derived aerosols, particularly Cr, Ni, Pb, and Zn, which are known to originate from man-made activities

  5. Effect of antioxidant on PTC properties of conductive carbon black/polyethylene composites

    International Nuclear Information System (INIS)

    Complete text of publication follows. Carbon black (CB)-filled high-density polyethylene (HDPE) composites have been used as self resetting fuse for a number of years. The main features of the positive temperature coefficient (PTC) materials are affected by crystallinity of the polymer. The crystallinity of the polymer is changed with thermal treatment. The HDPE/CB composites should be resistant to the severe conditions of high temperature. HDPE with a melt index of 0.35 was selected as the polymer matrix in this work. Carbon black with an average particle size of 86 nm was used. The CB and polymer were mixed in a Brabender Plastograph at 160 deg C for 15 min. The CB/polymer blend thus produced was sandwiched between a pair of copper foils (0.04 mm thick), that served as electrodes. Thermal aging of PTC samples was conducted in an oven at range from 50 deg C to 140 deg C in air. The composites containing 0.5 - 3wt% of Irganox as antioxidant were irradiated under nitrogen at room temperature with different doses of gamma rays from a Co60 source. The conductive composites with thermal aging treatment have the lower resistivity. The reproducibility of the conductive composites depended on the amount of antioxidants

  6. Implications of multiple scattering on the assessment of black carbon aerosol radiative forcing

    International Nuclear Information System (INIS)

    The effects of radiative coupling between scattering and absorbing aerosols, in an external mixture, on the aerosol radiative forcing (ARF) due to black carbon (BC), its sensitivity to the composite aerosol loading and composition, and surface reflectance are investigated using radiative transfer model simulations. The ARF due to BC is found to depend significantly on the optical properties of the ‘neighboring’ (non-BC) aerosol species. The scattering due to these species significantly increases the top of the atmospheric warming due to black carbon aerosols, and significant changes in the radiative forcing efficiency of BC. This is especially significant over dark surfaces (such as oceans), despite the ARF due to BC being higher over snow and land-surfaces. The spatial heterogeneity of this effect (coupling or multiple scattering by neighboring aerosol species) imposes large uncertainty in the estimation ARF due to BC aerosols, especially over the oceans. - Highlights: • Non-BC aerosol scattering in an external mixture increases TOA warming due to BC. • Effect of multiple scattering on BC ARF increases with total aerosol optical depth. • Contribution of multiple scattering on BC ARF is higher over oceans than over land

  7. Optics of Water Cloud Droplets Mixed with Black-Carbon Aerosols

    Science.gov (United States)

    Mishchenko, Michael I.; Liu, Li; Cairns, Brian; Mackowski, Daniel W.

    2014-01-01

    We use the recently extended superposition T-matrix method to calculate scattering and absorption properties of micrometer-sized water droplets contaminated by black carbon. Our numerically exact results reveal that, depending on the mode of soot-water mixing, the soot specific absorption can vary by a factor exceeding 6.5. The specific absorption is maximized when the soot material is quasi-uniformly distributed throughout the droplet interior in the form of numerous small monomers. The range of mixing scenarios captured by our computations implies a wide range of remote sensing and radiation budget implications of the presence of black carbon in liquid-water clouds. We show that the popular Maxwell-Garnett effective-medium approximation can be used to calculate the optical cross sections, single-scattering albedo, and asymmetry parameter for the quasi-uniform mixing scenario, but is likely to fail in application to other mixing scenarios and in computations of the elements of the scattering matrix.

  8. Structural, mechanical and electrical characterization of epoxy-amine/carbon black nanonocomposites

    Directory of Open Access Journals (Sweden)

    2008-05-01

    Full Text Available This work presents an insight into the effect of preparation procedure and the filler content on both electrical and mechanical properties of a nanocomposite system. For the preparation of the nanocomposites diglycidyl ether of bisphenol A (DGEBA was used with triethylenetetramine (TETA as a curing agent. As fillers carbon black (CB nanoparticles with size from 25 to 75 nm were used. The characterization was done using Dynamic Mechanical Analysis (DMA, Dielectric Relaxation Spectroscopy (DRS, Differential Scanning Calorimetry (DSC, Wide Angle X-ray Diffraction (WAXD and electrical conductivity measurements. The dependence of the dynamic mechanical and dielectric parameters (E′, E″, tanδ, ε', ε″, σ and Tg is associated with the filler content and is controlled by the employed curing conditions. An increase in electrical conductivity, which is observed at about 1% w/w of carbon black, indicates the creation of conducting paths and is associated with the Maxwell Wagner Sillars (MWS relaxation, probably due to the formation of aggregated microstructures in the bulk composite..

  9. Surface modification of carbon black for the reinforcement of polycarbonate/acrylonitrile–butadiene–styrene blends

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, B.B. [School of Chemical Engineering, Fuzhou University, Fuzhou 350108 (China); Chen, Y. [School of materials Engineering, Fujian Agriculture and Forestry University, Fuzhou 350002 (China); Wang, F. [School of Chemical Engineering, Fuzhou University, Fuzhou 350108 (China); Hong, R.Y., E-mail: rhong@suda.edu.cn [School of Chemical Engineering, Fuzhou University, Fuzhou 350108 (China); College of Chemistry, Chemical Engineering and Materials Science & Key Laboratory of Organic Synthesis of Jiangsu Province, Soochow University, SIP, Suzhou 215123 (China)

    2015-10-01

    Highlights: • CB was modified through the method of oxygen plasma treatment. • Surface modified CB applied in PC/ABS blends. • The treated CB showed better compatibility in PC/ABS blends. • PC/ABS blends with treated CB showed better mechanical and thermal properties. - Abstract: The surface of carbon black was modified by oxygen plasma treatment for different times (10, 20 and 30 min). In order to increase the applicability of carbon black (CB), functional groups were grafted on the generally inert surface of CB using oxygen plasma. The surface compositional and structural changes that occurred on CB were investigated by SEM, FT-IR, Raman spectroscopy, XRD and BET. Subsequently, CB reinforced polycarbonate (PC)/acrylonitrile-butadiene-styrene (ABS) composites were prepared by internal batch mixing with the addition of different content of CB (3, 6, 9, 12 wt%). The morphology of PC/ABS/CB (7/3/6 wt%) nanocomposites was studied through scanning electron microscopy. Observations of SEM images showed that the plasma-treated CB had a better dispersion in the blend matrix. Moreover, the mechanical tests showed that the tensile strength and impact strength were improved by 32.4% and 22.5%, respectively, with the addition of plasma-treated CB. In addition, the thermal stability was improved and glass transition temperatures of both PC and ABS increased as shown by TGA and DSC, respectively.

  10. 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.

  11. Ice sheet mass loss caused by dust and black carbon accumulation

    Directory of Open Access Journals (Sweden)

    T. Goelles

    2015-09-01

    Full Text Available Albedo is the dominant factor governing surface melt variability in the ablation area of ice sheets and glaciers. Aerosols such as mineral dust and black carbon (soot accumulate on the ice surface and cause a darker surface and therefore a lower albedo. The darkening effect on the ice surface is currently not included in sea level projections, and the effect is unknown. We present a model framework which includes ice dynamics, aerosol transport, aerosol accumulation and the darkening effect on ice albedo and its consequences for surface melt. The model is applied to a simplified geometry resembling the conditions of the Greenland ice sheet, and it is forced by several temperature scenarios to quantify the darkening effect of aerosols on future mass loss. The effect of aerosols depends non-linearly on the temperature rise due to the feedback between aerosol accumulation and surface melt. According to our conceptual model, accounting for black carbon and dust in future projections of ice sheet changes until the year 3000 could induce an additional volume loss of 7 %. Since we have ignored some feedback processes, the impact might be even larger.

  12. Ice sheet mass loss caused by dust and black carbon accumulation

    Science.gov (United States)

    Goelles, T.; Bøggild, C. E.; Greve, R.

    2015-09-01

    Albedo is the dominant factor governing surface melt variability in the ablation area of ice sheets and glaciers. Aerosols such as mineral dust and black carbon (soot) accumulate on the ice surface and cause a darker surface and therefore a lower albedo. The darkening effect on the ice surface is currently not included in sea level projections, and the effect is unknown. We present a model framework which includes ice dynamics, aerosol transport, aerosol accumulation and the darkening effect on ice albedo and its consequences for surface melt. The model is applied to a simplified geometry resembling the conditions of the Greenland ice sheet, and it is forced by several temperature scenarios to quantify the darkening effect of aerosols on future mass loss. The effect of aerosols depends non-linearly on the temperature rise due to the feedback between aerosol accumulation and surface melt. According to our conceptual model, accounting for black carbon and dust in future projections of ice sheet changes until the year 3000 could induce an additional volume loss of 7 %. Since we have ignored some feedback processes, the impact might be even larger.

  13. Biocompatible Label-Free Detection of Carbon Black Particles by Femtosecond Pulsed Laser Microscopy.

    Science.gov (United States)

    Bové, Hannelore; Steuwe, Christian; Fron, Eduard; Slenders, Eli; D'Haen, Jan; Fujita, Yasuhiko; Uji-I, Hiroshi; vandeVen, Martin; Roeffaers, Maarten; Ameloot, Marcel

    2016-05-11

    Although adverse health effects of carbon black (CB) exposure are generally accepted, a direct, label-free approach for detecting CB particles in fluids and at the cellular level is still lacking. Here, we report nonincandescence related white-light (WL) generation by dry and suspended carbon black particles under illumination with femtosecond (fs) pulsed near-infrared light as a powerful tool for the detection of these carbonaceous materials. This observation is done for four different CB species with diameters ranging from 13 to 500 nm, suggesting this WL emission under fs near-infrared illumination is a general property of CB particles. As the emitted radiation spreads over the whole visible spectrum, detection is straightforward and flexible. The unique property of the described WL emission allows optical detection and unequivocal localization of CB particles in fluids and in cellular environments while simultaneously colocalizing different cellular components using various specific fluorophores as shown here using human lung fibroblasts. The experiments are performed on a typical multiphoton laser-scanning microscopy platform, widely available in research laboratories. PMID:27104759

  14. 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.

  15. 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.

  16. 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.

  17. Surface modification of carbon black for the reinforcement of polycarbonate/acrylonitrile–butadiene–styrene blends

    International Nuclear Information System (INIS)

    Highlights: • CB was modified through the method of oxygen plasma treatment. • Surface modified CB applied in PC/ABS blends. • The treated CB showed better compatibility in PC/ABS blends. • PC/ABS blends with treated CB showed better mechanical and thermal properties. - Abstract: The surface of carbon black was modified by oxygen plasma treatment for different times (10, 20 and 30 min). In order to increase the applicability of carbon black (CB), functional groups were grafted on the generally inert surface of CB using oxygen plasma. The surface compositional and structural changes that occurred on CB were investigated by SEM, FT-IR, Raman spectroscopy, XRD and BET. Subsequently, CB reinforced polycarbonate (PC)/acrylonitrile-butadiene-styrene (ABS) composites were prepared by internal batch mixing with the addition of different content of CB (3, 6, 9, 12 wt%). The morphology of PC/ABS/CB (7/3/6 wt%) nanocomposites was studied through scanning electron microscopy. Observations of SEM images showed that the plasma-treated CB had a better dispersion in the blend matrix. Moreover, the mechanical tests showed that the tensile strength and impact strength were improved by 32.4% and 22.5%, respectively, with the addition of plasma-treated CB. In addition, the thermal stability was improved and glass transition temperatures of both PC and ABS increased as shown by TGA and DSC, respectively

  18. Microbiosensors based on DNA modified single-walled carbon nanotube and Pt black nanocomposites.

    Science.gov (United States)

    Shi, Jin; Cha, Tae-Gon; Claussen, Jonathan C; Diggs, Alfred R; Choi, Jong Hyun; Porterfield, D Marshall

    2011-12-01

    Glucose and ATP biosensors have important applications in diagnostics and research. Biosensors based on conventional materials suffer from low sensitivity and low spatial resolution. Our previous work has shown that combining single-walled carbon nanotubes (SWCNTs) with Pt nanoparticles can significantly enhance the performance of electrochemical biosensors. The immobilization of SWCNTs on biosensors remains challenging due to the aqueous insolubility originating from van der Waals forces. In this study, we used single-stranded DNA (ssDNA) to modify SWCNTs to increase solubility in water. This allowed us to explore new schemes of combining ssDNA-SWCNT and Pt black in aqueous media systems. The result is a nanocomposite with enhanced biosensor performance. The surface morphology, electroactive surface area, and electrocatalytic performance of different fabrication protocols were studied and compared. The ssDNA-SWCNT/Pt black nanocomposite constructed by a layered scheme proved most effective in terms of biosensor activity. The key feature of this protocol is the exploitation of ssDNA-SWCNTs as molecular templates for Pt black electrodeposition. The glucose and ATP microbiosensors fabricated on this platform exhibited high sensitivity (817.3 nA/mM and 45.6 nA/mM, respectively), wide linear range (up to 7 mM and 510 μM), low limit of detection (1 μM and 2 μM) and desirable selectivity. This work is significant to biosensor development because this is the first demonstration of ssDNA-SWCNT/Pt black nanocomposite as a platform for constructing both single-enzyme and multi-enzyme biosensors for physiological applications. PMID:21858297

  19. Variability in and agreement between modeled and personal continuously measured black carbon levels using novel smartphone and sensor technologies.

    Science.gov (United States)

    Nieuwenhuijsen, Mark J; Donaire-Gonzalez, David; Rivas, Ioar; de Castro, Montserrat; Cirach, Marta; Hoek, Gerard; Seto, Edmund; Jerrett, Michael; Sunyer, Jordi

    2015-03-01

    Novel technologies, such as smartphones and small personal continuous air pollution sensors, can now facilitate better personal estimates of air pollution in relation to location. Such information can provide us with a better understanding about whether and how personal exposures relate to residential air pollution estimates, which are normally used in epidemiological studies. The aims of this study were to examine (1) the variability in personal air pollution levels during the day and (2) the relationship between modeled home and school estimates and continuously measured personal air pollution exposure levels in different microenvironments (e.g., home, school, and commute). We focused on black carbon as an indicator of traffic-related air pollution. We recruited 54 school children (aged 7-11) from 29 different schools around Barcelona as part of the BREATHE study, an epidemiological study of the relation between air pollution and brain development. For 2 typical week days during 2012-2013, the children were given a smartphone with CalFit software to obtain information on their location and physical activity level and a small sensor, the micro-aethalometer model AE51, to measure their black carbon levels simultaneously and continuously. We estimated their home and school exposure to PM2.5 filter absorbance, which is well-correlated with black carbon, using a temporally adjusted PM2.5 absorbance land use regression (LUR) model. We found considerable variation in the black carbon levels during the day, with the highest levels measured during commuting periods (geometric mean = 2.8 μg/m(3)) and the lowest levels at home (geometric mean = 1.3 μg/m(3)). Hourly temporally adjusted LUR model estimates for the home and school showed moderate to good correlation with measured personal black carbon levels at home and school (r = 0.59 and 0.68, respectively) and lower correlation with commuting trips (r = 0.32 and 0.21, respectively). The correlation between modeled home

  20. Distribution, Transport, and Accumulation of Pyrogenic Black Carbon in Post-Wildfire Watersheds

    Science.gov (United States)

    Galanter, A.; Cadol, D. D.; Frey, B.; Lohse, K. A.

    2014-12-01

    Large, high severity wildfires greatly alter forest structure, water quality, and soil development/erosion. With increased frequency of such wildfires also follows heavy post-wildfire debris flows and flooding which deliver high loads of sediment and pyrogenic black carbon (PyC) to downstream waterways. The accumulation of PyC is a multi-faceted and dynamic issue in the critical zone. Generated by incomplete combustion of organic matter, PyC (in the form of soot and char) impacts turbidity, biological and chemical oxygen demand, and pH. In addition, PyC has the potential to sequester contaminants and can store carbon over short and long timescales. The impacts of two recent wildfires in Northern New Mexico are studied with the goal of understanding the fluxes and residence times of PyC in post-wildfire, mountainous watersheds. Employing burn severity maps and geospatial data, we selected three sites to collect soil and water samples to characterize PyC: a control, an area impacted by a large, severe burn (2011), and an area impacted by a smaller, less severe burn (2013). By collaborating with researchers at the Jemez Critical Zone Observatory, soil samples are being analyzed and will provide pre-wildfire PyC concentrations for the 2013 burn area. In this study, PyC is treated as both a particulate and a solute that is transported throughout the watershed as well as degraded in soils, surface water and groundwater. We used two black carbon quantification methods: the chemo-thermal oxidation (CTO-375) method to distinguish between soil soot and char, and the benzene polycarboxylic acids (BPCA) method to quantify the total concentrations of PyC in soil and water samples. Preliminary soil data from the CTO-375 method show comparable soot concentrations in the control, 2011, and 2013 burn indicating that the soot is more recalcitrant than char and remains in the watershed long after a wildfire. This data also suggests that the fluxes of black carbon over short time

  1. End of the "Little Ice Age" in the Alps not forced by industrial black carbon

    Science.gov (United States)

    Sigl, Michael; Osmont, Dimtri; Gabrieli, Jacopo; Barbante, Carlo; Schwikowski, Margit

    2016-04-01

    Light absorbing aerosols present in the atmosphere and cryosphere play an important role in the climate system. Their presence in ambient air and snow changes radiative properties of these media, thus contributing to increased atmospheric warming and snowmelt. High spatio-temporal variability of aerosol concentrations in these media and a shortage of long-term observations contribute to large uncertainties in properly assigning the climate effects of these aerosols through time. Glaciers in the European Alps began to retreat abruptly from their mid-19th century maximum, marking what appeared to be the end of the Little Ice Age. Radiative forcing by increasing deposition of industrial black carbon to snow has been suggested as the main driver of the abrupt glacier retreats in the Alps (Painter et al. 2012). Basis for this hypothesis were model simulations using ice-core measurements of elemental carbon at low temporal resolution from two ice cores in the Alps. Here we present sub-annually resolved, well replicated ice-core measurements of refractory black carbon (rBC; using a SP2 soot photometer), mineral dust (Fe, Ca), biomass burning (NH4, K) and distinctive industrial pollution tracers (Bi, Pb, SO4) from an ice core in the Alps covering the past 250 years. These reconstructions allow to precisely compare the timing of observed acceleration of glacier melt in the mid-19th century with that of the increase of soot deposition on ice-sheets caused by the industrialization of Western Europe. Our study suggests that at the time when European rBC emission rates started to significantly increase Alpine glaciers have already experienced more than 70% of their total 19th century length reduction. Industrial BC emissions can therefore not been considered as the primary forcing of the rapid deglaciation at the end of the Little Ice Age in the Alps. References: Painter, T. H., M. G. Flanner, G. Kaser, B. Marzeion, R. A. VanCuren, and W. Abdalati (2013), End of the Little Ice

  2. Black carbon exposure more strongly associated with census tract poverty compared to household income among US black, white, and Latino working class adults in Boston, MA (2003–2010)

    International Nuclear Information System (INIS)

    We investigated the association of individual-level ambient exposure to black carbon (spatiotemporal model-based estimate for latitude and longitude of residential address) with individual, household, and census tract socioeconomic measures among a study sample comprised of 1757 US urban working class white, black and Latino adults (age 25–64) recruited for two studies conducted in Boston, MA (2003–2004; 2008–2010). Controlling for age, study, and exam date, the estimated average annual black carbon exposure for the year prior to study enrollment at the participants' residential address was directly associated with census tract poverty (beta = 0.373; 95% confidence interval (CI) 0.322, 0.423) but not with annual household income or education; null associations with race/ethnicity became significant only after controlling for socioeconomic position. - Highlights: • The study included 1757 black, Latino, and white working class adults in Boston, MA. • Census tract poverty was associated with annual average black carbon exposure. • Annual household income was not associated with black carbon exposure. • Individual-level education was not associated with black carbon exposure. • The observed socioeconomic patterns varied by race/ethnicity. - In a US multiethnic urban working adult population, exposure to black carbon was more strongly associated with census tract as compared to household- or individual-level socioeconomic measures

  3. Black Carbon And Co-Pollutants Emissions And Energy Efficiency From Bricks Production In Guanajuato, Mexico

    Science.gov (United States)

    Molina, L. T.; Zavala, M.; Maiz, P.; Monsivais, I.; Chow, J.; Munguia, J.

    2013-12-01

    In many parts of the world, small-scale traditional brick kilns are a notorious informal sector source of urban air pollution. Many are both inefficient and burn highly polluting fuels that emit significant levels of black carbon and other pollutants into local communities and to the atmosphere, resulting in severe health and environmental impacts. It is estimated that there are nearly 20,000 traditional brick kilns in Mexico, in which bricks are still produced as they have been for centuries. They are made by hand, dried in the sun, and generally fired in small, one chamber kilns that use various types of fuels, including plastic refuse, used tires, manure, wood scrap, and used motor oil. Three brick kilns, two traditional kilns and an improved kiln (MK2), were sampled as part of the SLCFs-Mexico campaign in Guanajuato, Mexico during March of 2013. The concept of the MK-2 involves covering the kiln with a dome and channeling the output of an active kiln through a second, identical loaded kiln for its additional filtration of the effluents. The results of energy efficiency and carbon mass balance calculations are presented for comparing the production efficiency and carbon emissions from the sampled kilns. Measurements included PM2.5 mass with quartz filters and temporally-resolved elemental carbon and organic carbon composition obtained using thermo-optical methods. The carbon emissions obtained with the mass balance method are compared with concurrent, high- time resolution, emissions measurements obtained using the Aerodyne mobile laboratory employing the tracer method (see abstract by Fortner et al.)

  4. The Black Lake (Quebec, Canada) mineral carbonation experimental station: CO2 capture in mine waste

    Science.gov (United States)

    Beaudoin, G.; Constantin, M.; Duchesne, J.; Dupuis, C.; Entrazi, A.; Gras, A.; Huot, F.; Fortier, R.; Hebert, R.; Larachi, F.; Lechat, K.; Lemieux, J. M.; Molson, J. W. H.; Maldague, X.; Therrien, R.; Assima, G. P.

    2014-12-01

    Passive mineral carbonation of chrysotile mining and milling waste was discovered at the Black Lake mine, southern Québec, 10 years ago. Indurated crusts were found at the surface and within waste piles where mineral and rock fragments are cemented by hydrated magnesium carbonates. A long-term research program has yielded significant insight into the process of CO2 capture from the atmosphere, and how it can be implemented during mining operations. Laboratory experiments show that the waste mineralogy is crucial, brucite being more reactive than serpentine. Partial water saturation, circa 40%, is also critical to dissolve magnesium from minerals, and transport aqueous CO2 to precipitation sites. Grain armoring by iron oxidation induced by dissolved oxygen prevents further reaction. Two experimental cells constructed with milling waste and fitted with various monitoring probes (T, H2O content, leachate) and gas sampling ports, have been monitored for more than 3 years, along with environmental conditions. The interstitial gas in the cells remains depleted in CO2 indicating continuous capture of ambient atmospheric CO2 at rates faster than advection to reaction sites. The energy released by the exothermic mineral carbonation reactions has been observed both in laboratory experiments (up to 4 °C) and in the field. Warm air, depleted to 10 ppmv CO2, vents at the surface of the waste piles, indicating reaction with atmospheric CO2 deep inside the piles. A thermal anomaly, detected by airborne infrared and coincident with a known venting area, was selected for locating a 100 m deep borehole fitted with sensor arrays to monitor active mineral carbonation within the pile. The borehole has intersected areas where mineral carbonation has indurated the milling waste. The borehole will be monitored for the next 3 years to better understand the mineral carbonation process, and its potential to yield recoverable geothermal energy in mining environments.

  5. Comparison of pulp-mill-integrated hydrogen production from gasified black liquor with stand-alone production from gasified biomass

    International Nuclear Information System (INIS)

    When gasified black liquor is used for hydrogen production, significant amounts of biomass must be imported. This paper compares two alternative options for producing hydrogen from biomass: (A) pulp-mill-integrated hydrogen production from gasified back liquor; and (B) stand-alone production of hydrogen from gasified biomass. The comparison assumes that the same amount of biomass that is imported in Alternative A is supplied to a stand-alone hydrogen production plant and that the gasified black liquor in Alternative B is used in a black liquor gasification combined cycle (BLGCC) CHP unit. The comparison is based upon equal amounts of black liquor fed to the gasifier, and identical steam and power requirements for the pulp mill. The two systems are compared on the basis of total CO2 emission consequences, based upon different assumptions for the reference energy system that reflect different societal CO2 emissions reduction target levels. Ambitions targets are expected to lead to a more CO2-lean reference energy system, in which case hydrogen production from gasified black liquor (Alternative A) is best from a CO2 emissions' perspective, whereas with high CO2 emissions associated with electricity production, hydrogen from gasified biomass and electricity from gasified black liquor (Alternative B) is preferable. (author)

  6. Acid–base interaction between carbon black and polyurethane molecules with different amine values: Dispersion stability of carbon black suspension for use in lithium ion battery cathodes

    International Nuclear Information System (INIS)

    The dispersion properties of carbon black (CB) slurries as well as the accompanying electrochemical properties of Li(Ni1/3Co1/3Mn1/3)O2 (NCM) electrodes were investigated by controlling the amine value of polyurethane-based dispersants. The increase in amine value of dispersants leads to an increase in adsorption level on CB surface due to a strong acid/base interaction between dispersants and CB particles, providing the improvement of steric repulsion between particles at the solid–liquid interface. This results in the enhancement of the dispersion stability of CB and the related microstructure of the electrodes. Electrochemical experiments indicated that the rate capabilities and cycle performance of the electrodes are in good agreement with dispersion properties of CB slurries. However, it was found that the excessive addition of the dispersant was deleterious to electrochemical properties because the non-adsorbed dispersants act as an electronic conduction barrier between solid phases. Therefore, it is suggested that the amine value of dispersant and tailored amount of dispersant addition can be key roles for obtaining the optimized dispersion stability of CB and the corresponding excellent electrochemical properties of the cathode

  7. How surface fire in Siberian Scots pine forests affects soil organic carbon in the forest floor: Stocks, molecular structure, and conversion to black carbon (charcoal)

    OpenAIRE

    Czimczik, Claudia I; Preston, Caroline M; Schmidt, Michael W I; Schulze, Ernst-Detlef

    2003-01-01

    [1] In boreal forests, fire is a frequent disturbance and converts soil organic carbon (OC) to more degradation-resistant aromatic carbon, i.e., black carbon (BC) which might act as a long-term atmospheric-carbon sink. Little is known on the effects of fires on boreal soil OC stocks and molecular composition. We studied how a surface fire affected the composition of the forest floor of Siberian Scots pine forests by comparing the bulk elemental composition, molecular structure (13C-MAS NMR), ...

  8. Invited article summarizing the Science To Achieve Results research portfolio on Black Carbon for the journal EM of the Air and Waste Management Association.

    Science.gov (United States)

    Where there’s smoke, there’s fire – and black carbon. Black carbon is the sooty material emitted from combustion processes, including diesel engines and other sources that burn fossil fuels, biofuels, or biomass. This soot contributes to fine particulate matter,...

  9. 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.

  10. Black carbon measurements in the boundary layer over western and northern Europe

    Directory of Open Access Journals (Sweden)

    G. R. McMeeking

    2010-10-01

    Full Text Available Europe is a densely populated region that is a significant global source of black carbon (BC aerosol, but there is a lack of information regarding the physical properties and spatial/vertical distribution of rBC in the region. We present the first aircraft observations of sub-micron refractory BC (rBC aerosol concentrations and physical properties measured by a single particle soot photometer (SP2 in the lower troposphere over Europe. The observations spanned a region roughly bounded by 50° to 60° N and from 15° W to 30° E. The measurements, made between April and September 2008, showed that average rBC mass concentrations ranged from about 300 ng m−3 near urban areas to approximately 50 ng m−3 in remote continental regions, lower than previous surface-based measurements. rBC represented between 0.5 and 3% of the sub-micron aerosol mass. Black carbon mass size distributions were log-normally distributed and peaked at approximately 180 nm, but shifted to smaller diameters (~160 nm near source regions. rBC was correlated with carbon monoxide (CO but had different ratios to CO depending on location and air mass. Light absorption coefficients were measured by particle soot absorption photometers on two separate aircraft and showed similar geographic patterns to rBC mass measured by the SP2. We summarize the rBC and light absorption measurements as a function of longitude and air mass age and also provide profiles of rBC mass concentrations and size distribution statistics. Our results will help evaluate model-predicted regional rBC concentrations and properties and determine regional and global climate impacts from rBC due to atmospheric heating and surface dimming.

  11. What Role Should Black Carbon Play in Climate Change Mitigation Strategies?

    Science.gov (United States)

    Deangelo, B. J.

    2006-12-01

    The uncertainties of the black carbon-climate linkage remain large with regard to emissions quantification, temporal and regional atmospheric concentrations, and net radiative and other climatic effects. Given these physical uncertainties plus other economic and emission control considerations, what is the appropriate role for BC and organic carbon in any climate change mitigation strategy? If the climate effects of BC are considered `large enough' (a judgment call) to warrant emission controls to mitigate climate change, additional considerations are necessary to determine how best to do this. First, BC cannot be singly targeted, as BC is co-emitted with OC in various ratios depending on fuel type and combustion technology. The climate effects of any control strategy will depend on the net BC and OC, plus possible greenhouse gas, co-effects, which in turn will vary by specific emission source, sector and region. Second, the extent to which air quality policies (primarily targeting particulate matter for health concerns) control BC and OC can determine whether additional emission mitigation is necessary, or if additional mitigation is best pursued within the context of air quality policies, rather than being introduced into the climate area. In the U.S., on-road and off-road diesel vehicles are the largest sources of BC, but these emissions are expected to decline substantially over the next few decades due to recently issued U.S. EPA standards. Third is the issue of costs of BC reductions relative to the costs of other mitigation strategies. Results will be presented on 1) near-term (out to 2020) emission projections for the U.S. taking into account recent air quality regulations; 2) emerging work from the Energy Modeling Forum Black Carbon Subgroup on global and regional projections by region and sector, and mitigation scenarios; and 3) the costs of potential BC mitigation options for the U.S.

  12. Australia's Black Saturday fires - Comparison of techniques for estimating emissions from vegetation fires

    Science.gov (United States)

    Paton-Walsh, Clare; Emmons, Louisa K.; Wiedinmyer, Christine

    2012-12-01

    We present a comparison of techniques for estimating atmospheric emissions from fires using Australia's 2009 “Black Saturday” wildfires as a case study. Most of the fires started on Saturday the 7th of February 2009 (a date now known as “Black Saturday”) and then spread rapidly, fanned by gale force winds, creating several firestorms and killing 173 people. The fires continued into early March, when rain and cooler conditions allowed the fires to be extinguished. In this study, we compare two new techniques (and one more established method) to estimate the total emissions of a number of atmospheric trace gases from these fires. One of the new techniques is a “bottom-up” technique that combines existing inventories of fuel loads, combustion efficiencies and emission factors with an estimate of burned area derived from MODIS rapid response daily fire counts. The other new method is a “top-down” approach using MODIS aerosol optical depth as a proxy for total amounts of trace gases emitted by the fires. There are significant differences between the estimates of emissions from these fires using the different methods, highlighting the uncertainties associated with fire emission estimates. These differences are discussed along with their likely causes and used as a vehicle to explore the merits of the different methods, and further constrain fire emissions in the future.

  13. Mitigating and Tracking Black Carbon Exposure at Schools in the Mountain View Corridor of Salt Lake City

    Science.gov (United States)

    Roberts, P. T.; Brown, S. G.; Vaughn, D.; DeWinter, J. L.

    2015-12-01

    Black carbon (BC) is a short lived climate forcer and is associated with human health effects. We measured BC inside and outside at four schools in Salt Lake City during two studies in 2011-2014. In addition, PM2.5 was measured indoor and outdoor at one school, and gaseous air toxics outdoor at one school. The schools are within 500 m of a planned major freeway, and two of them will adjoin the freeway. The objectives included determining the outdoor and indoor concentrations of BC, the likely sources of BC, and once the freeway is built, the change in ambient BC at the schools. We determined the current state of air quality outdoors at these schools, to provide baseline data for comparison when the major freeway is operational, and indoors as a baseline before installing improved filtration to reduce BC in classrooms. Using MATES IV cancer risk values, we found that diesel particulate matter, as indicated by ambient, outdoor BC measurements, was responsible for 84% of the cancer risk at the schools. The HVAC system was moderately effective at filtrating PM mass (73% reduction), but very poor at filtering BC (7%-34% reduction), indicating that air toxics risk is similar indoors and outdoors. Improved filtration devices could potentially mitigate this risk, and improved filtration systems have been recommended for the schools. Lastly, we used the difference in absorption at two Aethalometer channels to determine that the majority of BC (> 90%) during the spring through fall is from fossil fuel emissions.

  14. Comparison of Intrinsic and Extrinsic Job-Related Factors among Assistant Coaches Employed in Predominantly White and Black Universities.

    Science.gov (United States)

    Evans, Virden; And Others

    Comparison was made of the job attitudes of assistant coaches employed in predominantly white and black universities to determine the following job-related factors: (1) professional recognition; (2) personal initiative; (3) personal satisfaction; (4) job security; (5) salary; and (6) racial balance. Responses to a questionnaire were received from…

  15. Influence of the Synthesis Method for Pt Catalysts Supported on Highly Mesoporous Carbon Xerogel and Vulcan Carbon Black on the Electro-Oxidation of Methanol

    OpenAIRE

    Cinthia Alegre; María Elena Gálvez; Rafael Moliner; María Jesús Lázaro

    2015-01-01

    Platinum catalysts supported on carbon xerogel and carbon black (Vulcan) were synthesized with the aim of investigating the influence of the characteristics of the support on the electrochemical performance of the catalysts. Three synthesis methods were compared: an impregnation method with two different reducing agents, sodium borohydride and formic acid, and a microemulsion method, in order to study the effect of the synthesis method on the physico-chemical properties of the catalysts. X-ra...

  16. Attribution of aerosol light absorption to black carbon, brown carbon, and dust in China ? interpretations of atmospheric measurements during EAST-AIRE

    OpenAIRE

    Yang, M.; S. G. Howell; Zhuang, J.; Huebert, B. J.

    2008-01-01

    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 a...

  17. Utilizing Colored Dissolved Organic Matter to Derive Dissolved Black Carbon Export by Arctic Rivers

    Science.gov (United States)

    Stubbins, Aron; Spencer, Robert; Mann, Paul; Holmes, R.; McClelland, James; Niggemann, Jutta; Dittmar, Thorsten

    2015-10-01

    Wildfires have produced black carbon (BC) since land plants emerged. Condensed aromatic compounds, a form of BC, have accumulated to become a major component of the soil carbon pool. Condensed aromatics leach from soils into rivers, where they are termed dissolved black carbon (DBC). The transport of DBC by rivers to the sea is a major term in the global carbon and BC cycles. To estimate Arctic river DBC export, 25 samples collected from the six largest Arctic rivers (Kolyma, Lena, Mackenzie, Ob’, Yenisey and Yukon) were analyzed for dissolved organic carbon (DOC), colored dissolved organic matter (CDOM), and DBC. A simple, linear regression between DOC and DBC indicated that DBC accounted for 8.9 ± 0.3% DOC exported by Arctic rivers. To improve upon this estimate, an optical proxy for DBC was developed based upon the linear correlation between DBC concentrations and CDOM light absorption coefficients at 254 nm (a254). Relatively easy to measure a254 values were determined for 410 Arctic river samples between 2004 and 2010. Each of these a254 values was converted to a DBC concentration based upon the linear correlation, providing an extended record of DBC concentration. The extended DBC record was coupled with daily discharge data from the six rivers to estimate riverine DBC loads using the LOADEST modeling program. The six rivers studied cover 53% of the pan-Arctic watershed and exported 1.5 ± 0.1 million tons of DBC per year. Scaling up to the full area of the pan-Arctic watershed, we estimate that Arctic rivers carry 2.8 ± 0.3 million tons of DBC from land to the Arctic Ocean each year. This equates to ~8% of Arctic river DOC export, slightly less than indicated by the simpler DBC vs DOC correlation-based estimate. Riverine discharge is predicted to increase in a warmer Arctic. DBC export was positively correlated with river runoff, suggesting that the export of soil BC to the Arctic Ocean is likely to increase as the Arctic warms.

  18. Utilizing Colored Dissolved Organic Matter to Derive Dissolved Black Carbon Export by Arctic Rivers

    Directory of Open Access Journals (Sweden)

    Aron eStubbins

    2015-10-01

    Full Text Available Wildfires have produced black carbon (BC since land plants emerged. Condensed aromatic compounds, a form of BC, have accumulated to become a major component of the soil carbon pool. Condensed aromatics leach from soils into rivers, where they are termed dissolved black carbon (DBC. The transport of DBC by rivers to the sea is a major term in the global carbon and BC cycles. To estimate Arctic river DBC export, 25 samples collected from the six largest Arctic rivers (Kolyma, Lena, Mackenzie, Ob’, Yenisey and Yukon were analyzed for dissolved organic carbon (DOC, colored dissolved organic matter (CDOM, and DBC. A simple, linear regression between DOC and DBC indicated that DBC accounted for 8.9 ± 0.3% DOC exported by Arctic rivers. To improve upon this estimate, an optical proxy for DBC was developed based upon the linear correlation between DBC concentrations and CDOM light absorption coefficients at 254 nm (a254. Relatively easy to measure a254 values were determined for 410 Arctic river samples between 2004 and 2010. Each of these a254 values was converted to a DBC concentration based upon the linear correlation, providing an extended record of DBC concentration. The extended DBC record was coupled with daily discharge data from the six rivers to estimate riverine DBC loads using the LOADEST modeling program. The six rivers studied cover 53% of the pan-Arctic watershed and exported 1.5 ± 0.1 million tons of DBC per year. Scaling up to the full area of the pan-Arctic watershed, we estimate that Arctic rivers carry 2.8 ± 0.3 million tons of DBC from land to the Arctic Ocean each year. This equates to ~8% of Arctic river DOC export, slightly less than indicated by the simpler DBC vs DOC correlation-based estimate. Riverine discharge is predicted to increase in a warmer Arctic. DBC export was positively correlated with river runoff, suggesting that the export of soil BC to the Arctic Ocean is likely to increase as the Arctic warms.

  19. Black carbon and trace gases over South Asia: Measurements and Regional Climate model simulations

    Science.gov (United States)

    Bhuyan, Pradip; Pathak, Binita; Parottil, Ajay

    2016-07-01

    Trace gases and aerosols are simulated with 50 km spatial resolution over South Asian CORDEX domain enclosing the Indian sub-continent and North-East India for the year 2012 using two regional climate models RegCM4 coupled with CLM4.5 and WRF-Chem 3.5. Both models are found to capture the seasonality in the simulated O3 and its precursors, NOx and CO and black carbon concentrations together with the meteorological variables over the Indian Subcontinent as well as over the sub-Himalayan North-Eastern region of India including Bangladesh. The model simulations are compared with the measurements made at Dibrugarh (27.3°N, 94.6°E, 111 m amsl). Both the models are found to capture the observed diurnal and seasonal variations in O3 concentrations with maximum in spring and minimum in monsoon, the correlation being better for WRF-Chem (R~0.77) than RegCM (R~0.54). Simulated NOx and CO is underestimated in all the seasons by both the models, the performance being better in the case of WRF-Chem. The observed difference may be contributed by the bias in the estimation of the O3 precursors NOx and CO in the emission inventories or the error in the simulation of the meteorological variables which influences O3 concentration in both the models. For example, in the pre-monsoon and winter season, the WRF-Chem model simulated shortwave flux overestimates the observation by ~500 Wm-2 while in the monsoon and post monsoon season, simulated shortwave flux is equivalent to the observation. The model predicts higher wind speed in all the seasons especially during night-time. In the post-monsoon and winter season, the simulated wind pattern is reverse to observation with daytime low and night-time high values. Rainfall is overestimated in all the seasons. RegCM-CLM4.5 is found to underestimate rainfall and other meteorological parameters. The WRF-Chem model closely captured the observed values of black carbon mass concentrations during pre-monsoon and summer monsoon seasons, but

  20. Modelling of Black and Organic Carbon Variability in the Northern Hemisphere

    Science.gov (United States)

    Kurganskiy, Alexander; Nuterman, Roman; Mahura, Alexander; Kaas, Eigil; Baklanov, Alexander; Hansen Sass, Bent

    2016-04-01

    Black and organic carbon as short-lived climate forcers have influence on air quality and climate in Northern Europe and Arctic. Atmospheric dispersion, deposition and transport of these climate forcers from remote sources is especially difficult to model in Arctic regions due to complexity of meteorological and chemical processes and uncertainties of emissions. In our study, the online integrated meteorology-chemistry/aerosols model Enviro-HIRLAM (Environment - High Resolution Limited Area Model) was employed for evaluating spatio-temporal variability of black and organic carbon aerosols in atmospheric composition in the Northern Hemisphere regions. The model setup included horizontal resolution of 0.72 deg, time step of 450 sec, 6 h meteorological surface data assimilation, 1 month spin-up; and model was run for the full year of 2010. Emissions included anthropogenic (ECLIPSE), shipping (AU_RCP&FMI), wildfires (IS4FIRES), and interactive sea salt, dust and DMS. Meteorological (from IFS at 0.75 deg) and chemical (from MACC Reanalysis at 1.125 deg) boundary conditions were obtained from ECMWF. Annual and month-to-month variability of mean concentration, accumulated dry/wet and total deposition fluxes is analyzed for the model domain and selected European and Arctic observation sites. Modelled and observed BC daily mean concentrations during January and July showed fair-good correlation (0.31-0.64) for stations in Germany, UK and Italy; however, for Arctic stations (Tiksi, Russia and Zeppelin, Norway) the correlations were negative in January, but higher correlations and positive (0.2-0.7) in July. For OC, it varied 0.45-0.67 in January and 0.19-0.57 in July. On seasonal scale, during both summer and winter seasons the BC and OC correlations are positive and higher for European stations compared with Arctic. On annual scale, both BC and OC correlations are positive and vary between 0.4-0.6 for European stations, and these are smoothed to negligible values for Arctic

  1. A Comparative Study on AC Conductivity and Dielectric Behavior of Multiwalled Carbon Nanotubes and Polyaniline Coated Multiwalled Carbon Nanotubes Filled High Density Polyethylene-Carbon Black Nanocomposites

    International Nuclear Information System (INIS)

    This paper presents an experimental investigation on AC conductivity and dielectric behavior of carbon black reinforced high density polyethylene (HDPE-CB) and HDPE-CB filled with multiwalled carbon nanotubes (MWNTs-CB-HDPE) and Polyaniline (PAni) coated MWNTs-CB-HDPE nanocomposites. The electrical properties such as dielectric constant (ε'), dissipation factor (tan δ) and AC conductivity (σac) of nanocomposites have been measured with reference to the weight fraction (0.5 and 1 wt% MWNTs), frequency (75 KHz-30 MHz), temperature (25-90 deg. C) and sea water ageing. The experimental results showed that the increased AC conductivity and dielectric constant of the nanocomposites were influenced by PAni coated MWNTs in HDPE-CB nanocomposites. The value of dielectric constant and tan δ decreased with increasing frequency. Further more, above 5 MHz the AC conductivity increases drastically whereas significant effect on tan δ was observed in less than 1 MHz.

  2. The effects of carbon nanotubes on electroactive shape-memory behaviors of hydro-epoxy/carbon black composite

    International Nuclear Information System (INIS)

    The objective of this work is to characterize the effect of multi-walled carbon nanotubes (MWCNTs) on the thermomechanical, electrical and shape-memory properties of hydro-epoxy/carbon black (CB) composite. The shape-memory hydro-epoxy composite is fabricated by adding MWCNTs and CB into shape-memory hydro-epoxy resin. The total amount of the fillers fixed at 1.9 wt%, five different composites are produced by varying the amount of MWCNTs between 0 and 0.8 wt% and the amount of CB between 1.1 and 1.9 wt%. The thermomechanical properties and shape-memory performance of the composites are studied. These results indicate that the glass transition temperature (Tg) and the storage modulus of the composites increases at first and then decreases as MWCNTs content increases. The shape recovery time decreases at first and then increases slightly as MWCNTs content increases. The composite presents good shape-memory behavior, and the shape recovery ratio is around 100%. Due to the synergic effect of CB and MWCNTs, the volume electrical resistivity of the composite could decrease by adding a small amount of MWCNTs. (paper)

  3. Acetylcholinesterase biosensor for inhibitor measurements based on glassy carbon electrode modified with carbon black and pillar[5]arene.

    Science.gov (United States)

    Shamagsumova, Rezeda V; Shurpik, Dmitry N; Padnya, Pavel L; Stoikov, Ivan I; Evtugyn, Gennady A

    2015-11-01

    New acetylcholinesterase (AChE) biosensor based on unsubstituted pillar[5]arene (P[5]A) as electron mediator was developed and successfully used for highly sensitive detection of organophosphate and carbamate pesticides. The AChE from electric eel was immobilized by carbodiimide binding on carbon black (CB) placed on glassy carbon electrode. The working potential of 200mV was obtained in chronoamperometric mode with the measurement time of 180 s providing best inter-biosensors precision of the results. The AChE biosensor developed made it possible to detect 1×10(-11)-1×10(-6) M of malaoxon, 1×10(-8)-7×10(-6) M of methyl-paraoxon, 1×10(-10)-2×10(-6) M of carbofuran and 7×10(-9)-1×10(-5) M of aldicarb with 10 min incubation. The limits of detection were 4×10(-12), 5×10(-9), 2×10(-11) and 6×10(-10) M, respectively. The AChE biosensor was tested in the analysis of pesticide residuals in spiked samples of peanut and beetroot. The protecting effect of P[5]A derivative bearing quaternary ammonia groups on malaoxon inhibition was shown. PMID:26452862

  4. Effects of Strain-Induced Crystallization on Mechanical Properties of Elastomeric Composites Containing Carbon Nanotubes and Carbon Black

    Energy Technology Data Exchange (ETDEWEB)

    Sung, Jong Hwan; Ryu, Sang Ryeoul; Lee, Dong Joo [Yeungnam University, Gyeongsan (Korea, Republic of)

    2011-09-15

    The effects of strain-induced crystallization (SIC) on the mechanical properties of elastomeric composites as functions of extension ratio ({lambda}), multi walled carbon nanotube (CNT) content, and carbon black (CB) content are investigated. The differential scanning calorimetry (DSC) analysis shows that the degree of crystallinity increases with the increase in the CB and CNT content. As {lambda} increases, the glass transition temperature (Tg) of the composites increases, and the latent heat of crystallization (LHc) of the composites is maximum at {lambda}=1.5. It is found that the mechanical properties have a linear relation with LHc, depending on the CNT content. According to the TGA (thermogravimetric analysis), the weight loss of the composite matrix is 94.3% and the weight of the composites decreases with the filler content. The ratio of tensile modulus (E{sub comp}/ E{sub matrix}) is higher than that of tensile strength ({sigma}{sub comp}/ {sigma}{sub matrix}) because of the CNT orientation inside the elastomeric composites.

  5. 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.

  6. Carbon black selection from simulated broth solution for ADU gel spheres

    International Nuclear Information System (INIS)

    The VHTR (Very High Temperature Gas Reactor) is one of the reactor concepts in the Gen IV International Collaboration. The nuclear fuel of a VHTR in the US is based on microspheres containing a mixture of UO2 and UC2 coated with multi carbon layers and a SiC layer. This mixture is called a 'UCO (uranium oxi carbide)' kernel. The fabrication process of this kernel was based on the sol-gel method between an ADUN and HMTA and urea, a process referred to as internal gelation. UCO kernel microspheres were first prepared at ORNL in the late 1970s. CB(Carbon Black) as a carbon source in the final UCO kernel is added during the broth solution preparation, in the processing of UCO kernel fabrication. The preparation of a good quality UCO kernel is very difficult due to the homogeneous distribution of carbon in a UCO kernel. The key requirement to obtain a good quality kernel is a uniform distribution of carbon in the ADU gel sphere forming process before the thermal treatment, i.e., during the gel formation step. The internal gelation concept was adapted in ADU gel sphere fabrication in the ORNL process of the US. Generally, UO2 kernel microspheres are prepared by an internal gelation method (USA, India) or external gelation method (Germany, China, Japan). The UCO kernel microspheres prepared only in the US, use an internal gelation method. A material flow chart on the preparation of the microsphere kernel is simply shown in Fig. 1. The broth solution preparation, the raw material, additives, and thermal steps such as calcining and sintering processes were different to compared with the external gelation and internal gelation methods. In this study, we first carried out the matching CB selection experiments among the various kinds of CBs in a broth solution, for UCO kernel preparation using an external gelation method.

  7. The Contribution of Carbon and Water in Modulating Wood Formation in Black Spruce Saplings.

    Science.gov (United States)

    Deslauriers, Annie; Huang, Jian-Guo; Balducci, Lorena; Beaulieu, Marilène; Rossi, Sergio

    2016-04-01

    Nonstructural carbohydrates (NSCs) play a crucial role in xylem formation and represent, with water, the main constraint to plant growth. We assessed the relationships between xylogenesis and NSCs in order to (1) verify the variance explained by NSCs and (2) determine the influence of intrinsic (tissue supplying carbon) and extrinsic (water availability and temperature) factors. During 2 years, wood formation was monitored in saplings of black spruce (Picea mariana) subjected to a dry period of about 1 month in June and exposed to different temperature treatments in a greenhouse. In parallel, NSC concentrations were determined by extracting the sugar compounds from two tissues (cambium and inner xylem), both potentially supplying carbon for wood formation. A mixed-effect model was used to assess and quantify the potential relationships. Total xylem cells, illustrating meristematic activity, were modeled as a function of water, sucrose, and d-pinitol (conditional r(2) of 0.79). Water availability was ranked as the most important factor explaining total xylem cell production, while the contribution of carbon was lower. Cambium stopped dividing under water deficit, probably to limit the number of cells remaining in differentiation without an adequate amount of water. By contrast, carbon factors were ranked as most important in explaining the variation in living cells (conditional r(2) of 0.49), highlighting the functional needs during xylem development, followed by the tissue supplying the NSCs (cambium) and water availability. This study precisely demonstrates the role of carbon and water in structural growth expressed as meristematic activity and tissue formation. PMID:26850274

  8. Intercomparison of Measurement Techniques for Black or Elemental Carbon Under Urban Background Conditions in Wintertime: Influence of Biomass Combustion

    OpenAIRE

    Reisinger, Peter; Wonaschutz, Anna; Hitzenberger, Regina; Petzold, Andreas; Bauer, Heidi; Jankowski, Nicole; Puxbaum, Hans; Chi, Xuguang; Maenhaut, Willy

    2008-01-01

    A generally accepted method to measure black carbon (BC) or elemental carbon (EC) still does not exist. An earlier study in the Vienna area comparing practically all measurement methods in use in Europe gave comparable BC and EC concentrations under summer conditions (Hitzenberger et al., 2006a).Undersummerconditions, Diesel traffic is the major source for EC or BC in Vienna. Under winter conditions, space heating (also with biomass as fuel) is another important source (Caseiro et al., 2007)....

  9. 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

  10. An algorithm for retrieving black carbon optical parameters from thermal-optical (OC/EC instruments

    Directory of Open Access Journals (Sweden)

    A. Andersson

    2011-02-01

    Full Text Available Through absorption of sun light atmospheric black carbon (BC is expected to influence regional/global climate by warming the atmosphere and dimming the surface. To evaluate the impact of these effects it is of interest to examine both the radiative properties of BC and the concentrations in air. Building on recent developments we present a novel application for combining these two aspects using the common thermal-optical (OC/EC instrument. By correlating the OC/EC laser transmission with the FID-carbon detection non-carbon contributions to the light attenuation are detected. Such analysis allows the calculation of mass absorption cross-sections (MACs for BC, corrected for certain in-organic components. This approach has been applied to data from two SS Asian and two SNS European sites, including a time series analysis for one of the SNS European sites. Taken together this study demonstrates broad applicability for this method while providing new insights into the optical properties of BC.

  11. Dynamic molecular structure of plant biomass-derived black carbon (biochar)

    Energy Technology Data Exchange (ETDEWEB)

    Keiluweit, M.; Nico, P.S.; Johnson, M.G.; Kleber, M.

    2009-11-15

    Char black carbon (BC), the solid residue of incomplete combustion, is continuously being added to soils and sediments due to natural vegetation fires, anthropogenic pollution, and new strategies for carbon sequestration ('biochar'). Here we present a molecular-level assessment of the physical organization and chemical complexity of biomass-derived chars and, specifically, that of aromatic carbon in char structures. BET-N{sub 2} surface area, X-ray diffraction (XRD), synchrotron-based Near-edge X-ray Absorption Fine Structure (NEXAFS), and Fourier transform infrared (FT-IR) spectroscopy are used to show how two plant materials (wood and grass) undergo analogous, but quantitatively different physical-chemical transitions as charring temperature increases from 100 to 700 C. These changes suggest the existence of four distinct categories of char consisting of a unique mixture of chemical phases and physical states: (i) in transition chars the crystalline character of the precursor materials is preserved, (ii) in amorphous chars the heat-altered molecules and incipient aromatic polycondensates are randomly mixed, (iii) composite chars consist of poorly ordered graphene stacks embedded in amorphous phases, and (iv) turbostratic chars are dominated by disordered graphitic crystallites. The molecular variations among the different char categories translate into differences in their ability to persist in the environment and function as environmental sorbents.

  12. Risk-Based Comparison of Carbon Capture Technologies

    Energy Technology Data Exchange (ETDEWEB)

    Engel, David W.; Dalton, Angela C.; Dale, Crystal; Jones, Edward

    2013-05-01

    In this paper, we describe an integrated probabilistic risk assessment methodological framework and a decision-support tool suite for implementing systematic comparisons of competing carbon capture technologies. Culminating from a collaborative effort among national laboratories under the Carbon Capture Simulation Initiative (CCSI), the risk assessment framework and the decision-support tool suite encapsulate three interconnected probabilistic modeling and simulation components. The technology readiness level (TRL) assessment component identifies specific scientific and engineering targets required by each readiness level and applies probabilistic estimation techniques to calculate the likelihood of graded as well as nonlinear advancement in technology maturity. The technical risk assessment component focuses on identifying and quantifying risk contributors, especially stochastic distributions for significant risk contributors, performing scenario-based risk analysis, and integrating with carbon capture process model simulations and optimization. The financial risk component estimates the long-term return on investment based on energy retail pricing, production cost, operating and power replacement cost, plan construction and retrofit expenses, and potential tax relief, expressed probabilistically as the net present value distributions over various forecast horizons.

  13. Significance of black carbon in the sediment-water partitioning of organochlorine pesticides (OCPs) in the Indus River, Pakistan.

    Science.gov (United States)

    Ali, Usman; Bajwa, Anam; Chaudhry, Muhammad Jamshed Iqbal; Mahmood, Adeel; Syed, Jabir Hussain; Li, Jun; Zhang, Gan; Jones, Kevin C; Malik, Riffat Naseem

    2016-04-01

    This study was conducted with the aim of assessing the levels and black carbon mediated sediment-water partitioning of organochlorine pesticides (OCPs) from the Indus River. ∑OCPs ranged between 52-285 ng L(-1) and 5.6-29.2 ng g(-1) in water and sediment samples respectively. However, the ranges of sedimentary fraction of total organic carbon (f(TOC)) and black carbon (f(BC)) were 0.82-2.26% and 0.04-0.5% respectively. Spatially, OCPs concentrations were higher at upstream sites as compared to downstream sites. Source diagnostic ratios indicated the technical usage of HCH (α-HCH/γ-HCH>4) and significant presence of DDT metabolites with fresh inputs into the Indus River as indicated by the ratios of (DDE+DDD)/∑DDTs (0.27-0.96). The partitioning of OCPs between the sediments and water can be explained by two carbon Freundlich adsorption model which included both organic carbon and black carbon pools as partitioning media. PMID:26761782

  14. A reliable light scattering computing for black carbon-containing particles: Hybrid discrete dipole approximation (h-DDA)

    Science.gov (United States)

    Moteki, N.

    2015-12-01

    Black carbon (BC) is a light-absorbing carbonaceous aerosol emitted from combustions of fossil fuels and biomasses and is estimated as the second most important contributor to positive climate forcing after the carbon dioxide. In the atmosphere, the fractal aggregate of BC-spherules may be mixed with non-absorbing (or weakly absorbing) compounds that forms morphologically complex "BC-containing particle". A reliable scattering code for BC-containing particles is necessary for predicting mass absorption efficiency of BC and designing/evaluating optical techniques for estimating microphysical properties (i.e., size distribution, mixing state, shape, refractive index) of BC-containing particles. The computational methods that derived from the volume-integral form of the Maxwell equation, such as discrete dipole approximation (DDA), are method of choice for morphologically complex object like BC-containing particles. In ordinary DDA, the entire particle volume is approximated as a collection of tiny cubical dipoles (with side length d) placed on a 3D cubic lattice. For several model BC-containing particles, the comparisons with numerically exact T-matrix method reveals that the ordinary DDA suffered from persistent positive systematic error (up to +30%) in absorption even under d DDA error is identified to be the shape error in BC-spherules. To eliminate the shape error in BC-spherules, we propose a new DDA methodology which may be called hybrid DDA (h-DDA): each primary BC sphere is assumed as a spherical dipole, while remaining particle volume of coating material is approximated by a collection of tiny cubical dipoles on a 3D cubic lattice. Positive absorption bias up to +30% in ordinary DDA is suppressed to within 3% in h-DDA. In h-DDA code, an efficient FFT-based algorithm for solving the matrix equation has been implemented, by utilizing the multilevel block-Toeplitz property of the submatrix corresponding to inter-dipole interaction within coating material.

  15. Reinforcing effect of plasma modified halloysite nanotubes in a carbon black filled natural rubber-butadien rubber matrix

    NARCIS (Netherlands)

    Poikelispaa, Minna; Das, Amit; Dierkes, Wilma; Vuorinen, Jyrki

    2011-01-01

    Rubber composites are generally produced by the direct incorporation of fillers like carbon black and/or silica into the rubber matrix. The incorporation of different types of nanofillers is the subject of recent research with the aim of preparing composites with special compositions and properties.

  16. DYNAMIC MECHANICAL PROPERTIES OF STYRENE-BUTADIENE COMPOSITES REINFORCED BY DEFATTED SOY FLOUR AND CARBON BLACK CO-FILLER

    Science.gov (United States)

    Carboxylated styrene-butadiene (SB) composites reinforced by a mixture of defatted soy flour (DSF) and carbon black (CB) were investigated in terms of their dynamic mechanical properties. DSF is an abundant renewable commodity and has a lower cost than CB. DSF contains soy protein, soy carbohydrat...

  17. Application of Conductive Carbon Black in Plastics%导电炭黑在塑料中的应用

    Institute of Scientific and Technical Information of China (English)

    邓毅

    2001-01-01

    Conductive carbon black for plastics and its application in plastics as well as its development prospect are introduced.%介绍塑料导电专用炭黑及其在塑料制品中的应用性能和该产品的应用前景。

  18. Effects of type of nanosized carbon black on the performance of an all-solid-state potentiometric electrode for nitrate

    International Nuclear Information System (INIS)

    The potentiometric properties of all-solid-state nitrate-selective electrodes based on plasticised PVC and containing different types of nanosized carbon black were investigated. The use of a carbon black interlayer is shown to significantly improve the potentiometric response. The electrodes display a close-to-Nernstian slope in the range from 10−1 to 10−6 M, highly stable potentials and low membrane resistance. However, different analytical features were found depending on the type of carbon black used. The best long-term potential stability was observed for the electrode with Printex XE2-B carbon black that has a relatively high BET surface area (1000 m2 · g−1) and an average particle size of 30 nm. Nevertheless, the electrodes with the Vulcan XC-72 (BET surface: 240 m2 · g−1; average size: 55 nm) showed the most repeatable and reproducible standard potential. The lowest detection limit for nitrate (2.5·10−7 M) is observed for an electrode containing Vulcan XC-72. (author)

  19. Three-dimensional shapes and spatial distributions of Pt and PtCr catalyst nanoparticles on carbon black

    DEFF Research Database (Denmark)

    Gontard, Lionel Cervera; Dunin-Borkowski, Rafal E.; Ozkaya, D.

    2008-01-01

    High-angle annular dark-field scanning transmission electron microscopy tomography is applied to the study of Pt and PtCr nanoparticles supported on carbon black, which are used as heterogeneous catalysts in the electrodes of proton exchange membrane fuel cells. By using electron tomography, the...

  20. Response behavior of an epoxy resin/amine curing agent/carbon black composite film to various solvents

    International Nuclear Information System (INIS)

    A novel polymer based sensitive film was prepared from thermosetting epoxy resins (EP) filled with carbon blacks. The curing reaction of amine curing agents with epoxy resins and the response of the curing resultants to solvent vapors were dealt with. The influence of the types and content of carbon blacks and curing agents, and curing temperatures and time on curing reactions and response selectivity of the conductive films were investigated. The structural characterization was conducted on a Fourier transform infrared spectrophotometer (FTIR). The results indicated that the conductive films showed high response selectivity to polar solvent vapors, especially to chloroform vapor, while no response was observed in non-polar solvent vapors. The responsivity of the film increased with the decreased carbon black contents. The film filled with acetylene carbon black gave an optimal response, with responsivity of about 700 times. The response performances were improved with the amount of curing agents increased, and an optimal response appeared at the amount of the curing agent of 8%. The film's responsivity was remarkably enhanced, the reversibility property, however, rapidly declined in the order of diethyleneltriamine < triethylenetetramine < ethylenediamine. The curing reaction tended to complete with the curing temperature elevated and the curing time prolonged. But the response performance dropped because of over cross-linking as the temperature was too high or the time was too long

  1. Structural differences between industrial carbon blacks indicated by uncorrected x-ray diffraction patterns

    Energy Technology Data Exchange (ETDEWEB)

    Shvartsman, A.S.; Rutman, A.M.; Ermolaev, V.A.; Fialkov, A.S.

    1986-08-20

    The authors have compared the ordering in specimens of commercial carbon blacks on various parameters; the values are repeated to the proportions of the atoms scattering coherently in a given direction, the sizes of the CSR, and the homogeneity int he components as regards size, defectiveness, and ordering. One does not use integral intensities in these ratios (one measures the peak heights, not the areas), so defects, which merely broaden the lines without altering the intensity distribution between lines and background, are also incorporated with these parameters. The authors found that the size parameters (interlayer distance d/sub 002/ and dimensions of the CSR L/sub ..cap alpha../ and L/sub c/) are insufficient to reveal structural differences between commercial blacks. One can compare the structures on additional diffraction characteristics that evaluate the redistribution of the scattered intensity between the lines and the diffuse background. There is a correlation between the order estimated in this way and the elemental composition, and in particular the ratio between the oxygen and hydrogen concentrations. The various production conditions lead to differing distributions of the noncarbon atoms, which are related to differences in crystallochemical role. The noncarbon redistribution on modification alters the properties considerably. The structure change on modification may be due to the reagent interacting with the defects (including noncarbon atoms). One of the possible mechanisms is intercalation.

  2. Continental Scale Antarctic deposition of sulphur and black carbon from anthropogenic and volcanic sources

    Directory of Open Access Journals (Sweden)

    H.-F. Graf

    2009-12-01

    Full Text Available While Antarctica is often described as a pristine environment, the potential threats from local pollution sources including tourist ships and emissions associated with scientific activities have recently been raised. However, to date there has been no systematic attempt to model the impacts of such pollutants at the continental scale. Indeed, until very recently there was not even a sulphur emission budget available for Antarctica. Here we present the first comprehensive study of atmospheric pollution in Antarctica using a limited area chemistry climate model, and a monthly emissions inventory for sulphur from maintenance of research stations, ground and air traffic, shipping and the active volcano Mt. Erebus. We find that ship emissions, both sulphurous and black carbon, dominate anthropogenic pollution near the ground. These are likely to rise considerably if recent trends in tourism continue.

  3. SYNTHESIS AND CHARACTERIZATION OF FUNCTIONALIZED CARBON BLACK/POLY(VINYL ALCOHOL) HIGH REFRACTIVE INDEX NANOCOMPOSITES

    Institute of Scientific and Technical Information of China (English)

    Peng-fei Xue; Ji-bin Wang; Yu-bin Bao; Qiu-ying Li; Chi-fei Wu

    2012-01-01

    Carbon black (CB)/polymer composites with high refractive index (RI) were fabricated from poly(vinyl alcohol) (PVA) and covalently functionalized nano-CB (PVA-es-CB) by simple esterification reaction.Transmission electron microscopy showed that uniform aggregates of PVA-es-CB nanoparticles with a size smaller than 100 nm formed in the nanocomposite films.Ellipsometric measurements indicated that the PVA-es-CB/PVA composite films had a RI in the range 1.520-1.598 linearly increased with the PVA-es-CB volume content.Theoretical equation based on Lorentz-Lorenz theory provided reasonably close estimation of the refractive indices to the experimentally observed values.The hybrid films also revealed relatively good surface planarity,thermal stability and optical transparency.

  4. Review of positron annihilation spectroscopy studies of rubber with carbon black filler

    International Nuclear Information System (INIS)

    Positron annihilation lifetime spectra have been measured for rubber polymers with carbon black (CB) fillers as a function of temperature, sulfur concentration, type of CB fillers and type of polymer. The purpose of the study is to understand how the CB fillers and other components of the vulcanized composite affect the positron lifetime in polymer materials. The polymer samples to be studied include natural rubber (NR) with different sulfur concentration, Sn-SSBR either unloaded or loaded with CB N115 or N762, both vulcanized and unvulcanized Duradene 706 samples. The results show that CB fillers have no effect on the ortho-positronium lifetime but decrease the intensity of ortho-positronium; and the decrease in intensity depends on the type of CB. On the other hand both ortho-positronium lifetime and intensity decrease as a function of sulfur concentration

  5. Improved dynamic properties of natural rubber filled with irradiation-modified carbon black

    Science.gov (United States)

    Wu, Yongpeng; Wen, Shipeng; Shen, Jing; Jiang, Jian; Hu, Shui; Zhang, Liqun; Liu, Li

    2015-06-01

    In this work, carbon black particles (CBs) were modified by high-energy electron beam (EB) irradiation at different doses. The influence of EB irradiation on the surface and particle size of CBs was investigated. Then, the CBs were compounded with natural rubber (NR), and the mechanical properties and dynamic properties of CBs/NR composite were further researched. The results showed that the irradiated CBs had more oxygen-containing groups and smaller particle sizes than original CBs. After irradiation, the content of bound rubber around the irradiated CBs increased, and the mechanical properties of CBs/NR composite were improved. Most importantly, NR filled with irradiated CBs has lower abrasion, higher wet skid resistance, and lower rolling resistance than NR filled with untreated CBs.

  6. Research on properties of carbon black/polypropylene composites by dynamic injection molding

    Science.gov (United States)

    Wu, Ming-Chun; He, Guang-Jian; Huang, Zhao-Xia; Zhou, Li-Ying; He, He-Zhi

    2016-03-01

    Polymer composites filled with conductive carbon black (CB) are gaining popularity for electromagnetic shielding applications. Dynamic injection molding method was adopted to study the influences of vibration force field on electrical properties of polypropylene/CB composites. The results showed that the percolation phenomenon of conductivity of composites occurred at 15wt% and the calculated SE was positive correlated with the variation trend of conductivity. The calculated SE of composite was more than 30dB at a CB concentration of 30wt%, which could obtain good shielding effects. The result could offer optimum vibration parameters for producing electromagnetic shielding composites by respectively changing the amplitudes and frequencies of the vibration force field.

  7. The influence of carbon black on curing kinetics and thermal aging of acrylonitrile–butadiene rubber

    Directory of Open Access Journals (Sweden)

    Jaroslava Budinski-Simendić

    2009-10-01

    Full Text Available Elastomers based on a copolymer of butadiene and acrylonitrile (NBR have excellent oil resistance but are very sensitive for degradation at very high temperatures. The aim of this applicative contribution was to determine the effect of high abrasion furnace carbon black with primary particle size 46 nm on aging properties of elastomeric materials based on NBR as network precursor. The curing kinetics was determined using the rheometer with an oscillating disk, in which the network formation process is registered by the torque variation during time. The vulcanizates were obtained in a hydraulic press at 150 °C. The mechanical properties of elastomeric composites were determined before and after thermal aging in an air circulating oven. The reinforcing effect of the filler particles was assessed according to mechanical properties before and after aging.

  8. Synthesis of SiC Powders by Carbothermal Reduction of Enriched Brown Sepiolite with Carbon Black

    Science.gov (United States)

    Bağci, Cengiz; Arik, Halil

    2013-04-01

    Ultrafine β-silicon carbide (β-SiC) powders were successfully synthesized by carbothermal-reduction reaction (CRR) of sepiolite. Sepiolite of Turkish deposits as a silica (SiO2) precursor and carbon black as a reducing agent were mixed with constant C/SiO2 molar ratio of 4. Mixed powders were subjected to CRR at temperatures of 1450, 1500, and 1550 °C for 1 h in an atmosphere-controlled tube furnace under argon flow of 5 cm3/min. The precursor and resultant powder products were characterized by XRD, SEM, and EDX. Phase transformation was observed in powder products after CRR as a function of the reaction temperature. The results show that the cotton-like nature of sepiolite makes it an effective mineral precursor for synthesis of SiC powders, and that SiC transformation was optimized at 1550 °C with a particle size of approximately 200 nm.

  9. 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.

  10. Variation of Radiative Properties During Black Carbon Aging. Theoretical and Experimental Intercomparison

    Energy Technology Data Exchange (ETDEWEB)

    He, Cenlin [Univ. of California, Los Angeles, CA (United States); Liou, K. N. [Univ. of California, Los Angeles, CA (United States); Takano, Y. [Univ. of California, Los Angeles, CA (United States); Zhang, Renyi [Texas A & M Univ., College Station, TX (United States); Zamora, Misty L. [Texas A & M Univ., College Station, TX (United States); Yang, Ping [Texas A & M Univ., College Station, TX (United States); Li, Qinbin [Univ. of California, Los Angeles, CA (United States); Leung, Lai-Yung R. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2015-10-28

    A theoretical model is developed to account for black carbon (BC) aging during three major evolution stages, i.e., freshly emitted aggregates, coated particles by soluble materials, and those after further hygroscopic growth. The geometric-optics surface-wave approach is employed to compute BC single-scattering properties at each stage, which are compared with laboratory measurements. Theoretical predictions using input parameters determined from experiments are consistent with measurements in extinction and scattering cross sections for coated BC (within 30 20%) and absorption enhancement from coating (within 15%). The calculated scattering cross sections of fresh BC aggregates are larger than those experimentally measured, because of uncertainties in measurements and calculations. We apply the aging model to compute BC direct radiative forcing (DRF) over the LA Basin using the CalNex 2010 field measurements. Our results demonstrate that accounting for the interactive radiative properties during BC aging is essential in obtaining reliable DRF estimates within a regional context.

  11. 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.

  12. Impact of California's Air Pollution Laws on Black Carbon and their Implications for Direct Radiative Forcing

    Science.gov (United States)

    Bahadur, R.; Feng, Y.; Russell, L. M.; Ramanathan, V.

    2010-12-01

    We examine the temporal and the spatial trends in the concentrations of black carbon (BC) - recorded by the IMPROVE monitoring network for the past 20 years - in California. Annual average BC concentrations in California have decreased by about 50% from 0.46 μg m-3 in 1989 to 0.24 μgm-3 in 2008 compared to a corresponding reductions in diesel BC emissions (also about 50%) from a peak of 0.013 Tg Yr-1 in 1990 to 0.006 Tg Yr-1 by 2008. We attribute the observed negative trends to the deployment of diesel particulate filters. Our conclusion that the reduction in diesel emissions is the primary cause of the observed BC reduction is also substantiated by a significant decrease in the ratio of BC to non-BC aerosols. The absorption efficiency of aerosols at visible wavelengths - determined from the observed scattering coefficient and the observed BC - also decreased by about 50% leading to a model-inferred negative direct radiative forcing (a cooling effect) of -1.4 Wm-2 (±60%) over California. Figure 1 (a) Annual means of measured Black Carbon (left axis) and BC fossil fuel emissions (right axis) in California from 1985 to 2008. Error bars correspond to standard deviation between measurements at each station. Dashed lines indicate a linear fit. Aerosol measurements from the IMPROVE network, emission inventories from (1) CARB, (2) [Ito and Penner, 2005] (b) Annual means of BC measured in Southern (South of 35 N), Northern (North of 38 N), and Central California (c) Annual means of measured Sulfate, Nitrate, and OC from IMPROVE network.

  13. Black carbon emissions from Russian diesel sources: case study of Murmansk

    Directory of Open Access Journals (Sweden)

    M. Evans

    2015-02-01

    Full Text Available Black carbon (BC is a potent pollutant because of its effects on climate change, ecosystems and human health. Black carbon has a particularly pronounced impact as a climate forcer in the Arctic because of its effect on snow albedo and cloud formation. We have estimated BC emissions from diesel sources in Murmansk Region and Murmansk City, the largest city in the world above the Arctic Circle. In this study we developed a detailed inventory of diesel sources including on-road vehicles, off-road transport (mining, locomotives, construction and agriculture, fishing and diesel generators. For on-road transport, we conducted several surveys to understand the vehicle fleet and driving patterns, and, for all sources, we also relied on publicly available local data sets and analysis. We calculated that BC emission in Murmansk Region were 0.40 Gg in 2012. The mining industry is the largest source of BC emissions in the region, emitting 70% of all BC emissions because of its large diesel consumption and absence of emissions controls. On-road vehicles are the second largest source emitting about 12% of emissions. Old heavy duty trucks are the major source of emissions. Emission controls on new vehicles limit total emissions from on-road transportation. Vehicle traffic and fleet surveys show that many of the older cars on the registry are lightly or never used. We also estimated that total BC emissions from diesel sources in Russia were 56.7 Gg in 2010, and on-road transport contributed 55% of diesel BC emissions. Agricultural machinery is also a significant source Russia-wide, in part because of the lack of controls on off-road vehicles.

  14. Mechanical and tribological properties of acrylonitrile–butadiene rubber filled with graphite and carbon black

    International Nuclear Information System (INIS)

    Highlights: ► Graphite/carbon black/rubber micro- and nano-composites were prepared. ► Nanocomposites showed better mechanical properties and wear resistance. ► The effect of load and sliding speed on friction and wear is significant. ► Graphite lubricant film can reduce friction coefficient and wear rate. -- Abstract: In this work, acrylonitrile–butadiene rubber (NBR)/expanded graphite (EG)/carbon black (CB) micro- and nanocomposites were prepared by two different methods, and the resulting mechanical and tribological properties were compared with those of NBR/CB composites. Meanwhile, the effects of graphite dispersion and loading content, as well as the applied load and sliding velocity on the tribological behavior of the above composites under dry friction condition were also evaluated. The worn surfaces were analyzed by scanning electron microscopy (SEM) to disclose wear mechanism. As expected, the better the dispersion of graphite, the more remarkable enhancement on tensile and dynamic mechanical properties, and the greater reduction in the coefficient of friction (COF) and specific wear rate (Ws). It was found that a small amount of EG could effectively decrease COF and Ws of NBR/CB composites because of the formation of graphite lubricant films. The COF and Ws of NBR/CB/EG composites show a decreasing trend with a rise in applied load and sliding velocity. NBR/CB/EG nanocomposite always shows a stable wearing process with relatively low COF and Ws. It is thought that well-dispersed graphite nano-sheets were beneficial to the formation of a fine and durable lubricant film.

  15. Black carbon emissions from Russian diesel sources: case study of Murmansk

    Science.gov (United States)

    Evans, M.; Kholod, N.; Malyshev, V.; Tretyakova, S.; Gusev, E.; Yu, S.; Barinov, A.

    2015-07-01

    Black carbon (BC) is a potent pollutant because of its effects on climate change, ecosystems and human health. Black carbon has a particularly pronounced impact as a climate forcer in the Arctic because of its effect on snow albedo and cloud formation. We have estimated BC emissions from diesel sources in the Murmansk Region and Murmansk City, the largest city in the world above the Arctic Circle. In this study we developed a detailed inventory of diesel sources including on-road vehicles, off-road transport (mining, locomotives, construction and agriculture), ships and diesel generators. For on-road transport, we conducted several surveys to understand the vehicle fleet and driving patterns, and, for all sources, we also relied on publicly available local data sets and analysis. We calculated that BC emissions in the Murmansk Region were 0.40 Gg in 2012. The mining industry is the largest source of BC emissions in the region, emitting 69 % of all BC emissions because of its large diesel consumption and absence of emissions controls. On-road vehicles are the second largest source, emitting about 13 % of emissions. Old heavy duty trucks are the major source of emissions. Emission controls on new vehicles limit total emissions from on-road transportation. Vehicle traffic and fleet surveys show that many of the older cars on the registry are lightly or never used. We also estimated that total BC emissions from diesel sources in Russia were 50.8 Gg in 2010, and on-road transport contributed 49 % of diesel BC emissions. Agricultural machinery is also a significant source Russia-wide, in part because of the lack of controls on off-road vehicles.

  16. Black Carbon Emissions from In-use Ships: Results from CalNex 2010

    Science.gov (United States)

    Buffaloe, Gina Marise

    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 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 EF BC values from these two categories are compared to previous observations from the Texas Air Quality Study (TexAQS) in 2006, in which the ships encountered were predominately operating high sulphur fuels. There is some indication that the EFBC values for SSD vessels during CalNex were lower than during TexAQS, although ship-to-ship variability in these data sets makes it difficult to draw firm conclusions about the influence of fuel quality on EFBC.

  17. Climate effects of reducing black carbon emissions: Dependence on location of emission

    Science.gov (United States)

    Fuglestvedt, J.; Berntsen, T.; Myhre, G.; Rive, N. A.; Rypdal, K.; Gerland, S.; Pedersen, C.; Strøm, J.

    2006-12-01

    The role played by emissions of black carbon aerosols (BC) on the Earth's climate is diverse and the overall effect is still quite uncertain: Black carbon not only absorbs sunlight (direct effect), but it also has a semi- direct effect on clouds, and when deposited on snow and ice it changes the reflectivity (albedo) of the ground surface. These mechanisms generally have a warming effect on the climate. This poster presents a Norwegian project that focus on the net effect of current BC emissions and future possible reductions in emissions of BC aerosols, taking into account scientific, economic, and political perspectives on the inclusion of BC in climate policies. Thus, the scope of the project is interdisciplinary and includes observations in the Arctic, model simulations of dispersion of BC aerosols, its radiative forcing and climate effects. Some initial results from measurements of BC content in snow from the Norwegian Arctic and corresponding measurements for surface reflectance will be presented. The radiative forcing of BC emissions from different geographical regions differs due to differences in the removal processes (i.e. the lifetime) and the amount of solar radiation available for absorption (depends on latitude, clouds, and surface albedo). The atmospheric burdens and RF (of the direct effect) of regional BC emissions from fossil fuel sources have been calculated by the global chemical transport model Oslo-CTM2 and a radiative transfer model, and first results of time-integrated RF per unit of emission (equivalent to absolute GWPs) are presented. Future plans including i) analysis of cost effective emission reduction strategies, taking into account regional differences the forcing efficiencies, but also cost estimates for BC reductions in the different regions, and ii) an evaluation of the climate effects of the emission reductions through model simulations, including climatic, economic and political perspectives exploring obstacles and opportunities

  18. Origin and radiative forcing of black carbon transported to the Himalayas and Tibetan Plateau

    Directory of Open Access Journals (Sweden)

    M. Kopacz

    2011-03-01

    Full Text Available The remote and high elevation regions of central Asia are influenced by black carbon (BC emissions from a variety of locations. BC deposition contributes to melting of glaciers and questions exist, of both scientific and policy interest, as to the origin of the BC reaching the glaciers. We use the adjoint of the GEOS-Chem model to identify the location from which BC arriving at a variety of locations in the Himalayas and Tibetan Plateau originates. We then calculate its direct and snow-albedo radiative forcing. We analyze the seasonal variation in the origin of BC using an adjoint sensitivity analysis, which provides a detailed map of the location of emissions that directly contribute to black carbon concentrations at receptor locations. We find that emissions from northern India and central China contribute the majority of BC to the Himalayas, although the precise location varies with season. The Tibetan Plateau receives most BC from western and central China, as well as from India, Nepal, the Middle East, Pakistan and other countries. The magnitude of contribution from each region varies with season and receptor location. We find that sources as varied as African biomass burning and Middle Eastern fossil fuel combustion can significantly contribute to the BC reaching the Himalayas and Tibetan Plateau. We compute radiative forcing in the snow-covered regions and find the forcing due to the BC induced snow-albedo effect to vary from 5–15 W m−2 within the region, an order of magnitude larger than radiative forcing due to the direct effect, and with significant seasonal variation in the northern Tibetan Plateau. Radiative forcing from reduced snow albedo likely accelerates glacier melting. Our analysis may help inform mitigation efforts to slow the rate of glacial melt by identifying regions that make the largest contributions to BC deposition in the Himalayas and Tibetan Plateau.

  19. GHG and black carbon emission inventories from Mezquital Valley: The main energy provider for Mexico Megacity.

    Science.gov (United States)

    Montelongo-Reyes, M M; Otazo-Sánchez, E M; Romo-Gómez, C; Gordillo-Martínez, A J; Galindo-Castillo, E

    2015-09-15

    The greenhouse gases and black carbon emission inventory from IPCC key category Energy was accomplished for the Mezquital Valley, one of the most polluted regions in Mexico, as the Mexico City wastewater have been continuously used in agricultural irrigation for more than a hundred years. In addition, thermoelectric, refinery, cement and chemistry industries are concentrated in the southern part of the valley, near Mexico City. Several studies have reported air, soil, and water pollution data and its main sources for the region. Paradoxically, these sources contaminate the valley, but boosted its economic development. Nevertheless, no research has been done concerning GHG emissions, or climate change assessment. This paper reports inventories performed by the 1996 IPCC methodology for the baseline year 2005. Fuel consumption data were derived from priority sectors such as electricity generation, refineries, manufacturing & cement industries, transportation, and residential use. The total CO2 emission result was 13,894.9 Gg, which constituted three-quarters of Hidalgo statewide energy category. The principal CO2 sources were energy transformation (69%) and manufacturing (19%). Total black carbon emissions were estimated by a bottom-up method at 0.66 Gg. The principal contributor was on-road transportation (37%), followed by firewood residential consumption (26%) and cocked brick manufactures (22%). Non-CO2 gas emissions were also significant, particularly SO2 (255.9 Gg), which accounts for 80% of the whole Hidalgo State emissions. Results demonstrated the negative environmental impact on Mezquital Valley, caused by its role as a Megacity secondary fuel and electricity provider, as well as by the presence of several cement industries. PMID:25981943

  20. Comparisons of eccentric binary black hole simulations with post-Newtonian models

    CERN Document Server

    Hinder, Ian; Laguna, Pablo; Shoemaker, Deirdre

    2008-01-01

    We present the first comparison between numerical relativity (NR) simulations of an eccentric binary black hole system with corresponding post-Newtonian (PN) results. We evolve an equal-mass, non-spinning configuration with an initial eccentricity e = 0.1 for 21 gravitational wave cycles before merger, and find agreement in the gravitational wave phase with an adiabatic eccentric PN model with 2 PN radiation reaction within 0.1 radians for 8 cycles. The NR and PN phase difference grows to 0.8 radians by 5 cycles before merger. We find that these results can be obtained by expanding the eccentric PN expressions in terms of the frequency-related variable x = (omega M)^{2/3} with M the total mass of the binary. When using instead the mean motion n = 2 pi/P, where P is the orbital period, the comparison leads to significant disagreements with NR. We also introduce a new method for matching NR and PN waveforms, based on extrapolating parameters determined from least squares fitting as t -> -infinity.

  1. Anatomy of methane-derived carbonate concretions and associated microbial communities in Black Sea sediments

    Science.gov (United States)

    Reitner, J.; Peckmann, J.; Reimer, A.; Schumann, G.; Blumenberg, M.; Thiel, V.

    2003-04-01

    Methane seeps on the northwestern shelf and slope of the Black Sea were investigated during the GHOSTDABS expedition with RV "Professor Logachev" and the research submersible "Jago" in July/August 2001. Seep areas close to the Dniepr Canyon are sites of intense carbonate formation. In anoxic waters, at depths between 200 and 400m, we found different modes of carbonate precipitation, such as cavernous chimney-like buildups projecting up to 4 m into the anoxic water column (Michaelis et al., Science 297, 813-815) and, lenticular concretions abundantly forming within the sediment. Isotope analyses of the concretionary Mg-calcite yielded δ13C values as low as -31 ppm PDB, suggesting that the carbonate predominantly derives from the anaerobic oxidation of methane (AOM). The concretions are surrounded by grey, pink, or orange colored microbial mats. These mats apparently mediate the formation of ca. 100 μm sized aggregates of fibrous calcite that fuse together to form the concretions. Surrounding sediment and concretional carbonates are clearly distinguishable by a strong UV-epifluorescence induced by large amounts of organic matter enclosed in the calcite aggregates. The conspicious angular arrangement of the crystallites appears to be controlled by the spatial organization of extracellular polymeric substances (EPS). Fluorescence in situ hybridization, TEM, and field emission electron microscopy reveal that the microbial mats harbour numerous types of microorganisms. Prominent members are large colonies of sulfate reducing bacteria (DSS 658 probe, Desulfosarcina group), surrounded by sheeted, rod-shaped archaea (ANME-1 probe, Methanosaeta group) and further ones. Three different types of AOM consortia are distinguishable. The metabolism of sulfate reducing bacteria apparently accounts for the observed, significant enrichment of the concretions in framboidal Fe-sulfides. In organic extracts from mat samples and concretional carbonate, we found distinctive, isoprene

  2. Adsorption removal of acid black 1 from aqueous solution using ordered mesoporous carbon

    Energy Technology Data Exchange (ETDEWEB)

    Peng, Xiaoming, E-mail: pengxiaoming70@126.com [School of Civil Engineering, Southeast University, Nanjing 210096 (China); Hu, Xijun [Department of Chemical and Biomolecular Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong,China (China); Fu, Dafang, E-mail: fdf@seu.edu.cn [School of Civil Engineering, Southeast University, Nanjing 210096 (China); Lam, Frank L.Y. [Department of Chemical and Biomolecular Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong,China (China)

    2014-03-01

    Highlights: • Ordered mesoporous carbon was prepared using template. • Ordered mesoporous carbon was introduced of N-containing group by Chemical vapor deposition method. • Modified CMK-3 have better adsorption capacity and efficiency than virgin CMK-3 to removal AB1 dye. - Abstract: A novel ordered mesoporous carbon CMK-3 and synthetic CMK-3 containing nitrogen functional groups by ammonia-treated were applied for acid black 1(AB1) dye adsorption. The ammonia-treated(chemical vapor deposition method) before and after CMK-3 were characterized by using a Micrometitics ASAP 2020 surface area analyzer (ASAP 2020), Fourier transform infrared spectrophotometer (FT–IR), X-ray Photoelectron Spectroscopy (XPS), transmission electron microscopy (TEM), scanning electron microscope (SEM) and equilibrium studies. This result indicates that the prepared CMK-3 and modified CMK-3 were almost uniform, as rope-like domains and their uniform mesopore with diameter centered at 3.2 nm and 3.7 nm. The FIIR analysis depicted that the presence of a variety of new basic functional groups on the modified CMK-3 surface. Several effect variables of pH, dye concentration and temperature were studied. The pseudo second-order model showed the fitter well to agree with the kinetic data. The experimental data were analyzed by the Langmuir and Freundlich models, with the latter found to closely the isotherm model. The adsorption kinetics was found to follow the pseudo-second-order kinetic model. The results show that CMK-3 using ammonia gas modified by thermal treatment system is an effective method to improvement capacity as it shows the highest adsorption capacity of AB1, as compared to the unmodified CMK-3 and the bamboo-based carbon, respectively.

  3. Quantifying immediate radiative forcing by black carbon and organic matter with the Specific Forcing Pulse

    Directory of Open Access Journals (Sweden)

    T. C. Bond

    2011-02-01

    Full Text Available Climatic effects of short-lived climate forcers (SLCFs differ from those of long-lived greenhouse gases, because they occur rapidly after emission and because they depend upon the region of emission. The distinctive temporal and spatial nature of these impacts is not captured by measures that rely on global averages or long time integrations. Here, we propose a simple measure, the Specific Forcing Pulse (SFP, to quantify climate warming or cooling by these pollutants, where we define "immediate" as occurring primarily within the first year after emission. SFP is the amount of energy added to or removed from a receptor region in the Earth-atmosphere system by a chemical species, per mass of emission in a source region. We limit the application of SFP to species that remain in the atmosphere for less than one year. Metrics used in policy discussions, such as total forcing or global warming potential, are easily derived from SFP. However, SFP conveys purely physical information without incurring the policy implications of choosing a time horizon for the global warming potential.

    Using one model (Community Atmosphere Model, or CAM, we calculate values of SFP for black carbon (BC and organic matter (OM emitted from 23 source-region combinations. Global SFP for both atmosphere and cryosphere impacts is divided among receptor latitudes. SFP is usually greater for open-burning emissions than for energy-related (fossil-fuel and biofuel emissions because of the timing of emission. Global SFP for BC varies by about 45% for energy-related emissions from different regions. This variation would be larger except for compensating effects. When emitted aerosol has larger cryosphere forcing, it often has lower atmosphere forcing because of less deep convection and a shorter atmospheric lifetime.

    A single model result is insufficient to capture uncertainty. We develop a best estimate and uncertainties for SFP by combining forcing results from

  4. Adsorption removal of acid black 1 from aqueous solution using ordered mesoporous carbon

    Science.gov (United States)

    Peng, Xiaoming; Hu, Xijun; Fu, Dafang; Lam, Frank L. Y.

    2014-03-01

    A novel ordered mesoporous carbon CMK-3 and synthetic CMK-3 containing nitrogen functional groups by ammonia-treated were applied for acid black 1(AB1) dye adsorption. The ammonia-treated(chemical vapor deposition method) before and after CMK-3 were characterized by using a Micrometitics ASAP 2020 surface area analyzer (ASAP 2020), Fourier transform infrared spectrophotometer (FT-IR), X-ray Photoelectron Spectroscopy (XPS), transmission electron microscopy (TEM), scanning electron microscope (SEM) and equilibrium studies. This result indicates that the prepared CMK-3 and modified CMK-3 were almost uniform, as rope-like domains and their uniform mesopore with diameter centered at 3.2 nm and 3.7 nm. The FIIR analysis depicted that the presence of a variety of new basic functional groups on the modified CMK-3 surface. Several effect variables of pH, dye concentration and temperature were studied. The pseudo second-order model showed the fitter well to agree with the kinetic data. The experimental data were analyzed by the Langmuir and Freundlich models, with the latter found to closely the isotherm model. The adsorption kinetics was found to follow the pseudo-second-order kinetic model. The results show that CMK-3 using ammonia gas modified by thermal treatment system is an effective method to improvement capacity as it shows the highest adsorption capacity of AB1, as compared to the unmodified CMK-3 and the bamboo-based carbon, respectively.

  5. Resolution of Adsorption and Partition Components of Organic Compounds on Black Carbons.

    Science.gov (United States)

    Chiou, Cary T; Cheng, Jianzhong; Hung, Wei-Nung; Chen, Baoliang; Lin, Tsair-Fuh

    2015-08-01

    Black carbons (BCs) may sequester non-ionic organic compounds by adsorption and/or partition to varying extents. Up to now, no experimental method has been developed to accurately resolve the combined adsorption and partition capacity of a compound on a BC. In this study, a unique "adsorptive displacement method" is introduced to reliably resolve the adsorption and partition components for a solute-BC system. It estimates the solute adsorption on a BC by the use of an adsorptive displacer to displace the adsorbed target solute into the solution phase. The method is validated by tests with uses of activated carbon as the model carbonaceous adsorbent, soil organic matter as the model carbonaceous partition phase, o-xylene and 1,2,3-trichlorobenzene as the reference solutes, and p-nitrophenol as the adsorptive displacer. Thereafter, the adsorption-partition resolution was completed for the two solutes on selected model BCs: four biochars and two National Institute of Standards and Technology (NIST) standard soots (SRM-2975 and SRM-1650b). The adsorption and partition components resolved for selected solutes with given BCs and their dependences upon solute properties enable one to cross-check the sorption data of other solutes on the same BCs. The resolved components also provide a theoretical basis for exploring the potential modes and extents of different solute uptakes by given BCs in natural systems. PMID:26114972

  6. Abiotic reduction of trifluralin and pendimethalin by sulfides in black-carbon-amended coastal sediments.

    Science.gov (United States)

    Gong, Wenwen; Liu, Xinhui; Xia, Shuhua; Liang, Baocui; Zhang, Wei

    2016-06-01

    Dinitroaniline herbicides such as trifluralin and pendimethalin are persistent bioaccumulative toxins to aquatic organisms. Thus, in-situ remediation of contaminated sediments is desired. This study investigated whether black carbons (BCs), including apple wood charcoal (BC1), rice straw biochar (BC2), and activated carbon (BC3), could facilitate abiotic reduction of trifluralin and pendimethalin by sulfides of environmentally-relevant concentrations in anoxic coastal sediments. The reduction rates of trifluralin and pendimethalin increased substantially with increasing BC dosages in the sediments. This enhancing effect was dependent on BC type with the greatest for BC3 followed by BC1 and BC2, which well correlated with their specific surface area. The pseudo-first order reduction rate constants (kobs) for BC3-amended sediment (2%) were 13- and 14 times the rate constants in the BC-free sediment. The reduction rates increased with increasing temperature from 8 to 25°C in the BC-amended sediment, following the Arrhenius relationship. Finally, through molecular modeling by density functional theory and reaction species identification from mass spectra, molecular pathways of trifluralin and pendimethalin reduction were elucidated. In contrary to the separate sequential reduction of each nitro group to amine group, both nitro groups, first reduced to nitroso, then eventually to amine groups. PMID:26905610

  7. Monitoring of black carbon concentration at an inland rural area including fixed sources in Korea.

    Science.gov (United States)

    Lee, Jeonghoon; Yun, Jeongseok; Kim, Kyeong Jun

    2016-01-01

    We monitored black carbon (BC) concentration for 6months to understand the characteristics of atmospheric aerosols of an inland rural area in Korea. A multi-angle absorption photometer was used to continuously monitor the BC concentration, which was compared with elemental carbon (EC) concentration measured by an OC/EC Analyzer. For the atmospheric aerosols less than 10μm, size distributions were measured using both an optical particle counter and a scanning mobility particle sizer. The diurnal variations for BC concentration show that the average BC concentration was 1.43μgm(-3) and exhibited peaks in the morning rush hours. However, the BC concentration measured at night from 20:00 to 08:00 was higher than that measured during the day. The reason why the BC concentration at night was higher would be partly due to the regional characteristics influenced by the combination of local fixed sources and traffic condition. It is suggested that the traffic and transporting of pollutants from the west influenced the increase in the BC concentration at inland rural area including fixed sources. PMID:25900115

  8. Light Fraction Carbon and Water-Stable Aggregates in Black Soils

    Institute of Scientific and Technical Information of China (English)

    SHI Yi; CHEN Xin; SHEN Shan-Min

    2007-01-01

    The distribution of light fraction carbon (LF-C) in the various size classes of aggregates and its relationship to waterstable aggregates as well as the influence of cultivation on the organic components in virgin and cultivated black soils were studied by wet sieving and density separation methods. The total organic carbon (TOC) and LF-C were significantly higher (P ≤ 0.05) in the virgin soils than in the cultivated soils. The LF-C in aggregates of different size classes varied from 0.9 to 2.5 g kg-1 in the cultivated soils and from 2.5 to 7.1 g kg-1 in the virgin soils, whereas the ratio of LF-C to TOC varied from 1.9% to 7.3% and from 5.0% to 12.2%, respectively. After being incubated under constant temperature and controlled humidity for three months, the contribution of LF-C to TOC sharply decreased to an amount (1.7%-8.5%)close to the level in soils that had been cultivated for 20 to 25 years (1.3%-8.8%). As a result, the larger water-stable macro-aggregates (especially > 1 mm) decreased sharply, indicating that the LF-C pool in virgin soils declined quickly after cultivation, which reduced the water stability of soil aggregates.

  9. Dopamine sensor based on a hybrid material composed of cuprous oxide hollow microspheres and carbon black

    International Nuclear Information System (INIS)

    We report on a novel electrochemical dopamine (DA) sensor based on a glassy carbon electrode (GCE) modified with a hybrid material composed of Cu(I) oxide hollow microspheres and carbon black. The hybrid material was synthesized in a mixed solvent composed of water and the deep eutectic solvent choline chloride/urea, and by in-situ reduction of Cu(II) by ascorbic acid. The surface morphology and structure of the materials were characterized by scanning electron microscopy, transmission electron microscopy and X-ray diffraction. Cyclic voltammetry and chronoamperometry were used to evaluate the electrocatalytic properties of the modified GCE toward DA oxidation in phosphate buffer solution of pH 5.7. The sensor displays a higher electrocatalytic activity toward DA oxidation compared to other modified electrodes. At a working potential of 0.25 V (vs. SCE), the sensor exhibits a rapid response (<3 s) and a wide linear range from 9.9 × 10−8 to 7.08 × 10−4 mol L−1. The detection limit is as low as 3.96 × 10−8 mol L−1 (S/N = 3). In addition to its high sensitivity, the sensor displays good reproducibility, long-term stability and fair selectivity. (author)

  10. Comparative Proteomics and Pulmonary Toxicity of Instilled Single Walled Carbon Nanotubes, Crocidolite Asbestos and Ultrafine Carbon Black in Mice

    Energy Technology Data Exchange (ETDEWEB)

    Teeguarden, Justin G.; Webb-Robertson, Bobbie-Jo M.; Waters, Katrina M.; Murray, Ashley; Kisin, Elena; Varnum, Susan M.; Jacobs, Jon M.; Pounds, Joel G.; Zangar, Richard C.; Shvedova, Anna

    2011-03-01

    Reflecting their exceptional potential to advance a range of biomedical, aeronautic, and other industrial products, carbon nanotube (CNT) production, and the potential for human exposure to aerosolized CNT’s, is increasing. CNT’s have toxicologically significant structural and chemical similarities to asbestos, and have repeatedly been shown to cause pulmonary inflammation, granuloma formation and fibrosis after inhalation/instillation/aspiration exposure in rodents, a pattern of effects similar to those observed following exposure to asbestos. To determine the degree to which responses to SWCNT and asbestos are similar or different, the pulmonary response of C57BL/6 mice to repeated exposure to SWCNT, crocidolite asbestos and ultrafine carbon black (UFCB) were compared using high-throughput global HPLC-FTICR-MS proteomics, histopathology and BAL cytokine analyses. Mice were exposed to material suspensions (40 μg/mouse) twice a week, for 3 weeks by pharyngeal aspiration. Histologically, the incidence and severity of inflammatory and fibrotic responses were greatest in mice treated with SWCNT. SWCNT treatment affected the greatest changes in abundance of identified lung tissue proteins. The trend in number of proteins affected (SWCNT (376)>asbestos (231)>UFCB (184)) followed the potency of these materials in 3 biochemical assays of inflammation (cytokines). SWCNT treatment uniquely affected the abundance of 109 proteins, but these proteins largely represent cellular processes affected by asbestos treatment as well, further evidence of broad similarity in the tissue-level response to asbestos and SWCNT. Two high sensitivity markers of inflammation, one (S100a9) observed in humans exposed to asbestos, were found and may be promising biomarkers of human response to SWCNT exposure.

  11. Effect Of Black Carbon Radiative Heating On Cloud Microphysics Over Indo-Gangetic Basin

    Science.gov (United States)

    Ghosh, A.; Tripathi, S. N.

    2008-12-01

    Airborne black carbon (BC), the most significant particulate absorber of solar radiation in the atmosphere, is an important contributor to both global and regional-scale climate forcing (Tripathi et al., 2005). In context of cloud microphysics, freshly emitted pure BC particles are hydrophobic (i.e., bad cloud condensation nuclei (CCN)). However, exposure in the atmosphere may transform BC to a hydrophilic state if these particles are coated with additional materials, such as sulfate and organic carbon (OC). In a recent study, Conant et al. (2002) has examined the effect of radiative heating of BC on the critical supersaturation spectrum of internally mixed aerosols. Two main uncertainties introduced in this work are due to lack of knowledge of actual state of mixing and realistic distributions of different aerosol species. Indo-Gangetic Basin (IGB) in the northern India is one of the most polluted regions in the world. The cloud microphysical processes in IGB are very complex and it requires an in depth investigation for understanding of the aerosol-cloud interaction in the region (Tripathi, et al., 2007). In the present work, an attempt has been made to study the effect of radiative heating due to BC particles coated with hydrophilic materials on cloud microphysics over IGB. For this purpose, we have used (a) a two-layer radiative parameter model based on Mie theory (Toon and Ackerman, 1981) to calculate the particle (monodisperse) absorption cross section; (b) a three-dimensional (3D) radiative transfer model, the spherical harmonics discrete ordinate method (SHDOM) (Evans,1998), which assumes a tropical continental atmosphere, to simulate the 3D spectral actinic flux over the study region; and (c) Extended Köhler theory (Conant et al., 2002) to simulate the effect the BC radiative heating on cloud droplet activation. The solar wavelength spectrum used ranges from 0.2 to 5 micrometer. Following the in situ measurements and modeling studies on mixing state (Dey

  12. Assessment of the surface chemistry of carbon blacks by TGA-MS, XPS and inverse gas chromatography using statistical chemometric analysis

    International Nuclear Information System (INIS)

    Highlights: • Carbon blacks with lower specific surface area had basic character (electron donor) due to C=O and C-O groups. • Carbon blacks with higher specific surface area had acidic character (acceptor electron) due to OH groups. • Total surface energy and its dispersive component of carbon blacks increased by increasing their specific surface area. (table) - Abstract: Four carbon blacks with different specific surface areas and surface chemistries (C32, C71, C159 and C178) were analyzed by transmission electron microscopy (TEM) and nitrogen adsorption isotherms at 77 K. Their surface chemistries were analyzed by X-ray photoelectron spectroscopy (XPS), thermal gravimetric analysis coupled with mass spectrometry (TGA-MS) and inverse gas chromatography (IGC). The carbon blacks contained 2.7–5.8 wt% volatiles corresponding to -OH, C-O, C=O and COO groups. The surface chemistry parameters obtained with the different experimental techniques were inter-related by using chemometric statistical analysis tools. The application of this methodology showed that the carbon blacks with lower specific surface area (C32 and C71) had basic character (electron donor) mainly due to C=O and C-O groups, whereas the carbon black with the highest specific surface area (C178) showed acidic character (acceptor electron) due to its high content of OH groups. Moreover, the total surface energy and the dispersive component of the surface energy of the carbon blacks increased with the increase of their specific surface area. In general the specific interactions of the carbon blacks also increased with the increase of their specific surface area although C71 is exceptional due to higher oxygen content corresponding to C-O groups

  13. 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.

  14. Dielectric constants of binary mixtures of propylene carbonate with dimethyl carbonate and ethylene carbonate from molecular dynamics simulation: comparison between non-polarizable and polarizable force fields

    Science.gov (United States)

    Lee, Sanghun; Park, Sung Soo

    2013-01-01

    Using non-polarizable and polarizable molecular dynamics simulations, binary mixtures of propylene carbonate + dimethyl carbonate and propylene carbonate + ethylene carbonate with various compositions were investigated. The polarizable model produces more reasonable estimation of dielectric constants than the non-polarizable model; however, combining the electronic continuum model with the non-polarizable MD improves the comparison between the two models. Fair agreement was found between the results from these simulations and available experimental data. In addition, for a better understanding of the mixing behaviour, the excess dielectric constants over the entire composition were calculated. By comparison of the two mixtures in various mole fractions, distinctive mixing behaviours of propylene carbonate + dimethyl carbonate (poorly symmetric mixture) and propylene carbonate + ethylene carbonate (highly symmetric mixture) were observed.

  15. Variation of total organic carbon content along the stream Harsit, Eastern Black Sea Basin, Turkey.

    Science.gov (United States)

    Bayram, Adem; Önsoy, Hizir; Akinci, Görkem; Bulut, Volkan Numan

    2011-11-01

    The TOC in surface waters and wastewater is an important analytical parameter describing the total content of all organic substances containing carbon. In practice, the TOC originated from natural and anthropogenic sources, and even if it is not directly responsible for dangers on human health, its determination is important for any kind of water that is used by public. The aim of this study was to determine variation of total organic carbon (TOC) and total carbon (TC) content in the stream Harsit, which courses in Eastern Black Sea Region, Turkey. Sampling was fortnightly conducted in each of the four seasons between March 2009 and February 2010. A total of 230 water samples were collected from ten sampling stations along the main branch of the stream Harsit with 143 km of length. Obtained TOC values were evaluated and used to classify the water quality of stream Harsit, according to the Turkish Water Pollution Control Regulation (TWPCR). The annual average TOC content values for the stations were found between 2.33 and 6.97 mg/L. It was seen that the TOC content have increased along the streamcourse of Harsit until the fourth station, where reaches its maximum value. The TOC content, then, has decreased and the minimum value was observed in the eighth station. The results showed that, except in winter season, maximum TOC content observed in many of the water samples were above Class I water standard indicated in TWPCR, which classifies the water resources according to the different area of uses. It was also found that TOC has a small contribution to TC and the highest TOC content in stream waters were measured in Gumushane station where direct discharge of city wastewaters and solid waste dumping to the stream were observed. PMID:21229304

  16. Measurement of black carbon emissions from in-use diesel-electric passenger locomotives in California

    Science.gov (United States)

    Tang, Nicholas W.; Apte, Joshua S.; Martien, Philip T.; Kirchstetter, Thomas W.

    2015-08-01

    Black carbon (BC) emission factors were measured for a California commuter rail line fleet of diesel-electric passenger locomotives (Caltrain). The emission factors are based on BC and carbon dioxide (CO2) concentrations in the exhaust plumes of passing locomotives, which were measured from pedestrian overpasses using portable analyzers. Each of the 29 locomotives in the fleet was sampled on 4-20 separate occasions at different locations to characterize different driving modes. The average emission factor expressed as g BC emitted per kg diesel consumed was 0.87 ± 0.66 g kg-1 (±1 standard deviation, n = 362 samples). BC emission factors tended to be higher for accelerating locomotives traveling at higher speeds with engines in higher notch settings. Higher fuel-based BC emission factors (g kg-1) were measured for locomotives equipped with separate "head-end" power generators (SEP-HEPs), which power the passenger cars, while higher time-based emission factors (g h-1) were measured for locomotives without SEP-HEPs, whose engines are continuously operated at high speeds to provide both head-end and propulsion power. PM10 emission factors, estimated assuming a BC/PM10 emission ratio of 0.6 and a typical power output-to-fuel consumption ratio, were generally in line with the Environmental Protection Agency's locomotive exhaust emission standards. Per passenger mile, diesel-electric locomotives in this study emit only 20% of the CO2 emitted by typical gasoline-powered light-duty vehicles (i.e., cars). However, the reduction in carbon footprint (expressed in terms of CO2 equivalents) due to CO2 emissions avoidance from a passenger commuting by train rather than car is appreciably offset by the locomotive's higher BC emissions.

  17. Measurement of black carbon emissions from in-use diesel-electric passenger locomotives in California

    Science.gov (United States)

    Tang, N. W.; Kirchstetter, T.; Martien, P. T.; Apte, J.

    2015-12-01

    Black carbon (BC) emission factors were measured for a California commuter rail line fleet of diesel-electric passenger locomotives (Caltrain). The emission factors are based on BC and carbon dioxide (CO2) concentrations in the exhaust plumes of passing locomotives, which were measured from pedestrian overpasses using portable analyzers. Each of the 29 locomotives in the fleet was sampled on 4-20 separate occasions at different locations to characterize different driving modes. The average emission factor expressed as g BC emitted per kg diesel consumed was 0.87 ± 0.66 g kg-1 (±1 standard deviation, n = 362 samples). BC emission factors tended to be higher for accelerating locomotives traveling at higher speeds with engines in higher notch settings. Higher fuel-based BC emission factors (g kg-1) were measured for locomotives equipped with separate "head-end" power generators (SEP-HEPs), which power the passenger cars, while higher time-based emission factors (g h-1) were measured for locomotives without SEP-HEPs, whose engines are continuously operated at high speeds to provide both head-end and propulsion power. PM10 emission factors, estimated assuming a BC/PM10 emission ratio of 0.6 and a typical power output-to-fuel consumption ratio, were generally in line with the Environmental Protection Agency's locomotive exhaust emission standards. Per passenger mile, diesel-electric locomotives in this study emit only 20% of the CO2 emitted by typical gasoline-powered light-duty vehicles (i.e., cars). However, the reduction in carbon footprint (expressed in terms of CO2 equivalents) due to CO2 emissions avoidance from a passenger commuting by train rather than car is appreciably offset by the locomotive's higher BC emissions.

  18. Variational estimates of black carbon emissions in the western United States

    Directory of Open Access Journals (Sweden)

    Y. H. Mao

    2014-08-01

    Full Text Available We estimate black carbon (BC emissions in the Western United States (WUS for July–September 2006 by inverting surface BC concentrations from the Interagency Monitoring of PROtected Visual Environment (IMPROVE network using a global chemical transport model (GEOS-Chem and its adjoint. Our best estimate of the BC emissions is 49.9 Gg at 2° × 2.5° (a factor of 2.1 increase and 47.3 Gg at 0.5° × 0.667° (1.9 times increase. Model results now capture the observed major fire episodes with substantial bias reductions (∼35% at 2° × 2.5° and ∼15% at 0.5° × 0.667°. The emissions are ∼20–50% larger than those from our earlier analytical inversions (Mao et al., 2014. The discrepancy is especially drastic in the partitioning of anthropogenic vs. biomass burning emissions. The August biomass burning BC emissions are 4.6–6.5 Gg and anthropogenic BC emissions 8.6–12.8 Gg, varying with the model resolution, error specifications, and subsets of observations used. On average both increase twofold relative to the respective a priori emissions, in distinct contrast to the halving of the anthropogenic and tripling of the biomass burning emissions in the analytical inversions. We attribute these discrepancies to the inability of the inversion system, with limited spatiotemporal coverage of the IMPROVE observations, to effectively distinguish collocated anthropogenic and biomass burning emissions on model grid scales. This calls for concurrent measurements of other tracers of biomass burning and fossil fuel combustion (e.g., carbon monoxide and carbon isotopes. We find that the inversion system as is has sufficient information content to constrain the total emissions of BC on the model grid scales.

  19. Microphysics-based black carbon aging in a global CTM: constraints from HIPPO observations and implications for global black carbon budget

    Science.gov (United States)

    He, Cenlin; Li, Qinbin; Liou, Kuo-Nan; Qi, Ling; Tao, Shu; Schwarz, Joshua P.

    2016-03-01

    We develop and examine a microphysics-based black carbon (BC) aerosol aging scheme that accounts for condensation, coagulation, and heterogeneous chemical oxidation processes in a global 3-D chemical transport model (GEOS-Chem) by interpreting the BC measurements from the HIAPER Pole-to-Pole Observations (HIPPO, 2009-2011) using the model. We convert aerosol mass in the model to number concentration by assuming lognormal aerosol size distributions and compute the microphysical BC aging rate (excluding chemical oxidation aging) explicitly from the condensation of soluble materials onto hydrophobic BC and the coagulation between hydrophobic BC and preexisting soluble particles. The chemical oxidation aging is tested in the sensitivity simulation. The microphysical aging rate is ˜ 4 times higher in the lower troposphere over source regions than that from a fixed aging scheme with an e-folding time of 1.2 days. The higher aging rate reflects the large emissions of sulfate-nitrate and secondary organic aerosol precursors hence faster BC aging through condensation and coagulation. In contrast, the microphysical aging is more than 5-fold slower than the fixed aging in remote regions, where condensation and coagulation are weak. Globally, BC microphysical aging is dominated by condensation, while coagulation contribution is largest over eastern China, India, and central Africa. The fixed aging scheme results in an overestimate of HIPPO BC throughout the troposphere by a factor of 6 on average. The microphysical scheme reduces this discrepancy by a factor of ˜ 3, particularly in the middle and upper troposphere. It also leads to a 3-fold reduction in model bias in the latitudinal BC column burden averaged along the HIPPO flight tracks, with largest improvements in the tropics. The resulting global annual mean BC lifetime is 4.2 days and BC burden is 0.25 mg m-2, with 7.3 % of the burden at high altitudes (above 5 km). Wet scavenging accounts for 80.3 % of global BC

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

    Science.gov (United States)

    Zhang, Yuxuan; Zhang, Qiang; Cheng, Yafang; Su, Hang; Kecorius, Simonas; Wang, Zhibin; Wu, Zhijun; Hu, Min; Zhu, Tong; Wiedensohler, Alfred; He, Kebin

    2016-04-01

    The morphology and density of black carbon (BC) cores in internally mixed BC (In-BC) particles affect their mixing state and absorption enhancement. In this work, we developed a new method to measure the morphology and effective density of the 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. This new measurement system can select size-resolved ambient In-BC particles and measure the mobility diameter and mass of the In-BC cores. The morphology and effective density of the ambient In-BC cores are then calculated. For the In-BC cores in the atmosphere, changes in their dynamic shape factor (χ) and effective density (ρeff) can be characterized as a function of the aging process (Dp/Dc) measured by SP2 and VTDMA. During an intensive field study, the ambient In-BC cores had an average shape factor 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 %. From the measured morphology and density, the average shell / core ratio and absorption enhancement (Eab) of ambient BC were estimated to be 2.1-2.7 and 1.6-1.9, respectively, for In-BC particles with sizes of 200-350 nm. When the In-BC cores were assumed to have a void-free BC sphere with a density of 1.8 g cm-3, the shell / core ratio and Eab were overestimated by ˜ 13 and ˜ 17 %, respectively. The new approach developed in this work improves the calculations of the mixing state and optical properties of ambient In-BC particles by quantifying the changes in the morphology and density of ambient In-BC cores during aging.

  1. A comparison of black hole growth in galaxy mergers with Gasoline and Ramses

    CERN Document Server

    Gabor, J M; Volonteri, Marta; Bournaud, Frédéric; Bellovary, Jillian; Governato, Fabio; Quinn, Thomas

    2015-01-01

    Supermassive black hole dynamics during galaxy mergers is crucial in determining the rate of black hole mergers and cosmic black hole growth. As simulations achieve higher resolution, it becomes important to assess whether the black hole dynamics is influenced by the treatment of the interstellar medium in different simulation codes. We here compare simulations of black hole growth in galaxy mergers with two codes: the Smoothed Particle Hydrodynamics code Gasoline, and the Adaptive Mesh Refinement code Ramses. We seek to identify predictions of these models that are robust despite differences in hydrodynamic methods and implementations of sub-grid physics. We find that the general behavior is consistent between codes. Black hole accretion is minimal while the galaxies are well-separated (and even as they "fly-by" within 10 kpc at first pericenter). At late stages, when the galaxies pass within a few kpc, tidal torques drive nuclear gas inflow that triggers bursts of black hole accretion accompanied by star fo...

  2. Disagreement over carbon footprints: A comparison of electric and LPG forklifts

    International Nuclear Information System (INIS)

    Carbon footprint is an increasingly popular concept: for labelling, marketing, finance and regulation. In individual cases, carbon footprints can also be contentious, for example in the case of LPG and electric forklifts. Therefore, the fuel carbon footprints of the two were investigated to see if a fair, robust comparison could be made. This investigation yielded two conclusions: (1) definitions will continue to complicate footprint comparisons and (2) fuel carbon footprints of electric and (liquefied petroleum gas) LPG forklifts are, in principle, about equal, while in actual practice, LPG's footprint is smaller than that of electricity. The paper concludes that carbon footprint definitions should be sensible and transparent, but not prescribed

  3. Disagreement over carbon footprints: A comparison of electric and LPG forklifts

    International Nuclear Information System (INIS)

    Carbon footprint is an increasingly popular concept: for labelling, marketing, finance and regulation. In individual cases, carbon footprints can also be contentious, for example in the case of LPG and electric forklifts. Therefore, the fuel carbon footprints of the two were investigated to see if a fair, robust comparison could be made. This investigation yielded two conclusions: (1) definitions will continue to complicate footprint comparisons and (2) fuel carbon footprints of electric and (liquefied petroleum gas) LPG forklifts are, in principle, about equal, while in actual practice, LPG's footprint is smaller than that of electricity. The paper concludes that carbon footprint definitions should be sensible and transparent, but not prescribed. (author)

  4. 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.

  5. Carbon and nitrogen isotopic ratios of suspended particulate organic matter (SPOM) in the Black Sea water column

    Science.gov (United States)

    Çoban-Yıldız, Yeşim; Altabet, Mark A.; Yılmaz, Ayşen; Tuğrul, Süleyman

    2006-08-01

    Carbon and nitrogen isotopic ratios ( δ15N and δ13C) of suspended particulate organic matter (SPOM) in the water column of the Black Sea were measured at a total of nine stations in September-October (autumn) 1999 and May 2001. For comparison, a station in the Mediterranean Sea and one in the Sea of Marmara were sampled in October 1999. Large-sized particle samples, as well as samples of surface sediment were also collected for N and C isotopic analysis. The results revealed important vertical and regional variations in N and C isotopic composition. Seasonal variations in SPOM δ15N and δ13C were not apparent. SPOM in the euphotic zone (EZ), oxycline, and suboxic/anoxic interface layers of the water column was characterized by distinct isotopic composition. In the EZ, the N and C isotopic ratios of SPOM were in the range typically observed for plankton-derived SPOM in the surface ocean (EZ means ranged from 2.7‰ to 5.9‰ for δ15N and from -24.0‰ to -21.5‰ for δ13C). Shelf region SPOM had higher δ15N and lower δ13C (EZ means of 5.9‰ and -24.0‰, respectively). Large-sized particles (LPOM) collected by zooplankton net tows had ˜3‰ higher δ15N values compared to SPOM, indicating fractionation during trophic transfer of nitrogen. SPOM in the oxycline increased by 3-6‰ for δ15N, while δ13C decreased by -2‰ to -4‰, which may be attributed to greater lipid content. In the suboxic/anoxic interface zone, SPOM isotopic ratios ( δ15N as low as 0.0‰ to -8.0‰) suggest chemoautotrophic production leading to dominance of new, in situ produced organic matter. The location of the most negative δ15N values indicates that chemoautotrophic production is most intense at the shelf-break regions, possibly enhanced by mixing of oxygenated and nitrate-rich Mediterranean inflow waters with suboxic/anoxic Black Sea water.

  6. Dissolved Organic Carbon in Boreal Black Spruce Forest: Sources, Chemistry, and Biodegradability

    Science.gov (United States)

    Wickland, K. P.; Neff, J. C.; Aiken, G. R.

    2006-12-01

    Northern terrestrial ecosystems are commonly characterized by large stores of soil organic matter and are a major source of dissolved organic carbon (DOC) to aquatic systems. Recent changes in climate may be impacting the fate of terrestrial DOC in these high latitude ecosystems. Terrestrially-derived DOC can be metabolized by microbes in soils, sorbed to mineral soils, or transported to ground or surface waters. To understand what determines the fate of terrestrial DOC in northern ecosystems, it is essential to quantify the chemical nature and potential biodegradability of this DOC, and to know how factors such as vegetation and hydrology influence these qualities. We examined the chemistry and potential biodegradability of DOC from black spruce forest, a dominant ecosystem type in the boreal regions of Alaska and Canada. Over the course of one year, soil pore waters were collected from three black spruce sites that spanned a range of hydrologic regimes and permafrost extents, designated as well drained (WD), moderately well drained (MD), and poorly drained (PD), and from thermokarst wetlands (TW) that had formed within the PD site due to permafrost melting. DOC chemistry was characterized using XAD resin fractionation, UV-Vis absorbance, and DOC fluorescence measurements. Potential biodegradability was assessed by incubating the samples for one month, and measuring CO2 production over time. We also measured chemistry and potential biodegradability of DOC leached from dominant vegetation species. Soil pore water DOC from all sites was dominated by hydrophobic acids and was highly aromatic, while the chemical composition of vegetation leachate DOC varied with species. There was no seasonal variability in soil pore water DOC chemistry or biodegradability; however DOC collected from PD was less biodegradable than DOC from the other sites (6% loss vs. 13-15% loss). The potential biodegradability of vegetation-derived DOC ranged from 10%-90% loss, and was strongly

  7. 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

  8. Accelerated ageing of an EAF black slag by carbonation and percolation for long-term behaviour assessment.

    Science.gov (United States)

    Gurtubay, L; Gallastegui, G; Elias, A; Rojo, N; Barona, A

    2014-07-01

    The efficient reuse of industrial by-products, such as the electric arc furnace (EAF) black slag, is still hindered by concern over their long-term behaviour in outdoor environments. The aim of this study was to develop an accelerated ageing method to simulate the long-term natural carbonation of EAF slag exposed to the elements. The degree of carbonation achieved in a freshly produced slag after accelerated ageing and in a slag used on a fifteen-year-old unpaved road was very similar. The influence of particle size on accelerated carbonation was assessed, with it being concluded that the slag sample with a particle size bigger than 5-6 mm underwent slight carbonation over time when it was exposed to CO2. The accelerated ageing procedure based on percolating a previously carbonated water solution through the slag column allowed gradual leaching with simulated acid rain, as well as providing information about the gradual and total chemical release from the slag. Three classification groups were established according to the release rate of the determined elements. The joint use of the accelerated carbonation method and the percolation test is proposed as a useful tool for environmental risk assessment concerning the long-term air exposure of EAF black slag. PMID:24726964

  9. Single particle characterization of black carbon aerosols at a tropospheric alpine site in Switzerland

    Directory of Open Access Journals (Sweden)

    D. Liu

    2010-08-01

    Full Text Available The refractory black carbon (rBC mass, size distribution (190–720 nm and mixing state in sub-micron aerosols were characterized from late February to March 2007 using a single particle incandescence method at the high alpine research station Jungfraujoch (JFJ, Switzerland (46.33° N, 7.59° E, 3580 m a.s.l.. JFJ is a ground based location, which is at times exposed to continental free tropospheric air. A median mass absorption coefficient (MAC of 10.2±3.2 m2 g−1 at λ=630 nm was derived by comparing single particle incandescence measurements of black carbon mass with continuous measurements of absorption coefficient. This value is comparable with other estimates at this location. The aerosols measured at the site were mostly well mixed and aged during transportation via the free troposphere. Pollutant sources were traced by air mass back trajectories, trace gases concentrations and the mass loading of rBC. In southeasterly wind directions, mixed or convective weather types provided the potential to vent polluted boundary layer air from the southern Alpine area and industrial northern Italy, delivering enhanced rBC mass loading and CN concentrations to the JFJ. The aerosol loadings at this site were also significantly influenced by precipitation, which led to the removal of rBC from the atmosphere. Precipitation events were shown to remove about 65% of the rBC mass from the free tropospheric background reducing the mean loading from 13±5 ng m−3 to 6±2 ng m−3(corrected to standard temperature and pressure. Overall, 40±15% of the observed rBC particles within the detectable size range were mixed with large amounts of non-refractory materials present as a thick coating. The growth of particle size into the accumulation mode was positively linked with the degree of rBC mixing, suggesting the important role of condensable materials in increasing particle size and leading to enhanced internal

  10. Simulation of Arctic Black Carbon using Hemispheric CMAQ: Role of Russia's BC Emissions, Transport, and Deposition

    Science.gov (United States)

    Huang, K.; Fu, J. S.

    2015-12-01

    Black carbon plays a unique role in the Arctic climate system due to its multiple effects. It causes Arctic warming by directly absorbing sunlight from space and by darkening the surface albedo of snow and ice, which indirectly leads to further warming and melting, thus inducing an Arctic amplification effect. BC depositions over the Arctic are more sensitive to regions in close proximity. In this study, we reconstruct BC emissions for Russian Federation, which is the country that occupies the largest area in the Arctic Circle. Local Russia information such as activity data, emission factors and other emission source data are used. In 2010, total anthropogenic BC emission of Russia is estimated to be around 254 Gg. Gas flaring, a commonly ignored black carbon source, contributes a dominant 43.9% of Russia's total anthropogenic BC emissions. Other sectors, i.e., residential, transportation, industry, and power plants, contribute 22.0%, 17.8%, 11.5%, and 4.8%, respectively. BC simulations were conducted using the hemispheric version of CMAQ with polar projection. Emission inputs are from a global emissions database EDGAR (Emissions Database for Global Atmospheric Research)-HTAPv2 (Hemispheric Transport of Air Pollution) and EDGAR-HTAPv2 with its Russian part replaced by the newly developed Russian BC emissions, respectively. The simulations using the new Russian BC emission inventory could improve 46 - 61% of the Absorption Aerosol Optical Depth (AAOD) measured at the AERONET sites in Russia throughout the whole year as compared to that using the default HTAPv2 emissions. At the four air monitoring sites (Zeppelin, Barrow, Alert, and Tiksi) in the Arctic Circle, surface BC simulations are improved the most during the Arctic haze periods (October - March). Emission perturbation studies show that Russia's BC emissions contribute over 50% of the surface BC concentrations over the Arctic during the cold seasons. This study demonstrates the good capability of H-CMAQ in

  11. Black Carbon aerosol measurements and simulation in two cities in south-west Spain

    Science.gov (United States)

    Milford, Celia; Fernández-Camacho, R.; Sánchez de la Campa, A. M.; Rodríguez, Sergio; Castell, Nuria; Marrero, Carlos; Bustos, J. J.; de la Rosa, J. D.; Stein, Ariel F.

    2016-02-01

    Black carbon (BC) has been simulated for south-west Spain with the air quality model CAMx driven by the MM5 meteorological model, with a spatial resolution of 2 km × 2 km and a temporal resolution of 1 h. The simulation results were evaluated against hourly equivalent black carbon (EBC) concentrations obtained in the cities of Seville and Huelva for a winter period (January 2013) and a summer period (June 2013). A large seasonal variability was observed in PM2.5 EBC concentration in the two cities, with higher concentrations in wintertime; summertime EBC concentrations were typically less than half those of the wintertime. The model captured the large diurnal, seasonal and day to day variability in these urban areas, mean biases ranged between -0.14 and 0.07 μg m-3 in winter and between 0.01 and 0.29 μg m-3 in summer while hourly PM2.5 EBC observations ranged between 0.03 μg m-3 to 10.9 μg m-3. The diurnal variation in EBC concentrations was bimodal, with a morning and evening peak. However, the EBC evening peak was much smaller in summer than in winter. The modelling analysis demonstrates that the seasonal and day to day variability in EBC concentration in these urban areas is primarily driven by the variation in meteorological conditions. An evaluation of the role of regional versus local contributions to EBC concentrations indicates that in the medium size city of Seville, local on-road sources are dominant, whereas in the small size city of Huelva, local as well as regional sources produce a similar contribution. Considering the large diesel share of the vehicle fleet in Spain (currently ˜ 56%), we conclude that continued reduction of BC from diesel on-road sources in these urban areas is indeed a priority, and we suggest that targeted mitigation strategies, for example reducing the heaviest emitters in wintertime, would yield the greatest benefits.

  12. Is the radiative forcing due to black carbon aerosols as large as some recent studies suggest?

    Science.gov (United States)

    Boucher, O.; Wang, R.; Balkanski, Y.; Tao, S.; Myhre, G.; Valari, M.; Huneeus, N.

    2013-12-01

    Anthropogenic black carbon aerosols is responsible for a radiative forcing due to aerosol-radiation interactions (RFari), aerosol-cloud interactions (RFaci) and aerosol-snow interactions (RFasi). All estimates are very uncertain but some recent studies (e.g. Chung et al., 2012; Bond et al., 2013) have suggested that global models significantly underestimate aerosol absorption and have applied scaling factors to correct for this underestimation. As a result Bond et al. estimate RFari to be +0.5 (+0.1 to +0.9) Wm-2 for fossil fuel and biofuel only. The fifth assessment report adopted an estimate of +0.4 (+0.05 to +0.8) Wm-2. In this presentation we will show that a number of factors are likely to lead to overestimate the discrepancy in aerosol absorption between observations and models, which questions the need for very large scaling factors to reconcile models with observations. Issues with past methodological include a too small correction for NO2 absorption in AERONET retrievals of aerosol absorption optical depth (AAOD) at 440 nm, representativity errors when comparing outputs from global models with AERONET retrievals, and model biases in aerosol vertical profiles. We will show in particular how a new emission inventory and high-resolution aerosol modelling over Asia can resolve a significant fraction of the discrepancy with observations. Bond, T. C., et al., 2013: Bounding the role of black carbon in the climate system: A scientific assessment. Journal of Geophysical Research, 118, 5380-5552, doi:10.1002/jgrd.50171. Chung, C. E., V. Ramanathan, and D. Decremer, 2012: Observationally constrained estimates of carbonaceous aerosol radiative forcing. Proceedings of the National Academy of Sciences of the United States of America, 109, 11624-11629 Geographic distributions of BC emission density (A, MACCity; B, PKU-BC), modeled surface BC concentrations (C, by MACCity/INCA; D, by PKU-BC/INCA-zA), and modeled BC AAOD (E, by MACCity/INCA; F, by PKU-BC/INCA-zA). The

  13. Development of expanded graphite filled natural rubber vulcanizates in presence and absence of carbon black: Mechanical, thermal and morphological properties

    International Nuclear Information System (INIS)

    Highlights: ► Fabricate natural rubber based nanocomposites containing expanded graphite (EG). ► Study the effect of EG and modified EG on the properties of natural rubber. ► Comparison of the results of EG/MEG filled and (EG/CB)/(MEG/CB) filled NR vulcanizates. ► EG can reduce the dose of CB in tire application. ► MEG loaded NR vulcanizates in presence and absence of CB show superior properties. -- Abstract: As nanosized expanded graphite (EG) reveals a similar layered structure like organoclay and also it has a high expansion ratio so rubber chains can easily be intercalated into the gallery space. To improve the dispersion of EG in the rubber matrices, primarily the surface modification of the expanded graphite have been done and then the modified expanded graphite (MEG)/polar compatibilizer [epoxidized natural rubber (ENR)] master batch have been prepared by solution mixing method in the laboratory. After that the MEG/ENR master batch have been mixed with bulk natural rubber (NR) in presence and absence of carbon black (CB) in a laboratory scale open two roll mixing mill. Wide angle X-ray diffraction (WAXD) and high resolution transmission electron microscopic (HR-TEM) analysis of the nanocomposites revealed that MEG was intercalated and as well as delaminated in the NR matrix. Scanning electron microscope (SEM) images of the nanocomposites showed very rough surface than the pure NR matrix. In presence of expanded graphite the crack paths are channelized and coincide in one point suggesting the effect of plate like expanded graphite to acts as a barrier. We have got improved mechanical, thermal and dynamic mechanical properties for the MEG and MEG/CB loaded NR compounds compared to EG and EG/CB loaded NR compounds.

  14. Potential contributions of asphalt and coal tar to black carbon quantification in urban dust, soils, and sediments

    Science.gov (United States)

    Yang, Y.; Mahler, B.J.; Van Metre, P.C.; Ligouis, B.; Werth, C.J.

    2010-01-01

    Measurements of black carbon (BC) using either chemical or thermal oxidation methods are generally thought to indicate the amount of char and/or soot present in a sample. In urban environments, however, asphalt and coal-tar particles worn from pavement are ubiquitous and, because of their pyrogenic origin, could contribute to measurements of BC. Here we explored the effect of the presence of asphalt and coal-tar particles on the quantification of BC in a range of urban environmental sample types, and evaluated biases in the different methods used for quantifying BC. Samples evaluated were pavement dust, residential and commercial area soils, lake sediments from a small urban watershed, and reference materials of asphalt and coal tar. Total BC was quantified using chemical treatment through acid dichromate (Cr2O7) oxidation and chemo-thermal oxidation at 375??C (CTO-375). BC species, including soot and char/charcoal, asphalt, and coal tar, were quantified with organic petrographic analysis. Comparison of results by the two oxidation methods and organic petrography indicates that both coal tar and asphalt contribute to BC quantified by Cr2O7 oxidation, and that coal tar contributes to BC quantified by CTO-375. These results are supported by treatment of asphalt and coal-tar reference samples with Cr2O7 oxidation and CTO-375. The reference asphalt is resistant to Cr2O7 oxidation but not to CTO-375, and the reference coal tar is resistant to both Cr2O7 oxidation and CTO-375. These results indicate that coal tar and/or asphalt can contribute to BC measurements in samples from urban areas using Cr2O7 oxidation or CTO-375, and caution is advised when interpreting BC measurements made with these methods. ?? 2010 Elsevier Ltd.

  15. Sources of carbonaceous aerosols and deposited black carbon in the Arctic in winter-spring: implications for radiative forcing

    Directory of Open Access Journals (Sweden)

    Q. Wang

    2011-12-01

    Full Text Available We use a global chemical transport model (GEOS-Chem CTM to interpret observations of black carbon (BC and organic aerosol (OA from the NASA ARCTAS aircraft campaign over the North American Arctic in April 2008, as well as longer-term records in surface air and in snow (2007–2009. BC emission inventories for North America, Europe, and Asia in the model are tested by comparison with surface air observations over these source regions. Russian open fires were the dominant source of OA in the Arctic troposphere during ARCTAS but we find that BC was of prevailingly anthropogenic (fossil fuel and biofuel origin, particularly in surface air. This source attribution is confirmed by correlation of BC and OA with acetonitrile and sulfate in the model and in the observations. Asian emissions are the main anthropogenic source of BC in the free troposphere but European, Russian and North American sources are also important in surface air. Russian anthropogenic emissions appear to dominate the source of BC in Arctic surface air in winter. Model simulations for 2007–2009 (to account for interannual variability of fires show much higher BC snow content in the Eurasian than the North American Arctic, consistent with the limited observations. We find that anthropogenic sources contribute 90% of BC deposited to Arctic snow in January-March and 60% in April–May 2007–2009. The mean decrease in Arctic snow albedo from BC deposition is estimated to be 0.6% in spring, resulting in a regional surface radiative forcing consistent with previous estimates.

  16. Black Cat Carbon Black Company's Net Profit of the First Three Quarters of this Year Doubled%Black Cat Carbon Black Company's Net Profit of the First Three Quarters of this Year Doubled

    Institute of Scientific and Technical Information of China (English)

    Jin You

    2011-01-01

    Recently, Jiangxi Black Cat publi- cized the financial statements of the first three quarters. The realized business in- come of this Company from January to September shall be RMB 2.847 billion yuan, with a year-on-year growth of 32.32%; the realized business profit shall be RMB 108 million yuan, with a year-on-year growth of 150.14%; and the realized net profit attributable to the par- ent company shall be RMB 81,759,200 yuan, with a year-on-year growth of 110.51%.

  17. Dissolved black carbon along the land to ocean continuum of Paraiba do Sul River, Brazil

    Science.gov (United States)

    Marques da Silva Junior, Jomar; Dittmar, Thorsten; Niggemann, Jutta; Gomes de Almeida, Marcelo; de Rezende, Carlos Eduardo

    2016-04-01

    Rivers annually carry 25-28 Tg of pyrogenic dissolved organic matter (or dissolved black carbon, DBC) into the ocean, which is equivalent to about 10% of the entire land-ocean flux of dissolved organic carbon (Jaffé et al., Science 340, 345-347). Objective of this study was to identify the main processes behind the release and turnover of DBC on a riverine catchment scale. As model system we chose the land to ocean continuum of Paraíba do Sul River (Brazil), the only river system for which long-term DBC flux data exist (Dittmar, Rezende et al., Nature Geoscience 5, 618-622). The catchment was originally covered by Atlantic rain forest (mainly C3 plants) which was almost completely destroyed over the past centuries by slash-and-burn. As a result, large amounts of wood-derived charcoal reside in the soils. Today, fire-managed pasture and sugar cane (both dominated by C4 plants) cover most of the catchment. Water samples were collected at 24 sites along the main channel of the river, at 14 sites of the main tributaries and at 21 sites along the salinity gradient in the estuary and up to 35 km offshore. Sampling was performed in the wet seasons of 2013 and 2014, and the dry season of 2013. DBC was determined on a molecular level as benzenepolycarboxylic acids after nitric acid oxidation (Dittmar, Limnology and Oceanography: Methods 6, 230-235). Stable carbon isotopes (δ13C) were determined in solid phase extractable dissolved organic carbon (SPE-DOC) to distinguish C4 and C3 sources. Our results clearly show a relationship between hydrology and DBC concentrations in the river, with highest DBC concentrations in the wet season and lowest in the dry season. This relationship indicates that DBC is mainly mobilized from the upper soil horizons during heavy rainfalls. A significant correlation between DBC concentrations and δ13C-SPE-DOC indicated that most of DBC in the river system originates from C3 plants, i.e. from the historic burning event of the Atlantic rain

  18. Removal of 2-propanol from water by pervaporation using poly(vinylidene fluoride) membrane filled with carbon black

    Science.gov (United States)

    Sardarabadi, Hamideh; Mousavi, Seyed Mahmoud; Saljoughi, Ehsan

    2016-04-01

    In the present study, several filled poly(vinylidene fluoride) (PVDF) membranes by the addition of various weight fractions from carbon black (CB) to the casting solution were prepared for the removal of 2-propanol from aqueous solution in pervaporation process. Scanning electron microscopy (SEM), differential scanning calorimetry (DSC), X-ray diffraction (XRD), contact angle and swelling degree measurements were used to study morphology and properties of the prepared membranes. Separation experiments were carried out at a feed temperature of 45 °C and a permeate pressure of 18 mmHg. The results demonstrated that the addition of carbon black filler resulted in formation of the membranes with denser structure; lower permeation flux and degree of swelling; and higher crystallinity, separation factor, contact angle, and pervaporation separation index.

  19. 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.

  20. DNA Damage Following Pulmonary Exposure by Instillation to Low Doses of Carbon Black (Printex 90) Nanoparticles in Mice

    DEFF Research Database (Denmark)

    Kyjovska, Zdenka O.; Jacobsen, Nicklas R.; Saber, Anne T.;

    2015-01-01

    for the genotoxic effects of carbon black. In this study, we investigated inflammatory and acute phase response in addition to genotoxic effects occurring following exposure to nanoparticulate carbon black (NPCB) at even lower doses. C57BL/6JBomTac mice were examined 1, 3, and 28 days after a single...... instillation of 0.67, 2, 6, and 162 mu g Printex 90 NPCB and vehicle. Cellular composition and protein concentration was evaluated in BAL fluid as markers of inflammatory response and cell damage. DNA strand breaks in BAL cells, lung, and liver tissue were assessed using the alkaline comet assay. The pulmonary...... acute phase response was analyzed by Saa3 mRNA real-time quantitative PCR. Instillation of the low doses of NPCB induced a slight neutrophil influx one day after exposure. Pulmonary exposure to small doses of NPCB caused an increase in DNA strand breaks in BAL cells and lung tissue measured using the...

  1. Experimental and thermochemical evaluation of induction thermal plasma grown single-walled carbon nanotube synthesized by commercial carbon blacks with different sulfur contents

    Energy Technology Data Exchange (ETDEWEB)

    Hekmat-Ardakan, Alireza, E-mail: A.Hekmat@USherbrooke.ca; Alinejad, Yasaman, E-mail: Yasaman.Alinejad@USherbrooke.ca; Shahverdi, Ali, E-mail: Ali.Shahverdi@USherbrooke.ca; Soucy, Gervais, E-mail: Gervais.Soucy@USherbrooke.ca

    2013-08-10

    Highlights: • Synthesize of SWCNTs was carried out with different commercial carbon blacks. • Sulfur content in carbon black affected the quality of plasma grown SWCNTs product. • Increasing sulfur, up to 2 wt%, will improve the quality of SWCNT. • Thermodynamic model relates the quality of SWCNT to the formation of Y{sub 2}S{sub 3} and YS. • Reduction in quality is observed for the sample with 2.5 wt% sulfur. - Abstract: The structural quality of induction thermal plasma grown-SWCNTs synthesized through the injection of five different powder mixtures containing {sub 87.2} commercial carbon black/{sub 2.6}Ni/{sub 2.6}Co/{sub 7.6}Y{sub 2}O{sub 3} (wt%) with variable sulfur content of 0.02, 0.6, 1.1, 2 and 2.5 (wt%) in carbon black was investigated using Raman spectroscopy. The results showed an increase in G/D intensity ratio with sulfur content up to 2.0% implying higher structural quality of SWCNTs followed by reduction of intensity with 2.5%. The equilibrium composition of the mixtures as a function of temperature calculated using FactSage thermo-chemical software revealed a lower end temperature of total gas phase as a result of the sulfur addition and the heat related to the formation of Y{sub 2}S{sub 3} solid phase which eventually increases the structural quality of SWCNTs. However, the higher amount of dissolved sulfur in the liquid solution of metallic catalysts for the mixture with 2.5% sulfur can results in the poisoning effect.

  2. Effects of wet deposition on the abundance and size distribution of black carbon in East Asia

    Science.gov (United States)

    Kondo, Y.; Moteki, N.; Oshima, N.; Ohata, S.; Koike, M.; Shibano, Y.; Takegawa, N.; Kita, K.

    2016-05-01

    An improved understanding of the variations in the mass concentration and size distribution of black carbon (BC) in the free troposphere (FT) over East Asia, where BC emissions are very high, is needed to reliably estimate the radiative forcing of BC in climate models. We measured these parameters and the carbon monoxide (CO) concentration by conducting the Aerosol Radiative Forcing in East Asia (A-FORCE) 2013W aircraft campaign in East Asia in winter 2013 and compared these data with measurements made in the same region in spring 2009. The median BC concentrations in the FT originating from North China (NC) and South China (SC) showed different seasonal variations, which were primarily caused by variations in meteorological conditions. CO concentrations above the background were much higher in SC than in NC in both seasons, suggesting a more active upward transport of CO. In SC, precipitation greatly increased from winter to spring, leading to an increased wet deposition of BC. As a result, the median BC concentration in the FT was highest in SC air in winter. This season and region were optimal for the effective transport of BC from the planetary boundary layer to the FT. The count median diameters of the BC size distributions generally decreased with altitude via wet removal during upward transport. The altitude dependence of the BC size distributions was similar in winter and spring, in accord with the similarity in the BC mixing state. The observed BC concentrations and microphysical properties will be useful for evaluating the performance of climate models.

  3. Anthropogenic Black Carbon Emission Increase during the Last 150 Years at Coastal Jiangsu, China.

    Directory of Open Access Journals (Sweden)

    Kunshan Bao

    Full Text Available Black carbon (BC is one of the major drivers of climate change and a useful indicator of environmental pollution from industrialization, and thus it is essential to reconstruct the historical trend in BC flux to better understand its impact. The Yancheng coastal wetland reserve in Jiangsu province is an area sensitive to global sea level change and is also located in the most developed as well as most polluted region of China. We investigated the concentration and historical flux of BC over the past 150 years through geochemical analysis of two 210Pb-dated sediment cores from Yancheng coastal wetland. Measured BC contents ranged from 0.24 mg g-1 to 1.41 mg g-1 with average values of 0.51mg g-1-0.69 mg g-1, and BC fluxes ranged from 0.69 g m-2 yr-1 to 11.80 g m-2 yr-1 with averages of 2.94g m-2 yr-1-3.79 g m-2 yr-1. These values are consistent with other records worldwide. Both BC content and flux show a gradual and continuous increase over time and clearly reflect increased emissions from anthropogenic activities. The BC records have a significant peak in recent years (from 2000 to 2007, which is accompanied by the sharp increase of energy consumption and total carbon emission in the region. It is reasonable to conclude that changes in BC from increasing human activities have controlled BC fluxes during the last 150 years. Industrial contamination, especially BC emission, in the coastal region of eastern China should be taken into account when developing management strategies for protecting the natural environment.

  4. Anthropogenic Black Carbon Emission Increase during the Last 150 Years at Coastal Jiangsu, China

    Science.gov (United States)

    Bao, Kunshan; Shen, Ji; Wang, Guoping; Gao, Chuanyu

    2015-01-01

    Black carbon (BC) is one of the major drivers of climate change and a useful indicator of environmental pollution from industrialization, and thus it is essential to reconstruct the historical trend in BC flux to better understand its impact. The Yancheng coastal wetland reserve in Jiangsu province is an area sensitive to global sea level change and is also located in the most developed as well as most polluted region of China. We investigated the concentration and historical flux of BC over the past 150 years through geochemical analysis of two 210Pb-dated sediment cores from Yancheng coastal wetland. Measured BC contents ranged from 0.24 mg g-1 to 1.41 mg g-1 with average values of 0.51mg g-1-0.69 mg g-1, and BC fluxes ranged from 0.69 g m-2 yr-1 to 11.80 g m-2 yr-1 with averages of 2.94g m-2 yr-1-3.79 g m-2 yr-1. These values are consistent with other records worldwide. Both BC content and flux show a gradual and continuous increase over time and clearly reflect increased emissions from anthropogenic activities. The BC records have a significant peak in recent years (from 2000 to 2007), which is accompanied by the sharp increase of energy consumption and total carbon emission in the region. It is reasonable to conclude that changes in BC from increasing human activities have controlled BC fluxes during the last 150 years. Industrial contamination, especially BC emission, in the coastal region of eastern China should be taken into account when developing management strategies for protecting the natural environment. PMID:26200665

  5. Development of an improved optical transmission technique for black carbon (BC) analysis

    Science.gov (United States)

    Ballach, J.; Hitzenberger, R.; Schultz, E.; Jaeschke, W.

    A new optical transmission technique for black carbon (BC) analysis was developed to minimize interferences due to scattering effects in filter samples. A standard thermal analysis method (VDI, 1999) is used to link light attenuation by the filter samples to elemental carbon (EC) concentration. Scattering effects are minimized by immersion of the filters in oil of a similar refractive index, as is often done for microscopy purposes. Light attenuation was measured using both a white light source and a red LED of 650 nm. The usual increase in overestimation of BC concentrations with decreasing BC amount in filter samples was found considerably reduced. Some effects of BC properties (e.g. fractal dimension, microstructure and size distribution) on the specific attenuation coefficient BATN, however, are still present for the treated samples. BATN was found close to 1 m 2 g -1 for dry-dispersed industrial BC and 7 m 2 g -1 for nebulized BC. Good agreement was found between the oil immersion, integrating sphere and a polar photometer technique and Mie calculations. The average specific attenuation coefficient of ambient samples in oil varied between 7 and 11 m 2 g -1 for white light and 6 and 9 m 2 g -1 for red light (LED). BATN was found to have much less site variation for the treated than for the untreated samples. The oil immersion technique improved also the correlation with thermally analyzed EC. This new immersion technique therefore presents a considerable improvement over conventional optical transmission techniques and may therefore serve as a simple, fast and cost-effective alternative to thermal methods.

  6. Measured Wavelength-Dependent Absorption Enhancement of Internally Mixed Black Carbon with Absorbing and Nonabsorbing Materials.

    Science.gov (United States)

    You, Rian; Radney, James G; Zachariah, Michael R; Zangmeister, Christopher D

    2016-08-01

    Optical absorption spectra of laboratory generated aerosols consisting of black carbon (BC) internally mixed with nonabsorbing materials (ammonium sulfate, AS, and sodium chloride, NaCl) and BC with a weakly absorbing brown carbon surrogate derived from humic acid (HA) were measured across the visible to near-IR (550 to 840 nm). Spectra were measured in situ using a photoacoustic spectrometer and step-scanning a supercontinuum laser source with a tunable wavelength and bandwidth filter. BC had a mass-specific absorption cross section (MAC) of 7.89 ± 0.25 m(2) g(-1) at λ = 550 nm and an absorption Ångström exponent (AAE) of 1.03 ± 0.09 (2σ). For internally mixed BC, the ratio of BC mass to the total mass of the mixture was chosen as 0.13 to mimic particles observed in the terrestrial atmosphere. The manner in which BC mixed with each material was determined from transmission electron microscopy (TEM). AS/BC and HA/BC particles were fully internally mixed, and the BC was both internally and externally mixed for NaCl/BC particles. The AS/BC, NaCl/BC, and HA/BC particles had AAEs of 1.43 ± 0.05, 1.34 ± 0.06, and 1.91 ± 0.05, respectively. The observed absorption enhancement of mixed BC relative to the pure BC was wavelength dependent for AS/BC and decreased from 1.5 at λ = 550 nm with increasing wavelength while the NaCl/BC enhancement was essentially wavelength independent. For HA/BC, the enhancement ranged from 2 to 3 and was strongly wavelength dependent. Removal of the HA absorption contribution to enhancement revealed that the enhancement was ≈1.5 and independent of wavelength. PMID:27359341

  7. The black gender gap in educational attainment: historical trends and racial comparisons.

    Science.gov (United States)

    McDaniel, Anne; DiPrete, Thomas A; Buchmann, Claudia; Shwed, Uri

    2011-08-01

    It is often asserted that the gender gap in educational attainment is larger for blacks than whites, but historical trends comparing the black and white gender gap have received surprisingly little attention. Analysis of historical data from the U.S. census IPUMS samples shows that the gender gap in college completion has evolved differently for whites and blacks. Historically, the female advantage in educational attainment among blacks is linked to more favorable labor market opportunities and stronger incentives for employment for educated black women. Blacks, particularly black males, still lag far behind whites in their rates of college completion, but the striking educational gains of white women have caused the racial patterns of gender differences in college completion rates to grow more similar over time. While some have linked the disadvantaged position of black males to their high risk of incarceration, our estimates suggest that incarceration has a relatively small impact on the black gender gap and the racial gap in college completion rates for males in the United States. PMID:21638226

  8. The Comparison of the Contents of Sugar, Amadori, and Heyns Compounds in Fresh and Black Garlic.

    Science.gov (United States)

    Yuan, Heng; Sun, Linjuan; Chen, Min; Wang, Jun

    2016-07-01

    Black garlic is produced through thermal processing and is used as a healthy food throughout the world. Compared with fresh garlic, there are obvious changes in the color, taste, and biological functions of black garlic. To analyze and explain these changes, the contents of water-soluble sugars, fructan, and the key intermediate compounds (Heyns and Amadori) of the Maillard reaction in fresh raw garlic and black garlic were investigated, which were important to control and to evaluate the quality of black garlic. The results showed that the fructan contents in the black garlics were decreased by more than 84.6% compared with the fresh raw garlics, which translated into changes in the fructose and glucose contents. The water-soluble sugar content was drastically increased by values ranging from 187.79% to 790.96%. Therefore, the taste of the black garlic became very sweet. The sucrose content in black garlic was almost equivalent to fresh garlic. The Amadori and Heyns compounds were analyzed by HPLC-MS/MS in multiple reaction monitoring mode using the different characteristic fragment ions of Heyns and Amadori compounds. The total content of the 3 main Amadori and 3 Heyns compounds in black garlic ranged from 762.53 to 280.56 μg/g, which was 40 to 100-fold higher than the values in fresh raw garlic. This result was significant proof that the Maillard reaction in black garlic mainly utilized fructose and glucose, with some amino acids. PMID:27300762

  9. Catalytic Oxidation of Propylene, Toluene, Carbon Monoxide, and Carbon Black over Au/CeO 2 Solids: Comparing the Impregnation and the Deposition-Precipitation Methods

    OpenAIRE

    Antoine Aboukaïs; Samer Aouad; Houda El-Ayadi; Mira Skaf; Madona Labaki; Renaud Cousin; Edmond Abi-Aad

    2013-01-01

    Au/CeO2 solids were prepared by two methods: deposition-precipitation (DP) and impregnation (Imp). The prepared solids were calcined under air at 400°C. Both types of catalysts have been tested in the total oxidation of propylene, toluene, carbon monoxide, and carbon black. Au/CeO2-DP solids were the most reactive owing to the high number of gold nanoparticles and Au+ species and the low concentration of Cl- ions present on its surface compared to those observed in Au/CeO2-Imp solids.

  10. Outdoor/indoor 1 relationships of PM1 and black carbon: 2 sources and infiltration processes in an urban environment

    OpenAIRE

    M. Viana; Díez, S.; C. Reche

    2014-01-01

    Ambient air emissions of sub-micron particles infiltrate into indoor environments and play a 15 major role in indoor air quality. Discriminating between particles of indoor vs. outdoor origin is 16 therefore essential when assessing indoor air pollutant levels and characteristics. Outdoor/indoor relationships of traffic-derived nanoscaled particulates (PM1 and black carbon) were determined in a typical Mediterranean environment. Results evidenced the major impact of outdoor vehicular traff...

  11. Highway proximity and black carbon from cookstoves as a risk factor for higher blood pressure in rural China

    OpenAIRE

    Baumgartner, Jill; Zhang, Yuanxun; Schauer, James J.; Huang, Wei; Wang, Yuqin; Ezzati, Majid

    2014-01-01

    Air pollution is a leading health risk factor and important contributor to regional climate change in China and other parts of Asia. China’s particulate matter (PM) air pollution dramatically exceeds health guidelines and is impacted by industrial emissions, motor vehicles, and household use of biomass and coal fuels. Black carbon (BC) from biomass and fossil fuel burning is a major climate-forcing component of PM. We found that BC exposure from biomass smoke is more strongly associated with ...

  12. Activated Fraction Of Black Carbon By Cloud Droplets And Ice Crystals At The High Alpine Site Jungfraujoch (3580 m asl)

    Energy Technology Data Exchange (ETDEWEB)

    Cozic, J.; Mertes, S. [IFT Leipzig (Georgia); Verheggen, B.; Petzold, A. [DLR, Oberpfaffenhofen (Georgia); Weingartner, E.; Baltensperger, U.

    2005-03-01

    Measurements of black carbon (BC) were made in winter and summer 2004 at the high Alpine site Jungfraujoch in order to study the activation of BC into cloud droplets and ice crystals. Main results showed that the activated fraction represents 61% in summer and that for a large temperature range between -25 C and 5 C, the activated BC fraction increases with increasing temperature and increasing liquid water content. (author)

  13. Effect of carbon black nanomaterial on biological membranes revealed by shape of human erythrocytes, platelets and phospholipid vesicles

    OpenAIRE

    Drašler, Barbara; Pajnič, Manca; Šuštar, Vid; Štukelj, Roman; Kononenko, Veno; Šimundić, Metka; Hägerstrand, Henry; Kralj-Iglič, Veronika; Makovec, Darko; Drobne, Damjana; Krek, Judita Lea

    2016-01-01

    Background We studied the effect of carbon black (CB) agglomerated nanomaterial on biological membranes as revealed by shapes of human erythrocytes, platelets and giant phospholipid vesicles. Diluted human blood was incubated with CB nanomaterial and observed by different microscopic techniques. Giant unilamellar phospholipid vesicles (GUVs) created by electroformation were incubated with CB nanomaterial and observed by optical microscopy. Populations of erythrocytes and GUVs were analyzed: t...

  14. Snow cover sensitivity to black carbon deposition in the Himalayas: from atmospheric and ice core measurements to regional climate simulations

    OpenAIRE

    M. Ménégoz; G. Krinner; Balkanski, Y.; Boucher, O.; Cozic, A.; Lim, S.; Ginot, P.; Laj, P.; H. Gallée; P. Wagnon; Marinoni, A.; Jacobi, H. W.

    2014-01-01

    We applied a climate-chemistry global model to evaluate the impact of black carbon (BC) deposition on the Himalayan snow cover from 1998 to 2008. Using a stretched grid with a resolution of 50 km over this complex topography, the model reproduces reasonably well the remotely sensed observations of the snow cover duration. Similar to observations, modelled atmospheric BC concentrations in the central Himalayas reach a minimum during the monsoon and a maximum during the post- ...

  15. Two-year black carbon observations at Everest-Pyramid GAW Station (Nepal, 5079 m a.s.l.)

    Science.gov (United States)

    Marinoni, A.; Cristofanelli, P.; Duchi, R.; Calzolari, F.; Roccato, F.; Laj, P.; Vuillermoz, E.; Verza, G. P.; Bonasoni, P.

    2009-04-01

    Carbonaceous aerosol play a complex role in atmospheric radiative balance; in particular black carbon, primary produced by fossil fuel combustion and biomass burning, both absorbs and reflects incoming solar radiation, thus heating the lower troposphere and cooling the Earth surface. India and China, the most populated and rapidly developing countries, are between the actual major emitters. Thus the Himalayas range is an ideal location to investigate atmospheric composition changes. Due to technical and logistic difficulties, only few continuous observations of atmospheric constituents are available in this area. One of these observation sites is located in the Khumbu valley at 5079 m a.s.l, where black carbon and other aerosol parameters as well as trace gas concentrations measurements are carried out since March 2006. The BC seasonal behaviour clearly shows a minimum in summer monsoon season with an averaged concentration of 52 ng m-3 and a standard deviation of 62 ng m-3; the seasonal maximum appears in pre-monsoon period with an averaged concentration of 340 ng m-3 and a standard deviation of 415 ng m-3. During this season black carbon values reached sometime very high levels up to 5 μg m-3 on 30 minutes base, showing high polluted conditions even at 5000 m. Aerosol mass (PM-1), as well as accumulation particle number show very similar seasonal trends, while ultrafine (Aitken+Nucleation) particles are more influenced by nucleation processes. In this work, we present an analysis of black carbon and aerosol mass variations during the first two years of measurements at the Everest-Pyramid station with the aim to identify background and polluted conditions.

  16. Bayesian bias adjustments of the lung cancer SMR in a cohort of German carbon black production workers

    Directory of Open Access Journals (Sweden)

    Morfeld Peter

    2010-08-01

    Full Text Available Abstract Background A German cohort study on 1,528 carbon black production workers estimated an elevated lung cancer SMR ranging from 1.8-2.2 depending on the reference population. No positive trends with carbon black exposures were noted in the analyses. A nested case control study, however, identified smoking and previous exposures to known carcinogens, such as crystalline silica, received prior to work in the carbon black industry as important risk factors. We used a Bayesian procedure to adjust the SMR, based on a prior of seven independent parameter distributions describing smoking behaviour and crystalline silica dust exposure (as indicator of a group of correlated carcinogen exposures received previously in the cohort and population as well as the strength of the relationship of these factors with lung cancer mortality. We implemented the approach by Markov Chain Monte Carlo Methods (MCMC programmed in R, a statistical computing system freely available on the internet, and we provide the program code. Results When putting a flat prior to the SMR a Markov chain of length 1,000,000 returned a median posterior SMR estimate (that is, the adjusted SMR in the range between 1.32 (95% posterior interval: 0.7, 2.1 and 1.00 (0.2, 3.3 depending on the method of assessing previous exposures. Conclusions Bayesian bias adjustment is an excellent tool to effectively combine data about confounders from different sources. The usually calculated lung cancer SMR statistic in a cohort of carbon black workers overestimated effect and precision when compared with the Bayesian results. Quantitative bias adjustment should become a regular tool in occupational epidemiology to address narrative discussions of potential distortions.

  17. On the Use of the Field Sunset Semi-continuous Analyzer to Measure Equivalent Black Carbon Concentrations.

    Czech Academy of Sciences Publication Activity Database

    Zíková, Naděžda; Vodička, Petr; Ludwig, W.; Hitzenberger, R.; Schwarz, Jaroslav

    2016-01-01

    Roč. 50, č. 3 (2016), s. 284-296. ISSN 0278-6826 R&D Projects: GA ČR(CZ) GBP503/12/G147; GA MŠk 7AMB12AT021; GA MŠk(CZ) LO1415 Institutional support: RVO:67985858 Keywords : black carbon * aerosols * aethalometer Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.413, year: 2014

  18. The Measurement of Thermal Conductivities of Silica and Carbon Black Powders at Different pressures by Thermal COnductivity Probe

    Institute of Scientific and Technical Information of China (English)

    X.G.Liang; X.S.Ge; 等

    1992-01-01

    This investigation was done to study the gas filled powder insulation and thermal conductivity probe for the measurent of thermal conductivity of powders.The mathematical analysis showed that the heat capacity of the probe itself and the thermal rsistance between the probe and powder must be considered .The authors developed a slender probe and measured the effective thermal conductivity of sillca and carbon black powders under a variety of conditions.

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

    OpenAIRE

    Williams Andrew; Møller Peter; Boisen Anne; Bornholdt Jette; Folkmann Janne K; Halappanavar Sabina; Saber Anne T; Yauk Carole; Vogel Ulla; Loft Steffen; Wallin Håkan

    2009-01-01

    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)-induc...

  20. Reinforcing effect of plasma modified halloysite nanotubes in a carbon black filled natural rubber-butadien rubber matrix

    OpenAIRE

    Poikelispaa, Minna; Das, Amit; Dierkes, Wilma; Vuorinen, Jyrki

    2011-01-01

    Rubber composites are generally produced by the direct incorporation of fillers like carbon black and/or silica into the rubber matrix. The incorporation of different types of nanofillers is the subject of recent research with the aim of preparing composites with special compositions and properties. A successful application of such composites depends mainly on the degree of dispersion of the nano-sized fillers. Recently, a naturally occurring clay mineral, halloysite nanotubes (HNTs), is inve...

  1. 15,000 years of black carbon deposition – A post-glacial fire record from maar lake sediments (Germany)

    OpenAIRE

    Eva Lehndorff; Mareike Wolf; Thomas Litt; Achim Brauer; Wulf Amelung

    2015-01-01

    Fires accompanied human development throughout the Holocene, leaving behind black carbon (BC) as residues from incomplete biomass burning. Here we used molecular fire markers, benzene polycarboxylic acids (BPCAs), to reconstruct fire history in two Eifel maar lakes, Germany. We hypothesized to find indications for (i) changes in BC related to ecosystem changes, (ii) an increase in BC influx at the onset of agriculture until modern times, and (iii) a change in BC quality due to technical progr...

  2. Acute Respiratory Inflammation in Children and Black Carbon in Ambient Air before and during the 2008 Beijing Olympics

    OpenAIRE

    Lin, Weiwei; Huang, Wei; ZHU, TONG; Hu, Min; Brunekreef, Bert; Zhang, Yuanhang; Liu, Xingang; Cheng, Hong; Gehring, Ulrike; Li, Chengcai; Tang, Xiaoyan

    2011-01-01

    Background: Epidemiologic evidence for a causative association between black carbon (BC) and health outcomes is limited. Objectives: We estimated associations and exposure–response relationships between acute respiratory inflammation in schoolchildren and concentrations of BC and particulate matter with an aerodynamic diameter of ≤ 2.5 μm (PM2.5) in ambient air before and during the air pollution intervention for the 2008 Beijing Olympics. Methods: We measured exhaled nitric oxide (eNO) as an...

  3. Modeling temporal and spatial variability of traffic-related air pollution: Hourly land use regression models for black carbon

    OpenAIRE

    Dons, Evi; Van Poppel, Martine; Kochan, Bruno; Wets, Geert; Int Panis, Luc

    2013-01-01

    Land use regression (LUR) modeling is a statistical technique used to determine exposure to air pollutants in epidemiological studies. Time-activity diaries can be combined with LUR models, enabling detailed exposure estimation and limiting exposure misclassification, both in shorter and longer time lags. In this study, the traffic related air pollutant black carbon was measured with mu-aethalometers on a 5-mm time base at 63 locations in Flanders, Belgium. The measurements show that hourly c...

  4. Anti-oxidative and inflammatory responses induced by fly ash particles and carbon black in lung epithelial cells

    Energy Technology Data Exchange (ETDEWEB)

    Diabate, Silvia; Plaumann, Diana; Uebel, Caroline; Weiss, Carsten [Karlsruhe Institute of Technology, Institute of Toxicology and Genetics, Eggenstein-Leopoldshafen (Germany); Bergfeldt, Britta [Karlsruhe Institute of Technology, Institute of Technical Chemistry, Eggenstein-Leopoldshafen (Germany)

    2011-12-15

    Combustion-derived nanoparticles as constituents of ambient particulate matter have been shown to induce adverse health effects due to inhalation. However, the components inducing these effects as well as the biological mechanisms are still not fully understood. The fine fraction of fly ash particles collected from the electrostatic precipitator of a municipal solid waste incinerator was taken as an example for real particles with complex composition released into the atmosphere to study the mechanism of early biological responses of BEAS-2B human lung epithelial cells. The studies include the effects of the water-soluble and -insoluble fractions of the fly ash and the well-studied carbon black nanoparticles were used as a reference. Fly ash induced reactive oxygen species (ROS) and increased the total cellular glutathione (tGSH) content. Carbon black also induced ROS generation; however, in contrast to the fly ash, it decreased the intracellular tGSH. The fly ash-induced oxidative stress was correlated with induction of the anti-oxidant enzyme heme oxygenase-1 and increase of the redox-sensitive transcription factor Nrf2. Carbon black was not able to induce HO-1. ROS generation, tGSH increase and HO-1 induction were only induced by the insoluble fraction of the fly ash, not by the water-soluble fraction. ROS generation and HO-1 induction were markedly inhibited by pre-incubation of the cells with the anti-oxidant N-acetyl cysteine which confirmed the involvement of oxidative stress. Both effects were also reduced by the metal chelator deferoxamine indicating a contribution of bioavailable transition metals. In summary, both fly ash and carbon black induce ROS but only fly ash induced an increase of intracellular tGSH and HO-1 production. Bioavailable transition metals in the solid water-insoluble matrix of the fly ash mostly contribute to the effects. (orig.)

  5. Relationship between Polymer Dielectric Constant and Percolation Threshold in Conductive Poly(styrene)-Type Polymer and Carbon Black Composites

    OpenAIRE

    Mariana Castro Martínez; Susana Hernández López; Enrique Vigueras Santiago

    2015-01-01

    We study the effect of dielectric constant of some poly(styrene)-type polymer matrix on the percolation threshold in conductive polymer composites with carbon black (CB). We demonstrate that percolation threshold diminishes with an increment of the dielectric constant of polymer matrix. We chose polystyrene and other three polymers similar in structure and molecular weight but with different chemical nature. The corresponding dielectric constant and critical concentration, Xc, in volume frac...

  6. Black carbon mass size distributions of diesel exhaust and urban aerosols measured using differential mobility analyzer in tandem with Aethalometer

    OpenAIRE

    Chan, K. L.; Wong, K. C.; Westerdahl, Dane; Cheung, C. S.; Močnik, Griša; Ning, Zhi; Zhou, J. H.

    2015-01-01

    Black carbon (BC) is the dominant component of the light absorbing aerosols in the atmosphere, changing earthʼs radiative balance and affecting the climate. The mixing state and size distribution of atmospheric BC are largely unknown and cause uncertainties in climate models. BC is also a major component of diesel PM emissions, recently classified by World Health Organization as Category I Carcinogen, and has been associated with various adverse health effects. This study presents a novel app...

  7. An inferred relationship between some uranium deposits and calcium carbonate cement in southern Black Hills, South Dakota

    Science.gov (United States)

    Gott, Garland B.

    1956-01-01

    Evidence resulting from geologic mapping in the southern Black Hills indicates that the areas marginal to some of the larger carbonate-cemented sandstones constitute favorable geochemical environments for the localization of uranium deposits. To determine whether these favorable environments are predictable a limited experimental core-drilling program was carried out. An extensive deposit was discovered in an area marginal to a sandstone well-cemented with calcium carbonate. The deposit has not yet been developed, but from the available data it appears that there is a significant quantity of mineralized rock present containing as much as 3.0 percent eU3O8.

  8. Physicochemical characteristics and toxic effects of ozone-oxidized black carbon particles

    Science.gov (United States)

    Li, Qian; Shang, Jing; Zhu, Tong

    2013-12-01

    Black carbon (BC) or soot particles formed by combustion are ubiquitous in the atmosphere and have a significant effect on climate and human health. Oxidation can change the physicochemical characteristics of BC, thereby increasing its toxicity. The physicochemical properties of BC and ozone-oxidized BC are investigated in this study through transmission electron microscopy, X-ray photoelectron spectroscopy, diffuse reflectance infrared Fourier transform spectroscopy, ultraviolet-visible spectrophotometry, and electron paramagnetic resonance. The contents of oxygen-containing functional groups, hydrophilicity, water-soluble organic compounds, and free radicals increased after ozone treatment. The redox capacity and cytotoxicity of BC particles were enhanced by ozone oxidation as detected by dithiothreitol (DTT) and 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazoliumbromide assays. The redox activities of different BC particles are compared. Particle phase contributed significantly to total redox activity as detected by the DTT assay. Results indicate that BC particles that have undergone aging in the atmosphere may be more toxic and harmful to human health.

  9. Characterisation of black carbon-rich samples by (13)C solid-state nuclear magnetic resonance.

    Science.gov (United States)

    Novotny, Etelvino H; Hayes, Michael H B; Deazevedo, Eduardo R; Bonagamba, Tito J

    2006-09-01

    There are difficulties in quantifying and characterising the organic matter (OM) in soils that contain significant amounts of partially oxidised char or charcoal materials. The anthropogenic black carbon (BC), such as that found in the Terra Preta de Indio soils of the Amazon region, is a good example of the OM that is difficult to analyse in such soils. (13)C direct polarisation/magic angle spinning (DP/MAS) at high MAS frequency, (1)H-(13)C cross polarisation (CP)/MAS with total suppression of spinning sidebands (TOSS), and chemical shift anisotropy (CSA) filter nuclear magnetic resonance techniques have been applied successfully for quantifying the different components of OM. However, because pyrogenic materials present strong local magnetic susceptibility heterogeneities, the use of CSA-filter and TOSS make the pulse sequences very sensitive to imperfections in the pi pulses. In this study, the DP/MAS pulse sequence was replaced by a CP with a radio frequency ramp--variable amplitude CP (VACP)--VACP/MAS pulse sequence, and composite pi pulses were used in the CSA-filter and TOSS pulse sequences. In that way, the component functionalities in a humic acid from a BC soil were successfully determined. The spectrometer time needed was greatly decreased by employing this VACP/MAS technique. This development provides an accurate method for characterising BC-rich samples from different origins. PMID:16688435

  10. Characterisation of black carbon-rich samples by 13C solid-state nuclear magnetic resonance

    Science.gov (United States)

    Novotny, Etelvino H.; Hayes, Michael H. B.; Deazevedo, Eduardo R.; Bonagamba, Tito J.

    2006-09-01

    There are difficulties in quantifying and characterising the organic matter (OM) in soils that contain significant amounts of partially oxidised char or charcoal materials. The anthropogenic black carbon (BC), such as that found in the Terra Preta de Índio soils of the Amazon region, is a good example of the OM that is difficult to analyse in such soils. 13C direct polarisation/magic angle spinning (DP/MAS) at high MAS frequency, 1H-13C cross polarisation (CP)/MAS with total suppression of spinning sidebands (TOSS), and chemical shift anisotropy (CSA) filter nuclear magnetic resonance techniques have been applied successfully for quantifying the different components of OM. However, because pyrogenic materials present strong local magnetic susceptibility heterogeneities, the use of CSA-filter and TOSS make the pulse sequences very sensitive to imperfections in the π pulses. In this study, the DP/MAS pulse sequence was replaced by a CP with a radio frequency ramp—variable amplitude CP (VACP)—VACP/MAS pulse sequence, and composite π pulses were used in the CSA-filter and TOSS pulse sequences. In that way, the component functionalities in a humic acid from a BC soil were successfully determined. The spectrometer time needed was greatly decreased by employing this VACP/MAS technique. This development provides an accurate method for characterising BC-rich samples from different origins.

  11. A Study on the Properties of Carbon Black Mortar Using Granulated Blast Furnace Slag and Polymer.

    Science.gov (United States)

    Jang, Hong-Seok; Jeon, Ui-Hyeon; So, Seung-Young

    2015-11-01

    White Portland Cement (WPC) and inorganic pigment have been used in colored concrete, but there are some physical problems such as increases in efflorescence, and poor workability and low economics. The aim of this study was to investigate the effects of GBFS and polymer (methyl cellulose) on the physical properties of carbon black mortar. For this purpose, a flow test, compressive strength test and color evaluation and was carried out on cement mortar mixed with polymer by changing the proportion of cement and ratio of GBFS. The results show that the addition of polymer influences significantly the color value efficiency in colored mortar. This is due to the reduction of overall amount of micro pore. This polymer films prevent the transport of soluble calcium towards the surface, and decreases efflorescence. And the flow of colored mortar was increased in proportion to the addition rate of the GBFS. In addition the strength of colored mortars with GBFS at the long-term aged (after 28 days) was higher than that of the general WPC mortar, although its strength was developed slowly at the early ages. PMID:26726652

  12. 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; Zhang, Renyi

    2016-04-19

    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. PMID:27035993

  13. Contactless microfluidic pumping using microchannel-integrated carbon black composite membranes.

    Science.gov (United States)

    Fu, Xiaotong; Gagnon, Zachary

    2015-09-01

    The ability to pump and manipulate fluid at the micron-scale is a basic requirement for microfluidic platforms. Many current manipulation methods, however, require expensive and bulky external supporting equipment, which are not typically compatible for portable applications. We have developed a contactless metal electro-osmotic micropump capable of pumping conductive buffers. The pump operates using two pairs of gallium metal electrodes, which are activated using an external voltage source and separated from a main flow channel by a thin micron-scale polydimethylsiloxane (PDMS) membrane. The thin contactless membrane allows for field penetration and electro-osmotic flow within the microchannel, but eliminates electrode damage and sample contamination commonly associated with traditional DC electro-osmotic pumps that utilize electrodes in direct contact with the working fluid. Our previous work has demonstrated the effectiveness of this method in pumping deionized water. However, due to the high resistivity of PDMS, this method proved difficult to apply towards manipulating conductive buffers. To overcome this limitation, we fabricated conductive carbon black (CB) powder directly into the contactless PDMS membranes. The increased electrical conductivity of the contactless PDMS membrane significantly increased micropump performance. Using a microfluidic T-channel device and an electro-osmotic flow model, we determined the influence that CB has on pump pressure for CB weight percents varying between 0 and 20. The results demonstrate that the CB increases pump pressure by two orders of magnitude and enables effective operations with conductive buffers. PMID:26543514

  14. DNA biosensor based on a glassy carbon electrode modified with electropolymerized Eriochrome Black T

    International Nuclear Information System (INIS)

    We report on an electrochemical DNA biosensor consisting of a glassy carbon electrode modified with a film of electropolymerized Eriochrome Black T (pEBT) that serves as a functional platform for the immobilization of probe DNA. pEBT was deposited via cyclic voltammetry, and the amino-modified DNA capture probe was covalently linked to the surface via a sulfanilamide coupling reaction. The single step of the assembly process was monitored by atomic force microscopy and electrochemistry. The surface density of DNA probe on the biosensor interface was calculated to be 1.7 × 10−10 mol cm−2 using methylene blue as an electroactive probe. Hybridization experiments showed the peak currents of methylene blue to decrease with increasing concentration of complementary sequence in the range from 5.0 f. to 5.0 pM. The detection limit is as low as 0.11 fM. Selectivity studies showed that the biosensor can discriminate a fully complementary sequence from a single-base mismatch, three-base mismatch, and a fully non-complementary sequence. The biosensor displays good stability and can be regenerated due to the beneficial effects of electropolymerization and covalent immobilization of probe DNA. (author)

  15. On the explanation of hysteresis in the adsorption of ammonia on graphitized thermal carbon black.

    Science.gov (United States)

    Zeng, Yonghong; Do, D D; Horikawa, Toshihide; Nicholson, D; Nakai, Kazuyuki

    2016-01-14

    We present a Monte Carlo simulation and experimental study of ammonia adsorption on graphitized thermal carbon black. Our new molecular model for the adsorbent is composed of basal plane graphene surfaces with ultrafine pores grafted with hydroxyl groups at the junctions between graphene layers. The simulated adsorption isotherms and isosteric heats are in good agreement with the experimental data of Holmes and Beebe, and the simulations reproduce the unusual experimental hysteresis of ammonia adsorption on an open graphite surface for the first time in the literature. The detailed mechanisms of adsorption and desorption, and the origin of hysteresis, are investigated by the microscopic analysis of the adsorbate structures to show that restructuring occurs during adsorption. The main results from this work are: (i) at the triple point, ammonia adsorbs preferentially around the functional groups to form clusters in the ultrafine pores and spills-over onto the basal plane as the loading is increased; followed by a 2D condensation on the graphite surface to form a bilayer adsorbate; (ii) at the boiling point, adsorption occurs on the basal plane due to the increasing importance of thermal fluctuations (an entropic effect); (iii) the isosteric heat is very high at zero loading due to the strong interaction between ammonia and the functional groups, decreases steeply when the functional group is saturated, and eventually reaches the heat of condensation as the fluid-fluid interaction increases. PMID:26661571

  16. Corrosion behavior of modified nano carbon black/epoxy coating in accelerated conditions

    International Nuclear Information System (INIS)

    Graphical abstract: - Highlights: • By using SDS as a surfactant, nano particles of CB were uniformly dispersed. • CB nanoparticle in the epoxy coating improved the corrosion resistance of the coating. • By addition of CB nanoparticles to the epoxy diffusion ions and water became limited. • The dominance of barrier mechanism was proved by calculation of the diffusion coefficients. - Abstract: The electrochemical behavior and anticorrosion properties of modified carbon black (CB) nanoparticles in epoxy coatings were investigated in accelerated conditions. Nanoparticles of CB were modified by sodium dodecyl sulfate (SDS) as surfactant. Dispersion of nanoparticles into epoxy was confirmed by Transmission Electron Microscopy (TEM). The accelerated condition was prepared at 65 °C. CB nanoparticles improved corrosion resistance of the epoxy coating. The optimum concentration of CB in the epoxy coating was 0.75 wt%. Results showed that the CB hinder the corrosion due to its barrier properties. CB can decrease the diffusion coefficient of water in the coating with filling the micropores

  17. Corrosion behavior of modified nano carbon black/epoxy coating in accelerated conditions

    Energy Technology Data Exchange (ETDEWEB)

    Ghasemi-Kahrizsangi, Ahmad; Shariatpanahi, Homeira, E-mail: shariatpanahih@ripi.ir; Neshati, Jaber; Akbarinezhad, Esmaeil

    2015-03-15

    Graphical abstract: - Highlights: • By using SDS as a surfactant, nano particles of CB were uniformly dispersed. • CB nanoparticle in the epoxy coating improved the corrosion resistance of the coating. • By addition of CB nanoparticles to the epoxy diffusion ions and water became limited. • The dominance of barrier mechanism was proved by calculation of the diffusion coefficients. - Abstract: The electrochemical behavior and anticorrosion properties of modified carbon black (CB) nanoparticles in epoxy coatings were investigated in accelerated conditions. Nanoparticles of CB were modified by sodium dodecyl sulfate (SDS) as surfactant. Dispersion of nanoparticles into epoxy was confirmed by Transmission Electron Microscopy (TEM). The accelerated condition was prepared at 65 °C. CB nanoparticles improved corrosion resistance of the epoxy coating. The optimum concentration of CB in the epoxy coating was 0.75 wt%. Results showed that the CB hinder the corrosion due to its barrier properties. CB can decrease the diffusion coefficient of water in the coating with filling the micropores.

  18. Simulated responses of terrestrial aridity to black carbon and sulfate aerosols

    Science.gov (United States)

    Lin, L.; Gettelman, A.; Xu, Y.; Fu, Q.

    2016-01-01

    Aridity index (AI), defined as the ratio of precipitation to potential evapotranspiration (PET), is a measure of the dryness of terrestrial climate. Global climate models generally project future decreases of AI (drying) associated with global warming scenarios driven by increasing greenhouse gas and declining aerosols. Given their different effects in the climate system, scattering and absorbing aerosols may affect AI differently. Here we explore the terrestrial aridity responses to anthropogenic black carbon (BC) and sulfate (SO4) aerosols with Community Earth System Model simulations. Positive BC radiative forcing decreases precipitation averaged over global land at a rate of 0.9%/°C of global mean surface temperature increase (moderate drying), while BC radiative forcing increases PET by 1.0%/°C (also drying). BC leads to a global decrease of 1.9%/°C in AI (drying). SO4 forcing is negative and causes precipitation a decrease at a rate of 6.7%/°C cooling (strong drying). PET also decreases in response to SO4 aerosol cooling by 6.3%/°C cooling (contributing to moistening). Thus, SO4 cooling leads to a small decrease in AI (drying) by 0.4%/°C cooling. Despite the opposite effects on global mean temperature, BC and SO4 both contribute to the twentieth century drying (AI decrease). Sensitivity test indicates that surface temperature and surface available energy changes dominate BC- and SO4-induced PET changes.

  19. 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.

  20. 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.

  1. Investigation of Black Carbon Effects on Precipitation and Surface Hydrology over the Western United States

    Science.gov (United States)

    Tseng, H. L. R.; Liou, K. N.; Gu, Y.; Fovell, R. G.; Li, Q.

    2015-12-01

    The current Exceptional Drought (US Drought Monitor) over the western United States warrants an in-depth investigation of possible causes of decreased precipitation and surface hydrology. Black carbon (BC), being the most radiatively-absorptive of any aerosol species, has the potential to semi-directly influence atmospheric physics and dynamics. Aloft, BC can exacerbate the aridity in some areas while increasing precipitation in other locations. On the surface, BC can also alter surface hydrology parameters such as surface runoff and snow water equivalent. In this study, we examine the role of BC and its possible effect on spatial precipitation redistribution and surface hydrology west of and over the Rocky Mountains from an online and coupled meteorological and chemical perspective. In particular, we utilize the Weather Research and Forecasting-Chemistry (WRF-Chem) model at the horizontal resolution of 30 km, employing the Fu-Liou-Gu plane-parallel radiation scheme and a three-dimensional radiation parameterization over mountainous areas to account for BC feedback with clouds, radiation, local circulation, and precipitation. Preliminary results of a January 2005 low pressure system show the inclusion of BC increases (decreases) precipitation on the windward (leeward) side of the Transverse and Peninsular Ranges, and the Sierra Nevada. Results also show BC contributes to an increase in surface runoff on the windward side of the Transverse and Peninsular Ranges, the Sierra Nevada, and Rocky Mountains, but a decrease in snow water equivalent over Sierra Nevada and Rocky Mountains.

  2. Improved dynamic properties of natural rubber filled with irradiation-modified carbon black

    International Nuclear Information System (INIS)

    In this work, carbon black particles (CBs) were modified by high-energy electron beam (EB) irradiation at different doses. The influence of EB irradiation on the surface and particle size of CBs was investigated. Then, the CBs were compounded with natural rubber (NR), and the mechanical properties and dynamic properties of CBs/NR composite were further researched. The results showed that the irradiated CBs had more oxygen-containing groups and smaller particle sizes than original CBs. After irradiation, the content of bound rubber around the irradiated CBs increased, and the mechanical properties of CBs/NR composite were improved. Most importantly, NR filled with irradiated CBs has lower abrasion, higher wet skid resistance, and lower rolling resistance than NR filled with untreated CBs. - Highlights: • Irradiated CBs had more oxygen-containing groups than original CBs. • Irradiated CBs had smaller particle sizes than original CBs. • NR filled with irradiated CBs has lower abrasion than NR filled with untreated CBs. • NR filled with irradiated CBs has lower rolling resistance than NR filled with untreated CBs

  3. Photochemistry of Dissolved Black Carbon Released from Biochar: Reactive Oxygen Species Generation and Phototransformation.

    Science.gov (United States)

    Fu, Heyun; Liu, Huiting; Mao, Jingdong; Chu, Wenying; Li, Qilin; Alvarez, Pedro J J; Qu, Xiaolei; Zhu, Dongqiang

    2016-02-01

    Dissolved black carbon (BC) released from biochar can be one of the more photoactive components in the dissolved organic matter (DOM) pool. Dissolved BC was mainly composed of aliphatics and aromatics substituted by aromatic C-O and carboxyl/ester/quinone moieties as determined by solid-state nuclear magnetic resonance. It underwent 56% loss of absorbance at 254 nm, almost complete loss of fluorescence, and 30% mineralization during a 169 h simulated sunlight exposure. Photoreactions preferentially targeted aromatic and methyl moieties, generating CH2/CH/C and carboxyl/ester/quinone functional groups. During irradiation, dissolved BC generated reactive oxygen species (ROS) including singlet oxygen and superoxide. The apparent quantum yield of singlet oxygen was 4.07 ± 0.19%, 2-3 fold higher than many well-studied DOM. Carbonyl-containing structures other than aromatic ketones were involved in the singlet oxygen sensitization. The generation of superoxide apparently depended on electron transfer reactions mediated by silica minerals in dissolved BC, in which phenolic structures served as electron donors. Self-generated ROS played an important role in the phototransformation. Photobleaching of dissolved BC decreased its ability to further generate ROS due to lower light absorption. These findings have significant implications on the environmental fate of dissolved BC and that of priority pollutants. PMID:26717492

  4. Effects of humic acid coatings on phenanthrene sorption to black carbon

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Black carbon (BC) can strongly adsorb hydrophobic organic compounds (HOCs). The HOC sorption to coated BC could be attenuated in soil and sediment compared with that of the parent BC. To study the potential causes of the sorption attenuation, humic acid (HA) and BC were isolated. Phenanthrene (PHE) was selected as the representative of HOCs. BC was coated with the precipitated HA. The PHE sorption to the HA-coated BC was determined. The HA coatings on BC could result in the significant sorption attenuation of PHE to BC. The attenuation varied in different HA origin and was positively correlated to the aromaticity of HA. The attenuation could be explained by the direct competition between HA and PHE for the available sorption sites on BC and the reduction of the available sorption sites as a result of the pore blockage of BC caused by the HA coatings. Therefore, the HA coatings on BC was one potential cause of the attenuation of HOC sorption to BC in soil and sediment.

  5. 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.

  6. Enhancement effects of two kinds of carbon black on piezoelectricity of PVDF-HFP composite films

    Science.gov (United States)

    Hu, Bin; Hu, Ning; Wu, Liangke; Cui, Hao; Ying, Ji

    2015-12-01

    Two kinds of carbon black (CB) (i.e., CB#300 and CB#3350) were added into poly(vinylidene fluoride-hexafluoropropylene) (PVDF-HFP), respectively, to improve its piezoelectricity. The results revealed that when 0.5 wt.% CB was added, the best performance of the PVDF-HFP/CB composite films was obtained. The calibrated open circuit voltage and the density of harvested power of 0.5 wt.% CB#3350 contained composite films were 204%, and 464% (AC) and 561% (DC) of those of neat PVDF-HFP films. Similarly, for 0.5 wt.% CB#300 contained films, they were 211%, and 475% (AC) and 624% (DC), respectively. The enhancement mechanisms of piezoelectricity were clarified by the observation of Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC) and scanning electron microscope (SEM). We found that the added CBs act as nucleate agents to promote the formation of elongated, oriented and fibrillar β-phase crystals during the fabrication process, which increase the piezoelectricity. Overdosed CBs lead to a lower crystallinity degree, resulting in the lower piezoelectricity. Compared with CB#3350, CB#300 performs slightly better, which may be ascribed to its higher specific surface area.

  7. Size-dependent wet removal of black carbon in Canadian biomass burning plumes

    Directory of Open Access Journals (Sweden)

    J. W. Taylor

    2014-07-01

    Full Text Available Wet deposition is the dominant mechanism for removing black carbon (BC from the atmosphere, and is key in determining its atmospheric lifetime, vertical gradient and global transport. Despite the importance of BC in the climate system, especially in terms of its ability to modulate the radiative energy budget, there are few quantitative case studies of wet removal in ambient environments. We present a case study of BC wet removal by examining aerosol size distributions and BC coating properties sampled in three Canadian boreal biomass burning plumes, one of which passed through a precipitating cloud. In this plume, the largest and most coated BC particles were found to be preferentially removed, suggesting that nucleation scavenging was the likely dominant mechanism. Calculated mass absorption coefficient (MAC in the plumes showed no significant variation, as the shifts to smaller BC cores and thinner coatings had opposing effects. Similarly, calculated single-scatter albedo (SSA showed little variation, as a large number of non-BC particles were also present in the precipitation-affected plume. The remaining BC cores were smaller than those observed in previous studies of BC in post-precipitation outflow over Asia, possibly due to the thick coatings associated with the biomass burning particles. This study provides important constraints to model parameterisations of BC wet removal in biomass burning regions, which will help to reduce uncertainty in radiative forcing calculations.

  8. 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.

  9. 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.

  10. Pt-Free Counter Electrodes with Carbon Black and 3D Network Epoxy Polymer Composites

    Science.gov (United States)

    Kang, Gyeongho; Choi, Jongmin; Park, Taiho

    2016-03-01

    Carbon black (CB) and a 3D network epoxy polymer composite, representing dual functions for conductive corrosion protective layer (CCPL) and catalytic layer (CL) by the control of CB weight ratio against polymer is developed. Our strategy provides a proper approach which applies high catalytic ability and chemical stability of CB in corrosive triiodide/iodide (I3‑/I‑) redox electrolyte system. The CB and a 3D network epoxy polymer composite coated on the stainless steel (SS) electrode to alternate counter electrodes in dye sensitized solar cells (DSSCs). A two-step spray pyrolysis process is used to apply a solution containing epoxy monomers and a polyfunctional amine hardener with 6 wt% CB to a SS substrate, which forms a CCPL. Subsequently, an 86 wt% CB is applied to form a CL. The excellent catalytic properties and corrosion protective properties of the CB and 3D network epoxy polymer composites produce efficient counter electrodes that can replace fluorine-doped tin oxide (FTO) with CCPL/SS and Pt/FTO with CL/CCPL/SS in DSSCs. This approach provides a promising approach to the development of efficient, stable, and cheap solar cells, paving the way for large-scale commercialization.

  11. 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 comp