WorldWideScience

Sample records for thermal carbon black

  1. 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.

  2. Thermal conductivity and stability of nano size carbon black filled PDMS: Fuel cell perspective

    CSIR Research Space (South Africa)

    Chen, H

    2011-01-01

    Full Text Available conductivity measurements of the CB-PDMS composites in a fuel cell bipolar plate perspective. PDMS composite samples with specific wt %( 10-25%) of Carbon black loadings were prepared. This range was chosen to study because these composites have shown good... of experimental procedure are described elsewhere [6]. Fig.1 shows the variation of thermal conductivity k as a function temperature for PDMS composites filled with carbon black with different filler fraction ranging from 10-25 wt %. The measurements...

  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

  4. 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

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

    OpenAIRE

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

    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...

  6. Hydrogen and Carbon Black Production from Thermal Decomposition of Sub-Quality Natural Gas

    Directory of Open Access Journals (Sweden)

    M. Javadi

    2010-03-01

    Full Text Available The objective of this paper is computational investigation of the hydrogen and carbon black production through thermal decomposition of waste gases containing CH4 and H2S, without requiring a H2S separation process. The chemical reaction model, which involves solid carbon, sulfur compounds and precursor species for the formation of carbon black, is based on an assumed Probability Density Function (PDF parameterized by the mean and variance of mixture fraction and β-PDF shape. The effects of feedstock mass flow rate and reactor temperature on hydrogen, carbon black, S2, SO2, COS and CS2 formation are investigated. The results show that the major factor influencing CH4 and H2S conversions is reactor temperature. For temperatures higher than 1100° K, the reactor CH4 conversion reaches 100%, whilst H2S conversion increases in temperatures higher than 1300° K. The results reveal that at any temperature, H2S conversion is less than that of CH4. The results also show that in the production of carbon black from sub-quality natural gas, the formation of carbon monoxide, which is occurring in parallel, play a very significant role. For lower values of feedstock flow rate, CH4 mostly burns to CO and consequently, the production of carbon black is low. The results show that the yield of hydrogen increases with increasing feedstock mass flow rate until the yield reaches a maximum value, and then drops with further increase in the feedstock mass flow rate.

  7. 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.

  8. 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.

  9. 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

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

    Science.gov (United States)

    1985-06-01

    RUBBER COMPOSITES FOR ARMY APPLICATIONS 6. PERFORMING ORO. REPORT NUMBER 7. AUTHOR(q) S. CONTRACT OR GRANT NUMBER(41) Robert E. Sacher, Domenic P...Roadwheei Side SP - Standard Products SBR - Styrene-butadiene Rubber SR - Synthetic Rubber ( SBR or SBR -BR) TR - Track Rubber U - Uncured iii... applications ranging from automotive and aircraft tires to rubber belts, hoses, and seals. Although thermal studies on rubber materials closely

  11. Thermal BEC Black Holes

    Directory of Open Access Journals (Sweden)

    Roberto Casadio

    2015-10-01

    Full Text Available We review some features of Bose–Einstein condensate (BEC models of black holes obtained by means of the horizon wave function formalism. We consider the Klein–Gordon equation for a toy graviton field coupled to a static matter current in a spherically-symmetric setup. The classical field reproduces the Newtonian potential generated by the matter source, while the corresponding quantum state is given by a coherent superposition of scalar modes with a continuous occupation number. An attractive self-interaction is needed for bound states to form, the case in which one finds that (approximately one mode is allowed, and the system of N bosons can be self-confined in a volume of the size of the Schwarzschild radius. The horizon wave function formalism is then used to show that the radius of such a system corresponds to a proper horizon. The uncertainty in the size of the horizon is related to the typical energy of Hawking modes: it decreases with the increasing of the black hole mass (larger number of gravitons, resulting in agreement with the semiclassical calculations and which does not hold for a single very massive particle. The spectrum of these systems has two components: a discrete ground state of energy m (the bosons forming the black hole and a continuous spectrum with energy ω > m (representing the Hawking radiation and modeled with a Planckian distribution at the expected Hawking temperature. Assuming the main effect of the internal scatterings is the Hawking radiation, the N-particle state can be collectively described by a single-particle wave-function given by a superposition of a total ground state with energy M = Nm and Entropy 2015, 17 6894 a Planckian distribution for E > M at the same Hawking temperature. This can be used to compute the partition function and to find the usual area law for the entropy, with a logarithmic correction related to the Hawking component. The backreaction of modes with ω > m is also shown to reduce

  12. A composition for a carbon black compound

    Energy Technology Data Exchange (ETDEWEB)

    Mednikov, M.M.; Babyuk, V.N.; Kasatkin, G.P.; Khaykin, M.S.; Kozlov, L.A.; Stroyev, V.N.

    1983-01-01

    Paraffinylendiamine is additionally introduced into a known compound of a carbon black paste in order to increase the degree of blackness and the total stability. The ratio of components in parts is: carbon black 100; petroleum oil, 150 to 300; butadiene and 2-methyl-5-vinylpyridine copolymer, 0.1 to 10.0 and paraffinylendiamine, 0.5 to 5.0. Furnace, thermal, channel and acetylene carbon black with a specific Brunauer Emmett Teller surface of 10 to 1,000 square meters per grain, of high, medium and low structural states, modified by different compounds, for instance, 02, are used as the carbon black. Petroleum oil with a kinematic viscosity at 50 degrees of 15 to 40 centistokes (for instance, vaseline, transformer oil and so on) is used as the petroleum oil. The compound is prepared in the following manner. The petroleum oil, carbon black, copolymer and paraffinylendiamine are loaded into an apparatus with a mixer. The compound is mixed for two hours at 80 degrees, cooled to 25 degrees, unloaded and are ground in a color mill. The coloring force is determined in the following manner. The components are mixed for 30 minutes in a glue mixer, unloaded and is ground in the color mill ten times. One gram is taken off from each sample (Ob). The sample which contains no paraffinylendiamine is used as the control sample. One gram of each sample is mixed with ZnO until the color of the compound is transformed from shiny black to a gray matte (brightening). The ratio of the ZnO volume which went to brightening of the sample to the volume which went to brightening of the control sample (1.2 grams), multiplied by 100 percent is used as the coloring force. It is shown that the composition of the proposed carbon black paste has a high degree of blackness and a high aggregate stability.

  13. A first step towards identification of tannin-derived black carbon: Conventional pyrolysis (Py–GC–MS) and thermally assisted hydrolysis and methylation (THM–GC–MS) of charred condensed tannins

    NARCIS (Netherlands)

    Kaal, J.; Nierop, K.G.J.; Kraal, P.; Preston, C.M.

    2012-01-01

    Tannins account for a significant proportion of plant biomass and are likely to contribute to the residues formed by incomplete biomass combustion (black carbon, BC). Nonetheless, the molecular properties of thermally modified tannins have not been investigated in laboratory charring experiments. We

  14. Thermal hair of a quantum black hole

    Science.gov (United States)

    Itoh, Y.; Hotta, M.; Futamase, T.; Morikawa, M.

    1998-09-01

    We reexamine the possibility which has been argued since just after the discovery of Hawking radiation: the statistical explanation of Bekenstein-Hawking entropy by counting quasibounded modes of thermal fluctuation in two-dimensional black hole spacetime. While string theory has made much progress recently, it may be still interesting to study black hole entropy with field theories. The black hole concerned is quantum in the sense that it is in thermal equilibrium with its Hawking radiation. It is shown that the fluctuation around such a black hole obeys a wave equation with a potential whose peaks are located near the black hole and which is caused by quantum effects. We can construct models in which the potential in the above sense has several positive peaks and there are quasibounded modes confined between these peaks. This suggests that these modes contribute to black hole entropy. However, it is shown that the entropy associated with these modes does not obey the ordinary area law. We can call these modes additional thermal hair of the quantum black hole. Therefore the situation for the possibility is more difficult and we might find other ways to explain the entropy. From recent progress counting the number of states in string theory, it becomes more convincing that we expect Bekenstein-Hawking entropy for the Schwarzschild black hole will be explained exactly from the string theoretical point of view.

  15. Aerosol Optical Properties and Black Carbon Measurements (Ambient and Thermally-Denuded) from Detling, UK During the ClearfLo IOP in Winter 2012

    Science.gov (United States)

    Gorkowski, K.; Aiken, A. C.; Dubey, M. K.; Herndon, S. C.; Williams, L. R.; Worsnop, D. R.; Massoli, P.; Fortner, E.; Freedman, A.; Ng, N. L.; Allan, J. D.

    2012-12-01

    Continuous direct online aerosol and trace gas measurements were made in Delting, UK over the course of four weeks during the winter of 2012 as a part of the ClearfLo (Clean Air for London) campaign. Aerosols were sampled from the London plume (~33 miles WNW), fresh highway (~0.15 mi and 1.5 mi S, A249 and M20), urban (Maidstone; ~3 mi SW), power station (~8 mi N), and Continental European outflow (~50+ mi E/SE). LANL measurements include aerosol absorption and scattering at four wavelengths (375, 405, 532, 781 nm; PASS), aerosol extinction at 450 nm (CAPS), single particle black carbon (BC) number and mass concentrations (SP2), aerosol size distributions (LAS and SMPS), ambient and thermally-denuded aerosol filter samples for SEM and EDS analysis, PM10 C-13 aerosol filter samples, gas-phase CO2, H2O, and CH4 (Picarro). The SP2, PASS, and CAPS were located behind a valve-switching set-up to enable ambient and thermally-denuded (TD) samples to be collected at 10 minute intervals during the campaign, cycling between four temperature settings of 50, 120, 180, and 250C. Absorption from organics and coatings on BC are characterized by comparing the ambient data with the TD samples for the different aerosol sources that were sampled. Measurements from the SP2 are combined with absorption measurements from the three-wavelength photoacoustic soot spectrometer (PASS-3) at 405, 532, and 781 nm to determine wavelength-dependent mass absorption coefficients (MACs) and absorption angstrom exponents (AAEs). Extinction measurements from the CAPS compare well with the PASS using extinction angstrom exponents calculated from the PASS. BC increases with CO/CO2, a marker for inefficient combustion. We examine the mixing state of BC in the aged aerosol plumes by using the time lag between the scattering and incandescence signals measured by the SP2 and SEM analysis as a function of denuding temperature. The Detling/ClearfLo dataset is one of the most comprehensive in situ sets of

  16. Recommendations for reporting "black carbon" measurements

    National Research Council Canada - National Science Library

    Petzold, A; Ogren, J. A; Fiebig, M; Laj, P; Li, S.-M; Baltensperger, U; Holzer-Popp, T; Kinne, S; Pappalardo, G; Sugimoto, N; Wehrli, C; Wiedensohler, A; Zhang, X.-Y

    2013-01-01

      Although black carbon (BC) is one of the key atmospheric particulate components driving climate change and air quality, there is no agreement on the terminology that considers all aspects of specific properties, definitions...

  17. Black carbon emissions in China

    Science.gov (United States)

    Streets, David G.; Gupta, Shalini; Waldhoff, Stephanie T.; Wang, Michael Q.; Bond, Tami C.; Yiyun, Bo

    Black carbon (BC) is an important aerosol species because of its global and regional influence on radiative forcing and its local effects on the environment and human health. We have estimated the emissions of BC in China, where roughly one-fourth of global anthropogenic emissions is believed to originate. China's high rates of usage of coal and biofuels are primarily responsible for high BC emissions. This paper pays particular attention to the application of appropriate emission factors for China and the attenuation of these emissions where control devices are used. Nevertheless, because of the high degree of uncertainty associated with BC emission factors, we provide ranges of uncertainty for our emission estimates, which are approximately a factor of eight. In our central case, we calculate that BC emissions in China in 1995 were 1342 Gg, about 83% being generated by the residential combustion of coal and biofuels. We estimate that BC emissions could fall to 1224 Gg by 2020. This 9% decrease in BC emissions can be contrasted with the expected increase of 50% in energy use; the reduction will be obtained because of a transition to more advanced technology, including greater use of coal briquettes in place of raw coal in cities and towns. The increased use of diesel vehicles in the future will result in a greater share of the transport sector in total BC emissions. Spatially, BC emissions are predominantly distributed in an east-west swath across China's heartland, where the rural use of coal and biofuels for cooking and heating is widespread. This is in contrast to the emissions of most other anthropogenically derived air pollutants, which are closely tied to population and industrial centers.

  18. Soil Black Carbon Loss and Sediment Black Carbon Accumulation in a Central Texas Woodland

    Science.gov (United States)

    Schieve, E. A.; Hockaday, W. C.; White, J. D.

    2016-12-01

    The Balcones Canyonlands National Wildlife Refuge is located along the eastern edge of the Edwards Plateau in Texas, and was established in 1992 for the purpose of conserving habitat for two endangered bird species. The landscape is composed of hilly, mesa-valley terrain, which is mostly covered by grasslands and woodlands dominated by juniper with intermingling of various oak species. Based on historical photo analysis and tree fire scar dendrochronology, the area has experienced major land use changes over the last century due to wildfire, logging, and drought affecting soil stability and woodland species composition. A previous study on soil black carbon showed that site-specific soil erosion potential and time since last fire may act as controls on soil black carbon concentrations. However, the black carbon transport flux, depositional fate, or the magnitude of soil erosion effects upon the black carbon budget are unconstrained at the watershed scale. To address this, we sampled the sediments accumulating in small ponds constructed during the 1950's for livestock watering. We are quantifying black carbon in sediments using solid-state 13C nuclear magnetic resonance spectroscopy. Preliminary data suggest that the pond sediments are a black carbon sink. Black carbon comprises 15 % - 25 %, of the sedimentary organic carbon, as substantial enrichment relative to soils within the watershed. We will present an early assessment of the black carbon erosion and sediment accumulation rates in first- and second-order watersheds.

  19. Black Carbon in Marine Sediments: Quantification and Implications for the Sorption of Polycyclic Aromatic Hydrocarbons

    National Research Council Canada - National Science Library

    Accardi-Dey, AmyMarie

    2003-01-01

    ...) fraction and adsorption onto a combustion-derived, black carbon (BC) fraction. To study BC adsorption, a 375 deg C thermal oxidation method was employed to remove OC and isolate the BC fraction...

  20. Trans-Himalayan Transport of Black Carbon

    Science.gov (United States)

    Panday, A. K.; Dhungel, S.; Mahata, K. S.

    2012-12-01

    Aerosol optical depth and black carbon concentrations over the Indo-Gangetic Plains and the Himalayan foothills have increased significantly in recent years, with potentially large consequences on monsoon circulation, air quality, and agriculture. At the same time, snowfields and glaciers on the Himalaya and the Tibetan Plateau have been shrinking in many areas, potentially driven by the arrival of increasing quantities of atmospheric black carbon from the Indo-Gangetic Plains. The high peaks of the Himalaya form a barrier that blocks the transport of moisture and pollutants from South Asia to the Tibetan Plateau. Thus it is likely that the handful of valleys that cut across the Himalaya would play a significant role in channeling the trans-Himalayan transport of black carbon. The Kali Gandaki Valley in Nepal is one such valley. It has long provided easy transit for migrating birds and traders traveling between South Asia and the Tibetan Plateau, and we have hypothesized that it is a major transit route for Tibetan Plateau bound black carbon. A network of weather stations set up by the University of Virginia and ICIMOD in 2009-2010 has found day-time up-valley winds with sustained speeds that often exceed 10-15 m/s throughout the year, occasionally reaching 25 m/s. Since Summer 2011 we have measured black carbon concentrations, aerosol optical depth, carbon monoxide and ozone at a station in Jomsom, Nepal, at the point north of the Annapurna Himalaya where the Kali Gandaki Valley opens up onto the Tibetan Plateau. Together with observations we have been carrying out south of the Annapurna, this provides the first set of observational data to allow an estimation of the transport of Black Carbon up through cross-Himalayan valleys. We provide initial calculations of the annual BC flux up the Kali Gandaki Valley, as well as first estimates of the flux through valleys across the entire Himalaya.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-09-13

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

  2. 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.

  3. 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

  4. 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...

  5. 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.

  6. Modified carbon black materials for lithium-ion batteries

    Science.gov (United States)

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

    2016-06-14

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

  7. Thermal characterization of nanoporous 'black silicon' surfaces

    Science.gov (United States)

    Nichols, Logan; Duan, Wenqi; Toor, Fatima

    2016-09-01

    In this work we characterize the thermal conductivity properties of nanoprous `black silicon' (bSi). We fabricate the nanoporous bSi using the metal assisted chemical etching (MACE) process utilizing silver (Ag) metal as the etch catalyst. The MACE process steps include (i) electroless deposition of Ag nanoparticles on the Si surface using silver nitrate (AgNO3) and hydrofluoric acid (HF), and (ii) a wet etch in a solution of HF and hydrogen peroxide (H2O2). The resulting porosity of bSi is dependent on the ratio of the concentration of HF to (HF + H2O2); the ratio is denoted as rho (ρ). We find that as etch time of bSi increases the thermal conductivity of Si increases as well. We also analyze the absorption of the bSi samples by measuring the transmission and reflection using IR spectroscopy. This study enables improved understanding of nanoporous bSi surfaces and how they affect the solar cell performance due to the porous structures' thermal properties.

  8. A black carbon air quality network

    Science.gov (United States)

    Kirchstetter, T.; Caubel, J.; Cados, T.; Preble, C.; Rosen, A.

    2016-12-01

    We developed a portable, power efficient black carbon sensor for deployment in an air quality network in West Oakland, California. West Oakland is a San Francisco Bay Area residential/industrial community adjacent to regional port and rail yard facilities, and is surrounded by major freeways. As such, the community is affected by diesel particulate matter emissions from heavy-duty diesel trucks, locomotives, and ships associated with freight movement. In partnership with Environmental Defense Fund, the Bay Area Air Quality Management District, and the West Oakland Environmental Indicators Project, we are collaborating with community members to build and operate a 100-sensor black carbon measurement network for a period of several months. The sensor employs the filter-based light transmission method to measure black carbon. Each sensor node in the network transmits data hourly via SMS text messages. Cost, power consumption, and performance are considered in choosing components (e.g., pump) and operating conditions (e.g., sample flow rate). In field evaluation trials over several weeks at three monitoring locations, the sensor nodes provided black carbon concentrations comparable to commercial instruments and ran autonomously for a week before sample filters and rechargeable batteries needed to be replaced. Buildup to the 100-sensor network is taking place during Fall 2016 and will overlap with other ongoing air monitoring projects and monitoring platforms in West Oakland. Sensors will be placed along commercial corridors, adjacent to freeways, upwind of and within the Port, and throughout the residential community. Spatial and temporal black carbon concentration patterns will help characterize pollution sources and demonstrate the value of sensing networks for characterizing intra-urban air pollution concentrations and exposure to air pollution.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2008-04-24

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

  10. Black carbon: The reverse of its dark side

    NARCIS (Netherlands)

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

    2006-01-01

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

  11. Effect of thermal fluctuations on a charged dilatonic black Saturn

    Directory of Open Access Journals (Sweden)

    Behnam Pourhassan

    2016-04-01

    Full Text Available In this paper, we will analyze the effect of thermal fluctuations on the thermodynamics of a charged dilatonic black Saturn. These thermal fluctuations will correct the thermodynamics of the charged dilatonic black Saturn. We will analyze the corrections to the thermodynamics of this system by first relating the fluctuations in the entropy to the fluctuations in the energy. Then, we will use the relation between entropy and a conformal field theory to analyze the fluctuations in the entropy. We will demonstrate that similar physical results are obtained from both these approaches. We will also study the effect of thermal fluctuations on the phase transition in this charged dilatonic black Saturn.

  12. Effect of thermal fluctuations on a charged dilatonic black Saturn

    Energy Technology Data Exchange (ETDEWEB)

    Pourhassan, Behnam, E-mail: b.pourhassan@du.ac.ir [School of Physics, Damghan University, Damghan (Iran, Islamic Republic of); Faizal, Mir, E-mail: f2mir@uwaterloo.ca [Department of Physics and Astronomy, University of Lethbridge, Lethbridge, AB T1K 3M4 (Canada)

    2016-04-10

    In this paper, we will analyze the effect of thermal fluctuations on the thermodynamics of a charged dilatonic black Saturn. These thermal fluctuations will correct the thermodynamics of the charged dilatonic black Saturn. We will analyze the corrections to the thermodynamics of this system by first relating the fluctuations in the entropy to the fluctuations in the energy. Then, we will use the relation between entropy and a conformal field theory to analyze the fluctuations in the entropy. We will demonstrate that similar physical results are obtained from both these approaches. We will also study the effect of thermal fluctuations on the phase transition in this charged dilatonic black Saturn.

  13. Effect of Thermal Fluctuations on a Charged Dilatonic Black Saturn

    CERN Document Server

    Pourhassan, Behnam

    2016-01-01

    In this paper, we will analyze the effect of thermal fluctuations on the thermodynamics of a charged dilatonic black Saturn. These thermal fluctuations will correct the thermodynamics of the charged dilatonic black Saturn. We will analyze the corrections to the thermodynamics of this system by first relating the fluctuations in the entropy to the fluctuations in the energy. Then, we will use the relation between entropy and a conformal field theory to analyze the fluctuations in the entropy. We will demonstrate that similar physical results are obtained from both these approaches. We will also study the effect of thermal fluctuations on the phase transition in this charged dilatonic black Saturn.

  14. Black carbon network in Mexico. First Results

    Science.gov (United States)

    Barrera, Valter; Peralta, Oscar; Granado, Karen; Ortinez, Abraham; Alvarez-Ospina, Harry; Espinoza, Maria de la Luz; Castro, Telma

    2017-04-01

    After the United Nations Framework Convention on Climate Change celebrated in Paris 2016, many countries should adopt some mechanisms in the next years to contribute to mitigate greenhouse gas emissions and support sustainable development. Mexico Government has adopted an unconditional international commitment to carry out mitigation actions that would result in the reduction of 51% in black carbon (BC) emissions by year 2030. However, many BC emissions have been calculated by factor emissions. Since optical measurements of environmental BC concentrations can vary according the different components and their subsequence wavelength measure, it's important to obtain more accurate values. BC is formally defined as an ideally light-absorbing substance composed by carbon (Bond et al., 2013), and is the second main contributor (behind Carbon Dioxide; CO2) to positive radiative forcing (Ramanathan and Carmichael, 2008). Recently, BC has been used as an additional indicator in air quality management in some cities because is emitted from the incomplete combustion of fossil fuels, biofuel and biomass burning in both anthropogenic and it is always emitted with other particles and gases, such as organic carbon (OC), nitrogen oxides (NOx), and sulfur dioxide (SO2). Black Carbon, PM2.5 and pollutant gases were measured from January 2015 to December 2015 at three main cities in Mexico, and two other places to evaluate the BC concentration levels in the country. The urban background sites (Mexico City, Monterrey, Guadalajara, MXC-UB, GDL-UB, MTY-UB), a sub-urban background site (Juriquilla, Queretaro, JUR-SUB) and a regional background site (Altzomoni, ALT-RB). Results showed the relationship between BC and PM2.5 in the 3 large cities, with BC/PM2.5 ratios near 0.14 to 0.09 and a high BC-CO relationship in all the year in Mexico City, who showed that mobile sources are a common, at least in cities with a non-significant biomass burning emission related to agriculture or coal

  15. Geologic framework of thermal springs, Black Canyon, Nevada and Arizona

    Science.gov (United States)

    Beard, L. Sue; Anderson, Zachary W.; Felger, Tracey J.; Seixas, Gustav B.

    2014-01-01

    Thermal springs in Black Canyon of the Colorado River, downstream of Hoover Dam, are important recreational, ecological, and scenic features of the Lake Mead National Recreation Area. This report presents the results from a U.S. Geological Survey study of the geologic framework of the springs. The study was conducted in cooperation with the National Park Service and funded by both the National Park Service and National Cooperative Geologic Mapping Program of the U.S. Geological Survey. The report has two parts: A, a 1:48,000-scale geologic map created from existing geologic maps and augmented by new geologic mapping and geochronology; and B, an interpretive report that presents results based on a collection of fault kinematic data near springs within Black Canyon and construction of 1:100,000-scale geologic cross sections that extend across the western Lake Mead region. Exposures in Black Canyon are mostly of Miocene volcanic rocks, underlain by crystalline basement composed of Miocene plutonic rocks or Proterozoic metamorphic rocks. The rocks are variably tilted and highly faulted. Faults strike northwest to northeast and include normal and strike-slip faults. Spring discharge occurs along faults intruded by dacite dikes and plugs; weeping walls and seeps extend away from the faults in highly fractured rock or relatively porous volcanic breccias, or both. Results of kinematic analysis of fault data collected along tributaries to the Colorado River indicate two episodes of deformation, consistent with earlier studies. The earlier episode formed during east-northeast-directed extension, and the later during east-southeast-directed extension. At the northern end of the study area, pre-existing fault blocks that formed during the first episode were rotated counterclockwise along the left-lateral Lake Mead Fault System. The resulting fault pattern forms a complex arrangement that provides both barriers and pathways for groundwater movement within and around Black

  16. New Potential Sources for Black Onaping Carbon

    Science.gov (United States)

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

    1997-01-01

    One intriguing and important issue of the Sudbury Structure concerns the source of the relatively large amount of C in the Onaping Formation Black member. This dilemma was recently addressed, and the conclusion was reached that an impactor could not have delivered all of the requisite C. Becker et al. have suggested that much of the C came from the impactor and reported the presence of interstellar He "caged" inside some fullerenes that may have survived the impact. So, conceivably, the C inventory in the Sudbury Structure comes from both target and impactor materials, although the known target rocks have little C. We discuss here the possibility of two terrestrial sources for at least some of the C: (1) impact evaporation/dissociation of C from carbonate target rocks and (2) the presence of heretofore-unrecognized C-rich (up to 26 wt%) siliceous "shale," fragments, which are found in the upper, reworked Black member. Experimental: Hypervelocity impact of a 0.635-diameter Al projectile into dolomite at 5.03 km/s (performed at the Ames Research Center vertical gun range) produced a thin, black layer (= 0.05 mm thick) that partially lined the crater and coated impactor remnants. Scanning electronic microscope (SEM) imagery shows this layer to be spongelike on a submicron scale and Auger spectroscopic analyses yield: 33% C, 22% Mg, 19% 0, and 9% Al (from the projectile). Elemental mapping shows that all of the available 0 is combined with Ca and Mg, Al is not oxidized, and C is in elemental form. Dissociation efficiency of C from CO2 is estimated to be lonsdaleite/chaoite (oxidizing collector). These experiments confirm the reduction of C from carbonates in impact vapor plumes. Observational: SEM observations and microprobe analyses of small, black shalelike inclusions in the upper Black Onaping indicate high C contents (7-26 wt% avg. = 16%). They contain mostly quartz and carbonaceous matter with small amounts of altered K-feldspar, clays, Fe oxide, and a sulfide. No

  17. Studies on Enhancing Transverse Thermal Conductivity Carbon/Carbon Composites

    National Research Council Canada - National Science Library

    Manocha, Lalit M; Manocha, Satish M; Roy, Ajit

    2007-01-01

    The structure derived potential properties of Graphite such as high stiffness coupled with high thermal conductivity and low coefficient of thermal expansion have been better achieved in Carbon fibers...

  18. Black Carbon Measurement and Modeling in the Arabian Peninsula

    Science.gov (United States)

    Zawad, Faisal Al; Khoder, Mamdouh; Almazroui, Mansour; Alghamdi, Mansour; Lihavainen, Heikki; Hyvarinen, Antti; Henriksson, Svante

    2017-04-01

    Black carbon is an important atmospheric aerosol as an effective factor in public health, changing the global and regional climate, and reducing visibility. Black carbon absorbs light, warms the atmosphere, and modifies cloud droplets and the amount of precipitation. In spite of this significance, knowledge of black carbon over the Arabian Peninsula is hard to find in literature until recently. The total mass of black carbon and wind direction and speeds were measured continuously at Hada Al-Sham, Saudi Arabia for the year 2013. In addition, a state of the art global aerosol - climate model (ECHAM5-HAM) was used to determine black carbon climatology over the Arabian Peninsula. Simulation of the model was carried out for the years eight years (2004 - 2011). The daily mean values of the concentrations of black carbon had a minimum of 15.0 ng/m3 and a maximum of 6372 ng/m3 with a mean of at 1899 ng/m3. The diurnal pattern of black carbon showed higher values overnight, and steady low values during daytimes caused by sea and land breezes. Seasons of black carbon vary over the Arabian Peninsula, and the longest is in the Northern Region where it lasts from July to October. High concentrations of black carbon at Hada Al-Sham was observed with a mean of 1.9 µm/m3, and seasons of black carbon vary widely across the Arabian Peninsula. Assessment of the effects of black carbon over the Arabian Peninsula on the global radiation balance. Initiating a black carbon monitoring network is highly recommended to assess its impacts on health, environment, and climate.

  19. Electrochemical Biosensors Based on Nanostructured Carbon Black: A Review

    Directory of Open Access Journals (Sweden)

    Tiago Almeida Silva

    2017-01-01

    Full Text Available Carbon black (CB is a nanostructured material widely used in several industrial processes. This nanomaterial features a set of remarkable properties including high surface area, high thermal and electrical conductivity, and very low cost. Several studies have explored the applicability of CB in electrochemical fields. Recent data showed that modified electrodes based on CB present fast charge transfer and high electroactive surface area, comparable to carbon nanotubes and graphene. These characteristics make CB a promising candidate for the design of electrochemical sensors and biosensors. In this review, we highlight recent advances in the use of CB as a template for biosensing. As will be seen, we discuss the main biosensing strategies adopted for enzymatic catalysis for several target analytes, such as glucose, hydrogen peroxide, and environmental contaminants. Recent applications of CB on DNA-based biosensors are also described. Finally, future challenges and trends of CB use in bioanalytical chemistry are discussed.

  20. 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%.

  1. Depilating Global Charge From Thermal Black Holes

    CERN Document Server

    March-Russell, John David; March-Russell, John; Wilczek, Frank

    2001-01-01

    At a formal level, there appears to be no difficulty involved in introducing a chemical potential for a globally conserved quantum number into the partition function for space-time including a black hole. Were this possible, however, it would provide a form of black hole hair, and contradict the idea that global quantum numbers are violated in black hole evaporation. We demonstrate dynamical mechanisms that negate the formal procedure, both for topological charge (Skyrmions) and complex scalar-field charge. Skyrmions collapse to the horizon; scalar-field charge fluctuates uncontrollably.

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

    Science.gov (United States)

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

    1999-03-01

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

  3. 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

  4. 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.

  5. Chemically treated carbon black waste and its potential applications

    Energy Technology Data Exchange (ETDEWEB)

    Dong, Pengwei; Maneerung, Thawatchai; Ng, Wei Cheng; Zhen, Xu [NUS Environmental Research Institute, National University of Singapore, 1 Create Way, Create Tower #15-02, 138602 (Singapore); Dai, Yanjun [School of Mechanical Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China); Tong, Yen Wah [NUS Environmental Research Institute, National University of Singapore, 1 Create Way, Create Tower #15-02, 138602 (Singapore); Department of Chemical and Biomolecular Engineering, National University of Singapore, 4 Engineering Drive 4, 117585 (Singapore); Ting, Yen-Peng [Department of Chemical and Biomolecular Engineering, National University of Singapore, 4 Engineering Drive 4, 117585 (Singapore); Koh, Shin Nuo [Sembcorp Industries Ltd., 30 Hill Street #05-04, 179360 (Singapore); Wang, Chi-Hwa, E-mail: chewch@nus.edu.sg [Department of Chemical and Biomolecular Engineering, National University of Singapore, 4 Engineering Drive 4, 117585 (Singapore); Neoh, Koon Gee, E-mail: chenkg@nus.edu.sg [Department of Chemical and Biomolecular Engineering, National University of Singapore, 4 Engineering Drive 4, 117585 (Singapore)

    2017-01-05

    Highlights: • Hazardous impurities separated from carbon black waste with little damage to solid. • Heavy metals were effectively removed from carbon black waste by HNO{sub 3} leaching. • Treated carbon black waste has high adsorption capacity (∼356.4 mg{sub dye}/g). • Carbon black waste was also found to show high electrical conductivity (10 S/cm). - Abstract: In this work, carbon black waste – a hazardous solid residue generated from gasification of crude oil bottom in refineries – was successfully used for making an absorbent material. However, since the carbon black waste also contains significant amounts of heavy metals (especially nickel and vanadium), chemical leaching was first used to remove these hazardous impurities from the carbon black waste. Acid leaching with nitric acid was found to be a very effective method for removal of both nickel and vanadium from the carbon black waste (i.e. up to 95% nickel and 98% vanadium were removed via treatment with 2 M nitric acid for 1 h at 20 °C), whereas alkali leaching by using NaOH under the same condition was not effective for removal of nickel (less than 10% nickel was removed). Human lung cells (MRC-5) were then used to investigate the toxicity of the carbon black waste before and after leaching. Cell viability analysis showed that the leachate from the original carbon black waste has very high toxicity, whereas the leachate from the treated samples has no significant toxicity. Finally, the efficacy of the carbon black waste treated with HNO{sub 3} as an absorbent for dye removal was investigated. This treated carbon black waste has high adsorption capacity (∼361.2 mg {sub dye}/g {sub carbonblack}), which can be attributed to its high specific surface area (∼559 m{sup 2}/g). The treated carbon black waste with its high adsorption capacity and lack of cytotoxicity is a promising adsorbent material. Moreover, the carbon black waste was found to show high electrical conductivity (ca. 10 S

  6. Black carbon aerosol size in snow.

    Science.gov (United States)

    Schwarz, J P; Gao, R S; Perring, A E; Spackman, J R; Fahey, D W

    2013-01-01

    The effect of anthropogenic black carbon (BC) aerosol on snow is of enduring interest due to its consequences for climate forcing. Until now, too little attention has been focused on BC's size in snow, an important parameter affecting BC light absorption in snow. Here we present first observations of this parameter, revealing that BC can be shifted to larger sizes in snow than are typically seen in the atmosphere, in part due to the processes associated with BC removal from the atmosphere. Mie theory analysis indicates a corresponding reduction in BC absorption in snow of 40%, making BC size in snow the dominant source of uncertainty in BC's absorption properties for calculations of BC's snow albedo climate forcing. The shift reduces estimated BC global mean snow forcing by 30%, and has scientific implications for our understanding of snow albedo and the processing of atmospheric BC aerosol in snowfall.

  7. Geolocating Russian sources for Arctic black carbon

    Science.gov (United States)

    Cheng, Meng-Dawn

    2014-08-01

    To design and implement an effective emission control strategy for black carbon (BC), the locations and strength of BC sources must be identified. Lack of accurate source information from the Russian Federation has created difficulty for a range of research and policy activities in the Arctic because Russia occupies the largest landmass in the Arctic Circle. A project was initiated to resolve emission sources of BC in the Russian Federation by using the Potential Source Contribution Function (PSCF). It used atmospheric BC data from two Arctic sampling stations at Alert Nunavut, Canada, and Tiksi Bay, Russia. The geographical regions of BC emission sources in Russia were identified and summarized as follows: (1) a region surrounding Moscow, (2) regions in Eurasia stretching along the Ural Mountains from the White Sea to the Black Sea, and (3) a number of scattered areas from western Siberia to the Russian Far East. Particulate potassium ions, non-marine sulfate, and vanadium were used to assist in resolving the source types: forest fire/biomass burning, coal-fired power plant, and oil combustion. Correlating these maps with the BC map helped to resolve source regions of BC emissions and connect them to their corresponding source types. The results imply that a region south of Moscow and another north of the Ural Mountains could be significant BC sources, but none of the grid cells in these regions could be linked to forest fires, oil combustion, or coal-fired power plants based on these three markers.

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

    Science.gov (United States)

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

    2014-12-01

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

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

    DEFF Research Database (Denmark)

    Ashton, Sean James; Arenz, Matthias

    2012-01-01

    Publication year: 2012 Source:Journal of Power Sources, Volume 217 Sean J. Ashton, Matthias Arenz The intention of the study presented here is to compare the electrochemical oxidation tendencies of a pristine Ketjen Black EC300 high surface area (HSA) carbon black, and four graphitised counterparts...... the characterisation and comparison of the complete electrochemical oxidation rates and behaviours of the various carbon blacks. It is observed that the behaviour of the carbon black towards electrochemical oxidation is highly dynamic, and dependent on the properties of the pristine carbon back, the degree...... 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...

  10. Thermal responses of Symbiodinium photosynthetic carbon assimilation

    Science.gov (United States)

    Oakley, Clinton A.; Schmidt, Gregory W.; Hopkinson, Brian M.

    2014-06-01

    The symbiosis between hermatypic corals and their dinoflagellate endosymbionts, genus Symbiodinium, is based on carbon exchange. This symbiosis is disrupted by thermally induced coral bleaching, a stress response in which the coral host expels its algal symbionts as they become physiologically impaired. The disruption of the dissolved inorganic carbon (DIC) supply or the thermal inactivation of Rubisco have been proposed as sites of initial thermal damage that leads to the bleaching response. Symbiodinium possesses a highly unusual Form II ribulose bisphosphate carboxylase/oxygenase (Rubisco), which exhibits a lower CO2:O2 specificity and may be more thermally unstable than the Form I Rubiscos of other algae and land plants. Components of the CO2 concentrating mechanism (CCM), which supplies inorganic carbon for photosynthesis, may also be temperature sensitive. Here, we examine the ability of four cultured Symbiodinium strains to acquire and fix DIC across a temperature gradient. Surprisingly, the half-saturation constant of photosynthesis with respect to DIC concentration ( K P), an index of CCM function, declined with increasing temperature in three of the four strains, indicating a greater potential for photosynthetic carbon acquisition at elevated temperatures. In the fourth strain, there was no effect of temperature on K P. Finding no evidence for thermal inhibition of the CCM, we conclude that CCM components are not likely to be the primary sites of thermal damage. Reduced photosynthetic quantum yields, a hallmark of thermal bleaching, were observed at low DIC concentrations, leaving open the possibility that reduced inorganic carbon availability is involved in bleaching.

  11. Physicochemical Characteristics of Black Garlic after Different Thermal Processing Steps.

    Science.gov (United States)

    Kang, Ok-Ju

    2016-12-01

    This study investigated the physicochemical characteristics of black garlic (BG) after different thermal processing steps. Compared with fresh garlic (FG), the moisture content and pH in BG decreased significantly, while the ash content and browning intensity increased during thermal processing. The total mineral and the free sugar contents were significantly higher than that of the BG2 and BG4 samples, respectively. The free sugar content increased by 16-fold in the BG cloves compared with that of FG, while the amino acid content increased during the first stage of thermal processing, and subsequently decreased. The thiosulfinate content in all samples decreased to during thermal processing. The pyruvic acid content initially increased and then decreased during thermal processing. These results contribute to our understanding of the role of thermal processing in the quality formation of BG.

  12. 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.

  13. Black carbon sequestration as an alternative to bioenergy

    Energy Technology Data Exchange (ETDEWEB)

    Fowles, Malcolm [Department of Technology Management, The Open University, Walton Hall, Milton Keynes, MK7 6AA (United Kingdom)

    2007-06-15

    Most policy and much research concerning the application of biomass to reduce global warming gas emissions has concentrated either on increasing the Earth's reservoir of biomass or on substituting biomass for fossil fuels, with or without CO{sub 2} sequestration. Suggested approaches entail varied risks of impermanence, delay, high costs, and unknowable side-effects. An under-researched alternative approach is to extract from biomass black (elemental) carbon, which can be permanently sequestered as mineral geomass and may be relatively advantageous in terms of those risks. This paper reviews salient features of black carbon sequestration and uses a high-level quantitative model to compare the approach with the alternative use of biomass to displace fossil fuels. Black carbon has been demonstrated to produce significant benefits when sequestered in agricultural soil, apparently without bad side-effects. Black carbon sequestration appears to be more efficient in general than energy generation, in terms of atmospheric carbon saved per unit of biomass; an exception is where biomass can efficiently displace coal-fired generation. Black carbon sequestration can reasonably be expected to be relatively quick and cheap to apply due to its short value chain and known technology. However, the model is sensitive to several input variables, whose values depend heavily on local conditions. Because characteristics of black carbon sequestration are only known from limited geographical contexts, its worldwide potential will not be known without multiple streams of research, replicated in other contexts. (author)

  14. Global civil aviation black carbon emissions.

    Science.gov (United States)

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

    2013-09-17

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

  15. Thermal carbonization of nanoporous silicon: Formation of carbon ...

    Indian Academy of Sciences (India)

    An interesting phenomenon is observed while carrying out thermal carbonization of porous silicon (PS) with an aim to arrest the natural surface degradation, and it is a burning issue for PS-based device applications. A tubular carbon structure has been observed on the PS surface. Raman, Fourier transform infrared ...

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

    NARCIS (Netherlands)

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

    2009-01-01

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

  17. Carbon Nanotubes as Thermally Induced Water Pumps

    DEFF Research Database (Denmark)

    Oyarzua, Elton; Walther, Jens Honore; Megaridis, Constantine M

    2017-01-01

    Thermal Brownian motors (TBMs) are nanoscale machines that exploit thermal fluctuations to provide useful work. We introduce a TBM-based nanopump which enables continuous water flow through a carbon nanotube (CNT) by imposing an axial thermal gradient along its surface. We impose spatial asymmetry...... along the CNT by immobilizing certain points on its surface. We study the performance of this molecular motor using molecular dynamics (MD) simulations. From the MD trajectories, we compute the net water flow and the induced velocity profiles for various imposed thermal gradients. We find that spatial...

  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

    Energy Technology Data Exchange (ETDEWEB)

    Arora, Neha, E-mail: n4neha31@gmail.com [Department of Mechanical Engineering, Birla Institute of Technology and Science, Pilani (India); Sharma, N. N. [Department of Mechanical Engineering, Birla Institute of Technology and Science, Pilani (India); Director, School of Automobile, Mechanical & Mechatronics, Manipal University,Jaipur,India (India)

    2016-04-13

    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. Adsorption of Remazol Black B dye on Activated Carbon Felt

    Directory of Open Access Journals (Sweden)

    Donnaperna Lucio

    2008-11-01

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

  1. The atmospheric lifetime of black carbon

    Science.gov (United States)

    Cape, J. N.; Coyle, M.; Dumitrean, P.

    2012-11-01

    Black carbon (BC) in the atmosphere contributes to the human health effects of particulate matter and contributes to radiative forcing of climate. The lifetime of BC, particularly the smaller particle sizes (PM2.5) which can be transported over long distances, is therefore an important factor in determining the range of such effects, and the spatial footprint of emission controls. Theory and models suggest that the typical lifetime of BC is around one week. The frequency distributions of measurements of a range of hydrocarbons at a remote rural site in southern Scotland (Auchencorth Moss) between 2007 and 2010 have been used to quantify the relationship between atmospheric lifetime and the geometric standard deviation of observed concentration. The analysis relies on an assumed common major emission source for hydrocarbons and BC, namely diesel-engined vehicles. The logarithm of the standard deviation of the log-transformed concentration data is linearly related to hydrocarbon lifetime, and the same statistic for BC can be used to assess the lifetime of BC relative to the hydrocarbons. Annual average data show BC lifetimes in the range 4-12 days, for an assumed OH concentration of 7 × 105 cm-3. At this site there is little difference in BC lifetime between winter and summer, despite a 3-fold difference in relative hydrocarbon lifetimes. This observation confirms the role of wet deposition as an important removal process for BC, as there is no difference in precipitation between winter and summer at this site. BC lifetime was significantly greater in 2010, which had 23% less rainfall than the preceding 3 years.

  2. Wet Removal of Organic and Black Carbon Aerosols

    Science.gov (United States)

    Torres, A.; Bond, T. C.; Lehmann, C.

    2012-12-01

    Organic carbon (OC) and black carbon (BC) aerosols derived from the combustion of fossil fuels and biomass are significant atmospheric pollutants that alter the Earth's radiation balance and affect human health. Carbonaceous aerosol lifetime and extent of its effects are mainly controlled by its wet removal, especially by rain. Limited work has been done to measure both BC and OC from rain events even though these aerosols are co-emitted and exist together in the atmosphere. The choices of analytical techniques for measuring OC and BC in water are limited, and researchers often employ the same techniques used for measuring atmospheric carbon particles. There is no agreement in the methods employed for monitoring carbon concentration in precipitation. As part of the method development, the Single Particle Soot Photometer (SP2), Thermal-Optical Analysis (TOA), Ultraviolet/Visible (UV/VIS) Spectrophotometer, and the Total Organic Carbon (TOC) Analyzer were evaluated for measuring BC suspended in water, water insoluble OC (WIOC) and dissolved OC (DOC). The study also monitored the concentration of BC, WIOC, and DOC in rainwater collected at Bondville (Illinois) for 18 months. Results indicated that 34% (±3%) of the BC mass was lost in the SP2 analysis, most probably during the nebulization process. Filtration required for TOA also had large losses (>75%) because quartz fiber filters were ineffective for capturing BC particles from water. Addition of NH4H2PO4 as a coagulant improved (>95%) the capture efficiency of the filters. UV/VIS spectrophotometry had good linearity, but the sensitivity for detecting BC particles (±20 μg/L) suspended in water was inadequate. TOC analysis was a robust technique for measuring both DOC and total carbon (BC + OC). The chosen techniques were TOC analysis for DOC, and TOA with an optimized filtration procedure for BC and WIOC. The mean concentrations in rainwater were 8.72 (±9.84) μg/L of BC, 88.97 (±62.64) μg/L of WIOC, and 1

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

    OpenAIRE

    Kaluža, Luděk

    2014-01-01

    Carbon supported Pt represents conventional catalyst in polymer electrolyte membrane fuel battery (PEM fuel cell). The aim of this work was to elucidate on the methods of Pt deposition on carbon black to achieve high loadings of Pt of about 60 wt.% in highly dispersed form.

  4. Enviro-HIRLAM Applicability for Black Carbon Studies in Arctic

    Science.gov (United States)

    Nuterman, Roman; Mahura, Alexander; Baklanov, Alexander; Kurganskiy, Alexander; Amstrup, Bjarne; Kaas, Eigil

    2015-04-01

    One of the main aims of the Nordic CarboNord project ("Impact of black carbon on air quality and climate in Northern Europe and Arctic") is focused on providing new information on distribution and effects of black carbon in Northern Europe and Arctic. It can be done through assessing robustness of model predictions of long-range black carbon distribution and its relation to climate change and forcing. In our study, the online integrated meteorology-chemistry/aerosols model - Enviro-HIRLAM (Environment - HIgh Resolution Limited Area Model) - is used. This study, at first, is focused on adaptation (model setup, domain for the Northern Hemisphere and Arctic region, emissions, boundary conditions, refining aerosols microphysics and chemistry, cloud-aerosol interaction processes) of Enviro-HIRLAM model and selection of most unfavorable weather and air pollution episodes for the Arctic region. Simulations of interactions between black carbon and meteorological processes in northern conditions for selected episodes will be performed (at DMI's supercomputer HPC CRAY-XT5), and then long-term simulations at regional scale for selected winter vs. summer months. Modelling results will be compared on a diurnal cycle and monthly basis against observations for key meteorological parameters (such as air temperature, wind speed, relative humidity, and precipitation) as well as aerosol concentration. Finally, evaluation of black carbon atmospheric transport, dispersion, and deposition patterns at different spatio-temporal scales; physical-chemical processes and transformations of black carbon containing aerosols; and interactions and effects between black carbon and meteorological processes in Arctic weather conditions will be done.

  5. Trade and the Future of China's Black Carbon Emissions

    Science.gov (United States)

    Persad, G.; Oppenheimer, M.; Naik, V.

    2016-12-01

    Emissions of black carbon aerosols in China have increased by over 200% during the last 50 years, with negative implications both for human health and for regional and global climate. The Representative Concentration Pathway (RCP) emissions scenarios all assume that China's future black carbon emissions will decrease. However, this decline partially depends on the assumption that the evolution of future pollutant emissions in developing nations will match the observed historical relationship between air quality and income in developed nations. Recent research has demonstrated that a substantial portion of China's current black carbon emissions are driven by the production of goods exported for consumption elsewhere. This constitutes an external demand for black carbon-emitting activity in China that is much smaller in the developed nations on which the historical air quality/income relationship is based. We here show using integrated assessment model output, general circulation modeling, and emissions and economic data that (1) China must achieve a faster technological and regulatory evolution than did developed countries in order achieve the same air quality/income trajectory; (2) China's uniquely large share of export-related black carbon-emitting activities and their potential growth are a plausible explanation for this disparity; and (3) the climate and health implications of these export-related black carbon emissions, if unmitigated, are of interest from a policy perspective. Together these results indicate that the production of goods for export will steepen the mitigation curve for China relative to developed nations, if China is to achieve the future black carbon emissions reductions assumed in the RCPs.

  6. Inkjet printing of carbon black electrodes for dielectric elastomer actuators

    Science.gov (United States)

    Schlatter, Samuel; Rosset, Samuel; Shea, Herbert

    2017-04-01

    Inkjet printing is an appealing technique to print electrodes for Dielectric Elastomer Actuators (DEAs). Here we present the preparation and ink-jet printing of a carbon black electrode mixture and characterise its properties. Carbon black has been used extensively in the past because it is very compliant; however, it has a high resistance and can be very dirty to work with. In this paper we show that carbon black remains an appropriate electrode material, and when inkjet printed can be used to fabricate devices meeting today's demanding requirements. DEAs are becoming thinner to decrease actuation voltages and are shrinking in size to match the scale of the devices in the biomedical field, tuneable optics, and microfluidics. Inkjet printing addresses both of these problems. Firstly, Inkjet printing is a non-contact technique and can print on very thin freestanding membranes. Secondly, the high precision of inkjet printers makes it possible to print complex electrode geometries in the millimetre scale. We demonstrate the advantages of inkjet printing and carbon black electrodes by conducting a full characterisation of the printed electrodes. The printed carbon black electrodes have resistances as low as 13kΩ/□, an elastic modulus of approximately 1MPa, and a cyclic resistance swing which increases by 7% over 1500 cycles at 50% stretch. We also demonstrate a DEA with printed carbon black electrodes with a diametral stretch of 8.8% at an electric field of approximately 94V/μm. Finally a qualitative test is conducted to show that the printed carbon black electrode is extremely hardwearing.

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

    Science.gov (United States)

    Talianu, Camelia; Marmureanu, Luminita; Nicolae, Doina

    2015-04-01

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

  8. Carbon black reinforced polymethyl methacrylate (PMMA)-based composite particles: preparation, characterization, and application

    Science.gov (United States)

    Liang, Tian; Yan, Chunjie; Zhou, Sen; Zhang, Yonghan; Yang, Bipeng

    2017-10-01

    Carbon black (CB) is an excellent filler to reinforce polymers because of its unique thermal and mechanical properties. Thus, a type of modified carbon black (MCB) was developed, which led to reduced filler aggregation in methyl methacrylate (MMA) monomers and resulted in homogeneous dispersion in the polymethyl methacrylate (PMMA) substrate. The PMMA-MCB composite particles that were prepared in this work possessed remarkable and stable properties. Therefore, they can be used as an ultra-lightweight proppant (ULWP). Fourier transform infrared spectroscopy showed that CB was successfully modified and the MCB was well dispersed in the PMMA matrix. Results of crushing rate and differential scanning calorimetry demonstrated that MCB could significantly enhance the thermal and mechanical performance of the ULWP. Heat treatment of the ULWP under a nitrogen atmosphere could also clearly enhance its performance in various aspects. The process of modifying CB, the approach of synthesizing PMMA-MCB composite particles, and their mechanism were systematically investigated in this work.

  9. Black carbon and organic matter stabilization in soil

    Science.gov (United States)

    Lehmann, J.; Liang, B.; Sohi, S.; Gaunt, J.

    2007-12-01

    Interaction with minerals is key to stabilization of organic matter in soils. Stabilization is commonly perceived to occur due to entrapment in pore spaces, encapsulation within aggregates or interaction with mineral surfaces. Typically only interactions between organic matter and minerals are considered in such a model. Here we demonstrate that black carbon may act very similar to minerals in soil in that it enhances the stabilization of organic matter. Mineralization of added organic matter was slower and incorporation into intra-aggregate fractions more rapid in the presence of black carbon. Added double-labeled organic matter was recovered in fractions with high amounts of black carbon. Synchrotron-based near-edge x-ray fine structure (NEXAFS) spectroscopy coupled to scanning transmission x-ray microscopy (STXM) suggested a possible interaction of microorganisms with black carbon surfaces and metabolization of residues. These findings suggest a conceptual model that includes carbon-carbon interactions and by-passing for more rapid stabilization of litter into what is commonly interpreted as stable carbon pools.

  10. Nanometer-scale surface modification of epoxy with carbon black and electromagnetic waves.

    Science.gov (United States)

    Kim, Bu Gi; Lee, Dai Gil

    2010-05-07

    The surface morphology of polymers and polymer composites strongly influences both the adhesive bonding strength of composite structures and the electrical conduction through carbon fiber composites. Conventional surface modification techniques (such as mechanical abrading, chemical treatment, plasma treatment and flame treatment) not only damage the surfaces of polymers and polymer composites but also increase production cost. In this study, the surface of epoxy was modified by heating carbon black with electromagnetic waves in order to generate nanometer-sized grooves. A thermal transfer model was developed to investigate the generation mechanism of the grooves and the process variables. In the surface modification technique, electromagnetic waves and carbon black were used to improve both the bonding strength and the electrical conductivity of the composite in a fast and efficient way.

  11. Very Long Time Scales and Black Hole Thermal Equilibrium

    CERN Document Server

    Barbón, José L F

    2003-01-01

    We estimate the very long time behaviour of correlation functions in the presence of eternal black holes. It was pointed out by Maldacena (hep-th 0106112) that their vanishing would lead to a violation of a unitarity-based bound. The value of the bound is obtained from the holographic dual field theory. The correlators indeed vanish in a semiclassical bulk approximation. We trace the origin of their vanishing to the continuum energy spectrum in the presence of event horizons. We elaborate on the two very long time scales involved: one associated with the black hole and the other with a thermal gas in the vacuum background. We find that assigning a role to the thermal gas background, as suggested in the above work, does restore the compliance with a time-averaged unitarity bound. We also find that additional configurations are needed to explain the expected time dependence of the Poincar\\'e recurrences and their magnitude. It is suggested that, while a semiclassical black hole does reproduce faithfully ``coars...

  12. Modeling soil thermal and carbon dynamics of a fire chronosequence in interior Alaska

    Science.gov (United States)

    Q. Zhuang; A. D. McGuire; K. P. O' Neill; J. W. Harden; V. E. Romanovsky; J. Yarie

    2003-01-01

    In this study, the dynamics of soil thermal, hydrologic, and ecosystem processes were coupled to project how the carbon budgets of boreal forests will respond to changes in atmospheric CO2, climate, and fire disturbance. The ability of the model to simulate gross primary production and ecosystem respiration was verified for a mature black spruce...

  13. Evaluation of Melanoidins Formed from Black Garlic after Different Thermal Processing Steps.

    Science.gov (United States)

    Kang, Ok-Ju

    2016-12-01

    The objective of this study was to evaluate the characteristics of melanoidins formed from black garlic (BG) after different thermal processing steps. The melanoidins formed from BG during thermal processing were produced in large amounts, and the initial (280 nm), intermediate (360 nm), and final stage product (420 nm) had similar tendencies. Compounds like degraded proteins, peptides, and phenolic acids were present in the melanoidins during thermal processing. All the melanoidin samples showed different absorptions in the UV-visible spectra, although these had similar shapes. Moreover, the carbon, hydrogen, and oxygen content of melanoidins formed from BG during thermal processing decreased initially, and then increased. However, the nitrogen content increased during thermal processing. As thermal processing progressed, the molecular weight of all the melanoidin samples showed increasing intensities, whereas the major peaks of each melanoidin sample had different retention times. Furthermore, the melanoidins formed from BG after different thermal processing steps contained -OH, -CH, amide I, and III groups. The crystallinity of the melanoidins was majorly formed at 31.58° and 43.62° (2θ).

  14. 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...

  15. Thermal Properties of Hybrid Carbon Nanotube/Carbon Fiber Polymer

    Science.gov (United States)

    Kang, Jin Ho; Cano, Roberto J.; Luong, Hoa; Ratcliffe, James G.; Grimsley, Brian W.; Siochi, Emilie J.

    2016-01-01

    Carbon fiber reinforced polymer (CFRP) composites possess many advantages for aircraft structures over conventional aluminum alloys: light weight, higher strength- and stiffness-to-weight ratio, and low life-cycle maintenance costs. However, the relatively low thermal and electrical conductivities of CFRP composites are deficient in providing structural safety under certain operational conditions such as lightning strikes. One possible solution to these issues is to interleave carbon nanotube (CNT) sheets between conventional carbon fiber (CF) composite layers. However, the thermal and electrical properties of the orthotropic hybrid CNT/CF composites have not been fully understood. In this study, hybrid CNT/CF polymer composites were fabricated by interleaving layers of CNT sheets with Hexcel (Registered Trademark) IM7/8852 prepreg. The CNT sheets were infused with a 5% solution of a compatible epoxy resin prior to composite fabrication. Orthotropic thermal and electrical conductivities of the hybrid polymer composites were evaluated. The interleaved CNT sheets improved the in-plane thermal conductivity of the hybrid composite laminates by about 400% and the electrical conductivity by about 3 orders of magnitude.

  16. 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

  17. Thermal Characterization of the Overload Carbon Resistors

    Directory of Open Access Journals (Sweden)

    Ivana Kostić

    2013-01-01

    Full Text Available In many applications, the electronic component is not continuously but only intermittently overloaded (e.g., inrush current, short circuit, or discharging interference. With this paper, we provide insight into carbon resistors that have to hold out a rarely occurring transient overload. Using simple electrical circuit, the resistor is overheating with higher current than declared, and dissipation is observed by a thermal camera.

  18. Black carbon emissions reductions from combustion of alternative jet fuels

    Science.gov (United States)

    Speth, Raymond L.; Rojo, Carolina; Malina, Robert; Barrett, Steven R. H.

    2015-03-01

    Recent measurement campaigns for alternative aviation fuels indicate that black carbon emissions from gas turbines are reduced significantly with the use of alternative jet fuels that are low in aromatic content. This could have significant climate and air quality-related benefits that are currently not accounted for in environmental assessments of alternative jet fuels. There is currently no predictive way of estimating aircraft black carbon emissions given an alternative jet fuel. We examine the results from available measurement campaigns and propose a first analytical approximation (termed 'ASAF') of the black carbon emissions reduction associated with the use of paraffinic alternative jet fuels. We establish a relationship between the reduction in black carbon emissions relative to conventional jet fuel for a given aircraft, thrust setting relative to maximum rated thrust, and the aromatic volume fraction of the (blended) alternative fuel. The proposed relationship is constrained to produce physically meaningful results, makes use of only one free parameter and is found to explain a majority of the variability in measurements across the engines and fuels that have been tested.

  19. Evaluation of black carbon estimations in global aerosol models

    NARCIS (Netherlands)

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

    2009-01-01

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

  20. Coarsening of carbon black supported Pt nanoparticles in hydrogen

    DEFF Research Database (Denmark)

    Simonsen, Søren Bredmose; Wang, Yan; Jensen, Jens Oluf

    2017-01-01

    This study addresses coarsening mechanisms of Pt nanoparticles supported on carbon black in hydrogen. By means of in situ transmission electron microscopy (TEM), Pt nanoparticle coarsening was monitored in 6 mbar 20 % H2/Ar while ramping up the temperature to almost 1000 °C. Time-resolved TEM...

  1. Aircraft measurements of aerosol black carbon from a coastal ...

    Indian Academy of Sciences (India)

    ICARB) over India, high-resolution airborne measurements of the altitude profiles of the mass concentrations (MB) of aerosol black carbon (BC) were made off Bhubaneswar (BBR, 85.82°E, 20.25°N), over northwest Bay of Bengal, in the altitude ...

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

    DEFF Research Database (Denmark)

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

    2011-01-01

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

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

    NARCIS (Netherlands)

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

    2015-01-01

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

  4. 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

  5. Effect of Carbon Black Blends on the Mechanical Properties of a Tread Compound for Passenger Radial Tires

    Directory of Open Access Journals (Sweden)

    Mir Hamid Reza Ghoreishy

    2013-04-01

    Full Text Available This study is devoted to the study of carbon black blends in passenger tire tread compounds with respect to their mechanical, dynamical and thermal properties. A reference compound based on SBR/BR and 60 phr carbon black as reinforcing filler was initially designed. Ten samples based on this compound were prepared usingfour different types of carbon black. The mechanical, dynamical and thermal tests were carried out on appropriate samples made from these compounds to determine tensile strength, elongation-at-break, abrasion resistance, hardness, resilience, tan δ and heat build-up. The results indicated that the compound containing N550 carbonblack has the lowest abrasion resistance and temperature rise. On the other hand, the compound containing N220 carbon black showed the highest temperature rise, energy dissipation and abrasion resistance due to high structure and iodine adsorption number. To achieve improvement in mechanical and dynamical properties, mixturesof carbon blacks were used and the best results (low rolling resistance, high abrasion resistance and high traction were obtained. We have shown in our previous research works that the viscoelastic behavior of cured compounds can be accurately described by the experimental data of tensile deformation vs. force of rubber strips and itscorresponding finite element models. Therefore, a new method for calculating the energy dissipation was proposed which was based on the finite element modeling of the tension in an in-house designed rubber sample. The results obtained by employing this technique were in very good agreement with the experimentally measureddynamical data.

  6. Carbon and black carbon in Yosemite National Park soils: sources, prescribed fire impacts, and policies

    Science.gov (United States)

    Shrestha, G.; Traina, S. J.

    2012-12-01

    We investigated the chemical and radiocarbon properties of black carbon recently deposited and accumulated in surface soils of six sites along an altitudinal gradient in Yosemite National Park, central California. The effect of prescribed (or controlled) forest burning on existing carbon and black carbon in surface soils was assessed to illuminate the role of this forest management and wildfire control strategy in the soil carbon cycle. The proportional contribution of fossil fuel or radiocarbon dead carbon versus biomass sources on these black carbon materials was analyzed to elucidate their origin, estimate their ages and explore the possible effects of prescribed burning on the amount of black carbon produced recently as well as historically. Supplementing these field results, we conducted a comparative spatial analysis of recent prescribed burn and wildfire coverage in Central California's San Joaquin Valley to approximate the effectiveness of prescribed burning for wildfire prevention. Federal and California policies pertaining to prescribed forest fires and/or black carbon were then evaluated for their effectiveness, air quality considerations, and environmental benefits. 13C NMR spectrum of soil surface char from study sites Prescribed burn coverage versus wildfires in central California

  7. Replacement of Carbon Black on Natural Rubber Composites and Nanocomposites — Part 1

    Science.gov (United States)

    Martín-Cortés, Guillermo R.; Esper, Fabio J.; de Araujo, Antonio J. Santana; Hennies, Wildor T.; Valenzuela, Maria G. Silva; Valenzuela-Díaz, Francisco R.

    Seeking to replace carbon-black as filler of rubber in the production of vulcanized goods, researchers from University of São Paulo have studied different materials types as minerals, vegetal or wastes agricultural and industry. Results of rubber composites filled with MA1 a waste of mineral treatment provided by Esper Industries are presented. MA1 was characterized through X-ray diffraction; Thermal analysis; Scanning Electronic Microscopy; and others laboratory methods. The composite and shaped masses were evaluated by these methods plus their mechanical properties such as tensile strength, elongation at break and hardness. Exceptional results were obtained in the mechanical properties evaluated, better than those obtained with the traditional carbon-black. Seeing the kind of material used as filler, it can conclude that the environmental benefit is present, as well as economic development, giving credibility to the use of these alternative material in replacement carbonblack.

  8. Temperature Coefficients of Electrical Conductivity and Conduction Mechanisms in Butyl Rubber-Carbon Black Composites

    Science.gov (United States)

    Alzamil, M. A.; Alfaramawi, K.; Abboudy, S.; Abulnasr, L.

    2017-12-01

    Electrical properties of butyl rubber filled with General Purpose Furnace (GPF) carbon black were studied. The carbon black concentration (X) in the compound was X = 40, 60, 70, 80, and 100 parts by weight per hundred parts by weight of rubber (phr). The corresponding volume fractions of GPF carbon black were 0.447 ± 0.022, 0.548 ± 0.027, 0.586 ± 0.029, 0.618 ± 0.031 and 0.669 ± 0.034, respectively. The concentration dependence of conductivity ( σ ) at constant temperature showed that σ follows a percolation theory; σ ∝ ( {X - Xo } )^{γ } , where X o is the concentration at percolation threshold. The exponent γ was found as 6.6 (at room temperature 30°C). This value agrees with other experimental values obtained by many authors for different rubber-carbon black systems. Electron tunneling between the aggregates, which are dispersed in the insulator rubber, was mainly the conduction process proposed at constant temperature in the butyl-GPF carbon black composites. Temperature dependence of conductivity was investigated in the temperature range from 30°C up to 120°C. All samples exhibit negative temperature coefficients of conductivity (NTCC). The values obtained are - 0.130°C-1, - 0.019°C-1, - 0.0082°C-1, - 0.0094°C-1, and - 0.072°C-1 for carbon black concentrations of 40 phr, 60 phr, 70 phr, 80 phr, and 100 phr, respectively. The samples of concentrations 40 phr and 60 phr have also positive temperature coefficients of conductivity (PTCC) of values + 0.031 and + 0.013, respectively. Electrical conduction at different temperatures showed various mechanisms depending on the carbon black concentration and/or the interval of temperature. The hopping conduction mechanism was noticed at the lower temperature region while carrier thermal activation mechanisms were recorded at the higher temperature range.

  9. Temperature Coefficients of Electrical Conductivity and Conduction Mechanisms in Butyl Rubber-Carbon Black Composites

    Science.gov (United States)

    Alzamil, M. A.; Alfaramawi, K.; Abboudy, S.; Abulnasr, L.

    2018-02-01

    Electrical properties of butyl rubber filled with General Purpose Furnace (GPF) carbon black were studied. The carbon black concentration ( X) in the compound was X = 40, 60, 70, 80, and 100 parts by weight per hundred parts by weight of rubber (phr). The corresponding volume fractions of GPF carbon black were 0.447 ± 0.022, 0.548 ± 0.027, 0.586 ± 0.029, 0.618 ± 0.031 and 0.669 ± 0.034, respectively. The concentration dependence of conductivity ( σ ) at constant temperature showed that σ follows a percolation theory; σ ∝ ( {X - Xo } )^{γ } , where X o is the concentration at percolation threshold. The exponent γ was found as 6.6 (at room temperature 30°C). This value agrees with other experimental values obtained by many authors for different rubber-carbon black systems. Electron tunneling between the aggregates, which are dispersed in the insulator rubber, was mainly the conduction process proposed at constant temperature in the butyl-GPF carbon black composites. Temperature dependence of conductivity was investigated in the temperature range from 30°C up to 120°C. All samples exhibit negative temperature coefficients of conductivity (NTCC). The values obtained are - 0.130°C-1, - 0.019°C-1, - 0.0082°C-1, - 0.0094°C-1, and - 0.072°C-1 for carbon black concentrations of 40 phr, 60 phr, 70 phr, 80 phr, and 100 phr, respectively. The samples of concentrations 40 phr and 60 phr have also positive temperature coefficients of conductivity (PTCC) of values + 0.031 and + 0.013, respectively. Electrical conduction at different temperatures showed various mechanisms depending on the carbon black concentration and/or the interval of temperature. The hopping conduction mechanism was noticed at the lower temperature region while carrier thermal activation mechanisms were recorded at the higher temperature range.

  10. Bird specimens track 135 years of atmospheric black carbon and environmental policy

    Science.gov (United States)

    DuBay, Shane G.; Fuldner, Carl C.

    2017-10-01

    Atmospheric black carbon has long been recognized as a public health and environmental concern. More recently, black carbon has been identified as a major, ongoing contributor to anthropogenic climate change, thus making historical emission inventories of black carbon an essential tool for assessing past climate sensitivity and modeling future climate scenarios. Current estimates of black carbon emissions for the early industrial era have high uncertainty, however, because direct environmental sampling is sparse before the mid-1950s. Using photometric reflectance data of >1,300 bird specimens drawn from natural history collections, we track relative ambient concentrations of atmospheric black carbon between 1880 and 2015 within the US Manufacturing Belt, a region historically reliant on coal and dense with industry. Our data show that black carbon levels within the region peaked during the first decade of the 20th century. Following this peak, black carbon levels were positively correlated with coal consumption through midcentury, after which they decoupled, with black carbon concentrations declining as consumption continued to rise. The precipitous drop in atmospheric black carbon at midcentury reflects policies promoting burning efficiency and fuel transitions rather than regulating emissions alone. Our findings suggest that current emission inventories based on predictive modeling underestimate levels of atmospheric black carbon for the early industrial era, suggesting that the contribution of black carbon to past climate forcing may also be underestimated. These findings build toward a spatially dynamic emission inventory of black carbon based on direct environmental sampling.

  11. 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...

  12. Carbon-carbon turbopump concept for Space Nuclear Thermal Propulsion

    Science.gov (United States)

    Overholt, David M.

    1993-06-01

    The U.S. Air Force Space Nuclear Thermal Propulsion (SNTP) program is placing high priority on maximizing specific impulse (ISP) and thrust-to-weight ratio in the development of a practical high-performance nuclear rocket. The turbopump design is driven by these goals. The liquid hydrogen propellant is pressurized and pumped to the reactor inlet by the turbopump assembly (TPA). Rocket propulsion is from rapid heating of the propellant from 180 R to thousands of degrees in the particle bed reactor (PBR). The exhausted propellant is then expanded through a high-temperature nozzle. A high-performance approach is to use an uncooled carbon-carbon nozzle and duct turbine inlet. Carbon-carbon components are used throughout the TPA hot section to obtain the high-temperature capability. Several carbon-carbon components are in development including structural parts, turbine nozzles/stators, and turbine rotors. The technology spinoff is applicable to conventional liquid propulsion engines and many other turbomachinery applications.

  13. Advanced Thermal Protection Systems (ATPS), Aerospace Grade Carbon Bonded Carbon Fiber Material Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Carbon bonded carbon fiber (CBCF) insulating material is the basis for several highly successful NASA developed thermal protection systems (TPS). Included among...

  14. Advanced Thermal Protection Systems (ATPS), Aerospace Grade Carbon Bonded Carbon Fiber Material Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Carbon bonded carbon fiber (CBCF) insulating material is the basis for several highly successful NASA developed thermal protection systems (TPS). Among the...

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

    Directory of Open Access Journals (Sweden)

    F. Inam

    2014-01-01

    Full Text Available 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 indentation. For comprehensive comparison, fracture toughness and percolation threshold were analysed as well. Because of the systematically induced indentation damage, a sharp decrease of 89% was observed in the electrical conductivity of epoxy – CNT nanocomposite as compared to 25% in the electrical conductivity of epoxy – CB nanocomposite. CNTs impart superior damage sensing capability in brittle nanocomposite structures, in comparison to CB, due to their high aspect ratio (fibrous nature and high electrical conductivity.

  16. 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)

  17. Development of a carbon cloth heat post module for thermal vacuum testing of a spinning spacecraft

    Science.gov (United States)

    Levine, M. B.; Nelson, L. A.

    1972-01-01

    Development of a high temperature, high power density, isothermal, rapid transient, infrared thermal module is described. The investigation of various alternative approaches is discussed, as well as the rationale leading to the choice of a carbon cloth concept. Evolution of module design configurations and a summary of the development test results are included, along with a detailed description of the final design, which incorporated a black plate emitter radiantly heated by the carbon cloth. The final module configuration met design criteria during a 200-hour thermal vacuum performance test at 1000 F operating temperature without contaminating a solar cell array.

  18. Topographic controls on black carbon accumulation in Alaskan black spruce forest soils: implications for organic matter dynamics

    Science.gov (United States)

    E.S. Kane; W.C. Hockaday; M.R. Turetsky; C.A. Masiello; D.W. Valentine; B.P. Finney; J.A. Badlock

    2010-01-01

    There is still much uncertainty as to how wildfire affects the accumulation of burn residues (such as black carbon [BC]) in the soil, and the corresponding changes in soil organic carbon (SOC) composition in boreal forests. We investigated SOC and BC composition in black spruce forests on different landscape positions in Alaska, USA. Mean BC stocks in surface mineral...

  19. Electromagnetic wave absorption properties of carbon powder from catalysed carbon black in X and Ku bands

    Energy Technology Data Exchange (ETDEWEB)

    Wen Bin [School of Materials Science and Engineering and Laboratory of Special Processing of Raw Materials, Dalian University of Technology, Dalian 116023 (China); State Key Laboratory of Materials Modification by Laser, Electron and Ion Beams, Dalian University of Technology, Dalian 116023 (China); Zhao Jijun [State Key Laboratory of Materials Modification by Laser, Electron and Ion Beams, Dalian University of Technology, Dalian 116023 (China); College of Advanced Science and Technology, Dalian University of Technology, Dalian 116023 (China); Duan Yuping [School of Materials Science and Engineering and Laboratory of Special Processing of Raw Materials, Dalian University of Technology, Dalian 116023 (China); Zhang Xingguo [School of Materials Science and Engineering and Laboratory of Special Processing of Raw Materials, Dalian University of Technology, Dalian 116023 (China); Zhao Yanbo [School of Materials Science and Engineering and Laboratory of Special Processing of Raw Materials, Dalian University of Technology, Dalian 116023 (China); Dong Chuang [State Key Laboratory of Materials Modification by Laser, Electron and Ion Beams, Dalian University of Technology, Dalian 116023 (China); Liu Shunhua [School of Materials Science and Engineering and Laboratory of Special Processing of Raw Materials, Dalian University of Technology, Dalian 116023 (China); Li Tingju [School of Materials Science and Engineering and Laboratory of Special Processing of Raw Materials, Dalian University of Technology, Dalian 116023 (China)

    2006-05-07

    Carbon powder from catalysed carbon black (CPCCB) was prepared after a pyrogenation of carbon black (CB) with nanosized iron catalyst at atmospheric pressure and a temperature of 1100 deg. C. The complex relative permittivity and permeability of the CPCCB were measured by a reflection/transmission technique in the X and Ku bands. The reflection loss of CPCCB/paraffin wax composite was recorded. A wider absorption frequency range in the X band and Ku band could be obtained by adding 3 vol.% and 6 vol.% CPCCB in paraffin wax, respectively. Our results indicate that CPCCB could be a promising microwave absorption material.

  20. Thermal Conductivity of Carbon Nanoreinforced Epoxy Composites

    Directory of Open Access Journals (Sweden)

    C. Kostagiannakopoulou

    2016-01-01

    Full Text Available The present study attempts to investigate the influence of multiwalled carbon nanotubes (MWCNTs and graphite nanoplatelets (GNPs on thermal conductivity (TC of nanoreinforced polymers and nanomodified carbon fiber epoxy composites (CFRPs. Loading levels from 1 to 3% wt. of MWCNTs and from 1 to 15% wt. of GNPs were used. The results indicate that TC of nanofilled epoxy composites increased with the increase of GNP content. Quantitatively, 176% and 48% increase of TC were achieved in nanoreinforced polymers and nanomodified CFRPs, respectively, with the addition of 15% wt. GNPs into the epoxy matrix. Finally, micromechanical models were applied in order to predict analytically the TC of polymers and CFRPs. Lewis-Nielsen model with optimized parameters provides results very close to the experimental ones in the case of polymers. As far as the composites are concerned, the Hashin and Clayton models proved to be sufficiently accurate for the prediction at lower filler contents.

  1. Carbon nanotube thermal interfaces and related applications

    Science.gov (United States)

    Hodson, Stephen L.

    The development of thermal interface materials (TIMs) is necessitated by the temperature drop across interfacing materials arising from macro and microscopic irregularities of their surfaces that constricts heat through small contact regions as well as mismatches in their thermal properties. Similar to other types of TIMs, CNT TIMs alleviate the thermal resistance across the interface by thermally bridging two materials together with cylindrical, high-aspect ratio, and nominally vertical conducting elements. Within the community of TIM engineers, the vision driving the development of CNT TIMs was born from measurements that revealed impressively high thermal conductivities of individual CNTs. This vision was then projected to efforts focused on packing many individual CNTs on a single substrate that efficiently conduct heat in parallel and ultimately through many contact regions at CNT-to-substrate contacts. This thesis encompasses a comprehensive investigation of the viability of carbon nanotube based thermal interface materials (CNT TIMs) to efficiently conduct heat across two contacting materials. The efforts in this work were initially devoted to engaging CNT TIMs with an opposing substrate using two bonding techniques. Using palladium hexadecanethiolate, Pd(SC16H35)2 the CNT ends were bonded to an opposing substrate (one-sided interface) or opposing CNT array (two-sided interface) to enhance contact conductance while maintaining a compliant joint. The palladium weld is particularly attractive for its mechanical stability at high temperatures. The engagement of CNT TIMs with an opposing substrate was also achieved by inserting a solder foil between the CNT TIM and opposing substrate and subsequently raising the temperature of the interface above the eutectic point of the solder foil. This bonding technique creates a strong weld that not only reduces the thermal resistance significantly but also minimizes the change in thermal resistance with an applied

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

    Science.gov (United States)

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

    2017-03-01

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

  3. 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.

  4. 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

  5. Toxicity assessment of carbon black waste: A by-product from oil refineries

    Energy Technology Data Exchange (ETDEWEB)

    Zhen, Xu; Ng, Wei Cheng [NUS Environmental Research Institute, National University of Singapore, 1 Create Way, Create Tower #15-02, 138602 (Singapore); Fendy; Tong, Yen Wah [Department of Chemical and Biomolecular Engineering, National University of Singapore, 4 Engineering Drive 4, 117585 (Singapore); Dai, Yanjun [School of Mechanical Engineering, Shanghai Jiaotong University, Shanghai, 200240 (China); Neoh, Koon Gee, E-mail: chenkg@nus.edu.sg [Department of Chemical and Biomolecular Engineering, National University of Singapore, 4 Engineering Drive 4, 117585 (Singapore); Wang, Chi-Hwa, E-mail: chewch@nus.edu.sg [Department of Chemical and Biomolecular Engineering, National University of Singapore, 4 Engineering Drive 4, 117585 (Singapore)

    2017-01-05

    Highlights: • Carbon black waste extract decreased cell viability in a dose and time-dependent manner. • Apoptosis of human cell lines was induced by carbon black waste extract. • Carbon black waste extract elicited oxidative stress by increasing intracellular ROS generation. • Carbon black waste extract impaired antioxidant enzymatic activities of human cell lines. • The high toxicity of carbon black waste extract could be attributed mainly to the effect of vanadium. - Abstract: In Singapore, approximately 30 t/day of carbon-based solid waste are produced from petrochemical processes. This carbon black waste has been shown to possess physical properties that are characteristic of a good adsorbent such as high external surface area. Therefore, there is a growing interest to reutilize and process this carbon black waste into secondary materials such as adsorbents. However, the carbon black waste obtained from petrochemical industries may contain heavy metals that are hazardous to human health and the environment, hence restricting its full potential for re-utilization. Therefore, it is important to examine the possible toxicity effects and toxicity mechanism of carbon black waste on human health. In this study, inductively coupled plasma optical emission spectroscopy (ICP-OES) analysis showed that the heavy metals, vanadium (V), molybdenum (Mo) and nickel (Ni), were present in the carbon black waste in high concentrations. Three human cell lines (HepG2 cells, MRC-5 cells and MDA-MB-231 cells) were used to investigate the toxicity of carbon black waste extract in a variety of in vitro assays. Results from MTS assays indicated that carbon black waste extract decreased the viability of all three cell lines in a dose and time-dependent manner. Observations from confocal microscopy further confirmed this phenomenon. Flow cytometry assay also showed that carbon black waste extract induced apoptosis of human cell lines, and the level of apoptosis increased with

  6. Magnetic microwave heating of magnetite-carbon black mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Ishizaki, K., E-mail: kotaro.ishizaki@empa.ch [Empa, Swiss Federal Laboratories for Materials Science and Technology, Advanced Materials Processing, Feuerwerkerstr. 39, CH-3602 Thun (Switzerland); Stir, M. [Empa, Swiss Federal Laboratories for Materials Science and Technology, Advanced Materials Processing, Feuerwerkerstr. 39, CH-3602 Thun (Switzerland); Gozzo, F. [Paul Scherrer Institute, CH-5232 Villigen (Switzerland); Catala-Civera, J.M. [Universidad Politecnica de Valencia, Camino Vera s/n E-46022 Valencia (Spain); Vaucher, S.; Nicula, R. [Empa, Swiss Federal Laboratories for Materials Science and Technology, Advanced Materials Processing, Feuerwerkerstr. 39, CH-3602 Thun (Switzerland)

    2012-06-15

    The kinetics of the carbothermal reduction of magnetite to iron using carbon black was investigated in situ using the time-resolved X-ray powder diffraction synchrotron radiation technique for the case of magnetic microwave heating in an H-field maximum and conventional heating, respectively. The phase transformation sequence and the reaction kinetics were studied with respect to the case of heating in a microwave E-field maximum investigated earlier. The reduction to iron proceeds an order of magnitude faster when using microwaves. It proceeds at comparable rates in the E- and the H-field microwave heating, yet the reaction temperature is lowered to 770 Degree-Sign C in magnetic H-field microwave heating, compared to nearly 1200 Degree-Sign C for the E-field case. - Highlights: Black-Right-Pointing-Pointer First in situ synchrotron study of reduction of Fe{sub 3}O{sub 4} to Fe during H-field microwave heating. Black-Right-Pointing-Pointer Faster kinetics of the carbothermal reaction when microwaves are used. Black-Right-Pointing-Pointer The carbothermal reaction occurs at much lower temperature in microwave H-field than in E-field.

  7. Thermal stability analysis of nonlinearly charged asymptotic AdS black hole solutions

    Science.gov (United States)

    Dehghani, M.; Hamidi, S. F.

    2017-08-01

    In this paper, the four-dimensional nonlinearly charged black hole solutions have been considered in the presence of the power Maxwell invariant electrodynamics. Two new classes of anti-de Sitter (AdS) black hole solutions have been introduced according to different amounts of the parameters in the nonlinear theory of electrodynamics. The conserved and thermodynamical quantities of either of the black hole classes have been calculated from geometrical and thermodynamical approaches, separately. It has been shown that the first law of black hole thermodynamics is satisfied for either of the AdS black hole solutions we just obtained. Through the canonical and grand canonical ensemble methods, the black hole thermal stability or phase transitions have been analyzed by considering the heat capacities with the fixed black hole charge and fixed electric potential, respectively. It has been found that the new AdS black holes are stable if some simple conditions are satisfied.

  8. Carbonaceous aerosols influencing atmospheric radiation: Black and organic carbon

    Energy Technology Data Exchange (ETDEWEB)

    Penner, J.E. [Lawrence Livermore National Lab., CA (United States). Global Climate Research Div.

    1994-09-01

    Carbonaceous particles in the atmosphere may both scatter and absorb solar radiation. The fraction associated with the absorbing component is generally referred to as black carbon (BC) and is mainly produced from incomplete combustion processes. The fraction associated with condensed organic compounds is generally referred to as organic carbon (OC) or organic matter and is mainly scattering. Absorption of solar radiation by carbonaceous aerosols may heat the atmosphere, thereby altering the vertical temperature profile, while scattering of solar radiation may lead to a net cooling of the atmosphere/ocean system. Carbonaceous aerosols may also enhance the concentrations of cloud condensation nuclei. This paper summarizes observed concentrations of aerosols in remote continental and marine locations and provides estimates for the fine particle (D < 2.5 {mu}m) source rates of both OC and BC. The source rates for anthropogenic organic aerosols may be as large as the source rates for anthropogenic sulfate aerosols, suggesting a similar magnitude of direct forcing of climate. The role of BC in decreasing the amount of reflected solar radiation by OC and sulfates is discussed. The total estimated forcing depends on the source estimates for organic and black carbon aerosols which are highly uncertain. The role of organic aerosols acting as cloud condensation nuclei (CCN) is also described.

  9. Intercomparison of methods to estimate black carbon emissions from cookstoves.

    Science.gov (United States)

    de la Sota, Candela; Kane, Moustapha; Mazorra, Javier; Lumbreras, Julio; Youm, Issakha; Viana, Mar

    2017-10-01

    Black carbon is the second largest contributor to climate change and also poses risks to human health. Despite the need for black carbon (BC) emissions estimates from residential biomass burning for cooking, quantitative data are still scarce. This scarcity is mainly due to the scattered location of the stoves, as well as relatively costly and complex analytical methods available. Two low cost and easy-to-use optical methods, a cell-phone based system and smoke stain reflectometry, where compared to elemental carbon (EC) concentrations by the Sunset OCEC Analyzer (TOT). The three techniques were challenged with different aerosol types (urban and biomass cookstoves), and different filter substrates (quartz and glass fibre). A good agreement was observed between the two low cost techniques and the reference system for the aerosol types and concentrations assessed, although the relationship was statistically different for each type of aerosol. The quantification of correction factors with respect to the reference method for the specific conditions under study is essential with either of the low-cost techniques. BC measurements from the cell-phone system and the reflectometer were moderately affected by the filter substrate. The easy use of the cell-phone based system may allow engaging cookstove users in the data collection process, increasing the amount and frequency of data collection which may, otherwise, not be feasible in resourced constrained locations. This would help to raise public awareness about environmental and health issues related to cookstoves. Copyright © 2017 Elsevier B.V. All rights reserved.

  10. 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.

  11. 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.

  12. 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).

  13. 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......, Ce1-xREExO2-δ (REE = Pr, Sm)) and metal oxides (LiMn2O4, Ag2O). Materials showing the highest activity in carbon black (Mn2O3, CeO2, Ce0.6Pr0.4O2-δ, Ag2O) were subsequently tested for catalytic activity toward bituminous coal, as revealed by both I-V-P curves and electrochemical impedance...... was investigated using current-voltage-power density curves. In the anode chamber, catalysts are mixed with the carbon-carbonate mixture. These catalysts include various manganese oxides (MnO2, Mn2O3, Mn3O4, MnO), metal carbonates (Ag2CO3, MnCO3, Ce2(CO3)3), metals (Ag, Ce, Ni), doped-ceria (CeO2, Ce1-xGdxO2-x/2...

  14. Black carbon in Central California: soil carbon and air quality implications

    Science.gov (United States)

    Shrestha, G.; Traina, S. J.

    2008-12-01

    Black carbon (BC) plays a significant role in the carbon cycle, simultaneously influencing the quality of air from local to regional scales from its point of origin. We are investigating these influences with respect to BC recently produced in the Central Valley and Sierra Nevada Forest area of California. Surface biomass, charred matter and soil (0-5 cm) were collected after prescribed fires in Yosemite National Park (YNP) locations along an elevational gradient ranging from 1148 m to 1992 m. Surface soils and aerosols from a protected (non-burnt) grassland in Merced (central valley) were also collected. Soil organic carbon (SOC) concentrations in burnt sites were analyzed and compared with concentrations in adjacent unburnt soils (controls). The SOC concentrations ranged from 3 to 15% in the control soils and 2 to 12% in post-burn soils. Initial results show a lack of significant change in surface SOC concentration from prescribed fires in the YNP forest sites. The relative contribution of fossil fuel combustion versus biomass combustion on soil deposited aerosol BC (soot) was determined using radiocarbon analysis with accelerator mass spectrometry. Initial findings show an increase in the contribution of fossil fuel combustion to soot BC with decreasing elevation in YNP, with little difference between burnt and recently unburnt sites. The BET surface area of BC from the field samples will also be analyzed and compared with BC produced in the lab from field-collected biomass. Bulk carbon composition and an assessment of the relative percentage BC present in the samples will be conducted with 13-C NMR analysis. This will help in the establishment of a relationship between black carbon and total carbon in central California. In this poster, will be presenting some of our initial findings and their implications for air quality and carbon budget balance in central California. The effects of prescribed fires on soil carbon and black carbon properties will also be

  15. Penelitian pengaruh campuran carbon black dan china clay terhadap sifat tegangan putus dan kekerasan karet vulkanisat

    Directory of Open Access Journals (Sweden)

    Supraptiningsih Supraptiningsih

    1999-07-01

    Full Text Available It has been done a research of the influence of mixed carbon black and hardness properties on the vulcanization of rubber. It has been made with additive of carbon black and china clay mixed, in total variation. The result is seen that total variation of carbon black and china clay not influence to tensile strength, but their interacton can do it. The hardness of vulcanization of rubber will be influence by total variation of carbon black china clay anad their interaction.

  16. Monumental heritage exposure to urban black carbon pollution

    Science.gov (United States)

    Patrón, D.; Lyamani, H.; Titos, G.; Casquero-Vera, J. A.; Cardell, C.; Močnik, G.; Alados-Arboledas, L.; Olmo, F. J.

    2017-12-01

    In this study, aerosol light-absorption measurements obtained at three sites during a winter campaign were used to analyse and identify the major sources of Black Carbon (BC) particles in and around the Alhambra monument, a UNESCO World Heritage Site that receives over 2 million visitors per year. The Conditional Bivariate Probability Function and the Aethalometer model were employed to identify the main sources of BC particles and to estimate the contributions of biomass burning and fossil fuel emissions to the total Equivalent Black Carbon (EBC) concentrations over the monumental complex. Unexpected high levels of EBC were found at the Alhambra, comparable to those measured in relatively polluted European urban areas during winter. EBC concentrations above 3.0 μg/m3, which are associated with unacceptable levels of soiling and negative public reactions, were observed at Alhambra monument on 13 days from 12 October 2015 to 29 February 2016, which can pose a risk to its long-term conservation and may cause negative social and economic impacts. It was found that road traffic emissions from the nearby urban area and access road to the Alhambra were the main sources of BC particles over the monument. However, biomass burning emissions were found to have very small impact on EBC concentrations at the Alhambra. The highest EBC concentrations were observed during an extended stagnant episode associated with persistent high-pressure systems, reflecting the large impact that can have these synoptic conditions on BC over the Alhambra.

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

    Science.gov (United States)

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

  18. Graded Density Carbon Bonded Carbon Fiber (CBCF) Preforms for Lightweight Ablative Thermal Protection Systems (TPS) Project

    Data.gov (United States)

    National Aeronautics and Space Administration — FMI currently manufactures Phenolic Impregnated Carbon Ablator (PICA) material for Thermal Protection Systems (TPS) systems, such as the Stardust Sample Return...

  19. Nanoporous Carbon Monoliths with Tunable Thermal Insulation and Mechanical Properties.

    Science.gov (United States)

    Wang, Xiaopeng; Chen, Fenghua; Luo, Zhenhua; Li, Hao; Zhao, Tong

    2016-01-01

    In this work, nanoscale porous carbon monoliths, with excellent compressive strength and thermal insulation, were obtained with a simple method of carbonizing cured phenol-formaldehyde resin/poly(methyl methacrylate) blends. Apparent density, pore size and morphology of the carbon monoliths were tailored by changing the composition, curing process and carbonization temperature. The continuous nanopores played a key role in enhancing mechanical and thermal performance of the carbon materials. When PMMA concentration was 25%, apparent density and thermal conductivity of the nanoporous carbonaceous monoliths were obtained as low as 1.07 g · cm⁻³ and 0.42 W/(m · K), decreasing by 29.4% and 35.4% than that of carbonaceous monoliths obtained from pure PF; while compressive strength of the nanoporous carbonaceous monoliths was as high as 34 MPa, which was improved over five times than that of pure PF carbon monoliths.

  20. Light-absorbing properties of ambient black carbon and brown carbon from fossil fuel and biomass burning sources

    Science.gov (United States)

    Healy, R. M.; Wang, J. M.; Jeong, C.-H.; Lee, A. K. Y.; Willis, M. D.; Jaroudi, E.; Zimmerman, N.; Hilker, N.; Murphy, M.; Eckhardt, S.; Stohl, A.; Abbatt, J. P. D.; Wenger, J. C.; Evans, G. J.

    2015-07-01

    The optical properties of ambient black carbon-containing particles and the composition of their associated coatings were investigated at a downtown site in Toronto, Canada, for 2 weeks in June 2013. The objective was to assess the relationship between black carbon (BC) coating composition/thickness and absorption. The site was influenced by emissions from local vehicular traffic, wildfires in Quebec, and transboundary fossil fuel combustion emissions in the United States. Mass concentrations of BC and associated nonrefractory coatings were measured using a soot particle-aerosol mass spectrometer (SP-AMS), while aerosol absorption and scattering were measured using a photoacoustic soot spectrometer (PASS). Absorption enhancement was investigated both by comparing ambient and thermally denuded PASS absorption data and by relating absorption data to BC mass concentrations measured using the SP-AMS. Minimal absorption enhancement attributable to lensing at 781 nm was observed for BC using both approaches. However, brown carbon was detected when the site was influenced by wildfire emissions originating in Quebec. BC coating to core mass ratios were highest during this period (~7), and while direct absorption by brown carbon resulted in an absorption enhancement at 405 nm (>2.0), no enhancement attributable to lensing at 781 nm was observed. The efficiency of BC coating removal in the denuder decreased substantially when wildfire-related organics were present and may represent an obstacle for future similar studies. These findings indicate that BC absorption enhancement due to lensing is minimal for downtown Toronto, and potentially other urban locations, even when impacted by long-range transport events.

  1. Inferring black carbon concentrations in particulate organic matter by observing pyrene fluorescence losses.

    Science.gov (United States)

    Flores-Cervantes, D Xanat; Reddy, Christopher M; Gschwend, Philip M

    2009-07-01

    Black carbon (BC), the soot and char formed during incomplete combustion of fossil and biomass fuels, is ubiquitous, participates in diverse environmental processes, and has adverse effects on human health. However, uncertainty persists regarding how accurately the present measurement methods quantify total BC or even defined subportions of the BC continuum. Hence, we sought to improve this situation by developing a new, low-sample manipulation methodology that does not require any oxidative or pyrolytic treatments but rather differentiates BC from other non-BC organic carbon (OC) using its sorbent properties. The procedure, referred to as the pyrene fluorescence loss (PFL) method, infers BC concentrations in particulate organic matter (POM) by observing the decrease in fluorescence from pyrene spiked into aqueous POM suspensions. The method was first tested using diverse materials previously utilized in an international BC method intercomparison study, and then its effectiveness (e.g., sensitivity and geochemical reasonableness) was tested by applying itto sediment and seawater POM samples collected from a coastal area downwind of important BC sources. Parallel evaluation of BC, using the PFL method and CTO-375 procedure, suggested we can characterize the predominant BC in a given sample as (i) thermally recalcitrant and highly sorptive per mass (e.g., soot), (ii) thermally labile and highly sorptive per mass (e.g., char), or (iii) thermally recalcitrant but not highly sorptive (e.g., lignite coal).

  2. Feedbacks between climate, fire severity, and differential permafrost degradation in Alaskan black spruce forests - implications for carbon cycling

    Science.gov (United States)

    Kasischke, E. S.; Kane, E. S.; O'Donnell, J. A.; Christensen, N. L.; Mitchell, S. R.; Turetsky, M. R.; Hayes, D. J.; Hoy, E.; Barrett, K. M.; McGuire, A. D.; Yuan, F.

    2011-12-01

    Black spruce forests are the dominant forest cover type in the boreal region of Alaska and Canada In the northern portion of its range, permafrost is common to sites occupied by black spruce forest, which in turn, leads topromotes the accumulation of large reservoirs of organic carbon in mineral and organic soils. Another important trait of black spruce forests is the high occurrence of fire which is enhanced by the presence of flammable foliage, surface litter (duff), dead stems, aboreal lichens, and understory vegetation that is highly flammable during the dry conditions found during the summer fire season. In turn, fire plays an important role in carbon cycling in black spruce forests through direct burning of vegetation and organic soils, initiation of secondary succession, and alteration of the ambient environmental conditions, in particular, the permafrost and the soil thermal regimes, including permafrost stability. The spatial and temporal characteristics of permafrost (e.g. ice content and, seasonal deepening thawing of the active layer) not only control fire severity in terms of depth of burning of the active layer, but also the level of permafrost degradation that occurs in the post-fire environment. Fire severity, in combination with soil thermal properties (e.g. temperature, moisture, permafrost state), moisture and temperature conditions controlled by rates of permafrost warming and drying then controls the biological processes (plant succession and growth and heterotrophic respiration), thus regulating post-fire re-accumulation of carbon in biomass. In this paper, we will review research that investigates the interactions between fire and permafrost regimes that influence and how they influence carbon cycling in black spruce forests in interior Alaska.

  3. An improved method for quantitatively measuring the sequences of total organic carbon and black carbon in marine sediment cores

    Science.gov (United States)

    Xu, Xiaoming; Zhu, Qing; Zhou, Qianzhi; Liu, Jinzhong; Yuan, Jianping; Wang, Jianghai

    2017-04-01

    Understanding global carbon cycle is critical to uncover the mechanisms of global warming and remediate its adverse effects on human activities. Organic carbon in marine sediments is an indispensable part of the global carbon reservoir in global carbon cycling. Evaluating such a reservoir calls for quantitative studies of marine carbon burial, which closely depend on quantifying total organic carbon and black carbon in marine sediment cores and subsequently on obtaining their high-resolution temporal sequences. However, the conventional methods for detecting the contents of total organic carbon or black carbon cannot resolve the following specific difficulties, i.e., (1) a very limited amount of each subsample versus the diverse analytical items, (2) a low and fluctuating recovery rate of total organic carbon or black carbon versus the reproducibility of carbon data, and (3) a large number of subsamples versus the rapid batch measurements. In this work, (i) adopting the customized disposable ceramic crucibles with the micropore-controlled ability, (ii) developing self-made or customized facilities for the procedures of acidification and chemothermal oxidization, and (iii) optimizing procedures and carbon-sulfur analyzer, we have built a novel Wang-Xu-Yuan method (the WXY method) for measuring the contents of total organic carbon or black carbon in marine sediment cores, which includes the procedures of pretreatment, weighing, acidification, chemothermal oxidation and quantification; and can fully meet the requirements of establishing their highresolution temporal sequences, whatever in the recovery, experimental efficiency, accuracy and reliability of the measurements, and homogeneity of samples. In particular, the usage of disposable ceramic crucibles leads to evidently simplify the experimental scenario, which further results in the very high recovery rates for total organic carbon and black carbon. This new technique may provide a significant support for

  4. Thermodynamics of higher dimensional black holes with higher order thermal fluctuations

    Science.gov (United States)

    Pourhassan, B.; Kokabi, K.; Rangyan, S.

    2017-12-01

    In this paper, we consider higher order corrections of the entropy, which coming from thermal fluctuations, and find their effect on the thermodynamics of higher dimensional charged black holes. Leading order thermal fluctuation is logarithmic term in the entropy while higher order correction is proportional to the inverse of original entropy. We calculate some thermodynamics quantities and obtain the effect of logarithmic and higher order corrections of entropy on them. Validity of the first law of thermodynamics investigated and Van der Waals equation of state of dual picture studied. We find that five-dimensional black hole behaves as Van der Waals, but higher dimensional case have not such behavior. We find that thermal fluctuations are important in stability of black hole hence affect unstable/stable black hole phase transition.

  5. 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

  6. Plasma polymerization surface modification of Carbon black and its effect in elastomers

    NARCIS (Netherlands)

    Mathew, T.; Datta, Rabin; Dierkes, Wilma K.; Talma, Auke; Ooij, W.J.; Noordermeer, Jacobus W.M.

    2011-01-01

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

  7. 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

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

    DEFF Research Database (Denmark)

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

    2012-01-01

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

  9. Importance of fullerenic active sites in surface modification of carbon black by plasma polymerisation

    NARCIS (Netherlands)

    Mathew, T.; Datta, Rabin; Dierkes, Wilma K.; Ooij, W.J.; Noordermeer, Jacobus W.M.; Probst, N.; Gruenberger, T.M.; Probst, N.

    2009-01-01

    Carbon black is widely used as an active filler in rubber to improve the physical properties. The surface energy of carbon black is high compared to that of various elastomers like Styrene–Butadiene rubber, Butadiene rubber and Ethylene–Propylene Diene rubber. Reducing the surface energy and

  10. Final Project Report for "Interfacial Thermal Resistance of Carbon Nanotubes”

    Energy Technology Data Exchange (ETDEWEB)

    Cumings, John [Univ. of Maryland, College Park, MD (United States)

    2016-04-15

    This report describes an ongoing project to comprehensively study the interfacial thermal boundary resistance (Kapitza resistance) of carbon nanotubes. It includes a list of publications, personnel supported, the overall approach, accomplishments and future plans.

  11. High-Conductance Thermal Interfaces Based on Carbon Nanotubes Project

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose to develop a novel thermal interface material (TIM) that is based on an array of vertical carbon nanotubes (CNTs) for high heat flux applications. For...

  12. 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.

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

    Science.gov (United States)

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

    2013-12-01

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

  14. Black carbon vertical profiles strongly affect its radiative forcing uncertainty

    Directory of Open Access Journals (Sweden)

    B. H. Samset

    2013-03-01

    Full Text Available 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.

  15. Application of thermal analysis techniques in activated carbon production

    Science.gov (United States)

    Donnals, G.L.; DeBarr, J.A.; Rostam-Abadi, M.; Lizzio, A.A.; Brady, T.A.

    1996-01-01

    Thermal analysis techniques have been used at the ISGS as an aid in the development and characterization of carbon adsorbents. Promising adsorbents from fly ash, tires, and Illinois coals have been produced for various applications. Process conditions determined in the preparation of gram quantities of carbons were used as guides in the preparation of larger samples. TG techniques developed to characterize the carbon adsorbents included the measurement of the kinetics of SO2 adsorption, the performance of rapid proximate analyses, and the determination of equilibrium methane adsorption capacities. Thermal regeneration of carbons was assessed by TG to predict the life cycle of carbon adsorbents in different applications. TPD was used to determine the nature of surface functional groups and their effect on a carbon's adsorption properties.

  16. Characterization of black carbon in the ambient air of Agra, India: Seasonal variation and meteorological influence

    Science.gov (United States)

    Gupta, Pratima; Singh, Shalendra Pratap; Jangid, Ashok; Kumar, Ranjit

    2017-09-01

    This study characterizes the black carbon in Agra, India home to the Taj Mahal—and situated in the Indo-Gangetic basin. The mean black carbon concentration is 9.5 μg m-3 and, owing to excessive biomass/fossil fuel combustion and automobile emissions, the concentration varies considerably. Seasonally, the black carbon mass concentration is highest in winter, probably due to the increased fossil fuel consumption for heating and cooking, apart from a low boundary layer. The nocturnal peak rises prominently in winter, when the use of domestic heating is excessive. Meanwhile, the concentration is lowest during the monsoon season because of the turbulent atmospheric conditions and the process of washout by precipitation. The ratio of black carbon to brown carbon is less than unity during the entire study period, except in winter (December). This may be because that biomass combustion and diesel exhaust are major black carbon contributors in this region, while a higher ratio in winter may be due to the increased consumption of fossil fuel and wood for heating purposes. ANOVA reveals significant monthly variation in the concentration of black carbon; plus, it is negatively correlated with wind speed and temperature. A high black carbon mass concentration is observed at moderate (1-2 m s-1) wind speed, as compared to calm or turbulent atmospheric conditions.

  17. Nanoscale mapping of carbon oxidation in pyrogenic black carbon from ancient Amazonian anthrosols.

    Science.gov (United States)

    Archanjo, B S; Baptista, D L; Sena, L A; Cançado, L G; Falcão, N P S; Jorio, A; Achete, C A

    2015-04-01

    Understanding soil organic matter is necessary for the development of soil amendments, which are important for sustaining agriculture in humid tropical climates. Ancient Amazonian anthrosols are uniquely high in black recalcitrant carbon, making them extremely fertile. In this study, we use high-resolution electron microscopy and spectroscopy to resolve the oxidation process of carbon in the nanoscale crystallites within the black carbon grains of this special soil. Most alkali and acid chemical extraction methods are known to cause chemical modifications in soil organic matter and to give poor or no information about the real spatial structure of soil aggregates. However, here we show that carbon-oxygen functional groups such as phenol, carbonyl, and carboxyl dominate over different spatial regions, with areas varying from over tens to hundreds of nm(2). The chemical maps show that in the nanoscale grain, the surface has a tendency to be less aromatic than the grain core, where higher oxidative-degradation levels are indicated by the presence of carbonyl and carboxyl groups. A deep understanding of these structures could allow artificial reproduction of these natural events.

  18. Comprehensive NMR analysis of compositional changes of black garlic during thermal processing.

    Science.gov (United States)

    Liang, Tingfu; Wei, Feifei; Lu, Yi; Kodani, Yoshinori; Nakada, Mitsuhiko; Miyakawa, Takuya; Tanokura, Masaru

    2015-01-21

    Black garlic is a processed food product obtained by subjecting whole raw garlic to thermal processing that causes chemical reactions, such as the Maillard reaction, which change the composition of the garlic. In this paper, we report a nuclear magnetic resonance (NMR)-based comprehensive analysis of raw garlic and black garlic extracts to determine the compositional changes resulting from thermal processing. (1)H NMR spectra with a detailed signal assignment showed that 38 components were altered by thermal processing of raw garlic. For example, the contents of 11 l-amino acids increased during the first step of thermal processing over 5 days and then decreased. Multivariate data analysis revealed changes in the contents of fructose, glucose, acetic acid, formic acid, pyroglutamic acid, cycloalliin, and 5-(hydroxymethyl)furfural (5-HMF). Our results provide comprehensive information on changes in NMR-detectable components during thermal processing of whole garlic.

  19. Black carbon emissions in Russia: A critical review

    Energy Technology Data Exchange (ETDEWEB)

    Evans, Meredydd; Kholod, Nazar; Kuklinski, Teresa; Denysenko, Artur; Smith, Steven J.; Staniszewski, Aaron; Hao, Wei Min; Liu, Liang; Bond, Tami C.

    2017-08-01

    Russia has a particularly important role regarding black carbon (BC) emissions given the extent of its territory above the Arctic Circle, where BC emissions have a particularly pronounced effect on the climate. This study presents a comprehensive review of BC estimates from a range of studies. We assess underlying methodologies and data sources for each major emissions source based on their level of detail, accuracy and extent to which they represent current conditions. We then present reference values for each major emissions source. In the case of flaring, the study presents new estimates drawing on data on Russian associated petroleum gas and the most recent satellite data on flaring. We also present estimates of organic carbon (OC) for each source, either based on the reference studies or from our own calculations. In addition, the study provides uncertainty estimates for each source. Total BC emissions are estimated at 689 Gg in 2014, with an uncertainty range between (407-1,416), while OC emissions are 9,228 Gg (with uncertainty between 5,595 and 14,728). Wildfires dominated and contributed about 83% of the total BC emissions, however the effect on radiative forcing is mitigated by OC emissions. We also present an adjusted estimate of Arctic forcing from Russian OC and BC emissions. In recent years, Russia has pursued policies to reduce flaring and limit particulate emissions from on-road transport, both of which appear to significantly contribute to the lower emissions and forcing values found in this study.

  20. Uptake mechanism for iodine species to black carbon.

    Science.gov (United States)

    Choung, Sungwook; Um, Wooyong; Kim, Minkyung; Kim, Min-Gyu

    2013-09-17

    Natural organic matter (NOM) plays an important role in determining the fate and transport of iodine species such as iodide (I(-)) and iodate (IO3(-)) in groundwater system. Although NOM exists as diverse forms in environments, prior iodine studies have mainly focused on uptake processes of iodide and iodate to humic materials. This study was conducted to determine the iodide and iodate uptake potential for a particulate NOM (i.e., black carbon [BC]). A laboratory-produced BC and commercial humic acid were used for batch experiments to compare their iodine uptake properties. The BC exhibited >100 times greater uptake capability for iodide than iodate at low pH of ~3, while iodide uptake was negligible for the humic acid. The uptake properties of both solids strongly depend on the initial iodine aqueous concentrations. After uptake reaction of iodide to the BC, X-ray absorption fine structure spectroscopy results indicated that the iodide was converted to electrophilic species, and iodine was covalently bound to carbon atom in polycyclic aromatic hydrocarbons present in the BC. The computed distribution coefficients (i.e., Kd values) suggest that the BC materials retard significantly the transport of iodide at low pH in environmental systems containing even a small amount of BC.

  1. Gecko inspired carbon nanotube based thermal gap pads

    Science.gov (United States)

    Sethi, Sunny; Dhinojwala, Ali

    2012-02-01

    Thermal management has become a critical factor in designing the next generation of microprocessors. The bottleneck in design of material for efficient heat transfer from electronic units to heat sinks is to enhance heat flow across interface between two dissimilar, rough surfaces. Carbon nanotubes (CNT) have been shown to be promising candidates for thermal transport. However, the heat transport across the interface continues to be a challenging hurdle. In the current work we designed free standing thermal pads based on gecko-inspired carbon nanotube adhesives. The pads were made of metallic carbon nanotubes and the structure was designed such that it would allow large area of intimate contact. We showed that these adhesive pads can be used as electrical and thermal interconnects.

  2. 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

  3. Black Carbon at the Mt. Bachelor Observatory Field Campaign Report

    Energy Technology Data Exchange (ETDEWEB)

    Jaffe, Dan A. [Univ. of Washington, Bothell, WA (United States); Sedlacek, Arthur [Brookhaven National Lab. (BNL), Upton, NY (United States); Laing, James R. [Univ. of Washington, Bothell, WA (United States)

    2017-03-01

    This campaign was initiated to measure refractory black carbon (rBC, as defined in Schwarz et al. (2010)) at the Mt. Bachelor Observatory (MBO) using the U.S. Department of Energy (DOE) Atmospheric Radiation Measurement (ARM) Climate Research Facility single-particle soot photometer (SP2; unit 54). MBO is a high-elevation site located on the summit of Mt. Bachelor in central Oregon, USA (43.979°N, 121.687°W, 2,763 meters ASL). This site is operated by Professor Dan Jaffe’s group at the University of Washington Bothell and has been used continuously as an atmospheric observatory for the past 12 years (Jaffe et al., 2005; Gratz et al., 2014). The location of MBO allows frequent sampling of the free troposphere along with a wide array of plumes from regional and distant sources. MBO is currently supported with funding from the National Science Foundation (NSF) to the Principal Investigator (PI; D. Jaffe) via the project “Influence of Free Tropospheric Ozone and PM on Surface Air Quality in the Western U.S.” (#1447832) covering the period 03/15/2015 to 02/28/2018. The SP2 instrument from Droplet Measurement Technologies provides particle-resolved measurements of rBC mass loading, size and mass distributions, and mixing state. The SP2 was installed at MBO on 6/27/2016 and ran through 9/23/2016. Additional measurements at MBO during this campaign included carbon monoxide (CO), fine particulate matter (PM1), aerosol light scattering coefficients (σscat) at three wavelengths using a TSI nephelometer, aerosol absorption coefficients (σabs) with the Brechtel tricolor absorption photometer (TAP), aerosol number size distributions with a scanning mobility particle sizer spectrometer (SMPS), and black carbon (eBC) with an aethalometer. BC data from this campaign have been submitted to the ARM Data Archive. Black carbon (BC) is the predominant light-absorbing aerosol constituent in the atmosphere, and is estimated to exert a positive radiative forcing second only to CO

  4. Effect of carbon black content on the microwave absorbing properties of CB/epoxy composites

    Directory of Open Access Journals (Sweden)

    Pourya Mehdizadeh

    2016-04-01

    Full Text Available To prevent serious electromagnetic interference, a single-layer and double layer wave-absorbing coating employing complex absorbents composed of carbon black with epoxy resin as matrix was prepared. The morphologies of carbon black /epoxy composites were characterized by scanning electron microscope  and atomic force microscope, respectively. The carbon black  particles exhibit obvious polyaromatic were characterized by X-ray diffraction. The electromagnetic parameters of carbon black  were measured in the frequency range of 8–12 GHz by transmission/reflection technology, and the electromagnetic loss mechanisms of the two particles were discussed, respectively. The microwave absorption properties of the coatings were investigated by measuring reflection loss  using arch method. The effects of carbon black  mass ratio, thickness and double-layer on the microwave absorption properties were discussed, respectively. The results showed that the higher thickness, higher ratio and double-layer of carbon black /epoxy content could make the absorption band shift towards the lower frequency range. Significantly, the wave-absorbing coating could be applied in different frequency ranges according to actual demand by controlling the content of carbon black  in composites.

  5. 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

  6. Evaluating The Performance of Asphalt Concrete Mixes by Utilizing Carbon Black as Asphalt Modifier

    Directory of Open Access Journals (Sweden)

    Aliaa Faleh Al.ani

    2018-02-01

    Full Text Available Carbon black produced from several factories in Iraq is expected to provide a reinforcing agent for asphalt paving materials. Carbon black has many characteristics that distinguish  it from conventional mineral fillers, as well as their different function in pavement mixtures. Theory and exercise advanced  in the inclusive utilize of carbon black as a reinforcing agent for rubber has led to concept of asphalt reinforcement. The very fine particles of micro filler added in different contents will be dispersed in asphalt cement improving the mechanical properties of asphalt concrete mixes. In this Four percentages rates were utilized; 0, 3, 6, and 9 percent adding to asphalt grade (60-70. Mixes of asphalt concrete were destined at their optimum asphalt content (OAC then experienced to assess their engineering characteristics that contain moisture of damage, permanent deformation, modulus of resilient and characteristics of fatigue. These characteristics have been assessed utilizing indirect tensile strength, uniaxial repeated loading and repeated flexural beam tests. Mixtures improved with carbon black were existed to have amended permanent deformation and fatigue characteristics, else exhibited high resilient modulus and lower moisture susceptibility. Result showed that a rate changed from 3 to 9 percent has shown an increase in resilient modulus for increment of carbon black and modulus of resilient for mixes with 9 percent carbon black was 1.4 times that for mixes with 0 percent carbon black. The altering of carbon black from a range (3-9 percent has modified the fatigue property of the asphalt concrete mixes as determined by flexural test, Significantly, to modify the asphalt concrete manner taken the  percent of carbon black 6, and to produce the mixes more durable , higher resistance to distresses by adding the local knowledge.

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

    Science.gov (United States)

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

    2011-05-01

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

  8. 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)

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

    DEFF Research Database (Denmark)

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

    2016-01-01

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

  10. Comparison of PAN and Black Carbon Levels in Mexico City: 1997 and 2003

    Science.gov (United States)

    Gaffney, J. S.; Marley, N. A.

    2004-12-01

    Peroxyacetyl nitrate (PAN) is a secondary oxidant formed by the oxidation of hydrocarbons in the presence of nitrogen dioxide. PAN is a good indicator compound for hydrocarbon reactivity that leads to ozone formation. Black carbon (BC) is formed by incomplete combustion processes such as diesel soot formation and is a good indicator of primary carbonaceous aerosols in urban areas. We used a fast-response luminol method to measure PAN and BC during the Mexico City Metropolitan Area 2003/Mexico City Megacity 2003 field study in April 2003. We compare these results with our previous PAN measurements in Mexico City during February 1997, made with a gas chromatograph-electron capture detector system. The decreased PAN levels observed in 2003 are consistent with the application of emissions controls on spark ignition gasoline-fueled vehicles, leading to lower levels of the nitrogen oxides and reactive volatile hydrocarbons needed to form PAN. Black carbon data for Mexico City in 2003, taken with a seven-channel aethalometer, are compared with data from 1997, estimated from thermal analyses as elemental carbon (EC). The comparison indicates little change in the levels of BC/EC over the six-year period. This observation is consistent with the application of minimal controls to diesel engines, the likely major source of BC in the Mexico City megacity complex during this period. The authors wish to thank the researchers at Centro Nacional de Investigación en Calidad Ambiental (CENICA), Mexico City. This work was supported by the U.S. Department of Energy, Atmospheric Science Program. We also wish to acknowledge Drs. Mario and Luisa Molina for their help in organizing and directing the Mexico City Metropolitan Area 2003 field study, during which these data were collected.

  11. A Thermal Model for Carbon Nanotube Interconnects

    Directory of Open Access Journals (Sweden)

    Clay Mayberry

    2013-04-01

    Full Text Available In this work, we have studied Joule heating in carbon nanotube based very large scale integration (VLSI interconnects and incorporated Joule heating influenced scattering in our previously developed current transport model. The theoretical model explains breakdown in carbon nanotube resistance which limits the current density. We have also studied scattering parameters of carbon nanotube (CNT interconnects and compared with the earlier work. For 1 µm length single-wall carbon nanotube, 3 dB frequency in S12 parameter reduces to ~120 GHz from 1 THz considering Joule heating. It has been found that bias voltage has little effect on scattering parameters, while length has very strong effect on scattering parameters.

  12. 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

  13. The Evolution of Black Carbon Physicochemical Properties in Soils

    Science.gov (United States)

    Muñiz, Y.; Pyle, L. A.; Masiello, C. A.

    2016-12-01

    Black Carbon (BC) is a unique product of the incomplete combustion of biomass that occurs during wildfires. BC is a partially combusted solid residue of plant tissue that is highly porous, a source of soil organic carbon, and degrades more slowly than other forms of organic matter. A recent study by Westerling et al. 2006 showed that regional changes in climate led to increased wildfire activity over recent decades. One implication of this is that as the climate changes, increasing wildfire rates may increase production of BC. We analyzed how the physical and chemical properties of BC particles change over time in order to assess the stability of BC in soils. BC used in this study came from soils collected in Silas Little Experimental Forest (SLEF) which is a US Forest Service Site in the New Jersey Pine Barrens. This area has historical and geographical records on occurrences of fire events beginning in 1935. This allows us to simulate an almost 85 year study by looking at a range of BC particles of very different ages spanning the years between 1935 and 2015. BC particles from five different locations within SLEF were selected to represent the years 1930, 1963, 1995, and 2015. We used pycnometry to measure skeletal density where volume of pores is excluded and envelope density where volume of pores is included. Density of BC particles is important because it impacts BC mobility and interaction with soil and water which can affect whether BC will get stored in soils or be weathered away. We also used an elemental analyzer to measure the weight percent of carbon, hydrogen, and nitrogen of the BC particles to identify relative mineral and organic contributions. Pycnometry results revealed an overall increase in the skeletal density of aged BC particles from 1.64 to 1.70 g/cm3, and that BC particles from the O horizon had a lower skeletal density (1.60-1.71 g/cm3) than those from the A horizon (1.68- 1.77 g/cm3). Elemental analysis revealed a weight percent increase

  14. Solid-State 13C NMR Spectroscopy Applied to the Study of Carbon Blacks and Carbon Deposits Obtained by Plasma Pyrolysis of Natural Gas

    Directory of Open Access Journals (Sweden)

    Jair C. C. Freitas

    2016-01-01

    Full Text Available Solid-state 13C nuclear magnetic resonance (NMR spectroscopy was used in this work to analyze the physical and chemical properties of plasma blacks and carbon deposits produced by thermal cracking of natural gas using different types of plasma reactors. In a typical configuration with a double-chamber reactor, N2 or Ar was injected as plasma working gas in the first chamber and natural gas was injected in the second chamber, inside the arc column. The solid residue was collected at different points throughout the plasma apparatus and analyzed by 13C solid-state NMR spectroscopy, using either cross polarization (CP or direct polarization (DP, combined with magic angle spinning (MAS. The 13C CP/MAS NMR spectra of a number of plasma blacks produced in the N2 plasma reactor showed two resonance bands, broadly identified as associated with aromatic and aliphatic groups, with indication of the presence of oxygen- and nitrogen-containing groups in the aliphatic region of the spectrum. In contrast to DP experiments, only a small fraction of 13C nuclei in the plasma blacks are effectively cross-polarized from nearby 1H nuclei and are thus observed in spectra recorded with CP. 13C NMR spectra are thus useful to distinguish between different types of carbon species in plasma blacks and allow a selective study of groups spatially close to hydrogen in the material.

  15. Global anthropogenic emissions of particulate matter including black carbon

    Science.gov (United States)

    Klimont, Zbigniew; Kupiainen, Kaarle; Heyes, Chris; Purohit, Pallav; Cofala, Janusz; Rafaj, Peter; Borken-Kleefeld, Jens; Schöpp, Wolfgang

    2017-07-01

    This paper presents a comprehensive assessment of historical (1990-2010) global anthropogenic particulate matter (PM) emissions including the consistent and harmonized calculation of mass-based size distribution (PM1, PM2. 5, PM10), as well as primary carbonaceous aerosols including black carbon (BC) and organic carbon (OC). The estimates were developed with the integrated assessment model GAINS, where source- and region-specific technology characteristics are explicitly included. This assessment includes a number of previously unaccounted or often misallocated emission sources, i.e. kerosene lamps, gas flaring, diesel generators, refuse burning; some of them were reported in the past for selected regions or in the context of a particular pollutant or sector but not included as part of a total estimate. Spatially, emissions were calculated for 172 source regions (as well as international shipping), presented for 25 global regions, and allocated to 0.5° × 0.5° longitude-latitude grids. No independent estimates of emissions from forest fires and savannah burning are provided and neither windblown dust nor unpaved roads emissions are included. We estimate that global emissions of PM have not changed significantly between 1990 and 2010, showing a strong decoupling from the global increase in energy consumption and, consequently, CO2 emissions, but there are significantly different regional trends, with a particularly strong increase in East Asia and Africa and a strong decline in Europe, North America, and the Pacific region. This in turn resulted in important changes in the spatial pattern of PM burden, e.g. European, North American, and Pacific contributions to global emissions dropped from nearly 30 % in 1990 to well below 15 % in 2010, while Asia's contribution grew from just over 50 % to nearly two-thirds of the global total in 2010. For all PM species considered, Asian sources represented over 60 % of the global anthropogenic total, and residential combustion

  16. Global anthropogenic emissions of particulate matter including black carbon

    Directory of Open Access Journals (Sweden)

    Z. Klimont

    2017-07-01

    Full Text Available This paper presents a comprehensive assessment of historical (1990–2010 global anthropogenic particulate matter (PM emissions including the consistent and harmonized calculation of mass-based size distribution (PM1, PM2. 5, PM10, as well as primary carbonaceous aerosols including black carbon (BC and organic carbon (OC. The estimates were developed with the integrated assessment model GAINS, where source- and region-specific technology characteristics are explicitly included. This assessment includes a number of previously unaccounted or often misallocated emission sources, i.e. kerosene lamps, gas flaring, diesel generators, refuse burning; some of them were reported in the past for selected regions or in the context of a particular pollutant or sector but not included as part of a total estimate. Spatially, emissions were calculated for 172 source regions (as well as international shipping, presented for 25 global regions, and allocated to 0.5°  ×  0.5° longitude–latitude grids. No independent estimates of emissions from forest fires and savannah burning are provided and neither windblown dust nor unpaved roads emissions are included. We estimate that global emissions of PM have not changed significantly between 1990 and 2010, showing a strong decoupling from the global increase in energy consumption and, consequently, CO2 emissions, but there are significantly different regional trends, with a particularly strong increase in East Asia and Africa and a strong decline in Europe, North America, and the Pacific region. This in turn resulted in important changes in the spatial pattern of PM burden, e.g. European, North American, and Pacific contributions to global emissions dropped from nearly 30 % in 1990 to well below 15 % in 2010, while Asia's contribution grew from just over 50 % to nearly two-thirds of the global total in 2010. For all PM species considered, Asian sources represented over 60 % of the global

  17. Fast Cut Back Thermal Power Plant Load Rejection and Black Start Field Test Analysis

    Directory of Open Access Journals (Sweden)

    Kaiwen Zeng

    2014-04-01

    Full Text Available Fast and reliable black start plays a key role in improving the ability of the power system to resist the risk of large-scale blackouts. For a black start with high voltage and long-distance transmission lines, it is much easier to cause phenomena such as self-excitation and power frequency/operating overvoltage, which may lead to black start failure and impact the reliability of the system’s restoration. Meanwhile, the long time needed to crank up the non-black start units will impact the speed of the restoration. This paper addresses the advantages of using a thermal power unit with a fast cut back (FCB function as a black start unit, and studies the transient process of the FCB unit during the restoration. Firstly, key problems in the power system black start process are analyzed and a practical engineering criterion of self-excitation is proposed. Secondly, the dynamic model of the FCB unit is presented. Thirdly, the field test of the FCB unit load rejection and black start is introduced, which is the first successful field test of black start with 500 kV long-distance lines in China Southern Power Grid (CSG. Finally, the transient process of this test is simulated using the PSCAD/EMTDC software, and the simulation results accord well with the field test results, which verifies the correctness of the FCB model and the self-excitation engineering criterion proposed.

  18. Evaluation of the Black Carbon Measurements in the Arctic

    Science.gov (United States)

    Kondo, Y.; Sinha, P. R.; Koike, M.; Ogren, J. A.; Jefferson, A.; Barrett, T. E.; Sheesley, R. J.; Ohata, S.; Moteki, N.; Coe, H.; Liu, D.; Irwin, M.; Tunved, P.; Quinn, T.; Zhao, Y.

    2016-12-01

    Long-term measurements of light absorption coefficients (babs) have been reported by previous studies using particle soot absorption photometers (PSAP) at Barrow and Ny-Ålesund in the Arctic. However, the effects of other aerosol chemical species co-existing with black carbon (BC) on babs have not been critically evaluated. Furthermore, different values of mass absorption cross-sections (MACBC) have been used to convert babs to BC mass concentration (MBC = babs/MACBC). We measured babs at these sites for 3 years using COSMOS (babs (COSMOS)), which uses a heated inlet to remove non-BC compounds. Laboratory experiments showed babs (COSMOS) is affected by about 20% on average by sea-salt aerosols. The MBC values derived by COSMOS (MBC (COSMOS)) using the MACBC obtained by our previous studies, agree to within 1% with the elemental carbon concentrations at Barrow for 10 months. MBC (COSMOS) agreed to within 3% with the MBC measured by a single particle soot photometer (SP2) near Ny-Ålesund during the spring ACCACIA aircraft campaign. These results indicate high accuracy of MBC (COSMOS) at both sites. babs (PSAP) was systematically lower than babs (COSMOS) by 18 and 30% at Barrow (PM1) and Ny-Ålesund (PM10), respectively. Using babs (COSMOS) as a reference, we derived MBC (PSAP) from babs (PSAP) thus far. MBC (PSAP) values derived at Barrow during 1998-2015 decreased for all the seasons and the rate of decrease was estimated to be about -1.0±0.72 ng m-3 yr-1 for winter and spring. We also established the seasonal variations of MBC at these sites.

  19. A simplified model to estimate thermal resistance between carbon nanotube and sample in scanning thermal microscopy

    Science.gov (United States)

    Nazarenko, Maxim; Rosamond, Mark C.; Gallant, Andrew J.; Kolosov, Oleg V.; Dubrovskii, Vladimir G.; Zeze, Dagou A.

    2017-12-01

    Scanning thermal microscopy (SThM) is an attractive technique for nanoscale thermal measurements. Multiwalled carbon nanotubes (MWCNT) can be used to enhance a SThM probe in order to drastically increase spatial resolution while keeping required thermal sensitivity. However, an accurate prediction of the thermal resistance at the interface between the MWCNT-enhanced probe tip and a sample under study is essential for the accurate interpretation of experimental measurements. Unfortunately, there is very little literature on Kapitza interfacial resistance involving carbon nanotubes under SThM configuration. We propose a model for heat conductance through an interface between the MWCNT tip and the sample, which estimates the thermal resistance based on phonon and geometrical properties of the MWCNT and the sample, without neglecting the diamond-like carbon layer covering the MWCNT tip. The model considers acoustic phonons as the main heat carriers and account for their scattering at the interface based on a fundamental quantum mechanical approach. The predicted value of the thermal resistance is then compared with experimental data available in the literature. Theoretical predictions and experimental results are found to be of the same order of magnitude, suggesting a simplified, yet realistic model to approximate thermal resistance between carbon nanotube and sample in SThM, albeit low temperature measurements are needed to achieve a better match between theory and experiment. As a result, several possible avenues are outlined to achieve more accurate predictions and to generalize the model.

  20. Carbon nanotubes for thermal interface materials in microelectronic packaging

    Science.gov (United States)

    Lin, Wei

    As the integration scale of transistors/devices in a chip/system keeps increasing, effective cooling has become more and more important in microelectronics. To address the thermal dissipation issue, one important solution is to develop thermal interface materials with higher performance. Carbon nanotubes, given their high intrinsic thermal and mechanical properties, and their high thermal and chemical stabilities, have received extensive attention from both academia and industry as a candidate for high-performance thermal interface materials. The thesis is devoted to addressing some challenges related to the potential application of carbon nanotubes as thermal interface materials in microelectronics. These challenges include: 1) controlled synthesis of vertically aligned carbon nanotubes on various bulk substrates via chemical vapor deposition and the fundamental understanding involved; 2) development of a scalable annealing process to improve the intrinsic properties of synthesized carbon nanotubes; 3) development of a state-of-art assembling process to effectively implement high-quality vertically aligned carbon nanotubes into a flip-chip assembly; 4) a reliable thermal measurement of intrinsic thermal transport property of vertically aligned carbon nanotube films; 5) improvement of interfacial thermal transport between carbon nanotubes and other materials. The major achievements are summarized. 1. Based on the fundamental understanding of catalytic chemical vapor deposition processes and the growth mechanism of carbon nanotube, fast synthesis of high-quality vertically aligned carbon nanotubes on various bulk substrates (e.g., copper, quartz, silicon, aluminum oxide, etc.) has been successfully achieved. The synthesis of vertically aligned carbon nanotubes on the bulk copper substrate by the thermal chemical vapor deposition process has set a world record. In order to functionalize the synthesized carbon nanotubes while maintaining their good vertical alignment

  1. Field Measurements of Black Carbon Yields from Gas Flaring.

    Science.gov (United States)

    Conrad, Bradley M; Johnson, Matthew R

    2017-02-07

    Black carbon (BC) emissions from gas flaring in the oil and gas industry are postulated to have critical impacts on climate and public health, but actual emission rates remain poorly characterized. This paper presents in situ field measurements of BC emission rates and flare gas volume-specific BC yields for a diverse range of flares. Measurements were performed during a series of field campaigns in Mexico and Ecuador using the sky-LOSA optical measurement technique, in concert with comprehensive Monte Carlo-based uncertainty analyses. Parallel on-site measurements of flare gas flow rate and composition were successfully performed at a subset of locations enabling direct measurements of fuel-specific BC yields from flares under field conditions. Quantified BC emission rates from individual flares spanned more than 4 orders of magnitude (up to 53.7 g/s). In addition, emissions during one notable ∼24-h flaring event (during which the plume transmissivity dropped to zero) would have been even larger than this maximum rate, which was measured as this event was ending. This highlights the likely importance of superemitters to global emission inventories. Flare gas volume-specific BC yields were shown to be strongly correlated with flare gas heating value. A newly derived correlation fitting current field data and previous lab data suggests that, in the context of recent studies investigating transport of flare-generated BC in the Arctic and globally, impacts of flaring in the energy industry may in fact be underestimated.

  2. 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.

  3. Siberian Arctic black carbon sources constrained by model and observation

    Science.gov (United States)

    Winiger, Patrik; Andersson, August; Eckhardt, Sabine; Stohl, Andreas; Semiletov, Igor P.; Dudarev, Oleg V.; Charkin, Alexander; Shakhova, Natalia; Klimont, Zbigniew; Heyes, Chris; Gustafsson, Örjan

    2017-02-01

    Black carbon (BC) in haze and deposited on snow and ice can have strong effects on the radiative balance of the Arctic. There is a geographic bias in Arctic BC studies toward the Atlantic sector, with lack of observational constraints for the extensive Russian Siberian Arctic, spanning nearly half of the circum-Arctic. Here, 2 y of observations at Tiksi (East Siberian Arctic) establish a strong seasonality in both BC concentrations (8 ngṡm-3 to 302 ngṡm-3) and dual-isotope-constrained sources (19 to 73% contribution from biomass burning). Comparisons between observations and a dispersion model, coupled to an anthropogenic emissions inventory and a fire emissions inventory, give mixed results. In the European Arctic, this model has proven to simulate BC concentrations and source contributions well. However, the model is less successful in reproducing BC concentrations and sources for the Russian Arctic. Using a Bayesian approach, we show that, in contrast to earlier studies, contributions from gas flaring (6%), power plants (9%), and open fires (12%) are relatively small, with the major sources instead being domestic (35%) and transport (38%). The observation-based evaluation of reported emissions identifies errors in spatial allocation of BC sources in the inventory and highlights the importance of improving emission distribution and source attribution, to develop reliable mitigation strategies for efficient reduction of BC impact on the Russian Arctic, one of the fastest-warming regions on Earth.

  4. 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.

  5. Black carbon aerosols and the third polar ice cap

    Directory of Open Access Journals (Sweden)

    S. Menon

    2010-05-01

    Full Text Available Recent thinning of glaciers over the Himalayas (sometimes referred to as the third polar region have raised concern on future water supplies since these glaciers supply water to large river systems that support millions of people inhabiting the surrounding areas. Black carbon (BC aerosols, released from incomplete combustion, have been increasingly implicated as causing large changes in the hydrology and radiative forcing over Asia and its deposition on snow is thought to increase snow melt. In India BC emissions from biofuel combustion is highly prevalent and compared to other regions, BC aerosol amounts are high. Here, we quantify the impact of BC aerosols on snow cover and precipitation from 1990 to 2010 over the Indian subcontinental region using two different BC emission inventories. New estimates indicate that Indian BC emissions from coal and biofuel are large and transport is expected to expand rapidly in coming years. We show that over the Himalayas, from 1990 to 2000, simulated snow/ice cover decreases by ~0.9% due to aerosols. The contribution of the enhanced Indian BC to this decline is ~36%, similar to that simulated for 2000 to 2010. Spatial patterns of modeled changes in snow cover and precipitation are similar to observations (from 1990 to 2000, and are mainly obtained with the newer BC estimates.

  6. Black carbon aerosols and the third polar ice cap

    Science.gov (United States)

    Menon, S.; Koch, D.; Beig, G.; Sahu, S.; Fasullo, J.; Orlikowski, D.

    2010-05-01

    Recent thinning of glaciers over the Himalayas (sometimes referred to as the third polar region) have raised concern on future water supplies since these glaciers supply water to large river systems that support millions of people inhabiting the surrounding areas. Black carbon (BC) aerosols, released from incomplete combustion, have been increasingly implicated as causing large changes in the hydrology and radiative forcing over Asia and its deposition on snow is thought to increase snow melt. In India BC emissions from biofuel combustion is highly prevalent and compared to other regions, BC aerosol amounts are high. Here, we quantify the impact of BC aerosols on snow cover and precipitation from 1990 to 2010 over the Indian subcontinental region using two different BC emission inventories. New estimates indicate that Indian BC emissions from coal and biofuel are large and transport is expected to expand rapidly in coming years. We show that over the Himalayas, from 1990 to 2000, simulated snow/ice cover decreases by ~0.9% due to aerosols. The contribution of the enhanced Indian BC to this decline is ~36%, similar to that simulated for 2000 to 2010. Spatial patterns of modeled changes in snow cover and precipitation are similar to observations (from 1990 to 2000), and are mainly obtained with the newer BC estimates.

  7. Thermally Conductive Metal-Tube/Carbon-Composite Joints

    Science.gov (United States)

    Copeland, Robert J.

    2004-01-01

    An improved method of fabricating joints between metal and carbon-fiber-based composite materials in lightweight radiators and heat sinks has been devised. Carbon-fiber-based composite materials have been used in such heat-transfer devices because they offer a combination of high thermal conductivity and low mass density. Metal tubes are typically used to carry heat-transfer fluids to and from such heat-transfer devices. The present fabrication method helps to ensure that the joints between the metal tubes and the composite-material parts in such heat-transfer devices have both (1) the relatively high thermal conductances needed for efficient transfer of heat and (2) the flexibility needed to accommodate differences among thermal expansions of dissimilar materials in operation over wide temperature ranges. Techniques used previously to join metal tubes with carbon-fiber-based composite parts have included press fitting and bonding with epoxy. Both of these prior techniques have been found to yield joints characterized by relatively high thermal resistances. The present method involves the use of a solder (63 percent Sn, 37 percent Pb) to form a highly thermally conductive joint between a metal tube and a carbon-fiber-based composite structure. Ordinarily, the large differences among the coefficients of thermal expansion of the metal tube, solder, and carbon-fiber-based composite would cause the solder to pull away from the composite upon post-fabrication cooldown from the molten state. In the present method, the structure of the solder is modified (see figure) to enable it to deform readily to accommodate the differential thermal expansion.

  8. Characterization of Black and Brown Carbon Concentrations and Sources during winter in Beijing

    Science.gov (United States)

    Yan, Caiqing; Liu, Yue; Hansen, Anthony D. A.; Močnik, Griša; Zheng, Mei

    2017-04-01

    Carbonaceous aerosols, including black carbon (BC) and organic carbon (OC), play important roles in air quality, human health, and climate change. A better understanding of sources of light-absorbing carbonaceous aerosol (including black carbon and brown carbon) is particular critical for formulating emission-based control strategies and reducing uncertainties in current aerosol radiative forcing estimates. Beijing, the capital of China, has experienced serious air pollution problems and high concentrations of carbonaceous aerosols in recent years, especially during heating seasons. During November and December of 2016, several severe haze episodes occurred in Beijing, with hourly average PM2.5 mass concentration up to 400 μg/m3. In this study, concentration levels and sources of black carbon and brown carbon were investigated based on 7-wavelength Aethalometer (AE-33) with combination of other PM2.5 chemical composition information. Contributions of traffic and non-traffic emissions (e.g., coal combustion, biomass burning) were apportioned, and brown carbon was separated from black carbon. Our preliminary results showed that (1) Concentrations of BC were around 5.3±4.2 μg/m3 during the study period, with distinct diurnal variations during haze and non-haze days. (2) Traffic emissions contributed to about 37±17% of total BC, and exhibited higher contributions during non-haze days compared to haze days. (3) Coal combustion was a major source of black carbon and brown carbon in Beijing, which was more significant compared to biomass burning. Sources and the relative contributions to black carbon and brown carbon during haze and non-haze days will be further discussed.

  9. 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.

  10. 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

  11. 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. . . .

  12. Carbon Fiber Composites for Spacecraft Thermal Management Opportunities

    Science.gov (United States)

    Banisaukas, John J.; Shioleno, Mark A.; Levan, Chris D.; Rawal, Suraj P.; Silverman, Edward M.; Watts, Roland J.

    2005-02-01

    Under a prime contract (No.F33615-00-C-5009) with the U.S. Air Force Materials Lab, Cytec Carbon Fibers, LLC has completed a program to identify high risk, high payoff thermal management applications for the insertion of high thermal conductivity carbon fiber composite materials in future spacecraft. The program involved the identification of relevant design requirements, the design of components for thermal management applications utilizing the most appropriate high-conductivity carbon fiber composite material solution, the fabrication of prototype test articles, performance and characterization tests on the prototype articles, and test data correlation of measured results. The final step in the program required end-user acceptance or qualification testing of the designed components. This paper provides a technical overview of two of the most recent applications: 1) an aluminum-clad carbon fiber composite as a thermal doubler for efficient, light weight satellite radiator panels, and 2) a laminate-wrapped carbon fiber composite doubler for effective removal or spreading of heat associated with the high energy of a traveling wave tube amplifier (TWTA) unit as currently employed on the Mars Reconnaissance Orbiter.

  13. Dielectric and Microwave Properties of Siloxane Rubber/Carbon Black Nanocomposites and Their Correlation

    OpenAIRE

    Al-Hartomy, Omar A.; Falleh Al-Solamy; Ahmed Al-Ghamdi; Nikolay Dishovsky; Vladimir Iliev; Farid El-Tantawy

    2011-01-01

    In this paper, the dielectric and microwave properties of carbon black/siloxane rubber-based nanocomposites have been investigated in the frequency range from 1 GHz till 12 GHz according to the content of carbon black and the frequency. It has been established that the increasing frequency and filler content lead to an increase in the relative permittivity and tangent of dielectric loss angle. At higher filler content, the effects become more pronounced, especially those upon dielectric loss....

  14. 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

  15. The Toxicological Mechanisms of Environmental Soot (Black Carbon and Carbon Black: Focus on Oxidative Stress and Inflammatory Pathways

    Directory of Open Access Journals (Sweden)

    Rituraj Niranjan

    2017-06-01

    Full Text Available The environmental soot and carbon blacks (CBs cause many diseases in humans, but their underlying mechanisms of toxicity are still poorly understood. Both are formed after the incomplete combustion of hydrocarbons but differ in their constituents and percent carbon contents. For the first time, “Sir Percival Pott” described soot as a carcinogen, which was subsequently confirmed by many others. The existing data suggest three main types of diseases due to soot and CB exposures: cancer, respiratory diseases, and cardiovascular dysfunctions. Experimental models revealed the involvement of oxidative stress, DNA methylation, formation of DNA adducts, and Aryl hydrocarbon receptor activation as the key mechanisms of soot- and CB-induced cancers. Metals including Si, Fe, Mn, Ti, and Co in soot also contribute in the reactive oxygen species (ROS-mediated DNA damage. Mechanistically, ROS-induced DNA damage is further enhanced by eosinophils and neutrophils via halide (Cl− and Br− dependent DNA adducts formation. The activation of pulmonary dendritic cells, T helper type 2 cells, and mast cells is crucial mediators in the pathology of soot- or CB-induced respiratory disease. Polyunsaturated fatty acids (PUFAs were also found to modulate T cells functions in respiratory diseases. Particularly, telomerase reverse transcriptase was found to play the critical role in soot- and CB-induced cardiovascular dysfunctions. In this review, we propose integrated mechanisms of soot- and CB-induced toxicity emphasizing the role of inflammatory mediators and oxidative stress. We also suggest use of antioxidants and PUFAs as protective strategies against soot- and CB-induced disorders.

  16. Advantage of SBR/carbon black masterbatch for tire tread application

    Energy Technology Data Exchange (ETDEWEB)

    Sone, K.; Ishiguro, M.; Akimoto, H.; Ishida, M.

    1992-04-01

    The performance required of tire tread is becoming more severe and more various year by year, as social demands on tires have been changing. To improve wear resistance, driving safety and good drive feeling, new HP tires (high performance passenger car tires) are developed intensively. In addition, good fuel efficiency is required to satisfy the CAFE rule, which was proposed for a better global environment. To support this movement of the tire industry, material suppliers are making an effort to supply better materials. Mitsubishi Kasei has been improving the quality and production process of WMB, a SBR/carbon black master-batch produced by co-coagulation of SBR latex, carbon black and extender oil under the wet dispersion process. Compared to the tire tread made from dry-mixing compounds, that made from the WMB shows the following characteristics: (1) the abrasion resistance and the durability are higher; (2) from the viscoelastic properties, skid performance and driving stability are expected to be improved. These characteristics are remarkable when WMB is compounded in the recipes for HP and racing tires using fine carbon black. In this article, these features of WMB are studied from the view point of carbon black dispersion and polymer-carbon black interaction. Furthermore, the changes of carbon black structure during abrasion and fatigue process are analyzed and the mechanisms of these processes are discussed.

  17. 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.

  18. 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.

  19. Development, characterization, and application of the DRI model 2015 multiwavelength thermal-optical carbon analyzer

    Science.gov (United States)

    Sumlin, Benjamin J.

    A multiwavelength thermal/optical carbon analyzer (DRI Model 2015) equipped with a novel seven-wavelength light source (405, 445, 532, 635, 780, 808, and 980 nm) was developed to analyze chemical and optical properties of carbonaceous particles collected on quartz-fiber filters. Built upon on the DRI Model 2001 carbon analyzer at 633 nm, major modifications were made to mechanical and electrical components, flow control, and the carbon detector to adopt modern technologies, increase instrument reliability, and reduce costs and maintenance. This instrument quantifies organic and elemental carbon (OC and EC, respectively) and their thermal fractions. It also allows estimation of the amount of brown and black carbon (BrC and BC, respectively) on filters. Continuous monitoring of the light reflected from and transmitted through the filter along with carbon evolved from the filter when heated to different temperatures under either inert or oxidizing gas environments provides insights into the optical properties of the carbon released from the filter; it also allows examination of the charring process as pyrolyzed char has been one of the major uncertainties in quantifying OC and EC. The objectives of this study are: 1) characterize the Model 2015's performance parameters including detection limits, and optical behavior; 2) establish performance equivalence between the Model 2015 and Model 2001 DRI carbon analyzers when comparing similar laser wavelength to maintain consistency for long-term network sample analysis; and 3) conduct a preliminary analysis of the multiwavelength signal to estimate BrC and BC, and to optimize char correction. A selection of samples, including standard chemicals, as well as rural and urban ambient filter samples were measured by both the Model 2015 and Model 2001 analyzers. The design and construction experience will be discussed, as well as recommended future scientific research and engineering development.

  20. Multiscale Modeling of Thermal Conductivity of Polymer/Carbon Nanocomposites

    Science.gov (United States)

    Clancy, Thomas C.; Frankland, Sarah-Jane V.; Hinkley, Jeffrey A.; Gates, Thomas S.

    2010-01-01

    Molecular dynamics simulation was used to estimate the interfacial thermal (Kapitza) resistance between nanoparticles and amorphous and crystalline polymer matrices. Bulk thermal conductivities of the nanocomposites were then estimated using an established effective medium approach. To study functionalization, oligomeric ethylene-vinyl alcohol copolymers were chemically bonded to a single wall carbon nanotube. The results, in a poly(ethylene-vinyl acetate) matrix, are similar to those obtained previously for grafted linear hydrocarbon chains. To study the effect of noncovalent functionalization, two types of polyethylene matrices. -- aligned (extended-chain crystalline) vs. amorphous (random coils) were modeled. Both matrices produced the same interfacial thermal resistance values. Finally, functionalization of edges and faces of plate-like graphite nanoparticles was found to be only modestly effective in reducing the interfacial thermal resistance and improving the composite thermal conductivity

  1. Impact of warming and drought on carbon balance related to wood formation in black spruce.

    Science.gov (United States)

    Deslauriers, Annie; Beaulieu, Marilène; Balducci, Lorena; Giovannelli, Alessio; Gagnon, Michel J; Rossi, Sergio

    2014-08-01

    Wood formation in trees represents a carbon sink that can be modified in the case of stress. The way carbon metabolism constrains growth during stress periods (high temperature and water deficit) is now under debate. In this study, the amounts of non-structural carbohydrates (NSCs) for xylogenesis in black spruce, Picea mariana, saplings were assessed under high temperature and drought in order to determine the role of sugar mobilization for osmotic purposes and its consequences for secondary growth. Four-year-old saplings of black spruce in a greenhouse were subjected to different thermal conditions with respect to the outside air temperature (T0) in 2010 (2 and 5 °C higher than T0) and 2011 (6 °C warmer than T0 during the day or night) with a dry period of about 1 month in June of each year. Wood formation together with starch, NSCs and leaf parameters (water potential and photosynthesis) were monitored from May to September. With the exception of raffinose, the amounts of soluble sugars were not modified in the cambium even if gas exchange and photosynthesis were greatly reduced during drought. Raffinose increased more than pinitol under a pre-dawn water potential of less than -1 Mpa, presumably because this compound is better suited than polyol for replacing water and capturing free radicals, and its degradation into simple sugar is easier. Warming decreased the starch storage in the xylem as well the available hexose pool in the cambium and the xylem, probably because of an increase in respiration. Radial stem growth was reduced during drought due to the mobilization of NSCs for osmotic purposes and due to the lack of cell turgor. Thus plant water status during wood formation can influence the NSCs available for growth in the cambium and xylem. © The Author 2014. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  2. Thermal carbonization of nanoporous silicon: Formation of carbon ...

    Indian Academy of Sciences (India)

    of carbon nanofibres without a metal catalyst. GUNJAN AGGARWAL, PRABHASH MISHRA, BIPIN JOSHI and S S ISLAM. ∗. Nano-Sensor Research Laboratory, Department of Applied Sciences and Humanities, F/O of. Engineering and Technology, Jamia Millia Islamia (A Central University), New Delhi 110 025,. India. ∗.

  3. Extremely Black Vertically Aligned Carbon Nanotube Arrays for Solar Steam Generation.

    Science.gov (United States)

    Yin, Zhe; Wang, Huimin; Jian, Muqiang; Li, Yanshen; Xia, Kailun; Zhang, Mingchao; Wang, Chunya; Wang, Qi; Ma, Ming; Zheng, Quan-Shui; Zhang, Yingying

    2017-08-30

    The unique structure of a vertically aligned carbon nanotube (VACNT) array makes it behave most similarly to a blackbody. It is reported that the optical absorptivity of an extremely black VACNT array is about 0.98-0.99 over a large spectral range of 200 nm-200 μm, inspiring us to explore the performance of VACNT arrays in solar energy harvesting. In this work, we report the highly efficient steam generation simply by laminating a layer of VACNT array on the surface of water to harvest solar energy. It is found that under solar illumination the temperature of upper water can significantly increase with obvious water steam generated, indicating the efficient solar energy harvesting and local temperature rise by the thin layer of VACNTs. We found that the evaporation rate of water assisted by VACNT arrays is 10 times that of bare water, which is the highest ratio for solar-thermal-steam generation ever reported. Remarkably, the solar thermal conversion efficiency reached 90%. The excellent performance could be ascribed to the strong optical absorption and local temperature rise induced by the VACNT layer, as well as the ultrafast water transport through the VACNT layer due to the frictionless wall of CNTs. Based on the above, we further demonstrated the application of VACNT arrays in solar-driven desalination.

  4. Evolving non-thermal electrons in simulations of black hole accretion

    Science.gov (United States)

    Chael, Andrew A.; Narayan, Ramesh; Saḑowski, Aleksander

    2017-09-01

    Current simulations of hot accretion flows around black holes assume either a single-temperature gas or, at best, a two-temperature gas with thermal ions and electrons. However, processes like magnetic reconnection and shocks can accelerate electrons into a non-thermal distribution, which will not quickly thermalize at the very low densities found in many systems. Such non-thermal electrons have been invoked to explain the infrared and X-ray spectra and strong variability of Sagittarius A* (Sgr A*), the black hole at the Galactic Center. We present a method for self-consistent evolution of a non-thermal electron population in the general relativistic magnetohydrodynamic code koral. The electron distribution is tracked across Lorentz factor space and is evolved in space and time, in parallel with thermal electrons, thermal ions and radiation. In this study, for simplicity, energy injection into the non-thermal distribution is taken as a fixed fraction of the local electron viscous heating rate. Numerical results are presented for a model with a low mass accretion rate similar to that of Sgr A*. We find that the presence of a non-thermal population of electrons has negligible effect on the overall dynamics of the system. Due to our simple uniform particle injection prescription, the radiative power in the non-thermal simulation is enhanced at large radii. The energy distribution of the non-thermal electrons shows a synchrotron cooling break, with the break Lorentz factor varying with location and time, reflecting the complex interplay between the local viscous heating rate, magnetic field strength and fluid velocity.

  5. 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

  6. Impacts of black carbon and co-pollutant emissions from transportation sector in Mexico City

    Science.gov (United States)

    Zavala, Miguel; Almanza, Victor; Garcia, Agustin; Jazcilevich, Aron; Lei, Wenfang; Molina, Luisa

    2016-04-01

    Black carbon is one of the most important short-lived climate-forcing agents, which is harmful to human health and also contributes significantly to climate change. Transportation is one of the largest sources of black carbon emissions in many megacities and urban complexes, with diesel vehicles leading the way. Both on-road and off-road vehicles can emit substantial amounts of harmful BC-containing particulate matter (PM) and are also responsible for large emissions of carbon dioxide (CO2), carbon monoxide (CO), nitrogen oxides (NOx), and many other co-emitted volatile organic compounds (VOCs). Regionally, black carbon emissions contributions from mobile sources may vary widely depending on the technical characteristics of the vehicle fleet, the quality and chemical properties of the fuels consumed, and the degree of local development and economic activities that foster wider and more frequent or intensive use of vehicles. This presentation will review and assess the emissions of black carbon from the on-road and off-road transportation sector in the Mexico City Metropolitan Area. Viable mitigation strategies, including innovative technological alternatives to reduce black carbon and co-pollutants in diesel vehicles and their impacts on climate, human health and ecosystems will be described.

  7. Attribution of aerosol light absorption to black carbon and volatile aerosols.

    Science.gov (United States)

    Shrestha, Rijana; Kim, Sang-Woo; Yoon, Soon-Chang; Kim, Ji-Hyoung

    2014-08-01

    We investigated the contribution of volatile aerosols in light-absorption measurement by three filter-based optical instruments [aethalometer, continuous light-absorption photometer (CLAP), and continuous soot monitoring system (COSMOS)] at Gosan Climate Observatory (GCO) from February to June 2012. The aerosol absorption coefficient (σ abs) and the equivalent black carbon (BC) mass concentration (M BC) measured by the aethalometer and CLAP showed good agreement with a difference of 9 %, which is likely due to the instrumental uncertainty. However, σ abs and M BC measured by the COSMOS with a heated inlet were found to be approximately 44 and 49 % lower than those measured by the aethalometer and CLAP under ambient conditions, respectively. This difference can be attributed to the light absorption by the volatile aerosols coexisting with the BC. Even considering inherent observational uncertainty, it suggests that approximately 35-40 % difference in the σ abs and M BC can be contributed by volatile aerosols. Increase in the difference of M BC measured by the aethalometer and COSMOS with the increasing thermal organic carbon (OC) measured by Sunset OC/EC analyzer further suggests that the filter-based optical instruments without the use of a heater are likely to enhance the value of σ abs and M BC, because this sample air may contain both BC and volatile aerosols.

  8. Phonon and thermal properties of achiral single wall carbon ...

    Indian Academy of Sciences (India)

    A detailed theoretical study of the phonon and thermal properties of achiral single wall carbon nanotubes has been carried out using force constant model considering up to third nearest-neighbor interactions. We have calculated the phonon dispersions, density of states, radial breathing modes (RBM) and the specific heats ...

  9. Phonon and thermal properties of achiral single wall carbon ...

    Indian Academy of Sciences (India)

    This exceptionally high value of thermal conductivity reflects the one-dimensional conduction behavior of nanotubes with least phonon scattering. Recent ..... In this way one can interpret the double peak structure of the high-energy sub-band of carbon nanotubes. In the case of achiral tubes it was found that the magnitude ...

  10. Immunotoxicity of carbon black nanoparticles to blue mussel hemocytes.

    Science.gov (United States)

    Canesi, Laura; Ciacci, Caterina; Betti, Michele; Fabbri, Rita; Canonico, Barbara; Fantinati, Andrea; Marcomini, Antonio; Pojana, Giulio

    2008-11-01

    The potential for human and ecological toxicity associated with nanomaterials is a growing area of investigation. In mammalian cells, nanoparticles have been shown to induce inflammation and oxidative stress, and changes in cell signalling and gene expression. As the nanotechnology industries increase production, nanoscale products and by products will enter the aquatic environment, posing a possible threat to aquatic organisms. In particular, filter-feeding organisms may represent a unique target group for nanoparticle toxicology. In this work, the effects of commercial nanosized carbon black (NCB) on the immune cells, the hemocytes, of the bivalve mollusc Mytilus, and the possible mechanisms involved were investigated. The results demonstrate that NCB (1, 5, and 10 microg/ml), did not induce significant lysosomal membrane destabilization, as evaluated by the NR retention time assay. A concentration-dependent uptake of NCB by hemocytes was observed and it was associated by a rapid increase in extracellular lysozyme release, extracellular oxyradical production, and nitric oxide (NO) release. Moreover, at the highest concentration tested, NCB induced significant changes in mitochondrial parameters (decrease mitochondrial mass/number and membrane potential), as evaluated by flow cytometry. The effects of NCB were mediated by rapid activation of the stress-activated MAPKs (Mitogen Activated Protein Kinases) p38 and JNKs, that play a key role in immune and inflammatory responses. The results demonstrate that in mussel hemocytes like in mammalian cells NCB exposure can induce inflammatory processes, and indicate that bivalve immunocytes can represent a suitable model for investigating the effects and modes of action of nanoparticles in the cells of aquatic invertebrates.

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

    Science.gov (United States)

    Clack, Herek L

    2012-07-03

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

  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. Black carbon-mediated destruction of nitroglycerin and RDX by hydrogen sulfide.

    Science.gov (United States)

    Xu, Wenqing; Dana, Kathryn E; Mitch, William A

    2010-08-15

    The in situ remediation of sediments contaminated with explosives, including nitroglycerin and hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX), is desirable, particularly at bombing ranges where unexploded ordnance (UXO) renders excavation dangerous. Sulfides generated by biological sulfate reduction in sediments are potent nucleophiles and reductants that may contribute to the destruction of explosives. However, moderately hydrophobic explosives are likely to sorb to black carbons, which can constitute 10-30% of sediment organic carbon. In this study, we evaluated whether the black carbons accelerate these reactions or simply sequester explosives from aqueous phase reactions. Using environmentally-relevant sulfide and black carbon concentrations, our results indicated that black carbons accelerated the destruction of both compounds, yielding relatively harmless products on the time scale of hours. For both compounds, destruction increased with sulfide and graphite concentrations. Using sheet graphite as a model for graphene regions in black carbons, we evaluated whether graphene regions mediated the reduction of explosives by promoting electron transfer from sulfides. Our results demonstrated that the process was more complex. Using an electrochemical cell that enabled electron transfer from sulfides to explosives through graphite, but prevented nucleophilic substitution reactions, we found that nitroglycerin destruction, but not RDX destruction, could be explained by an electron transfer mechanism. Furthermore, surface area-normalized destruction rates for the same explosive varied for different black carbons. While black carbon-mediated destruction of explosives by sulfides is likely to be a significant contributor to their natural attenuation in sediments, a fundamental characterization of the reaction mechanisms is needed to better understand the process.

  14. Thermal Conductivity and Raman Spectra of Carbon Fibers

    Science.gov (United States)

    Liu, Xuebo; Dong, Hua; Li, Yan; Mei, Ning

    2017-10-01

    Due to its unique physical properties, carbon fiber (CF) has been widely studied for extensive application in aerospace and machinery. In this study, the thermal diffusivity of three kinds of CF sample is characterized by the transient electrothermal technique at room temperature. By subtracting the effect of radiative losses, the effective thermal diffusivity of CFs can be calculated as 6.46× 10^{-6} m2\\cdot s^{-1}, 6.58× 10^{-6} m2\\cdot s^{-1} and 2.01× 10^{-4} m2\\cdot s^{-1}, respectively. For the first time, the emissivity coefficient of carbon fiber is calibrated as 0.78. Combined with Raman spectra and phonon scattering, we found that the better crystalline structure and low defect in CF have an obvious impact on its thermal diffusivity.

  15. Thermal Transport Properties of Dry Spun Carbon Nanotube Sheets

    Directory of Open Access Journals (Sweden)

    Heath E. Misak

    2016-01-01

    Full Text Available The thermal properties of carbon nanotube- (CNT- sheet were explored and compared to copper in this study. The CNT-sheet was made from dry spinning CNTs into a nonwoven sheet. This nonwoven CNT-sheet has anisotropic properties in in-plane and out-of-plane directions. The in-plane direction has much higher thermal conductivity than the out-of-plane direction. The in-plane thermal conductivity was found by thermal flash analysis, and the out-of-plane thermal conductivity was found by a hot disk method. The thermal irradiative properties were examined and compared to thermal transport theory. The CNT-sheet was heated in the vacuum and the temperature was measured with an IR Camera. The heat flux of CNT-sheet was compared to that of copper, and it was found that the CNT-sheet has significantly higher specific heat transfer properties compared to those of copper. CNT-sheet is a potential candidate to replace copper in thermal transport applications where weight is a primary concern such as in the automobile, aircraft, and space industries.

  16. Methodical Specifics of Thermal Experiments with Thin Carbon Reinforced Plates

    Directory of Open Access Journals (Sweden)

    O. V. Denisov

    2015-01-01

    Full Text Available Polymer composite materials (CM are widely used in creation of large space constructions, especially reflectors of space antennas. Composite materials should provide high level of specific stiffness and strength for space structures. Thermal conductivity in reinforcement plane is a significant factor in case of irregular heating space antennas. Nowadays, data on CM reinforcement plane thermal conductivity are limited and existing methods of its defining are imperfect. Basically, traditional methods allow us to define thermal conductivity in perpendicular direction towards the reinforcement plane on the samples of round or rectangular plate. In addition, the thickness of standard samples is larger than space antenna thickness. Consequently, new methods are required. Method of contact heating, which was developed by BMSTU specialists with long hollow carbon beam, could be a perspective way. This article is devoted to the experimental method of contact heating on the thin carbon plates.Thermal tests were supposed to provide a non-stationary temperature field with a gradient being co-directional with the plane reinforcement in the material sample. Experiments were conducted in vacuum chamber to prevent unstructured convection. Experimental thermo-grams processing were calculated by 1-d thermal model for a thin plate. Influence of uncertainty of experimental parameters, such as (radiation emission coefficients of sample surface, glue, temperature sensors and uncertainty of sensors placement on the result of defined thermal conductivity has been estimated. New data on the thermal conductivity in reinforcement plane were obtained within 295 - 375 K temperature range, which can be used to design and develop reflectors of precision space antennas. In the future it is expedient to conduct tests of thin-wall plates from carbon fiber-reinforced plastic in wide temperature range, especially in the low-range temperatures.

  17. Dynamac molecular structure of plant biomass-derived black carbon (Biochar)

    Science.gov (United States)

    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 o...

  18. 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

  19. The effects of solar radiation and black body re-radiation on thermal comfort.

    Science.gov (United States)

    Hodder, Simon; Parsons, Ken

    2008-04-01

    When the sun shines on people in enclosed spaces, such as in buildings or vehicles, it directly affects thermal comfort. There is also an indirect effect as surrounding surfaces are heated exposing a person to re-radiation. This laboratory study investigated the effects of long wave re-radiation on thermal comfort, individually and when combined with direct solar radiation. Nine male participants (26.0 +/- 4.7 years) took part in three experimental sessions where they were exposed to radiation from a hot black panel heated to 100 degrees C; direct simulated solar radiation of 600 Wm(-2) and the combined simulated solar radiation and black panel radiation. Exposures were for 30 min, during which subjective responses and mean skin temperatures were recorded. The results showed that, at a surface temperature of 100 degrees C (close to maximum in practice), radiation from the flat black panel provided thermal discomfort but that this was relatively small when compared with the effects of direct solar radiation. It was concluded that re-radiation, from a dashboard in a vehicle, for example, will not have a major direct influence on thermal comfort and that existing models of thermal comfort do not require a specific modification. These results showed that, for the conditions investigated, the addition of re-radiation from internal components has an effect on thermal sensation when combined with direct solar radiation. However, it is not considered that it will be a major factor in a real world situation. This is because, in practice, dashboards are unlikely to maintain very high surface temperatures in vehicles without an unacceptably high air temperature. This study quantifies the contribution of short- and long-wave radiation to thermal comfort. The results will aid vehicle designers to have a better understanding of the complex radiation environment. These include direct radiation from the sun as well as re-radiation from the dashboard and other internal surfaces.

  20. An analysis of the changes on intermediate products during the thermal processing of black garlic.

    Science.gov (United States)

    Yuan, Heng; Sun, Linjuan; Chen, Min; Wang, Jun

    2018-01-15

    The thermal processing of black garlic was simulated. Fresh garlic was incubated at 55°C with 80% humidity and sampled every 5 or 10days. The changes in relevant products were as follows: the fructan content was decreased by 84.79%, and the fructose content was increased by 508.11%. The contents of Maillard reaction intermediate products were first increased and then decreased. The colour of garlic gradually became dark and the pH decreased from 6.13 to 4.00. By analyzing these changes, the mechanism of black garlic formation and the changes on the Maillard reaction were revealed. The sweetness of black garlic resulted mainly from the fructose that was produced, and the black colour was largely due to the Maillard reaction between fructose/glucose and amino acids. An understanding of this process is useful to explain the formation mechanism of black garlic and could lead to better control of the quality of black garlic. Copyright © 2017 Elsevier Ltd. All rights reserved.

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

    OpenAIRE

    G. M. Buffaloe; D. A. Lack; Williams, E. J.; Coffman, D.; Hayden, K. L.; B. M. Lerner; S-M. Li; I. Nuaaman; P. Massoli; Onasch, T.B.; Quinn, P.K.; Cappa, C. D.

    2013-01-01

    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 va...

  2. Insulating and sheathing materials of electric and optical cables: common test methods part 4-1: methods specific to polyethylene and polypropylene compounds – resistance to environmental stress cracking – measurement of the melt flow index – carbon black and/or mineral filler content measurement in polyethylene by direct combustion – measurement of carbon black content by thermogravimetric analysis (TGA) – assessment of carbon black dispersion in polyethylene using a microscope

    CERN Document Server

    International Electrotechnical Commission. Geneva

    2004-01-01

    Specifies the test methods to be used for testing polymeric insulating and sheathing materials of electric cables for power distribution and telecommunications including cables used on ships. Gives the methods for measurements of the resistance to environmental stress cracking, for wrapping test after thermal ageing in air, for measurement of melt flow index and for measurement of carbon black and/or mineral filler content, which apply to PE and PP coumpounds, including cellular compounds and foam skin for insulation.

  3. Flexible all-carbon photovoltaics with improved thermal stability

    Energy Technology Data Exchange (ETDEWEB)

    Tang, Chun; Ishihara, Hidetaka; Sodhi, Jaskiranjeet; Chen, Yen-Chang; Siordia, Andrew; Martini, Ashlie; Tung, Vincent C., E-mail: ctung@ucmerced.edu

    2015-04-15

    The structurally robust nature of nanocarbon allotropes, e.g., semiconducting single-walled carbon nanotubes (SWCNTs) and C{sub 60}s, makes them tantalizing candidates for thermally stable and mechanically flexible photovoltaic applications. However, C{sub 60}s rapidly dissociate away from the basal of SWCNTs under thermal stimuli as a result of weak intermolecular forces that “lock up” the binary assemblies. Here, we explore use of graphene nanoribbons (GNRs) as geometrically tailored protecting layers to suppress the unwanted dissociation of C{sub 60}s. The underlying mechanisms are explained using a combination of molecular dynamics simulations and transition state theory, revealing the temperature dependent disassociation of C{sub 60}s from the SWCNT basal plane. Our strategy provides fundamental guidelines for integrating all-carbon based nano-p/n junctions with optimized structural and thermal stability. External quantum efficiency and output current–voltage characteristics are used to experimentally quantify the effectiveness of GNR membranes under high temperature annealing. Further, the resulting C{sub 60}:SWCNT:GNR ternary composites display excellent mechanical stability, even after iterative bending tests. - Graphical abstract: The incorporation of solvent resistant, mechanically flexible and electrically addressable 2-D soft graphene nanoribbons facilitates the assembly of photoconductive carbon nano-p/n junctions for thermally stable and flexible photovoltaic cells.

  4. Thermal Properties of Carbon Nanotube–Copper Composites for Thermal Management Applications

    Directory of Open Access Journals (Sweden)

    Jia Chengchang

    2010-01-01

    Full Text Available Abstract Carbon nanotube–copper (CNT/Cu composites have been successfully synthesized by means of a novel particles-compositing process followed by spark plasma sintering (SPS technique. The thermal conductivity of the composites was measured by a laser flash technique and theoretical analyzed using an effective medium approach. The experimental results showed that the thermal conductivity unusually decreased after the incorporation of CNTs. Theoretical analyses revealed that the interfacial thermal resistance between the CNTs and the Cu matrix plays a crucial role in determining the thermal conductivity of bulk composites, and only small interfacial thermal resistance can induce a significant degradation in thermal conductivity for CNT/Cu composites. The influence of sintering condition on the thermal conductivity depended on the combined effects of multiple factors, i.e. porosity, CNTs distribution and CNT kinks or twists. The composites sintered at 600°C for 5 min under 50 MPa showed the maximum thermal conductivity. CNT/Cu composites are considered to be a promising material for thermal management applications.

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

    Science.gov (United States)

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

    2013-03-01

    A feasibility study regarding the production of radioactive carbon black and nanotubes has been performed by proton beam irradiation. Experimental and theoretical excitation functions of the nuclear reaction (nat)C(p,x)(7)Be in the proton energy range 24-38 MeV are reported, with an acceptable agreement. We have demonstrated that sufficient activities of (7)Be radioisotope can be produced in carbon black and nanotube that would facilitate studies of their possible impact on human and environment. Copyright © 2012 Elsevier Ltd. All rights reserved.

  6. 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

  7. 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%, PIrrigation could be the solution against the harmful effects of soot. This article was made under the projects TÁMOP-4.2.2/B-10/1-2010-0025 and TÁMOP-4.2.4. A/2-11-1-2012-0001. These projects are supported by the European Union and co-financed by the European Social Fund.

  8. Epoxy composites filled with high surface area-carbon fillers: Optimization of electromagnetic shielding, electrical, mechanical, and thermal properties

    Science.gov (United States)

    Kuzhir, P.; Paddubskaya, A.; Plyushch, A.; Volynets, N.; Maksimenko, S.; Macutkevic, J.; Kranauskaite, I.; Banys, J.; Ivanov, E.; Kotsilkova, R.; Celzard, A.; Fierro, V.; Zicans, J.; Ivanova, T.; Merijs Meri, R.; Bochkov, I.; Cataldo, A.; Micciulla, F.; Bellucci, S.; Lambin, Ph.

    2013-10-01

    A comprehensive analysis of electrical, electromagnetic (EM), mechanical, and thermal properties of epoxy resin composites filled with 0.25-2.0 wt. % of carbon additives characterized by high surface area, both nano-sized, like carbon nanotubes (CNTs) and carbon black (CBH), and micro-sized exfoliated graphite (EG), was performed. We found that the physical properties of both CNTs- and CBH-based epoxy resin composites increased all together with filler content and even more clearly for CBH than for CNTs. In the case of EG-based composites, good correlation between properties and filler amount was observed for concentrations below 1.5 wt. %. We conclude that CBH and, to a lower extent, EG could replace expensive CNTs for producing effective EM materials in microwave and low-frequency ranges, which are, in addition, mechanically and thermally stable.

  9. New method for binder and carbon black detection at nanometer scale in carbon electrodes for lithium ion batteries

    Science.gov (United States)

    Pfaffmann, Lukas; Jaiser, Stefan; Müller, Marcus; Scharfer, Philip; Schabel, Wilhelm; Bauer, Werner; Scheiba, Frieder; Ehrenberg, Helmut

    2017-09-01

    In the current work, graphite electrodes comprising PVDF binder and carbon black are subjected to characterization. An energy selective backscatter detector is used to localize carbon black and fluorine of PVDF. Therefore, it is necessary to distinguish between graphite, amorphous carbon and fluorine rich regions. Typically, an angular selective backscatter detector is employed to obtain an image providing the material contrast of the sample. Suitable materials for that detector are e.g. alloys to observe intermetallic phases, semiconductor for ;channeling contrast;, or imaging SiO2 and Au nanoparticles in biological cells. However, this detector cannot be used to distinguish between light elements with low atomic numbers, such as C to P. In addition, the contrast of fluorine rich regions and graphite is poor in normal in-lens images due to the low difference of the atomic mass between C and F. The aim of this study is to enhance the contrast of fluorine rich regions to graphite to carbon black. Therefore, the energy selective backscatter detector is used and its advantages and setup is described. Finally this technique is applied to investigate 400 μm thick cross-sections of graphite electrodes dried at different temperatures and obtain the carbon black distribution.

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

    Science.gov (United States)

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

    2013-08-06

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

  12. Modelling the Effect of Black Carbon and Sulfate Aerosol on the Regional Meteorology Factors

    Science.gov (United States)

    Ma, X.; Wen, W.

    2017-07-01

    In this study, we focus on the effect of black carbon aerosol and sulfate aerosol on meteorology factors during heavy pollution period and non-heavy pollution period. The version of WRF/chem V3.4 was used in this work, Four Simulation scenarios are applied to simulate the effect of the effect of black carbon aerosol and sulfate aerosol on solar radiation, temperature, PBL high. The analysis results show that the effect of black carbon and sulfate aerosol cause decline on three meteorological factors in both heavy pollution and non-heavy pollution period in both January and July. The influence of two aerosols on meteorological factors are less significant than winter. During heavy pollution, black carbon aerosol cause the loss of solar radiation is 29.1W/m2; the warming effect of black carbon aerosol caused temperature to rise 0.05°C PBL height decreased by an average of 73.1m. Sulfate aerosols cause the loss of solar radiation is 21.5W/m2; Temperature fell an average of 0.89°C PBL height decreased by 66.6m. The change of three meteorological factors due to aerosol feedback in non-heavy pollution period in much smaller than heavy pollution period.

  13. Determination of Thermal Properties of Graphite-Black-Coating by Photothermal and Electro-Pyroelectric Techniques

    Directory of Open Access Journals (Sweden)

    Najoua Bennaji

    2014-05-01

    Full Text Available In this study we will describe and compare photothermal and Electro-pyroelectric techniques which permit the determination of thermal properties of materials. We will give a brief account of the basic aspects of the photothermal model and of a setup with an alternative detection technique with a pyroelectric transducer. The possibilities of these measuring schemes for the simultaneous measurement of the thermal conductivity and diffusivity will be illustrated with results from a study of Graphite- black-coating. Finally, we will compare those two non-destructive techniques (photothermal and Electro-pyroelectric.

  14. Modeling soil thermal and carbon dynamics of a fire chronosequence in interior Alaska

    Science.gov (United States)

    Zhuang, Q.; McGuire, A. D.; O'Neill, K. P.; Harden, J. W.; Romanovsky, V. E.; Yarie, J.

    2003-01-01

    In this study, the dynamics of soil thermal, hydrologic, and ecosystem processes were coupled to project how the carbon budgets of boreal forests will respond to changes in atmospheric CO2, climate, and fire disturbance. The ability of the model to simulate gross primary production and ecosystem respiration was verified for a mature black spruce ecosystem in Canada, the age-dependent pattern of the simulated vegetation carbon was verified with inventory data on aboveground growth of Alaskan black spruce forests, and the model was applied to a postfire chronosequence in interior Alaska. The comparison between the simulated soil temperature and field-based estimates during the growing season (May to September) of 1997 revealed that the model was able to accurately simulate monthly temperatures at 10 cm (R > 0.93) for control and burned stands of the fire chronosequence. Similarly, the simulated and field-based estimates of soil respiration for control and burned stands were correlated (R = 0.84 and 0.74 for control and burned stands, respectively). The simulated and observed decadal to century-scale dynamics of soil temperature and carbon dynamics, which are represented by mean monthly values of these variables during the growing season, were correlated among stands (R = 0.93 and 0.71 for soil temperature at 20- and 10-cm depths, R = 0.95 and 0.91 for soil respiration and soil carbon, respectively). Sensitivity analyses indicate that along with differences in fire and climate history a number of other factors influence the response of carbon dynamics to fire disturbance. These factors include nitrogen fixation, the growth of moss, changes in the depth of the organic layer, soil drainage, and fire severity.

  15. Development of a Thermal/Optical Carbon Analyzer with Multi-Wavelength Capabilities

    Science.gov (United States)

    Sumlin, B.; Chow, J. C.; Watson, J. G.; Wang, X.; Gronstal, S.; Chen, L. W. A. A.; Trimble, D.

    2014-12-01

    A thermal/optical carbon analyzer (DRI Model 2015) equipped with a novel seven-wavelength light source (405, 445, 532, 635, 780, 808, and 980 nm) was developed to analyze chemical and optical properties of particles collected on quartz-fiber filters. Based on the DRI Model 2001 carbon analyzer at 633 nm, major modifications were made on mechanical and electrical components, flow control, and the carbon detector to adopt modern technologies, increase instrument reliability, and reduce costs and maintenance. The correlation between wavelength-dependent light attenuation and organic and elemental carbon (OC and EC, respectively) content allows estimation of the amount of brown and black carbon (BrC and BC, respectively) on filters. Continuous monitoring of the light reflected from and transmitted through the filter along with carbon evolved from the filter when heated to different temperatures under either inert or oxidizing gas environments provides insights into the optical properties of the carbon released from the filter; it also allows examination of the charring process as pyrolyzed char has been one of the major uncertainties in quantifying OC and EC. The objectives of this study are: 1) establish performance equivalency between the Model 2015 and Model 2001 DRI carbon analyzers when comparing similar laser wavelength to maintain consistency for long-term network sample analysis; and 2) analyze the multi-wavelength signal to quantify BrC and BC, and to optimize char correction. A selection of samples, including standard chemicals, rural and urban ambient filters, and emission sources from biomass burning, diesel and gasoline engine exhaust, and resuspended dust were measured by both the Model 2015 and Model 2001 analyzers. The instrument design, calibration, comparison with legacy analyzer, and interpretation of the multi-wavelengths measurement will be presented.

  16. 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.

  17. Interfacial thermal resistance and thermal rectification in carbon nanotube film-copper systems.

    Science.gov (United States)

    Duan, Zheng; Liu, Danyang; Zhang, Guang; Li, Qingwei; Liu, Changhong; Fan, Shoushan

    2017-03-02

    Thermal rectification occurring at interfaces is an important research area, which contains deep fundamental physics and has extensive application prospects. In general, the measurement of interfacial thermal rectification is based on measuring interfacial thermal resistance (ITR). However, ITRs measured via conventional methods cannot avoid extra thermal resistance asymmetry due to the contact between the sample and the thermometer. In this study, we employed a non-contact infrared thermal imager to monitor the temperature of super-aligned carbon nanotube (CNT) films and obtain the ITRs between the CNT films and copper. The ITRs along the CNT-copper direction and the reverse direction are in the ranges of 2.2-3.6 cm(2) K W(-1) and 9.6-11.9 cm(2) K W(-1), respectively. The obvious difference in the ITRs of the two directions shows a significant thermal rectification effect, and the rectifying coefficient ranges between 0.57 and 0.68. The remarkable rectification factor is extremely promising for the manufacture of thermal transistors with a copper/CNT/copper structure and further thermal logic devices. Moreover, our method could be extended to other 2-dimensional materials, such as graphene and MoS2, for further explorations.

  18. Biomarkers in Carbonate Thermal Springs: Implications for Mars

    Science.gov (United States)

    Allen, C. C.; Kivett, S. J.; McKay, D. S.

    1998-01-01

    Evidence of possible relict biogenic activity has been reported in carbonate inclusions within martian meteorite ALH 84001. The initial evidence included ovoid and elongated forms 50 - 500 nanometers in length, morphologically similar to but significantly smaller than many terrestrial microbes. More recently, thin structures resembling the remains of organic biofilms have been reported in the same meteorite. Carbonates have also been discussed in the context of Mars sample return missions. Thermal spring deposits have often been cited as prime locations for exobiological exploration. By analogy to Earth, specialized microbes may have existed in the heated, mineralized waters, and precipitates of carbonate and/or silica from these waters may have trapped and preserved evidence of life. Since the geological interactions that produce thermal springs can be recognized in orbital imagery, directed searches for microfossils in such deposits are deemed possible. We are engaged in a study of the signatures produced by contemporary biogenic activity (biomarkers) in carbonate thermal springs. We are examining the microbes that live in such environments and the preservation of microbial forms, biofilms, and petrographic fabrics indicative of life in thermal spring mineral deposits. This work is part of a much more extensive study to refine the appropriate tools, techniques, and approaches to seek evidence of life in a range of planetary samples. A deeper understanding of biological signatures will prepare us for the detailed search for life on Mars and eventually on other planets. Overall. the study of biomarkers in rocks and soils will provide insight into the evolution of life because such signatures are a record of how life interacts with its environment, how it adapts to changing conditions, and how life can influence geology and climate.

  19. Synthesis of silicon–carbon black composite as anode material for lithium ion battery

    Science.gov (United States)

    Kim, Hanvin; Yun, Yongsub; Lee, Young-Chan; Lee, Myeong-Hoon; Saito, Nagahiro; Kang, Jun

    2018-01-01

    Silicon has been attracting attention as an anode material that can be used for the design of high-capacity lithium ion batteries (LIB). However, the long-term cycling performance of silicon is limited owing to exfoliation from the current collector, resulting from volumetric expansion upon alloying with lithium in the charging process. However, carbon black is an agglomerate of primary particles that form a network and can incorporate a sufficient void space between network structures to accommodate the volumetric expansion of silicon. In this study, we propose the possibility of preventing the volume expansion and exfoliation of silicon by capturing silicon nanoparticles in the void space of the carbon black network. A silicon–carbon black composite material with this structure was successfully synthesized by solution plasma processing.

  20. Sonoelectrochemical one-pot synthesis of Pt - Carbon black nanocomposite PEMFC electrocatalyst.

    Science.gov (United States)

    Karousos, Dionysios S; Desdenakis, Kostantinos I; Sakkas, Petros M; Sourkouni, Georgia; Pollet, Bruno G; Argirusis, Christos

    2017-03-01

    Simultaneous electrocatalytic Pt-nanoparticle synthesis and decoration of Vulcan XC-72 carbon black substrate was achieved in a novel one-step-process, combining galvanostatic pulsed electrodeposition and pulsed ultrasonication with high power, low-frequency (20kHz) ultrasound. Aqueous chloroplatinic acid precursor baths, as well as carbon black suspensions in the former, were examined and decoration was proven by a combination of characterization methods, namely: dynamic light scattering, transmission electron microscopy, scanning electron microscopy with EDX-analysis and cyclic voltammetry. In particular, PVP was shown to have a beneficial stabilizing effect against free nanoparticle aggregation, ensuring narrow size distributions of the nanoparticles synthesized, but is also postulated to prevent the establishment of a strong metal-substrate interaction. Current pulse amplitude was identified as the most critical nanoparticle size-determining parameters, while only small size particles, under 10nm, appeared to be attached to carbon black. Copyright © 2016 Elsevier B.V. All rights reserved.

  1. Thermal conductive epoxy enhanced by nanodiamond-coated carbon nanotubes

    Science.gov (United States)

    Zhao, Bo; Jiang, Guohua

    2017-11-01

    Nanodiamond (ND) particles were coated on the surface of carbon nanotubes (CNTs) by chemical reactions. Reliable bonding was formed by the combination of acyl chloride on NDs and amine group on CNTs. ND coated CNTs (CNT-ND) were dispersed into epoxy to fabricate thermal conductive resins. The results show that the surface energy of CNTs is decreased by the coated NDs, which is contributed to the excellent dispersion of CNT-NDs in the epoxy matrix. The heat-transfer channels were built by the venous CNTs cooperating with the coated NDs, which not only plays an effective role of heat conduction for CNTs and NDs, but also avoids the electrical leakage by the protection of NDs surrounding outside of CNTs. Electrical and thermal conductance measurements demonstrate that the influence of the CNT-ND incorporation on the electrical conductance is minor, however, the thermal conductivity is improved significantly for the epoxy filled with CNT-ND.[Figure not available: see fulltext.

  2. Prediction of the biochar carbon stability by thermal analysis

    Science.gov (United States)

    Méndez, Ana; Cely, Paola; Plaza, César; Paz-Ferreiro, Jorge; Gascó, Gabriel

    2015-04-01

    Thermal analysis (DTA, DSC, TG and dTG) has been used for decades to characterize carbonaceous materials used as fuels (oil, coal). Our research group has used these techniques for the characterisation of different biochars in order to assess proportions of labile and recalcitrant organic matter and to study the evolution of soil organic matter in soils amended with biochar. Thermal analysis could be used to determine the proximate analysis, i.e., the percentage of humidity, volatile matter and fixed carbon or to calculate the thermostability index, previously identified as a reliable parameter for evaluating the level of stability of organic matter in organic wastes and biochar. Relationship between the stability of biochar, the raw material and the pyrolysis conditions could be established by thermal analysis techniques.

  3. Optimization of carbon black loading in compounding of natural rubber by unique cross point technique

    Energy Technology Data Exchange (ETDEWEB)

    Sohn, Bong Young [Kumho Technical R and D Center (Korea, Republic of); Park, Chan Young [Chonnam National Univ., Kwangju (Korea, Republic of)

    1996-02-01

    The unique Cross Point technique, offering uniquely the optimum loading of carbon blacks a reinforcing filler required in rubber compounds tire industry, has been proposed. The strength of the technique lies in optimizing the feasible loading by both Mooney viscosity and DSR(Dynamic Stress Relaxometer) simultaneously. In this study, the Mooney viscosity(ML1 + 4,125 degree){sub {eta}x} as a function of its loading X and characteristic value {gamma} was expressed as {eta}{sub x} = {eta}{sub 0}{center_dot}{gamma}{center_dot}(1 + a{sub 1}X + a{sub 2}X{sup 2}). And also Sr`, the relative integral in two seconds of torque from DSR, was a function of X as follow Sr` = b{sub 0} + b{sub 1}X. After thermal cure the natural rubber compounds loaded with the quantity designated by the cross section of the above two equations showed so feasible properties confirmed by tensile tester, Pico abrasion tester and Flexometer that the experimental coefficients of the equations applicable to fields are listed in Table 2. 12 refs., 4 tabs., 11 figs.

  4. Asian Black Carbon Influence on East Asian Summer Monsoons

    Science.gov (United States)

    Mahmood, R.; Li, S.

    2012-04-01

    Since the black carbon (BC) emission in East and South Asia has increased significantly during the last decades of the 20th century, there is an ever growing concern about its impact on Asian monsoon. In this study we provide an in-depth analysis of the influence by performing several ensemble sensitive experiments with or without historical BC concentrations over East Asia, South Asia, and the combined East and South Asia in an atmospheric general circulation model, GFDL AM2.1. The results show that: (a) The East Asian summer climate is sensitive to the East Asian BC (EABC) concentrations in a sense that EABC contributes significantly to the frequently occurring north-drought and south-flood patterns in Eastern China. In detail, the large scale precipitation anomalies induced by EABC characterize more rainfalls over central/south China, East China Sea and southern Japan and less rainfall over northern China and the west Pacific region between 10° to 20°N. These anomalous precipitation patterns are mainly attributed to the EABC induced large scale circulation changes including the weakened Western Pacific Subtropical High (WPSH), anomalous ascent motions over central-southern China (centering over the Yangtze River valley (YRV)) and the subsequent descent motions over northern China and the South China Sea. These modeled results suggest that the EABC experiment reproduces the climate shift event of eastern China during the late 1970s, including intensified rainfall in the YRV and the weakened summer monsoonal circulation. (b) The anomalous results of South Asian BC (SABC) experiment signify a tri-polar precipitation response over East Asia, with a reduction from the YRV to East China Sea and southern Japan sandwiched with increases over a northern domain from northern China/ Korea to northern Japan and over southern China. As for southern China, particularly the YRV, the impact of SABC is to offset a fraction of intensified rainfall induced by local BC of East

  5. Climatic Effects of Black Carbon Aerosols Over the Tibetan Plateau

    Science.gov (United States)

    He, Cenlin

    Black carbon (BC), also known as soot, has been identified as the second most important anthropogenic emissions in terms of global climate forcing in the current atmosphere. Ample evidence has shown that BC deposition is an important driver of rapid snow melting and glacier retreat over the Tibetan Plateau, which holds the largest snow/ice mass outside polar regions. However, the climatic effects of BC over the Tibetan Plateau have not been thoroughly investigated in such a manner as to understand, quantify, and reduce large uncertainties in the estimate of radiative and hydrological effects. Thus, this Ph.D. study seeks to understand and improve key processes controlling BC life cycle in global and regional models and to quantify BC radiative effects over the Tibetan Plateau. First, the capability of a state-of-the-art global chemical transport model (CTM), GEOS-Chem, and the associated model uncertainties are systematically evaluated in simulating BC over the Tibetan Plateau, using in situ measurements of BC in surface air, BC in snow, and BC absorption optical depth. The effects of three key factors on the simulation are also delineated, including Asian anthropogenic emissions, BC aging process, and model resolution. Subsequently, a microphysics-based BC aging scheme that accounts for condensation, coagulation, and heterogeneous chemical oxidation processes is developed and examined in GEOS-Chem by comparing with aircraft measurements. Compared to the default aging scheme, the microphysical scheme reduces model-observation discrepancies by a factor of 3, particularly in the middle and upper troposphere. In addition, a theoretical BC aging-optics model is developed to account for three typical evolution stages, namely, freshly emitted aggregates, coated BC by soluble material, and BC particles undergoing further hygroscopic growth. The geometric-optics surface-wave (GOS) approach is employed to compute the BC single-scattering properties at each aging stage

  6. Thermal conductivity of a film of single walled carbon nanotubes measured with infrared thermal imager

    Science.gov (United States)

    Feng, Ya; Inoue, Taiki; Xiang, Rong; Chiashi, Shohei; Maruyama, Shigeo

    Heat dissipation has restricted the modern miniaturization trend with the development of electronic devices. Theoretically proven to be with high axial thermal conductivity, single walled carbon nanotubes (SWNT) have long been expected to cool down the nanoscale world. Even though the tube-tube contact resistance limits the capability of heat transfer of the bulk film, the high intrinsic thermal conductivity of SWNT still glorify the application of films of SWNT network as a thermal interface material. In this work, we proposed a new method to straightly measure the thermal conductivity of SWNT film. We bridged two cantilevered Si thin plate with SWNT film, and kept a steady state heat flow in between. With the infrared camera to record the temperature distribution, the Si plates with known thermal conductivity can work as a reference to calculate the heat flux going through the SWNT film. Further, the thermal conductivity of the SWNT film can be obtained through Fourier's law after deducting the effect of thermal radiation. The sizes of the structure, the heating temperature, the vacuum degree and other crucial impact factors are carefully considered and analyzed. The author Y. F. was supported through the Advanced Integration Science Innovation Education and Research Consortium Program by the Ministry of Education, Culture, Sport, Science and Technology.

  7. A radiocarbon study of black carbon aerosol emissions in the Earth System

    OpenAIRE

    Mouteva, Gergana O.

    2016-01-01

    The black carbon (BC) aerosol is a major climate-forcing agent. Its high capacity for light absorption and its role in key atmospheric processes lead to a range of impacts in the Earth System. Black carbon is also a major constituent of fine particulate matter (PM2.5) and is linked to a broad array of adverse health effects. Increased fossil fuel and biomass burning have contributed to a significantly larger input of BC to the atmosphere, but the lack of measurement constraints on BC have li...

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

    Science.gov (United States)

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

    2016-04-01

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

  9. 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.

  10. Effects of Mixing Mode on the Fracture Properties of Silica and Carbon Black Filled NR Vulcanizates

    Energy Technology Data Exchange (ETDEWEB)

    Park, S.S. [Chonnam National University, Gwangju (Korea); Park, B.H. [Kumho Industry Co., Gwnagju (Korea); Song, K.C.; Kim, S.K. [Chonnam National University, Gwangju (Korea)

    2000-03-01

    Silica and carbon black filled natural rubber (NR) vulcanizates were prepared with different mixing modes and amounts of fillers. Curing characteristics, morphology, and tear properties of the NR vulcanizates were investigated. The NR vulcanizates filled with silica and carbon black sequentially showed longer induction time (t{sub 2}), cure index (t{sub 90}), and lower maximum torque (T{sub max}) than the NR vulcanizates filled with them simultaneously, during curing process. The former showed superior dispersion of fillers and tear properties to the latter. The NR vulcanizates containing 30 phr of silica showed excellent properties in the experimental range. (author). 15 refs., 1 tab., 10 figs.

  11. 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.; hide

    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

  12. Electrically conductive, black thermal control coatings for spacecraft application. I - Silicate matrix formulation

    Science.gov (United States)

    Bauer, J. L.; Odonnell, T. P.; Hribar, V. F.

    1986-01-01

    The formulation of the graphite silicate paints MH-11 and MH-11Z, which will serve as electrically conductive, heat-resistant thermal control coatings for the Galileo spacecraft's 400 Newton engine plume shield, 10 Newton thruster plume shields, and external shunt radiators, is described, and performance results for these paints are reported. The MH-11 is produced by combining a certain grade of graphite powder with a silicate base to produce a black, inorganic, electrically conductive, room temperature cure thermal control paint having high temperature capability. Zinc oxide is added to the MH-11 formulation to produce the blister resistant painta MH-11Z. The mechanical, chemical, thermal, optical, and radiation characteristics of the coatings are reported. The formulation, mixing, application, and surface preparation of the substrates are described, and a method of determining the electrical resistance of the coatings is demonstrated.

  13. The physical properties of black carbon and other light-absorbing material emitted from prescribed fires in the United States

    Science.gov (United States)

    McMeeking, G. R.; Kreidenweis, S. M.; Yokelson, R. J.; Sullivan, A. P.; Lee, T.; Collett, J. L.; Fortner, E.; Onasch, T. B.; Akagi, S. K.; Taylor, J.; Coe, H.

    2012-12-01

    Black carbon (BC) aerosol emitted from fires absorbs light, leading to visibility degradation as well as regional and global climate impacts. Fires also emit a wide range of trace gases and particulates that can interact with emitted BC and alter its optical properties and atmospheric lifetime. Non-BC particulate species emitted by fires can also scatter and absorb light, leading to additional effects on visibility. Recent work has shown that certain organic species can absorb light strongly at shorter wavelengths, giving it a brown or yellow color. This material has been classified as brown carbon, though it is not yet well defined. Land managers must find a balance between the negative impacts of prescribed fire emissions on visibility and air quality and the need to prevent future catastrophic wildfire as well as manage ecosystems for habitat restoration or other purposes. This decision process requires accurate assessments of the visibility impacts of fire emissions, including BC and brown carbon, which in turn depend on their optical properties. We present recent laboratory and aircraft measurements of black carbon and aerosol optical properties emitted from biomass burning. All measurement campaigns included a single particle soot photometer (SP2) instrument capable of providing size-resolved measurements of BC mass and number distributions and mixing state, which are needed to separate the BC and brown carbon contributions to total light absorption. The laboratory experiments also included a three-wavelength photoacoustic spectrometer that provided accurate measurements of aerosol light absorption. The laboratory systems also characterized emissions after they had been treated with a thermal denuder to remove semi-volatile coatings, allowing an assessment of the role of non-BC coatings on bulk aerosol optical properties. Emissions were also aged in an environmental smog chamber to examine the role of secondary aerosol production on aerosol optical properties.

  14. Comparative inhalation toxicity of multi-wall carbon nanotubes, graphene, graphite nanoplatelets and low surface carbon black.

    Science.gov (United States)

    Ma-Hock, Lan; Strauss, Volker; Treumann, Silke; Küttler, Karin; Wohlleben, Wendel; Hofmann, Thomas; Gröters, Sibylle; Wiench, Karin; van Ravenzwaay, Bennard; Landsiedel, Robert

    2013-06-17

    Carbon nanotubes, graphene, graphite nanoplatelets and carbon black are seemingly chemically identical carbon-based nano-materials with broad technological applications. Carbon nanotubes and carbon black possess different inhalation toxicities, whereas little is known about graphene and graphite nanoplatelets. In order to compare the inhalation toxicity of the mentioned carbon-based nanomaterials, male Wistar rats were exposed head-nose to atmospheres of the respective materials for 6 hours per day on 5 consecutive days. Target concentrations were 0.1, 0.5, or 2.5 mg/m3 for multi-wall carbon nanotubes and 0.5, 2.5, or 10 mg/m3 for graphene, graphite nanoplatelets and low-surface carbon black. Toxicity was determined after end of exposure and after three-week recovery using broncho-alveolar lavage fluid and microscopic examinations of the entire respiratory tract. No adverse effects were observed after inhalation exposure to 10 mg/m3 graphite nanoplatelets or relatively low specific surface area carbon black. Increases of lavage markers indicative for inflammatory processes started at exposure concentration of 0.5 mg/m3 for multi-wall carbon nanotubes and 10 mg/m3 for graphene. Consistent with the changes in lavage fluid, microgranulomas were observed at 2.5 mg/m3 multi-wall carbon nanotubes and 10 mg/m3 graphene. In order to evaluate volumetric loading of the lung as the key parameter driving the toxicity, deposited particle volume was calculated, taking into account different methods to determine the agglomerate density. However, the calculated volumetric load did not correlate to the toxicity, nor did the particle surface burden of the lung. The inhalation toxicity of the investigated carbon-based materials is likely to be a complex interaction of several parameters. Until the properties which govern the toxicity are identified, testing by short-term inhalation is the best option to identify hazardous properties in order to avoid unsafe applications or select

  15. Thermal Acclimation and Adaptation of Net Ecosystem Carbon Exchange (Invited)

    Science.gov (United States)

    Luo, Y.; Niu, S.; Fei, S.; Yuan, W.; Zhang, Z.; Schimel, D.; Fluxnet Pis, .

    2010-12-01

    Ecosystem responses to temperature change are collectively determined by its constituents, which are plants, animals, microbes, and their interactions. It has been long documented that all plant, animals, and microbial carbon metabolism (photosynthesis, respiration) can acclimate and respond to changing temperatures, influencing the response of ecosystem carbon fluxes to climate change. Climate change also can induce competition between species with different thermal responses leading to changes in community composition. While a great deal of research has been done on species-level responses to temperature, it is yet to examine thermal acclimation of adaptation of ecosystem carbon processes to temperature change. With the advent of eddy flux measurements, it is possible to directly characterize the ecosystem-scale temperature response of carbon storage. In this study, we quantified the temperature response functions of net ecosystem carbon exchange (NEE), from which the responses of apparent optimal temperatures across broad spatial and temporal scales were examined. While temperature responses are normally parameterized in terms of the physiological variables describing photosynthesis and respiration, we focus on the apparent optimal behavior of NEE. Because the measurement integrated over multiple individuals and species within the footprint of the measurement (100s to 1000s of ha), it is challenging to interpret this measurement in terms of classical physiological variables such as the Q10. Rather we focus on the realized behavior of the ecosystem and its sensitivity to temperature. These empirical response functions can then be used as a benchmark for model evaluation and testing. Our synthesis of 656 site-years of eddy covariance data over the world shows that temperature response curves of NEE are parabolic, with their optima temperature strongly correlated with site growing season temperature across the globe and with annual mean temperature over years at

  16. Black carbon cookstove emissions: A field assessment of 19 stove/fuel combinations

    Science.gov (United States)

    Garland, Charity; Delapena, Samantha; Prasad, Rajendra; L'Orange, Christian; Alexander, Donee; Johnson, Michael

    2017-11-01

    Black carbon (BC) emissions from household cookstoves consuming solid fuel produce approximately 25 percent of total anthropogenic BC emissions. The short atmospheric lifetime of BC means that reducing BC emissions would result in a faster climate response than mitigating CO2 and other long-lived greenhouse gases. This study presents the results of optical BC measurements of two new cookstove emissions field assessments and 17 archived cookstove datasets. BC was determined from attenuation of 880 nm light, which is strongly absorbed by BC, and linearly related between 1 and 125 attenuation units. A relationship was experimentally determined correlating BC mass deposition on quartz filters determined via thermal optical analysis (TOA) and on PTFE and quartz filters using transmissometry, yielding an attenuation cross-section (σATN) for both filter media types. σATN relates TOA measurements to optical measurements on PTFE and quartz (σATN(PTFE) = 13.7 cm-2 μg, R2 = 0.87, σATN(Quartz) = 15.6 cm-2 μg, R2 = 0.87). These filter-specific σATN, optical measurements of archived filters were used to determine BC emission factors and the fraction of particulate matter (PM) in the form of black carbon (BC/PM). The 19 stoves measured fell into five stove classes; simple wood, rocket, advanced biomass, simple charcoal, and advanced charcoal. Advanced biomass stoves include forced- and natural-draft gasifiers which use wood or biomass pellets as fuel. Of these classes, the simple wood and rocket stoves demonstrated the highest median BC emission factors, ranging from 0.051 to 0.14 g MJ-1. The lowest BC emission factors were seen in charcoal stoves, which corresponds to the generally low PM emission factors observed during charcoal combustion, ranging from 0.0084 to 0.014 g MJ-1. The advanced biomass stoves generally showed an improvement in BC emissions factors compared to simple wood and rocket stoves, ranging from 0.0031 to 0.071 g MJ-1. BC/PM ratios were highest for the

  17. 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...

  18. 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.

  19. 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...

  20. O2 electrocatalysis in acid media on iron naphthalocyanine impregnations. Effect of nitric acid treatment on different carbon black supports

    NARCIS (Netherlands)

    Coowar, F.; Contamin, O.; Savy, M.; Scarbeck, G.; van den Ham, D.; Riga, J.; Verbist, J.J.

    1991-01-01

    O2 electrocatalysis on (2,3)FeNPc impregnations on different carbon blacks was investigated in H2SO4 medium. The effect of nitric acid treatment on the carbon black support is to enhance both the activity and stability of the catalyst. Moreover, as seen by XPS, the dissolution of iron is impeded by

  1. 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.

  2. Critical review of black carbon and elemental carbon source apportionment in Europe and the United States

    Science.gov (United States)

    Briggs, Nicole L.; Long, Christopher M.

    2016-11-01

    An increasing number of air pollution source apportionment studies in Europe and the United States have focused on the black carbon (BC) fraction of ambient particulate matter (PM) given its linkage with adverse public health and climate impacts. We conducted a critical review of European and US BC source apportionment studies published since 2003. Since elemental carbon (EC) has been used as a surrogate measure of BC, we also considered source apportionment studies of EC measurements. This review extends the knowledge presented in previous ambient PM source apportionment reviews because we focus on BC and EC and critically examine the differences between source apportionment results for different methods and source categories. We identified about 50 BC and EC source apportionment studies that have been conducted in either Europe or the US since 2003, finding a striking difference in the commonly used source apportionment methods between the two regions and variations in the assigned source categories. Using three dominant methodologies (radiocarbon, aethalometer, and macro-tracer methods) that only allow for BC to be broadly apportioned into either fossil fuel combustion or biomass burning source categories, European studies generally support fossil fuel combustion as the dominant ambient BC source, but also show significant biomass burning contributions, in particular in wintertime at non-urban locations. Among US studies where prevailing methods such as chemical mass balance (CMB) and positive matrix factorization (PMF) models have allowed for estimation of more refined source contributions, there are fewer findings showing the significance of biomass burning and variable findings on the relative proportion of BC attributed to diesel versus gasoline emissions. Overall, the available BC source apportionment studies provide useful information demonstrating the significance of both fossil fuel combustion and biomass burning BC emission sources in Europe and the US

  3. Present-day climate forcing and response from black carbon in snow

    OpenAIRE

    Mark G. Flanner; Zender, Charles S.; Randerson, James T; Rasch, Philip J.

    2007-01-01

    We apply our Snow, Ice, and Aerosol Radiative (SNICAR) model, coupled to a general circulation model with prognostic carbon aerosol transport, to improve understanding of climate forcing and response from black carbon (BC) in snow. Building on two previous studies, we account for interannually varying biomass burning BC emissions, snow aging, and aerosol scavenging by snow meltwater. We assess uncertainty in forcing estimates from these factors, as well as BC optical properties and snow cover...

  4. Carbon fiber composite characterization in adverse thermal environments.

    Energy Technology Data Exchange (ETDEWEB)

    Gomez-Vasquez, Sylvia; Brown, Alexander L.; Hubbard, Joshua A.; Ramirez, Ciro J.; Dodd, Amanda B.

    2011-05-01

    The behavior of carbon fiber aircraft composites was studied in adverse thermal environments. The effects of resin composition and fiber orientation were measured in two test configurations: 102 by 127 millimeter (mm) test coupons were irradiated at approximately 22.5 kW/m{sup 2} to measure thermal response, and 102 by 254 mm test coupons were irradiated at approximately 30.7 kW/m{sup 2} to characterize piloted flame spread in the vertically upward direction. Carbon-fiber composite materials with epoxy and bismaleimide resins, and uni-directional and woven fiber orientations, were tested. Bismaleimide samples produced less smoke, and were more resistant to flame spread, as expected for high temperature thermoset resins with characteristically lower heat release rates. All materials lost approximately 20-25% of their mass regardless of resin type, fiber orientation, or test configuration. Woven fiber composites displayed localized smoke jetting whereas uni-directional composites developed cracks parallel to the fibers from which smoke and flames emanated. Swelling and delamination were observed with volumetric expansion on the order of 100% to 200%. The purpose of this work was to provide validation data for SNL's foundational thermal and combustion modeling capabilities.

  5. Hybrid Carbon-Carbon Ablative Composites for Thermal Protection in Aerospace

    Directory of Open Access Journals (Sweden)

    P. Sanoj

    2014-01-01

    Full Text Available Composite materials have been steadily substituting metals and alloys due to their better thermomechanical properties. The successful application of composite materials for high temperature zones in aerospace applications has resulted in extensive exploration of cost effective ablative materials. High temperature heat shielding to body, be it external or internal, has become essential in the space vehicles. The heat shielding primarily protects the substrate material from external kinetic heating and the internal insulation protects the subsystems and helps to keep coefficient of thermal expansion low. The external temperature due to kinetic heating may increase to about maximum of 500°C for hypersonic reentry space vehicles while the combustion chamber temperatures in case of rocket and missile engines range between 2000°C and 3000°C. Composite materials of which carbon-carbon composites or the carbon allotropes are the most preferred material for heat shielding applications due to their exceptional chemical and thermal resistance.

  6. Effect of carbon black on electrical and rheological properties of graphite nanoplatelets/poly(ethylene-butyl acrylate composites

    Directory of Open Access Journals (Sweden)

    H. Oxfall

    2015-01-01

    Full Text Available The effect of adding carbon black on the electrical and rheological properties of graphite nanoplatelets/poly(ethylene-butyl acrylate copolymer composites produced via melt or solution mixing was studied. By adding a small amount of low- or high-structured carbon black to the nanocomposite, the electrical percolation threshold decreased and the final conductivity (at higher filler contents increased. The effect on the percolation threshold was significantly stronger in case of the high-structured carbon black where replacing 10 wt% of the total filler content with carbon black instead of graphite nanoplatelets reduced the electrical percolation threshold from 6.9 to 4.6 vol%. Finally, the solution mixing process was found to be more efficient leading to a lower percolation threshold. For the composites containing high-structured carbon black, graphite nanoplatelets and their hybrids there was a quite reasonable correlation between the electrical and rheological percolation thresholds.

  7. THERMAL INSULATION FROM LIGNIN-DERIVED CARBON FIBERS

    Energy Technology Data Exchange (ETDEWEB)

    Albers, Tracy [GrafTech International; Chen, Chong [GrafTech International; Eberle, Cliff [ORNL; Webb, Daniel C [ORNL

    2014-01-01

    Oak Ridge National Laboratory (ORNL) and GrafTech International Holdings Inc. (GrafTech) have collaborated to develop and demonstrate the performance of high temperature thermal insulation prototypes made from lignin-based carbon fibers (LBCF). This was the first reported production of LBCF or resulting products at scale > 1 kg. The results will potentially lead to the first commercial application of LBCF. The goal of the commercial application is to replace expensive, foreign-sourced isotropic pitch carbon fibers with lower cost carbon fibers made from a domestically sourced, bio-derived (renewable) feedstock. LBCF can help resolve supply chain vulnerability and reduce the production cost for high temperature thermal insulation as well as create US jobs. The performance of the LBCF prototypes was measured and found to be comparable to that of the current commercial product. During production of the insulation prototypes, the project team demonstrated lignin compounding/pelletization, fiber production, heat treatment, and compositing at scales far surpassing those previously demonstrated in LBCF R&D or production.

  8. Black carbon emission reduction strategies in healthcare industry for effective global climate change management.

    Science.gov (United States)

    Raila, Emilia Mmbando; Anderson, David O

    2017-04-01

    Climate change remains one of the biggest threats to life on earth to date with black carbon (BC) emissions or smoke being the strongest cause after carbon dioxide (CO 2 ). Surprisingly, scientific evidence about black carbon emissions reduction in healthcare settings is sparse. This paper presents new research findings on the reduction of black carbon emissions from an observational study conducted at the UN Peacekeeping Operations (MINUSTAH) in Haiti in 2014. Researchers observed 20 incineration cycles, 30 minutes for each cycle of plastic and cardboard sharps healthcare waste (HCW) containers ranged from 3 to 14.6 kg. The primary aim was to determine if black carbon emissions from healthcare waste incineration can be lowered by mainstreaming the use of cardboard sharps healthcare waste containers instead of plastic sharps healthcare waste containers. Similarly, the study looks into whether burning temperature was associated with the smoke levels for each case or not. Independent samples t-tests demonstrated significantly lower black carbon emissions during the incineration of cardboard sharps containers (6.81 ± 4.79% smoke) than in plastic containers (17.77 ± 8.38% smoke); a statistically significant increase of 10.96% smoke (95% Confidence Interval ( CI) [4.4 to 17.5% smoke], p = 0.003). Correspondingly, lower bottom burner temperatures occurred during the incineration of cardboard sharps containers than in plastic (95% Cl [16 to 126°C], p = 0.014). Finally, we expect the application of the new quantitative evidence to form the basis for policy formulation, mainstream the use of cardboard sharps containers and opt for non-incineration disposal technologies as urgent steps for going green in healthcare waste management.

  9. Extremely Cost-Effective and Efficient Solar Vapor Generation under Nonconcentrated Illumination Using Thermally Isolated Black Paper.

    Science.gov (United States)

    Liu, Zhejun; Song, Haomin; Ji, Dengxin; Li, Chenyu; Cheney, Alec; Liu, Youhai; Zhang, Nan; Zeng, Xie; Chen, Borui; Gao, Jun; Li, Yuesheng; Liu, Xiang; Aga, Diana; Jiang, Suhua; Yu, Zongfu; Gan, Qiaoqiang

    2017-02-27

    Passive solar vapor generation represents a promising and environmentally benign method of water purification/desalination. However, conventional solar steam generation techniques usually rely on costly and cumbersome optical concentration systems and have relatively low efficiency due to bulk heating of the entire liquid volume. Here, an efficient strategy using extremely low-cost materials, i.e., carbon black (powder), hydrophilic porous paper, and expanded polystyrene foam is reported. Due to the excellent thermal insulation between the surface liquid and the bulk volume of the water and the suppressed radiative and convective losses from the absorber surface to the adjacent heated vapor, a record thermal efficiency of ≈88% is obtained under 1 sun without concentration, corresponding to the evaporation rate of 1.28 kg (m2 h)-1. When scaled up to a 100 cm2 array in a portable solar water still system and placed in an outdoor environment, the freshwater generation rate is 2.4 times of that of a leading commercial product. By simultaneously addressing both the need for high-efficiency operation as well as production cost limitations, this system can provide an approach for individuals to purify water for personal needs, which is particularly suitable for undeveloped regions with limited/no access to electricity.

  10. Sulfonated carbon black-based composite membranes for fuel cell ...

    Indian Academy of Sciences (India)

    sulfophenyl-phosphonate, heteropolyacid, layered silicates. (such as laponite, modified montmorillonite), zeolites, boron phosphate silicates and functionalized silicates, metal oxides and sulfated zirconia have been embedded into SPEEK membranes (Herring 2006). Recently, carbon nanotubes (CNTs) have attracted parti ...

  11. Electrochemical Biosensors Based on Nanostructured Carbon Black: A Review

    National Research Council Canada - National Science Library

    Tiago Almeida Silva; Fernando Cruz Moraes; Bruno Campos Janegitz; Orlando Fatibello-Filho

    2017-01-01

    .... Several studies have explored the applicability of CB in electrochemical fields. Recent data showed that modified electrodes based on CB present fast charge transfer and high electroactive surface area, comparable to carbon nanotubes and graphene...

  12. Distribution and Sources of Black Carbon in the Arctic

    Science.gov (United States)

    Qi, Ling

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

  13. Intrinsic and extrinsic electrical and thermal transport of bulk black phosphorus

    Science.gov (United States)

    Hu, Sile; Xiang, Junsen; Lv, Meng; Zhang, Jiahao; Zhao, Hengcan; Li, Chunhong; Chen, Genfu; Wang, Wenhong; Sun, Peijie

    2018-01-01

    We report a comprehensive investigation of the electrical, thermal, and thermoelectric transport properties of bulk single-crystalline black phosphorus in wide temperature (2-300 K) and field (0-9 T) ranges. Electrical transport below T ≈ 250 K is found to be dominated by extrinsic hole-type charge carriers with large mobility exceeding 104 cm2/V s at low temperatures. While thermal transport measurements reveal an enhanced in-plane thermal conductivity maximum κ = 180 W/m K at T ≈ 25 K, it appears still to be largely constrained by extrinsic phonon scattering processes, e.g., the electron-phonon process, in addition to intrinsic umklapp scattering. The thermoelectric power and Nernst effect seem to be strongly influenced by ambipolar transport of charge carriers with opposite signs in at least the high-temperature region above 200 K, which diminishes the thermoelectric power factor of this material. Our results provide a timely update to the transport properties of bulk black phosphorus for future fundamental and applied research.

  14. The thermal properties of a carbon nanotube-enriched epoxy: Thermal conductivity, curing, and degradation kinetics

    KAUST Repository

    Ventura, Isaac Aguilar

    2013-05-31

    Multiwalled carbon nanotube-enriched epoxy polymers were prepared by solvent evaporation based on a commercially available epoxy system and functionalized multiwalled carbon nanotubes (COOH-MWCNTs). Three weight ratio configurations (0.05, 0.5, and 1.0 wt %) of COOH-MWCNTs were considered and compared with neat epoxy and ethanol-treated epoxy to investigate the effects of nano enrichment and processing. Here, the thermal properties of the epoxy polymers, including curing kinetics, thermal conductivity, and degradation kinetics were studied. Introducing the MWCNTs increased the curing activation energy as revealed by differential scanning calorimetry. The final thermal conductivity of the 0.5 and 1.0 wt % MWCNT-enriched epoxy samples measured by laser flash technique increased by up to 15% compared with the neat material. The activation energy of the degradation process, investigated by thermogravimetric analysis, was found to increase with increasing CNT content, suggesting that the addition of MWCNTs improved the thermal stability of the epoxy polymers. © 2013 Wiley Periodicals, Inc.

  15. Penelitian pengaruh naphthenic oil dan carbon black terhadap sifat kekerasan lis kaca mobil

    Directory of Open Access Journals (Sweden)

    Any Setyaningsih

    1999-07-01

    Full Text Available This research have a purpose to know influence naphthenic oil and car bon black about properties hardness weather strip for auto mobile. Compound wea ther strip for auto mobile make for Natural Rubber (RSS and sintetic rubber (SBR 1502 with in creasing ingrediens such plasticizer, activator, filler, anti oxidant, accelerator and vulkanizing agent. Compount formula making variation naphthenic oil 3,5 and 7 part along with carbon black 45,50 and 55 part result hardness test with value 67 shore A for compount with naphthenic oil 7 part and carbon black 50 part and after perform make in to fill requrements SNI 1490 – 89 A weather strip auto mobile.

  16. Quantification of a Heterogeneous Ruthenium Catalyst on Carbon-black using ADF Imaging

    Science.gov (United States)

    Varambhia, A. M.; Jones, L.; Nellist, P. D.; Lozano-Perez, S.; Ozkaya, D.

    2015-10-01

    Using recent developments in ADF quantification techniques, we utilise a rapid atom counting procedure to document the evolution of a heterogeneous ruthenium catalyst on carbon black. Selected areas of the ruthenium catalyst were imaged for approximately 15 minutes. The imaged areas show that the Ru wets the support forming a thin amorphous layer that transforms to a crystalline layer under beam irradiation.

  17. Top-down estimates of biomass burning emissions of black carbon in the western United States

    Science.gov (United States)

    Y. H. Mao; Q. B. Li; D. Chen; L. Zhang; W. -M. Hao; K.-N. Liou

    2014-01-01

    We estimate biomass burning and anthropogenic emissions of black carbon (BC) in the western US for May-October 2006 by inverting surface BC concentrations from the Interagency Monitoring of PROtected Visual Environment (IMPROVE) network using a global chemical transport model. We first use active fire counts from the Moderate Resolution Imaging Spectroradiometer (MODIS...

  18. 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 ...

  19. Amazonian Dark Earth and its Black Carbon Particles Harbor Different Fungal Abundance and Diversity

    NARCIS (Netherlands)

    Reis Lucheta, Adriano; Souza Cannavan, F.S.; Tsai, S.M.; Kuramae, E.E.

    2017-01-01

    Amazonian Dark Earth (ADE) is a highly fertile soil of anthropogenic origin characterized by higher amount of charred black carbon (BC). ADE is considered a fertility model, however knowledge about the fungal community structure and diversity inhabiting ADE and BC is scarce. Fungal community

  20. The electrochemical performance of super P carbon black in reversible Li/Na ion uptake

    NARCIS (Netherlands)

    Peng, B.; Xu, Y.; Wang, Xiaoqun; Shi, Xinghua; Mulder, F.M.

    2017-01-01

    Super P carbon black (SPCB) has been widely used as a conducting additive in Li/Na ion batteries to improve the electronic conductivity. However, there has not yet been a comprehensive study on its structure and electrochemical properties for Li/Na ion uptake, though it is important to

  1. 40 CFR 721.10150 - Carbon black, (4-methylphenyl)-modified, substituted (generic).

    Science.gov (United States)

    2010-07-01

    ... substance identified generically as carbon black, (4-methylphenyl)-modified, substituted (PMN P-07-523) is...)-modified, substituted (generic). 721.10150 Section 721.10150 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) TOXIC SUBSTANCES CONTROL ACT SIGNIFICANT NEW USES OF CHEMICAL SUBSTANCES...

  2. 40 CFR 721.10149 - Carbon black, (3-methylphenyl)-modified, substituted (generic).

    Science.gov (United States)

    2010-07-01

    ... substance identified generically as carbon black, (3-methylphenyl)-modified, substituted (PMN P-07-522) is...)-modified, substituted (generic). 721.10149 Section 721.10149 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) TOXIC SUBSTANCES CONTROL ACT SIGNIFICANT NEW USES OF CHEMICAL SUBSTANCES...

  3. Projection of SO2, NOx, NMVOC, particulate matter and black carbon emissions - 2015-2030

    DEFF Research Database (Denmark)

    Nielsen, Ole-Kenneth; Plejdrup, Marlene Schmidt; Hjelgaard, Katja Hossy

    This report contains a description of models and background data for projection of SO2, NOX, NMVOC, PM2.5 and black carbon for Denmark. The emissions are projected to 2030 using basic scenarios together with the expected results of a few individual policy measures. Official Danish forecasts...

  4. Carbon Black - Polyethylene Composites for PTC (Positive Temperature Coefficient) Thermistor Applications

    Science.gov (United States)

    1987-12-01

    Different grades of carbon black are distinguished 4 mainly by their surface area, structure, and surface chemistry . High surface area, high porosity...I -to remove polUmer skin Diphasikc Trjhaslc RADIATE -20 megeRed exposureELTRD I IEELECTROD EL ECT RODE MEASUREMENTS] Figure 2.1.1 Outline of Sample

  5. Regional Responses to Black Carbon Aerosols: The Importance of Air-Sea Interaction

    Science.gov (United States)

    Gnanadesikan, A.; Scott, A. A.; Pradal, M.-A.; Seviour, W. J. M.; Waugh, D. W.

    2017-12-01

    The impact of modern black carbon aerosols on climate via their changes in radiative balance is studied using a coupled model where sea surface temperatures (SSTs) are allowed to vary and an atmosphere-only version of the same model where SSTs are held fixed. Allowing the ocean to respond is shown to have a profound impact on the pattern of temperature change. Particularly, large impacts are found in the North Pacific (which cools by up to 1 K in the coupled model) and in north central Asia (which warms in the coupled simulation and cools in the fixed SST simulation). Neither set of experiments shows large changes in surface temperatures in the Southeast Asian region where the atmospheric burden of black carbon is highest. These results are related to the stabilization of the atmosphere and changes in oceanic heat transport. Over the North Pacific, atmospheric stabilization results in an increase in stratiform clouds. The resulting shading reduces evaporation, freshening the surface layer of the ocean and reducing the inflow of warm subtropical waters. Over the land, a delicate balance between greater atmospheric absorption, shading of the surface and changes in latent cooling of the surface helps to determine whether warming or cooling is seen. Our results emphasize the importance of coupling in determining the response of the climate system to black carbon and suggest that black carbon may play an important role in modulating climate change over the North Pacific.

  6. Primary genotoxicity in the liver following pulmonary exposure to carbon black nanoparticles in mice

    DEFF Research Database (Denmark)

    Modrzynska, Justyna; Berthing, Trine; Ravn-Haren, Gitte

    2018-01-01

    Background Little is known about the mechanism underlying the genotoxicity observed in the liver following pulmonary exposure to carbon black (CB) nanoparticles (NPs). The genotoxicity could be caused by the presence of translocated particles or by circulating inflammatory mediators released during...

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

    DEFF Research Database (Denmark)

    Younesi, Reza

    including carbon black (CB) additives have a potential risk of degradation. Though the weight percentage of CB in commercial batteries is generally very small, the volumetric amount and thus the surface area of CB compose a rather large part of a cathode due to its small particle size (≈ 50 nm) and high...

  8. Net removal of dissolved organic carbon in the anoxic waters of the Black Sea

    NARCIS (Netherlands)

    Margolin, A.R.; Gerringa, L.J.A.; Hansell, D.A.; Rijkenberg, M.J.A.

    2016-01-01

    Dissolved organic carbon (DOC) concentrations in the deep Black Sea are ~2.5 times higher than found in the globalocean. The two major external sources of DOC are rivers and the Sea of Marmara, a transit point for waters from theMediterranean Sea. In addition, expansive phytoplankton blooms

  9. Total and size-resolved particle number and black carbon concentrations near an industrial area

    NARCIS (Netherlands)

    Keuken, M.P.; Moerman, M.; Zandveld, P.; Henzing, J.S.

    2015-01-01

    Total and size-resolved particle number and black carbon concentrations were investigated in urban areas of the city of Rotterdam (the Netherlands) situated near an industrial area. Several monitoring campaigns were conducted in the period 2011-2014 at three local locations and at a regional

  10. Influence of nanoclay-carbon black hybrid fillers on cure and properties of natural rubber compounds

    NARCIS (Netherlands)

    Sapkota, J.; Poikelispää, M.; Das, A.; Dierkes, Wilma K.; Vuorinen, J.

    2013-01-01

    The influence of organically modified nanoclay-carbon black (CB) hybrid filler on the curing behavior of natural rubber (NR) was explored in this investigation. Here an effort was paid to understand the curing kinetics of organomodified nanoclay filled rubber compounds. On the basis of two different

  11. Black carbon concentrations in a goods-movement neighborhood of Philadelphia, PA

    Science.gov (United States)

    Michelle C. Kondo; Chris Mizes; John Lee; Igor. Burstyn

    2014-01-01

    Communities along the Delaware River in Philadelphia, USA such as Port Richmond, are subject to traffic associated with goods movement to and from port facilities and local industry. Air pollution associated with this traffic poses an environmental health concern in this and other urban areas. Our study measures black carbon (BC) in Port Richmond and examines its...

  12. 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

    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...

  13. Quantification methods of Black Carbon: Comparison of Rock-Eval analysis with traditional methods

    NARCIS (Netherlands)

    Poot, A.; Quik, J.T.K.; Veld, H.; Koelmans, A.A.

    2009-01-01

    Black Carbon (BC) quantification methods are reviewed, including new Rock-Eval 6 data on BC reference materials. BC has been reported to have major impacts on climate, human health and environmental quality. Especially for risk assessment of persistent organic pollutants (POPs) it is important to

  14. Thermal diffusivity measurements on porous carbon fiber reinforced polymer tubes

    Science.gov (United States)

    Gruber, Jürgen; Gresslehner, Karl Heinz; Mayr, Günther; Hendorfer, Günther

    2017-02-01

    This work presents the application of methods for the determination of the thermal diffusivity well suited for flat bodies adapted to cylindrical bodies. Green's functions were used to get the temperature time history for small and large times, for the approach of intersecting these two straight lines. To verify the theoretical considerations noise free data are generated by finite element simulations. Furthermore effects of inhomogeneous excitation and the anisotropic heat conduction of carbon fiber reinforced polymers were taken into account in these numerical simulations. It could be shown that the intersection of the two straight lines is suitable for the determination of the thermal diffusivity, although the results have to be corrected depending on the ratio of the cylinders inner and outer radii. Inhomogeneous excitation affects the results of this approach as it lead to multidimensional heat flux. However, based on the numerical simulations a range of the azimuthal angle exists, where the thermal diffusivity is nearly independent of the angle. The method to determine the thermal diffusivity for curved geometries by the well suited Thermographic Signal Reconstruction method and taking into account deviations from the slab by a single correction factor has great advantages from an industrial point of view, just like an easy implementation into evaluation software and the Thermographic Signal Reconstruction methods rather short processing time.

  15. 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.

  16. Quantitative measurement of carbon nanotubes released from their composites by thermal carbon analysis

    Science.gov (United States)

    Ogura, I.; Kotake, M.; Ata, S.; Honda, K.

    2017-06-01

    The release of free carbon nanotubes (CNTs) and CNTs partly embedded in matrix debris into the air may occur during mechanical and abrasion processes involving CNT composites. Since the harmful effects of CNT-matrix mixtures have not yet been fully evaluated, it is considered that any exposure to CNTs, including CNT-matrix mixtures, should be measured and controlled. Thermal carbon analysis, such as Method 5040 of the National Institute for Occupational Safety and Health, is one of the most reliable quantitative methods for measuring CNTs in the air. However, when CNTs are released together with polymer matrices, this technique may be inapplicable. In this study, we evaluated the potential for using thermal carbon analysis to determine CNTs in the presence of polymer matrices. Our results showed that thermal carbon analysis was potentially capable of determining CNTs in distinction from polyamide 12, polybutylene terephthalate, polypropylene, and polyoxymethylene. However, it was difficult to determine CNTs in the presence of polyethylene terephthalate, polycarbonate, polyetheretherketone, or polyamide 6.

  17. Source contributions to black carbon mass fractions in aerosol particles over the northwestern Pacific

    Science.gov (United States)

    Koga, Seizi; Maeda, Takahisa; Kaneyasu, Naoki

    Aerosol particle number size distributions above 0.3 μm in diameter and black carbon mass concentrations in aerosols were observed on Chichi-jima of the Ogasawara Islands in the northwestern Pacific from January 2000 to December 2002. Chichi-jima is suitable to observe polluted air masses from East Asia in winter and clean air masses over the western North Pacific in summer. In winter, aerosols over Chichi-jima were strongly affected by anthropogenic emissions in East Asia. The form of energy consumption in East Asia varies in various regions. Hence, each source region is expected to be characterized by an individual black carbon mass fraction. A three-dimensional Eulerian transport model was used to estimate contribution rates to air pollutants from each source region in East Asia. Because the Miyake-jima eruption began at the end of June 2000, the influence of smokes from Miyake-jima was also considered in the model calculation. The results of model calculations represent what must be noticed about smokes from volcanoes including Miyake-jima to interpret temporal variations of sulfur compounds over the northwestern Pacific. To evaluate black carbon mass fractions in anthropogenic aerosols as a function of source region, the relationships between the volume concentration of aerosol particles and the black carbon mass concentration in the winter were classified under each source region in East Asia. Consequently, the black carbon mass fractions in aerosols from China, Japan and the Korean Peninsula, and other regions were estimated to be 9-13%, 5-7%, and 4-5%, respectively.

  18. 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.

  19. Terapi Sel Punca Mesenkimal Sumsum Tulang Tikus dalam Meregenerasi Sel Sitotrofoblas Nekrosis yang Dipapar Carbon Black (RAT BONE MARROW MESENCHYMAL STEM CELL THERAPY IN REGENERATING NECROTIC CYTOTROPHOBLAST CELL FOLLOWING EXPOSED TO CARBON BLACK

    Directory of Open Access Journals (Sweden)

    Widjiati .

    2015-08-01

    Full Text Available The objective of this study is to find out the potency of Rat Bone Marrow Mesenchymal Stem Cell(RBMMSC in regenerating necrotic cytotrophoblast cells of rats (Rattusnorvegicus following exposure tocarbon black at day 6 of gestation at different time of exposure (6 days and 12 days. This study usedrandomized factorial design with two factors (gestation day and treatment. Forty-eight gravid femalerats were divided into six treatment groups i.e. (i animals at day 6-11 gestation and not expose to carbonblack; (ii 6-11 days gestation animals + 532mg/m3 carbon black for 4 hours; (iii 6-11 days gestationanimals + 532mg/m3 carbon black for 4 hours +1x107/0.1ml RBMMSC intravenously; (iv animals at day6-17 gestation and not expose to carbon black; (v 6-17 days gestation animals + 532mg/m3 carbon blackfor 4 hours; (vi 6-17 days gestation animals + 532mg/m3 carbon black for 4 hours +1x107/0.1ml RBMMSCintravenously, respectively. Data were analyzed using univariat analysis and analysis of variance. Theresults showed that there were no significance differences in regenerating necrotic cytotrophoblast betweenthe groups treated with RBMMSC and carbon black exposure. The results indicated that the stem celltherapy following exposure to carbon black was incapable in regenerating the necrotic cytotrophoblastcells.

  20. Effects of thermal fluctuations on non-minimal regular magnetic black hole

    Science.gov (United States)

    Jawad, Abdul; Shahzad, M. Umair

    2017-05-01

    We analyze the effects of thermal fluctuations on a regular black hole (RBH) of the non-minimal Einstein-Yang-Mill theory with gauge field of magnetic Wu-Yang type and a cosmological constant. We consider the logarithmic corrected entropy in order to analyze the thermal fluctuations corresponding to non-minimal RBH thermodynamics. In this scenario, we develop various important thermodynamical quantities, such as entropy, pressure, specific heats, Gibb's free energy and Helmholtz free energy. We investigate the first law of thermodynamics in the presence of logarithmic corrected entropy and non-minimal RBH. We also discuss the stability of this RBH using various frameworks such as the γ factor (the ratio of heat capacities), phase transition, grand canonical ensemble and canonical ensemble. It is observed that the non-minimal RBH becomes globally and locally more stable if we increase the value of the cosmological constant.

  1. Effects of thermal fluctuations on non-minimal regular magnetic black hole

    Energy Technology Data Exchange (ETDEWEB)

    Jawad, Abdul [COMSATS Institute of Information Technology, Department of Mathematics, Lahore (Pakistan); Shahzad, M.U. [COMSATS Institute of Information Technology, Department of Mathematics, Lahore (Pakistan); University of Central Punjab, CAMS, UCP Business School, Lahore (Pakistan)

    2017-05-15

    We analyze the effects of thermal fluctuations on a regular black hole (RBH) of the non-minimal Einstein-Yang-Mill theory with gauge field of magnetic Wu-Yang type and a cosmological constant. We consider the logarithmic corrected entropy in order to analyze the thermal fluctuations corresponding to non-minimal RBH thermodynamics. In this scenario, we develop various important thermodynamical quantities, such as entropy, pressure, specific heats, Gibb's free energy and Helmholtz free energy. We investigate the first law of thermodynamics in the presence of logarithmic corrected entropy and non-minimal RBH. We also discuss the stability of this RBH using various frameworks such as the γ factor (the ratio of heat capacities), phase transition, grand canonical ensemble and canonical ensemble. It is observed that the non-minimal RBH becomes globally and locally more stable if we increase the value of the cosmological constant. (orig.)

  2. Platinum-carbon black-titanium dioxide nanocomposite ...

    Indian Academy of Sciences (India)

    Center for Electrochemical Science and Engineering, Department of Chemical Biological Engineering, Illinois Institute of Technology, Chicago, Illinois 60616, USA; Center for Renewable Energy Science and Technology (CREST), University of Texas at Arlington, Arlington, TX 76019, USA; Sid Richardson Carbon and ...

  3. The effect of pyrolytic carbon black prepared from junked tires on the properties of ethylene-propylene-diene copolymers (EPDM

    Directory of Open Access Journals (Sweden)

    2009-05-01

    Full Text Available Pyrolytic carbon black (PCB made from used tires was used in ethylene-propylene-diene copolymers (EPDM. The microstructure of PCB was characterized by scanning electron microscopy (SEM. PCB was compounded with EPDM to prepare EPDM vulcanizates. The effects of PCB on the processing properties of EPDM compounds and the mechanical properties of vulcanizates were investigated and compared with other traditional fillers such as semi-reinforcing furnace black (N774, light calcium carbonate (CaCO3 and thermal black (N990. At the same time, the rheological behavior of EPDM compounds filled with different fillers was characterized by capillary rheometrics. The SEM photos showed that the particle shape was quiet different from that of CaCO3 and N990, it was similar to that of N774. The primary particle size was smaller than that of N774, but the aggregate size of PCB was larger than that of N774. The effect of PCB on the processing properties of EPDM compounds was similar to that of other fillers. Among the four fillers, PCB imparted EPDM compounds with higher Mooney viscosity. With the increase of filler content, the scorch time and optimum curing time of EPDM compounds changed little. The reinforcing effect of PCB was similar to that of N990, but inferior to that of N774. With the increase of PCB content, tensile strength, tear strength, and modulus at 100% elongation of EPDM vulcanizates increased significantly. When EPDM was filled with 50 phr PCB, the tear strength of EPDM vulcanizates increased by 3 times, compared with that of EPDM gum vulcanizates. The appearance of EPDM extrudate filled with PCB was coarser than that of other fillers.

  4. Self-sensing and thermal energy experimental characterization of multifunctional cement-matrix composites with carbon nano-inclusions

    Science.gov (United States)

    D'Alessandro, A.; Pisello, A. L.; Sambuco, Sara; Ubertini, F.; Asdrubali, F.; Materazzi, A. L.; Cotana, F.

    2016-04-01

    The recent progress of Nanotechnology allowed the development of new smart materials in several fields of engineering. In particular, innovative construction materials with multifunctional enhanced properties can be produced. The paper presents an experimental characterization on cement-matrix pastes doped with Carbon Nanotubes, Carbon Nano-fibers, Carbon Black and Graphene Nano-platelets. Both electro-mechanical and thermo-physical investigations have been carried out. The conductive nano-inclusions provide the cementitious matrix with piezo-resistive properties allowing the detection of external strain and stress changes. Thereby, traditional building materials, such as concrete and cementitious materials in general, would be capable of self-monitoring the state of deformation they are subject to, giving rise to diffuse sensing systems of structural integrity. Besides supplying self-sensing abilities, carbon nano-fillers may change mechanical, physical and thermal properties of cementitious composites. The experimental tests of the research have been mainly concentrated on the thermal conductivity and the optical properties of the different nano-modified materials, in order to make a critical comparison between them. The aim of the work is the characterization of an innovative multifunctional composite capable of combining self-monitoring properties with proper mechanical and thermal-energy efficiency characteristics. The potential applications of these nano-modified materials cover a wide range of possibilities, such as structural elements, floors, geothermal piles, radiant systems and more.

  5. 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).

  6. Size-fractionated measurement of coarse black carbon particles in deposition samples

    Science.gov (United States)

    Schultz, E.

    In a 1-year field study, particle deposition flux was measured by transparent collection plates. Particle concentration was simultaneously measured with a cascade impactor. Microscopic evaluation of deposition samples provided the discrimination of translucent (mineral or biological) and black carbon particles, i.e. soot agglomerates, fly-ash cenospheres and rubber fragments in the size range from 3 to 50 μm. The deposition samples were collected in two different sampling devices. A wind- and rain-shielded measurement was achieved in the Sigma-2 device. Dry deposition data from this device were used to calculate mass concentrations of the translucent and the black particle fraction separately, approximating particle deposition velocity by Stokes' settling velocity. In mass calculations an error up to 20% has to be considered due to assumed spherical shape and unit density for all particles. Within the limitations of these assumptions, deposition velocities of the distinguished coarse particles were calculated. The results for total particulate matter in this range are in good agreement with those from impactor measurement. The coarse black carbon fraction shows a reduced deposition velocity in comparison with translucent particles. The deviation depends on precipitation amount. Further measurements and structural investigations of black carbon particles are in preparation to verify these results.

  7. A contribution of black and brown carbon to the aerosol light absorption

    Science.gov (United States)

    Kim, Sang-Woo; Cho, Chaeyoon; Jo, Duseong; Park, Rokjin

    2017-04-01

    Black carbon (BC) is functionally defined as the absorbing component of atmospheric total carbonaceous aerosols and is typically dominated by soot-like elemental carbon (EC). Organic carbon (OC) has also been shown to absorb strongly at visible to UV wavelengths and the absorbing organics are referred to as brown carbon (BrC; Alexander et al., 2008). These two aerosols contribute to solar radiative forcing through absorption of solar radiation and heating of the absorbing aerosol layer, but most optical instruments that quantify light absorption are unable to distinguish one type of absorbing aerosol from another (Moosmüller et al. 2009). In this study, we separate total aerosol absorption from these two different light absorbers from co-located simultaneous in-situ measurements, such as Continuous Soot Monitoring System (COSMOS), Continuous Light Absorption Photometer (CLAP) and Sunset EC/OC analyzer, at Gosan climate observatory, Korea. We determine the mass absorption cross-section (MAC) of BC, and then estimate the contribution of BC and BrC on aerosol light absorption, together with a global 3-D chemical transport model (GEOS-Chem) simulation. At 565 nm wavelength, BC MAC is found to be about 5.4±2.8 m2 g-1 from COSMOS and Sunset EC/OC analyzer measurements during January-May 2012. This value is similar to those from Alexander et al. (2008; 4.3 ˜ 4.8 m2 g-1 at 550 nm) and Chung et al. (2012; 5.1 m2 g-1 at 520 nm), but slightly lower than Bond and Bergstrom (2006; 7.5±1.2 m2 g-1 at 550 nm). The COMOS BC mass concentration calculated with 5.4 m2 g-1 of BC MAC shows a good agreement with thermal EC concentration, with a good slope (1.1). Aerosol absorption coefficient and BC mass concentration from COSMOS, meanwhile, are approximately 25 ˜ 30 % lower than those of CLAP. This difference can be attributable to the contribution of volatile light-absorbing aerosols (i.e., BrC). The absorption coefficient of BrC, which is determined by the difference of

  8. Sanitising black water by auto-thermal aerobic digestion (ATAD) combined with ammonia treatment.

    Science.gov (United States)

    Nordin, Annika C; Vinnerås, Björn

    2015-01-01

    The effect of a two-step process on the concentration of pathogens and indicator microorganisms in black water (0.9-1% total solids) was studied. The treatment combined auto-thermal aerobic digestion (ATAD) and ammonia sanitisation. First, the temperature of the black water was increased through ATAD and when a targeted temperature was reached (33, 41 and 45.5 °C studied), urea was added to a 0.5% concentration (total ammonia nitrogen >2.9 g L⁻¹). Escherichia coli and Salmonella spp. were reduced to non-detectable levels within 3 days following urea addition at temperatures above 40 °C, whereas when urea was added at 33 °C E. coli was still present after 8 days. By adding urea at temperatures of 40 °C and above, a 5 log10 reduction in Enterococcus spp. and a 3 log10 reduction in Ascaris suum eggs was achieved 1 week after the addition. With combined ATAD and ammonia treatment using 0.5% ww urea added at an aerobic digestion temperature >40 °C, black water was sanitised regarding the pathogens studied in 2 weeks of total treatment time.

  9. Effect of Mixing State on the Optical Absorption by Black Carbon Containing Particles

    Science.gov (United States)

    Onasch, T. B.; Cappa, C. D.; Forestieri, S.; Lambe, A. T.; Massoli, P.; Olfert, J. S.; Ghazi, R.; Sedlacek, A. J.; Lewis, E. R.; Croasdale, D.; Cummings, M.; Martin, A.; Freedman, A.; Worsnop, D. R.; Davidovits, P.

    2012-12-01

    The positive radiative forcing of black carbon (BC) aerosols may be as large as that of CO2 but remains highly uncertain. Modeling and laboratory studies show that BC-containing aerosols exhibit light absorption enhancements (Eabs) by as much as a factor of two relative to uncoated BC, due to a lensing effect; this effect has been incorporated into several global climate models. Yet contrary to expectations, recent field measurements during NOAA CalNex 2010 and DOE CARES 2010 report low Eabs (soot particles, coated by hydrophobic dioctyl sebacate (DOS) or hydrophilic sulfuric acid, was conducted as a function of coating thickness and relative humidity. Following coating and size-selection, aerosol mass distributions, size distributions, and mass spectra were measured with a centrifugal particle mass analyzer (CPMA), scanning mobility particle sizer (SMPS), and a soot particle - aerosol mass spectrometer (SP-AMS). Aerosol absorption and extinction were measured with a cavity ring down - photoacoustic aerosol spectrometer (CRD-PAS), and a cavity attenuated phase shift (CAPS) monitor. Eabs was derived as the ratio of absorption cross-sections of coated soot relative to thermally denuded soot. The Eabs of DOS-coated soot increased as a function of coating thickness and were consistent with the Mie theory "core-shell" model. In contrast, as the thickness of sulfuric acid coating and relative humidity were systematically varied we observed enhancements that were significantly lower than the theoretical predictions, similar to that observed in the field measurements. Our measurements suggest this suppressed Eabs may arise from morphological changes and/or phase separations incurred within BC-containing particles for hydrophilic coatings influenced by water vapor.

  10. Design and synthesis of palladium/graphitic carbon nitride/carbon black hybrids as high-performance catalysts for formic acid and methanol electrooxidation

    Science.gov (United States)

    Qian, Huayu; Huang, Huajie; Wang, Xin

    2015-02-01

    Here we report a facile two-step method to synthesize high-performance palladium/graphitic carbon nitride/carbon black (Pd/g-C3N4/carbon black) hybrids for electrooxidizing formic acid and methanol. The coating of g-C3N4 on carbon black surface is realized by a low-temperature heating treatment, followed by the uniform deposition of palladium nanoparticles (Pd NPs) via a wet chemistry route. Owning to the significant synergistic effects of the individual components, the preferred Pd/g-C3N4/carbon black electrocatalyst exhibits exceptional forward peak current densities as high as 2155 and 1720 mA mg-1Pd for formic acid oxidation in acid media and methanol oxidation in alkaline media, respectively, far outperforming the commercial Pd-C catalyst. The catalyst also shows reliable stability, demonstrating that the newly-designed hybrids have great promise in constructing high-performance portable fuel cell systems.

  11. Enhancing thermal conductivity of fluids with graphite nanoparticles and carbon nanotube

    Science.gov (United States)

    Zhang, Zhiqiang [Lexington, KY; Lockwood, Frances E [Georgetown, KY

    2008-03-25

    A fluid media such as oil or water, and a selected effective amount of carbon nanomaterials necessary to enhance the thermal conductivity of the fluid. One of the preferred carbon nanomaterials is a high thermal conductivity graphite, exceeding that of the neat fluid to be dispersed therein in thermal conductivity, and ground, milled, or naturally prepared with mean particle size less than 500 nm, and preferably less than 200 nm, and most preferably less than 100 nm. The graphite is dispersed in the fluid by one or more of various methods, including ultrasonication, milling, and chemical dispersion. Carbon nanotubes with graphitic structure is another preferred source of carbon nanomaterial, although other carbon nanomaterials are acceptable. To confer long term stability, the use of one or more chemical dispersants is preferred. The thermal conductivity enhancement, compared to the fluid without carbon nanomaterial, is proportional to the amount of carbon nanomaterials (carbon nanotubes and/or graphite) added.

  12. Thermal winds in stellar mass black hole and neutron star binary systems

    Science.gov (United States)

    Done, Chris; Tomaru, Ryota; Takahashi, Tadayuki

    2018-01-01

    Black hole binaries show equatorial disc winds at high luminosities, which apparently disappear during the spectral transition to the low/hard state. This is also where the radio jet appears, motivating speculation that both wind and jet are driven by different configurations of the same magnetic field. However, these systems must also have thermal winds, as the outer disc is clearly irradiated. We develop a predictive model of the absorption features from thermal winds, based on pioneering work of Begelman, McKee & Shields. We couple this to a realistic model of the irradiating spectrum as a function of luminosity to predict the entire wind evolution during outbursts. We show that the column density of the thermal wind scales roughly with luminosity, and does not shut off at the spectral transition, though its visibility will be affected by the abrupt change in ionizing spectrum. We re-analyse the data from H1743-322, which most constrains the difference in wind across the spectral transition, and show that these are consistent with the thermal wind models. We include simple corrections for radiation pressure, which allows stronger winds to be launched from smaller radii. These winds become optically thick around Eddington, which may even explain the exceptional wind seen in one observation of GRO J1655-40. These data can instead be fit by magnetic wind models, but similar winds are not seen in this or other systems at similar luminosities. Hence, we conclude that the majority (perhaps all) of current data can be explained by thermal or thermal-radiative winds.

  13. Time-resolved analysis of particle emissions from residential biomass combustion - Emissions of refractory black carbon, PAHs and organic tracers

    Science.gov (United States)

    Nielsen, Ingeborg E.; Eriksson, Axel C.; Lindgren, Robert; Martinsson, Johan; Nyström, Robin; Nordin, Erik Z.; Sadiktsis, Ioannis; Boman, Christoffer; Nøjgaard, Jacob K.; Pagels, Joakim

    2017-09-01

    Time-resolved particle emissions from a conventional wood stove were investigated with aerosol mass spectrometry to provide links between combustion conditions, emission factors, mixing state of refractory black carbon and implications for organic tracer methods. The addition of a new batch of fuel results in low temperature pyrolysis as the fuel heats up, resulting in strong, short-lived, variable emission peaks of organic aerosol-containing markers of anhydrous sugars, such as levoglucosan (fragment at m/z 60). Flaming combustion results in emissions dominated by refractory black carbon co-emitted with minor fractions of organic aerosol and markers of anhydrous sugars. Full cycle emissions are an external mixture of larger organic aerosol-dominated and smaller thinly coated refractory black carbon particles. A very high burn rate results in increased full cycle mass emission factors of 66, 2.7, 2.8 and 1.3 for particulate polycyclic aromatic hydrocarbons, refractory black carbon, total organic aerosol and m/z 60, respectively, compared to nominal burn rate. Polycyclic aromatic hydrocarbons are primarily associated with refractory black carbon-containing particles. We hypothesize that at very high burn rates, the central parts of the combustion zone become air starved, leading to a locally reduced combustion temperature that reduces the conversion rates from polycyclic aromatic hydrocarbons to refractory black carbon. This facilitates a strong increase of polycyclic aromatic hydrocarbons emissions. At nominal burn rates, full cycle emissions based on m/z 60 correlate well with organic aerosol, refractory black carbon and particulate matter. However, at higher burn rates, m/z 60 does not correlate with increased emissions of polycyclic aromatic hydrocarbons, refractory black carbon and organic aerosol in the flaming phase. The new knowledge can be used to advance source apportionment studies, reduce emissions of genotoxic compounds and model the climate impacts of

  14. Solar production of catalytic filamentous carbon by thermal decomposition of hydrocarbons and carbon monoxide

    Energy Technology Data Exchange (ETDEWEB)

    Kirillov, V.A.; Kuvshinov, G.G.; Mogilnykh, Yu.I. [Boreskov Institute of Catalysis, Novosibirsk (Russian Federation); Reller, A. [University of Hamburg (Germany); Steinfeld, A.; Weidenkaff, A.; Meier, A. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1999-08-01

    Concentrated solar radiation was used as the clean source of process heat for the production of Catalytic Filamentous Carbon (CFC) by thermal decomposition of gaseous hydrocarbons and by CO disproportionation in the presence of small metal catalyst particles. Depending on the catalyst, two different types of CFC, namely nano tubes and nano fibers, were obtained in solar experiments at the PSI solar furnace. (author) 2 figs., 1 tab., 7 refs.

  15. Lignin-based carbon fibers: Carbon nanotube decoration and superior thermal stability

    KAUST Repository

    Xu, Xuezhu

    2014-08-23

    Lignin-based carbon fibers (CFs) decorated with carbon nanotubes (CNTs) were synthesized and their structure, thermal stability and wettability were systematically studied. The carbon fiber precursors were produced by electrospinning lignin/polyacrylonitrile solutions. CFs were obtained by pyrolyzing the precursors and CNTs were subsequently grown on the CFs to eventually achieve a CF–CNT hybrid structure. The processes of pyrolysis and CNT growth were conducted in a tube furnace using different conditions and the properties of the resultant products were studied and compared. The CF–CNT hybrid structure produced at 850 °C using a palladium catalyst showed the highest thermal stability, i.e., 98.3% residual weight at 950 °C. A mechanism for such superior thermal stability was postulated based on the results from X-ray diffraction, Raman spectroscopy, scanning and transmission electron microscopy, and electron energy loss spectroscopy analyses. The dense CNT decoration was found to increase the hydrophobicity of the CFs.

  16. Graphene and Carbon Nanotubes Synergistically Improved the Thermal Conductivity of Phenolic Resin

    Directory of Open Access Journals (Sweden)

    Wang Han

    2017-01-01

    Full Text Available People discover the synergistic effect of graphene and carbon nanotubes on heat conduction in graphene carbon nanotubes / epoxy resin hybrid composites. In this article we added them into the phenolic resin and test the thermal conductivity. We found the thermal conductivity was increased by 6.5% in the phenolic resin by adding 0.45wt% graphene and 0.15wt% single wall carbon nanotubes (maintain the mass ratio 3:1. So if graphene and carbon nanotubes are added in proportion, thermal conductivity of phenolic resin will be improved significantly which is better than only carbon nanotubes or graphene.

  17. The Effects of Black Carbon on Arctic Sea Ice Surface Albedo with Sea Ice Type and Snow Cover

    Science.gov (United States)

    King, M. D.; Marks, A. A.

    2012-12-01

    Sea ice covers up to 7% of the Earth's surface and therefore changes in sea ice albedo have important global climatic consequences. Black carbon in sea ice will decrease surface albedo through increased absorption of incident solar radiation, which exacerbates sea ice melting through increased heating. Values of absorption cross-section calculated for typical multi-year and first year Arctic sea ice suggest that absorption in sea ice is due to black carbon in sea ice and not other absorbers. Radiative-transfer calculations were undertaken using the TUV-snow model to ascertain the effect on surface albedo of additional black carbon (from 1-1024 ng g-1) in the top 5 cm of 155 cm of a typical multi-year and first year ice. Black carbon is likely to be concentrated in the surface layer due to atmospheric deposition. A black carbon addition of 1024 ng g-1 to the top 5 cm of first year sea ice would decrease albedo at 500 nm by 0.33, and multi-year sea ice albedo would decrease by 0.21; highlighting the different response of different sea ice types. However, for the majority of the year sea ice is snow covered, which may mitigate the impact of black carbon in sea ice on surface albedo; an effect which to the author's knowledge has previously not been investigated. Absorption and scattering cross-section values were also obtained for a typical Arctic wet and dry snow. Radiative-transfer calculations were subsequently undertaken with wet and dry snow layers, of 0.5-10 cm of snow, overlying the first year and multi-year sea ice to ascertain the degree to which a snow layer will "mask" the effect of black carbon in sea ice on surface albedo. Just a 0.5 cm snow layer dramatically reduces the effect of black carbon in sea ice on surface albedo. However the underlying sea ice still impacts surface albedo with up to 10 cm of overlying snow, with all snow/sea ice types. A dry snow is more effective at masking black carbon in sea ice than a wet snow. Although the effects of black

  18. An Investigation of the Effects of Black Carbon on Precipitation in the Western United States

    Science.gov (United States)

    Tseng, Hsien-Liang Rose

    Black carbon (BC), the byproduct of incomplete combustion, is considered to be the second most important anthropogenic climate forcing agent after carbon dioxide. BC warms the atmosphere by absorbing solar radiation (direct effect), alters cloud and precipitation formation by acting as cloud condensation nuclei (indirect effect), and modifies cloud distribution via cloud burn-off (semi-direct effect). Currently, there are large discrepancies in general circulation model estimates of the influence of BC on precipitation. Even less known is how BC changes precipitation on regional scales. In the drought-stricken western United States (WUS), where BC emissions are known to affect the hydrological cycle, an investigation on how BC influences precipitation is warranted. In this study, we employ the Weather Research and Forecasting-Chemistry (WRF Chem) model (version 3.6.0) with the newly chemistry- and microphysics-coupled Fu-Liou-Gu radiation scheme to study how black carbon affects precipitation by separating BC-related effects into direct and semi-direct, and indirect effects. In this three-part study, we use a recent wet year (2005) to investigate black carbon effects. We first examine BC effects during a heavy wintertime heavy precipitation event (7-11 January 2005), a heavy summertime precipitation week for comparison to the wintertime event (20-24 July 2005), and finally, examine these same effects for the months of January to June 2005 to investigate month-long trends. We find that BC suppresses precipitation, predominantly through its direct and semi-direct effects. The direct and semi-direct effects warm the air aloft, and cool the lower levels of the atmosphere (surface dimming) through the reduction of downward shortwave radiation flux at the surface. These changes in vertical temperature increase the stability of the atmosphere and reduce convective precipitation. Convective precipitation reduction accounts for approximately 60 75% of the total

  19. 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)

  20. Anisotropic thermal diffusivity characterization of aligned carbon nanotube-polymer composites.

    Science.gov (United States)

    Borca-Tasciuc, T; Mazumder, M; Son, Y; Pal, S K; Schadler, L S; Ajayan, P M

    2007-01-01

    The anisotropic thermal diffusivity of aligned carbon nanotube-polymer composites was determined using a photothermoelectric technique. The composites were obtained by infiltrating poly-dimethyl siloxane (PDMS) in aligned multiwall CNT arrays grown by chemical vapor deposition on silicon substrates. The thermal diffusivities are insensitive to temperature in the range of 180 K-300 K. The thermal diffusivity values across the alignment direction are approximately 2-4 times smaller than along the alignment direction and larger than effective media theory predictions using reported values for the thermal diffusivity of millimeter thick aligned multiwall carbon nanotube arrays. The effective room temperature thermal conductivity of the composite along the carbon nanotube alignment direction is at least 6X larger than the thermal conductivity of the polymer matrix and is in good agreement with the effective media predictions. This work indicates that infiltration of long and aligned carbon nanotube arrays is currently the most efficient method to obtain high thermal conductivity polymer composites.

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

    Science.gov (United States)

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

    2017-07-01

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

  2. Extremely high thermal conductivity anisotropy of double-walled carbon nanotubes

    Science.gov (United States)

    Ma, Zhaoji; Guo, Zhengrong; Zhang, Hongwei; Chang, Tienchong

    2017-06-01

    Based on molecular dynamics simulations, we reveal that double-walled carbon nanotubes can possess an extremely high anisotropy ratio of radial to axial thermal conductivities. The mechanism is basically the same as that for the high thermal conductivity anisotropy of graphene layers - the in-plane strong sp2 bonds lead to a very high intralayer thermal conductivity while the weak van der Waals interactions to a very low interlayer thermal conductivity. However, different from flat graphene layers, the tubular structures of carbon nanotubes result in a diameter dependent thermal conductivity. The smaller the diameter, the larger the axial thermal conductivity but the smaller the radial thermal conductivity. As a result, a DWCNT with a small diameter may have an anisotropy ratio of thermal conductivity significantly higher than that for graphene layers. The extremely high thermal conductivity anisotropy allows DWCNTs to be a promising candidate for thermal management materials.

  3. Extremely high thermal conductivity anisotropy of double-walled carbon nanotubes

    Directory of Open Access Journals (Sweden)

    Zhaoji Ma

    2017-06-01

    Full Text Available Based on molecular dynamics simulations, we reveal that double-walled carbon nanotubes can possess an extremely high anisotropy ratio of radial to axial thermal conductivities. The mechanism is basically the same as that for the high thermal conductivity anisotropy of graphene layers - the in-plane strong sp2 bonds lead to a very high intralayer thermal conductivity while the weak van der Waals interactions to a very low interlayer thermal conductivity. However, different from flat graphene layers, the tubular structures of carbon nanotubes result in a diameter dependent thermal conductivity. The smaller the diameter, the larger the axial thermal conductivity but the smaller the radial thermal conductivity. As a result, a DWCNT with a small diameter may have an anisotropy ratio of thermal conductivity significantly higher than that for graphene layers. The extremely high thermal conductivity anisotropy allows DWCNTs to be a promising candidate for thermal management materials.

  4. Isotopically Light Organic Carbon in Phanerozoic Black Shales: Diagenetic, Source, or Environmental Signal?

    Science.gov (United States)

    Meyers, P. A.

    2011-12-01

    A curious depletion of 13C in the organic matter of marine black shales has been widely recognized ever since the advent of carbon isotope measurements half a century ago. Paleozoic and Mesozoic black shales commonly have del13C values between -29 and -26 permil, whereas modern marine organic matter has values between -22 and -18 permil. The black shale values mimic those of continental organic matter, yet sedimentary settings and Rock-Eval results indicate that the organic matter is marine in origin. This presentation will overview and discuss hypotheses to explain the isotopically light values of the black shales. First, the preferential removal of isotopically heavier organic matter components such as carbohydrates by diagenesis will be examined and shown to be wanting. Second, the possible oxidation of isotopically light methane released from clathrates that would have altered the DIC pool available to phytoplankton will be considered and also be found unlikely. A third possibility - that greater concentrations of CO2 in the greenhouse atmospheres that corresponded with deposition of many black shales allowed greater discrimination against 13C during photosynthesis - will be evaluated from del13C values of bulk carbon and of algal and land-plant biomarker molecules. Finally, the possibility that stronger stratification of the surface ocean may have magnified photic zone recycling of organic matter and reincorporation of its isotopically light carbon into fresh biomass will be considered. Although the fourth possibility is contrary to the conditions of vertical mixing of nutrients that exist in modern upwelling systems and that are responsible for their high productivity, it is consistent with the strongly stratified conditions that accompanied the high productivity that produced the Pliocene-Pleistocene sapropels of the Mediterranean Sea. Because the sapropels and most Phanerozic black shales share del15N values near 0 permil, nitrogen fixation evidently was

  5. Modulation of snow reflectance and snowmelt from Central Asian glaciers by anthropogenic black carbon.

    Science.gov (United States)

    Schmale, Julia; Flanner, Mark; Kang, Shichang; Sprenger, Michael; Zhang, Qianggong; Guo, Junming; Li, Yang; Schwikowski, Margit; Farinotti, Daniel

    2017-01-12

    Deposited mineral dust and black carbon are known to reduce the albedo of snow and enhance melt. Here we estimate the contribution of anthropogenic black carbon (BC) to snowmelt in glacier accumulation zones of Central Asia based on in-situ measurements and modelling. Source apportionment suggests that more than 94% of the BC is emitted from mostly regional anthropogenic sources while the remaining contribution comes from natural biomass burning. Even though the annual deposition flux of mineral dust can be up to 20 times higher than that of BC, we find that anthropogenic BC causes the majority (60% on average) of snow darkening. This leads to summer snowmelt rate increases of up to 6.3% (7 cm a-1) on glaciers in three different mountain environments in Kyrgyzstan, based on albedo reduction and snowmelt models.

  6. Modulation of snow reflectance and snowmelt from Central Asian glaciers by anthropogenic black carbon

    Science.gov (United States)

    Schmale, Julia; Flanner, Mark; Kang, Shichang; Sprenger, Michael; Zhang, Qianggong; Guo, Junming; Li, Yang; Schwikowski, Margit; Farinotti, Daniel

    2017-01-01

    Deposited mineral dust and black carbon are known to reduce the albedo of snow and enhance melt. Here we estimate the contribution of anthropogenic black carbon (BC) to snowmelt in glacier accumulation zones of Central Asia based on in-situ measurements and modelling. Source apportionment suggests that more than 94% of the BC is emitted from mostly regional anthropogenic sources while the remaining contribution comes from natural biomass burning. Even though the annual deposition flux of mineral dust can be up to 20 times higher than that of BC, we find that anthropogenic BC causes the majority (60% on average) of snow darkening. This leads to summer snowmelt rate increases of up to 6.3% (7 cm a-1) on glaciers in three different mountain environments in Kyrgyzstan, based on albedo reduction and snowmelt models.

  7. Mechanical properties and mophology natural rubber blend with bentonit and carbon black

    Science.gov (United States)

    Ginting, E. M.; Bukit, N.; Muliani; Frida, E.

    2017-07-01

    Purpose of this study was to determine the mechanical properties and morphology of composite natural rubber and natural bentonite with addition of Na-bentonite filler and carbon black to natural rubber. The method is carried material mixed with filler composition variations (0,10,20,30) phr using open mill for 6 min. Results of the open mill is vulcanized at a temperature of 170°C. Further testing mechanical properties and morphology. Results showed that the addition of Na-bentonite filler and carbon black influence on the mechanical properties of tensile strength, elongation at break, modulus of elasticity, hardness, and strong tear. Morphological results showed cavities in the rubber compound and the occurrence agglomeration.

  8. Incentives for small clubs of Arctic countries to limit black carbon and methane emissions

    Science.gov (United States)

    Aakre, Stine; Kallbekken, Steffen; Van Dingenen, Rita; Victor, David G.

    2018-01-01

    Although addressing climate change will ultimately require global cooperation, substantial progress may be achieved through small clubs of countries, where it is easier to forge and implement deals needed for policy coordination. Here we quantify the gains from cooperation in the Arctic region and find that nearly 90% of the potential for abating black carbon can be reached by countries acting in self-interest alone because soot, the main source of black carbon, causes severe harm to human health along with warming. Abating methane, by contrast, requires more cooperation because impacts are more diffused geographically. Well-designed clubs with as few as four members can realize more than 80% of the full group cooperation potential for reducing these pollutants. The pivotal player in every effective club is Russia—most other members of the Arctic Council, the institution most focused on advancing the collective interests of the region, offer little leverage on the problems at hand.

  9. Effects of prenatal exposure to nanoparticles titanium dioxide and carbon black on female germline DNA stability

    DEFF Research Database (Denmark)

    Boisen, Anne Mette Zenner

    are actively dividing. The aim of this PhD study was to determine if two widely used nanoparticles titanium dioxide UV-Titan and carbon black Printex 90 induce ESTR mutations in the germ cells of prenatally exposed females. Pregnant generation P mice were exposed to ~42 mg UV-Titan/m3/1 h/d during gestation...... days 8-18 or carbon black Printex 90 at gestation days (7,10,15 and 18) (total dose of 268 μg/animal) by intratracheal instillation. Maternal inflammation and DNA damage were assessed in order to assess the potential for indirect effects on offspring during pregnancy. Prenatally exposed F1 females were...... recently come into focus. Inhaled nanoparticles are cleared very slowly from the lungs and a small fraction may translocate into the bloodstream and compartments of the body. In the airways nanoparticles can induce a high degree of pulmonary inflammation and oxidative stress. Nanoparticles are more...

  10. Thermal effects of carbonated hydroxyapatite modified by glycine and albumin

    Science.gov (United States)

    Gerk, S. A.; Golovanova, O. A.; Kuimova, M. V.

    2017-01-01

    In this work calcium phosphate powders were obtained by precipitation method from simulated solutions of synovial fluid containing glycine and albumin. X-ray diffraction and IR spectroscopy determined that all samples are single-phase and are presented by carbonate containing hydroxyapatite (CHA). The thermograms of solid phases of CHA were obtained and analyzed; five stages of transformation in the temperature range of 25-1000°C were marked. It is shown that in this temperature range dehydration, decarboxylation and thermal degradation of amino acid and protein connected to the surface of solid phase occur. The tendency of temperature lowering of the decomposition of powders synthesized from a medium containing organic substances was determined. Results demonstrate a direct dependence between the concentration of the amino acid in a model solution and its content in the solid phase.

  11. A New Type of Carbon Resistance Thermometer with Excellent Thermal Contact at Millikelvin Temperatures

    Science.gov (United States)

    Samkharadze, Nodar; Kumar, Ashwani; Csáthy, Gábor A.

    2010-09-01

    Using a new brand of commercially available carbon resistor we built a cryogenic thermometer with an extremely good thermal contact to its thermal environment. Because of its superior thermal contact the thermometer is insensitive to low levels of spurious radio frequency heating. We calibrated our thermometer down to 5 mK using a quartz tuning fork He-3 viscometer and measured its thermal resistance and thermal response time.

  12. Thermal shock performance of carbon-bonded carbon fiber composite and ceramic matrix composite joints for thermal protection re-entry applications

    OpenAIRE

    Triantou, K.I.; Mergia, K.; Perez, B.; Florez, S.; Stefan, A.; Ban, C.; Pelin, G.; Ionescu, G.; Zuber, C.; Fischer, W.P.P.; Barcena, J.

    2017-01-01

    Hybrid thermal protection systems for aerospace applications based on carbon-bonded carbon fiber composite (CALCARB®) and ceramic matrix composites have been investigated. Two types of ceramic composite materials were considered, Cf/SiC (SiCARBON™) and C/C-SiC. The ablative material and the ceramic matrix composite were joined using alumina, graphite and zirconia-zirconium silicate based commercial high temperature adhesives and their performance on thermal shock tests was evaluated. Microstr...

  13. Modelling black spruce primary production and carbon allocation in the Quebec boreal forest

    Science.gov (United States)

    Gennaretti, Fabio; Guiot, Joel; Berninger, Frank; Boucher, Etienne; Gea-Izquierdo, Guillermo

    2017-04-01

    Boreal ecosystems are crucial carbon stores that must be urgently quantified and preserved. Their future evolution is extremely important for the global carbon budget. Here, we will show the progresses achieved with the MAIDEN forest ecophysiological model in simulating carbon fluxes of black spruce (Picea mariana (Mill.) B.S.P.) forests, the most representative ecosystem of the North American boreal biome. Starting from daily minimum-maximum air temperature, precipitation and CO2 atmospheric concentration, MAIDEN models the phenological (5 phenological phases are simulated each year) and meteorological controls on gross primary production (GPP) and carbon allocation to stem. The model is being calibrated on eddy covariance and tree-ring data. We will discuss the model's performance and the modifications introduced in MAIDEN to adapt the model to temperature sensitive forests of the boreal region.

  14. Analysis of the Interphase on Carbon Black Formed in High Voltage Batteries

    DEFF Research Database (Denmark)

    Younesi, Reza; Christiansen, Ane Sælland; Scipioni, Roberto

    2015-01-01

    Carbon black (CB) additives commonly used to increase the electrical conductivity of electrodes in Li-ion batteries are generally believed to be electrochemically inert additives in cathodes. Decomposition of electrolyte in the surface region of CB in Li-ion cells at high voltages up to 4.9 V...... is here studied using electrochemical measurements as well as structural and surface characterizations. LiPF6 and LiClO4 dissolved in ethylene carbonate:diethylene carbonate (1:1) were used as the electrolyte to study irreversible charge capacity of CB cathodes when cycled between 4.9 V and 2.5 V...... species is highest at the outermost surface of the CB. It is concluded that carboxylate and carbonate bonds (originating from solvent decomposition) and LiF (when LiPF6 was used) take part in the formation of the decomposed species. Electrochemical impedance spectroscopy measurements and transmission...

  15. Effects of black carbon and Icelandic dust on snow albedo, melt and density

    OpenAIRE

    Meinander, Outi

    2016-01-01

    Light-absorbing impurities in the cryosphere are of hydrological, environmental and climatic importance. The wet and dry deposition of black carbon (BC), organic carbon (OC), and dust particles affect the optical properties and melt of snow and ice. In the Arctic region, the climatic effects are amplified, and surface albedo feedback is often cited as the main contributor. The aim of this thesis is to fill in some of the gaps in our knowledge of the effects of BC, OC, and Icelandic dust ...

  16. Dust and Black Carbon Radiative Forcing Controls on Snowmelt in the Colorado River Basin

    OpenAIRE

    Skiles, Sara McKenzie

    2014-01-01

    Light absorbing impurities (LAIs), like dust and black carbon (BC), initiate powerful albedo feedbacks when deposited on snow cover, yet due to a scarcity of observations radiative forcing by LAIs is often neglected, or poorly constrained, in climate and hydrological models. This has important consequences for regions like the Colorado River Basin, where dust deposition to mountain snow cover frequently occurs in the upper basin in the springtime, a relatively new phenomenon since western exp...

  17. Patterns of total ecosystem carbon storage with changes in soil temperature in boreal black spruce forests

    Science.gov (United States)

    E.S. Kane; J.G. Vogel

    2009-01-01

    To understand how carbon (C) pools in boreal ecosystems may change with warming, we measured above- and belowground C pools and C increment along a soil temperature gradient across 16 mature upland black spruce (Picea mariana Mill. [B•S.P]) forests in interior Alaska. Total spruce C stocks (stand and root C) increased from 1.3 to 8.5 kg C m

  18. Effect of Vulcanization System and Carbon Black on Mechanical and Swelling Properties of EPDM Blends

    OpenAIRE

    Mayasari, Hesty Eka; Yuniari, Arum

    2016-01-01

    EPDM (Ethylene propylene diene monomer) is one of synthetic rubber that widely used in automotive. It must be vulcanized and added by other materials before used. The aim of this study is to investigate the effect of vulcanization system and the addition of carbon black (CB) to the mechanical properties and swelling characteristic of EPDM. This research used three vulcanization system, conventional vulcanization (CV), efficient vulcanization (EV) and semi-efficient vulcanization (SEV) with th...

  19. Effect of vulcanization system and carbon black on mechanical and swelling properties of EPDM blends

    OpenAIRE

    Hesty Eka Mayasari; Arum Yuniari

    2016-01-01

    EPDM (Ethylene propylene diene monomer) is one of synthetic rubber that widely used in automotive. It must be vulcanized and added by other materials before used. The aim of this study is to investigate the effect of vulcanization system and the addition of carbon black (CB) to the mechanical properties and swelling characteristic of EPDM. This research used three vulcanization system, conventional vulcanization (CV), efficient vulcanization (EV) and semi-efficient vulcanization (SEV) with th...

  20. Modeling spatial variations of black carbon particles in an urban highway-buildings environment

    OpenAIRE

    Tong, Zheming; Wang, Yan; Patel, Molini; Kinney, Patrick; Chrillrud, Steven; Zhang, K. Max

    2011-01-01

    Highway-building environments are prevalent in metropolitan areas. This paper presents our findings in investigating pollutant transport in a highway-building environment by combing field measurement and numerical simulations. We employ and improve the Comprehensive Turbulent Aerosol Dynamics and Gas Chemistry (CTAG) model to simulate the spatial variations of black carbon (BC) concentrations near highway I-87 and an urban school in the South Bronx, New York. The results of CTAG simulations a...

  1. 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

  2. Thermal decomposition of fullerene nanowhiskers protected by amorphous carbon mask

    Science.gov (United States)

    Guo, Hongxuan; Wang, Chengxiang; Miyazawa, Kun'Ichi; Wang, Hongxin; Masuda, Hideki; Fujita, Daisuke

    2016-12-01

    Fullerene nanostructures are well known for their unique morphology, physical and mechanical properties. The thermal stability of fullerene nanostructures, such as their sublimation at high temperature is also very important for studying their structures and applications. In this work, We observed fullerene nanowhiskers (FNWs) in situ with scanning helium ion microscopy (HIM) at elevated temperatures. The FNWs exhibited different stabilities with different thermal histories during the observation. The pristine FNWs were decomposed at the temperatures higher than 300 °C in a vacuum environment. Other FNWs were protected from decomposition with an amorphous carbon (aC) film deposited on the surface. Based on high spacial resolution, aC film with periodic structure was deposited by helium ion beam induced deposition (IBID) on the surface of FNWs. Annealed at the high temperature, the fullerene molecules were selectively sublimated from the FNWs. The periodic structure was formed on the surface of FNWs and observed by HIM. Monte Carlo simulation and Raman characterization proved that the morphology of the FNWs was changed by helium IBID at high temperature. This work provides a new method of fabricating artificial structure on the surface of FNWs with periodic aC film as a mask.

  3. The theory-practice gap of black carbon mitigation technologies in rural China

    Science.gov (United States)

    Zhang, Weishi; Li, Aitong; Xu, Yuan; Liu, Junfeng

    2018-02-01

    Black carbon mitigation has received increasing attention for its potential contribution to both climate change mitigation and air pollution control. Although different bottom-up models concerned with unit mitigation costs of various technologies allow the assessment of alternative policies for optimized cost-effectiveness, the lack of adequate data often forced many reluctant explicit and implicit assumptions that deviate away from actual situations of rural residential energy consumption in developing countries, where most black carbon emissions occur. To gauge the theory-practice gap in black carbon mitigation - the unit cost differences that lie between what is estimated in the theory and what is practically achieved on the ground - this study conducted an extensive field survey and analysis of nine mitigation technologies in rural China, covering both northern and southern regions with different residential energy consumption patterns. With a special focus on two temporal characteristics of those technologies - lifetimes and annual utilization rates, this study quantitatively measured the unit cost gaps and explain the technical as well as sociopolitical mechanisms behind. Structural and behavioral barriers, which have affected the technologies' performance, are discussed together with policy implications to narrow those gaps.

  4. In vitro cytotoxicity of carbon black nanoparticles synthesized from solution plasma on human lung fibroblast cells

    Science.gov (United States)

    Panomsuwan, Gasidit; Chokradjaroen, Chayanaphat; Rujiravanit, Ratana; Ueno, Tomonaga; Saito, Nagahiro

    2018-01-01

    Carbon black nanoparticles (CB-NPs) have been synthesized from liquid benzene by a solution plasma method at room temperature and atmospheric pressure. The morphological observation by scanning electron microscopy revealed the agglomeration of aggregated fine particles. The synthesized CB-NPs were predominantly amorphous as confirmed by X-ray diffraction. The in vitro cytotoxicity of CB-NPs on the human lung fibroblast (MRC-5) cell line was assessed by the 3-(4,5-dimethylthiazole-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and systematically compared with those of two types of commercial carbon blacks (i.e., Vulcan XC-72 and Ketjenblack EC-600JD). Cell viabilities were studied at different concentrations of 32.5, 65, 125, and 250 µg/mL. It was found that the CB-NPs derived from solution plasma exhibited a lower cytotoxicity on the MRC-5 cells than the other two comparative carbon blacks. The viability of MRC-5 cells exposed to CB-NPs remained higher than 90% even at a high concentration of 250 µg/mL. This result preliminarily confirmed the biosafety and potential use of CB-NPs in the field of biological applications.

  5. Coatings of black carbon in Tijuana, Mexico, during the CalMex Campaign

    Science.gov (United States)

    Takahama, S.; Russell, L. M.; Duran, R.; Subramanian, R.; Kok, G.

    2010-12-01

    Black carbon number and mass concentrations were measured by a single-particle soot photometer (SP2; by Droplet Measurement Technologies) in Tijuana, Mexico between May 15, 2010, and June 30, 2010, for the CalMex campaign. The measurement site, Parque Morelos, is a recreational area located in the Southeast region of Tijuana. The SP2 was equipped with 8-channels of signal detection that spans a wider range of sensitivity for incandescing and scattering measurements than traditional configurations. The campaign-average number concentration of incandescing particles was 280 #/cc, peaking during traffic activity in the mornings. Incandescing particles made up 50% of all particles (incandescing and purely scattering) detected by the SP2. The mode of the number size distribution estimated for black carbon, according to estimated mass-equivalent diameters, was approximately 100 nm or smaller. Temporal variations in estimated coating thicknesses for these black carbon particles are discussed together with co-located measurements of organic aerosol and inorganic salts.

  6. Hypervelocity impact resistance of reinforced carbon carbon/carbon foam thermal protection systems

    Science.gov (United States)

    Grujicic, M.; Pandurangan, B.; Zhao, C. L.; Biggers, S. B.; Morgan, D. R.

    2006-05-01

    Common aero vehicles (CAVs) are aerodynamically designed, (from orbit) re-entry, un-powered military vehicles planned to be used for deployment of the desired munitions with increased accuracy and range. In one of the currently considered designs of the CAVs, their outer skin is planned to be constructed from two-ply panels. The outer play is made of a carbon-carbon composite while the inner ply is constructed from a carbon-based foam. In the present work a transient non-linear-dynamics-based analysis is carried out in order to predict the extent of damage and the probability for failure of the carbon-carbon/carbon-foam CAV panels during potential hypervelocity impact of space debris with the outer surface of the CAVs. The results obtained show that the extent of damage scales with the normal component of the momentum associated with the debris particles just before the impact. In addition, it is found that despite its relatively low strength, the carbon-foam can provide a major increase in the resistance of the CAV panels towards penetration of the hypervelocity debris particles. This finding has been linked with an attendant consolidation of the foam, the process that is capable of absorbing a substantial amount of kinetic energy carried by the debris particles.

  7. Thermal Conversion of Pine Wood Char to Carbon Nanomaterials in the Presence of Iron Nanoparticles

    Science.gov (United States)

    Sung Phil Mun; Zhiyong Cai; Fumiya Watanabe; Umesh P. Agarwal; Jilei. Zhang

    2012-01-01

    Southern yellow pine (Pinus taeda) wood char powder was thermally treated at 1,000:C in the presence of a 25-nm-size Fe nanoparticle catalyst. The thermally treated carbon materials were analyzed by Raman spectroscopy and high-resolution transmission electron microscopy. Well-aligned graphitic carbon structures with 15 to 17 layers on...

  8. Carbon uptake in low dissolved inorganic carbon environments: the effect of limited carbon availability on photosynthetic organisms in thermal waters

    Science.gov (United States)

    Myers, K. D.; Omelon, C. R.; Bennett, P.

    2010-12-01

    Photosynthesis is the primary carbon fixation process in thermal waters below 70°C, but some hydrothermal waters have extremely low dissolved inorganic carbon (DIC), potentially limiting the growth of inorganic carbon fixing organisms such as algae and cyanobacteria. To address the issue of how carbon is assimilated by phototrophs in these environments, we conducted experiments to compare inorganic carbon uptake mechanisms by two phylogenetically distinct organisms collected from geographically distinct carbon limited systems: the neutral pH geothermal waters of El Tatio, Chile, and the acidic geothermal waters of Tantalus Creek in Norris Geyser Basin, Yellowstone National Park. Discharge waters at El Tatio have low total DIC concentrations (2 to 6 ppm) found mainly as HCO3-; this is in contrast to even lower measured DIC values in Tantalus Creek (as low as 0.13 ppm) that, due to a measured pH of 2.5, exists primarily as CO2. Cyanobacteria and algae are innately physiologically plastic, and we are looking to explore the possibility that carbon limitation in these environments is extreme enough to challenge that plasticity and lead to a suite of carbon uptake adaptations. We hypothesize that these microorganisms utilize adaptive modes of Ci uptake that allow them to survive under these limiting conditions. Cyanobacteria (primarily Synechococcus spp.) isolated from El Tatio can utilize either passive CO2 uptake or active HCO3- uptake mechanisms, in contrast to the eukaryotic alga Cyanidium spp. from Tantalus Creek, which is restricted to an energy-dependent CO2 uptake mechanism. To test this hypothesis, we conducted pH drift experiments (Omelon et al., 2008) to examine changes in pH and [DIC] under a range of pH and [DIC] culture conditions. This work provides baseline information upon which we will begin to investigate the effects of low [DIC] on the growth of phototrophs collected from these and other less carbon limited systems.

  9. Characterization of low thermal conductivity PAN-based carbon fibers

    Science.gov (United States)

    Katzman, Howard A.; Adams, P. M.; Le, T. D.; Hemminger, Carl S.

    1992-01-01

    The microstructure and surface chemistry of eight low thermal conductivity (LTC) PAN-based carbon fibers were determined and compared with PAN-based fibers heat treated to higher temperatures. Based on wide-angle x ray diffraction, the LTC PAN fibers all appear to have a similar turbostratic structure with large 002 d-spacings, small crystallite sizes, and moderate preferred orientation. Limited small-angle x ray scattering (SAXS) results indicate that, with the exception of LTC fibers made by BASF, the LTC fibers do not have well developed pores. Transmission electron microscopy shows that the texture of the two LTC PAN-based fibers studied (Amoco T350/23X and /25X) consists of multiple sets of parallel, wavy, bent layers that interweave with each other forming a complex three dimensional network oriented randomly around the fiber axis. X ray photoelectron spectroscopy (XPS) analysis finds correlations between heat treated temperatures and the surface composition chemistry of the carbon fiber samples.

  10. Thermal conductivity, electrical conductivity and specific heat of copper-carbon fiber composite

    Science.gov (United States)

    Kuniya, Keiichi; Arakawa, Hideo; Kanai, Tsuneyuki; Chiba, Akio

    1988-01-01

    A new material of copper/carbon fiber composite is developed which retains the properties of copper, i.e., its excellent electrical and thermal conductivity, and the property of carbon, i.e., a small thermal expansion coefficient. These properties of the composite are adjustable within a certain range by changing the volume and/or the orientation of the carbon fibers. The effects of carbon fiber volume and arrangement changes on the thermal and electrical conductivity, and specific heat of the composite are studied. Results obtained are as follows: the thermal and electrical conductivity of the composite decrease as the volume of the carbon fiber increases, and were influenced by the fiber orientation. The results are predictable from a careful application of the rule of mixtures for composites. The specific heat of the composite was dependent, not on fiber orientation, but on fiber volume. In the thermal fatigue tests, no degradation in the electrical conductivity of this composite was observed.

  11. Graphene and Carbon Nanotubes Synergistically Improved the Thermal Conductivity of Phenolic Resin

    OpenAIRE

    Wang Han

    2017-01-01

    People discover the synergistic effect of graphene and carbon nanotubes on heat conduction in graphene carbon nanotubes / epoxy resin hybrid composites. In this article we added them into the phenolic resin and test the thermal conductivity. We found the thermal conductivity was increased by 6.5% in the phenolic resin by adding 0.45wt% graphene and 0.15wt% single wall carbon nanotubes (maintain the mass ratio 3:1). So if graphene and carbon nanotubes are added in proportion, thermal conductiv...

  12. Observing the subsurface thermal signature of the Black Sea cold intermediate layer with Argo profiling floats

    Science.gov (United States)

    Akpinar, Anil; Fach, Bettina A.; Oguz, Temel

    2017-06-01

    Cold intermediate layers (CILs) constitute a key indicator of the subsurface thermal signature in many marginal and subarctic seas. Towards better understanding the impacts of natural and anthropogenic climate variability in the Black Sea, the present study elucidates processes leading to the observed changes of CIL characteristics at mesoscale and monthly-to-interannual scales by analyzing weekly temperature-salinity profiles provided by Argo floats for 2002-2015. The continuous time series data allowed to elucidate different types of CIL formation episodes. For the first time, it was possible to trace their subsequent evolution depending on the number and intensity of successive, but often intermittent, autumn-winter cooling events in addition to the ambient flow and stratification characteristics within the cyclonic interior and anticyclonic coastal eddies/gyres. The spatial distribution of CIL formation in the cold years 2003, 2006 and 2012 covered much of the Black Sea, even coastal anticyclonic eddies as a new feature which has not been documented before. The data also recorded modification of CIL during the rest of the year in terms of its thickness, position, temperature and salinity ranges in response to advective transport by the circulation system, interior turbulent mixing, and quasi-lateral intrusions associated with mesoscale features.

  13. Steady heat conduction-based thermal conductivity measurement of single walled carbon nanotubes thin film using a micropipette thermal sensor.

    Science.gov (United States)

    Shrestha, R; Lee, K M; Chang, W S; Kim, D S; Rhee, G H; Choi, T Y

    2013-03-01

    In this paper, we describe the thermal conductivity measurement of single-walled carbon nanotubes thin film using a laser point source-based steady state heat conduction method. A high precision micropipette thermal sensor fabricated with a sensing tip size varying from 2 μm to 5 μm and capable of measuring thermal fluctuation with resolution of ±0.01 K was used to measure the temperature gradient across the suspended carbon nanotubes (CNT) film with a thickness of 100 nm. We used a steady heat conduction model to correlate the temperature gradient to the thermal conductivity of the film. We measured the average thermal conductivity of CNT film as 74.3 ± 7.9 W m(-1) K(-1) at room temperature.

  14. AdS charged black holes in Einstein-Yang-Mills gravity's rainbow: Thermal stability and P - V criticality

    Science.gov (United States)

    Hendi, Seyed Hossein; Momennia, Mehrab

    2018-02-01

    Motivated by the interesting non-abelian gauge field, in this paper, we look for the analytical solutions of Yang-Mills theory in the context of gravity's rainbow. Regarding the trace of quantum gravity in black hole thermodynamics, we examine the first law of thermodynamics and also thermal stability in the canonical ensemble. We show that although the rainbow functions and Yang-Mills charge modify the solutions, the first law of thermodynamics is still valid. Based on the phenomenological similarities between the adS black holes and van der Waals liquid/gas systems, we study the critical behavior of the Yang-Mills black holes in the extended phase space thermodynamics. We also investigate the effects of various parameters on thermal instability as well as critical properties by using appropriate figures.

  15. Brazing of Carbon Carbon Composites to Cu-clad Molybdenum for Thermal Management Applications

    Science.gov (United States)

    Singh, M.; Asthana, R.; Shpargel, T> P.

    2007-01-01

    Advanced carbon carbon composites were joined to copper-clad molybdenum (Cu/Mo) using four active metal brazes containing Ti (Cu ABA, Cusin-1 ABA, Ticuni, and Ticusil) for potential use in thermal management applications. The brazed joints were characterized using scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and Knoop microhardness measurements across the joint region. Metallurgically sound C-C/Cu/Mo joints, devoid of interfacial cracks formed in all cases. The joint interfaces were preferentially enriched in Ti, with Cu ABA joints exhibiting the largest interfacial Ti concentrations. The microhardness measurements revealed hardness gradients across the joint region, with a peak hardness of 300-350 KHN in Cusin-1 ABA and Ticusil joints and 200-250 KHN in Cu ABA and Ticuni joints, respectively.

  16. The monolithic carbon aerogels and aerogel composites for electronics and thermal protection applications

    Science.gov (United States)

    Lu, Sheng; Guo, Hui; Zhou, Yugui; Liu, Yuanyuan; Jin, Zhaoguo; Liu, Bin; Zhao, Yingmin

    2017-09-01

    Monolithic carbon aerogels have been prepared by condensation polymerization and high temperature pyrolysis. The morphology of carbon aerogels are characterized by SEM. The pore structure is characterized by N2 adsorption-desorption technique. Monolithic carbon aerogels are mesoporous nanomaterials. Carbon fiber reinforced carbon aerogel composites are prepared by in-situ sol-gel process. Fiber reinforced carbon aerogel composites are of high mechanical strength. The thermal response of the fiber reinforced aerogel composite samples are tested in an arc plasma wind tunnel. Carbon aerogel composites show good thermal insulation capability and high temperature resistance in inert atmosphere even at ultrahigh temperature up to 1800 °C. The results show that they are suitable for applications in electrodes for supercapacitors/ Lithium-ion batteries and aerospace thermal protection area.

  17. In Situ Thermal Decomposition of Exfoliated Two-Dimensional Black Phosphorus.

    Science.gov (United States)

    Liu, Xiaolong; Wood, Joshua D; Chen, Kan-Sheng; Cho, EunKyung; Hersam, Mark C

    2015-03-05

    With a semiconducting band gap and high charge carrier mobility, two-dimensional (2D) black phosphorus (BP)—often referred to as phosphorene—holds significant promise for next generation electronics and optoelectronics. However, as a 2D material, it possesses a higher surface area to volume ratio than bulk BP, suggesting that its chemical and thermal stability will be modified. Herein, an atomic-scale microscopic and spectroscopic study is performed to characterize the thermal degradation of mechanically exfoliated 2D BP. From in situ scanning/transmission electron microscopy, decomposition of 2D BP is observed to occur at ∼400 °C in vacuum, in contrast to the 550 °C bulk BP sublimation temperature. This decomposition initiates via eye-shaped cracks along the [001] direction and then continues until only a thin, amorphous red phosphorus like skeleton remains. In situ electron energy loss spectroscopy, energy-dispersive X-ray spectroscopy, and energy-loss near-edge structure changes provide quantitative insight into this chemical transformation process.

  18. Black titania: effect of hydrogenation on structural and thermal stability of nanotitania

    Science.gov (United States)

    Khanam, Rizwin; Taparia, Dolly; Mondal, Biplob; Mohanta, Dambarudhar

    2016-02-01

    We report on the effect of hydrogenation on sol-gel-derived, anatase-phase TiO2 nanoparticles. The structural analysis of white nanotitania (W-TiO2) and hydrogenated black titania (B-TiO2) has been carried out by X-ray diffraction (XRD) studies, which confirms anatase phase for both the cases, but with weak diffraction signals in the latter system. Upon hydrogenation, nanotitania system is believed to acquire a disordered phase in the form of a thin amorphous layer surrounding the nanoparticles, which can be realized through transmission electron microscopy analyses. As compared to W-TiO2 (~3.15 eV), the optical band gap of B-TiO2 is substantially reduced with respective band gap values of ~1.99 and 1.53 eV for 0.5 and 1 % H2 inclusion cases. Moreover, thermogravimetric analysis reveals high temperature thermal stability of B-TiO2 system, especially in the range of 350-600 °C. Exploiting thermal, optical and electronic properties of hydrogenated nanotitania could find scope in infrared optics, hydrogen storage and suitable photocatalytic applications.

  19. Some results from a study of carbon minerals by the thermal method

    Energy Technology Data Exchange (ETDEWEB)

    Otakuziyev, E.; Kasymov, A.K.; Miralimova, N.M.

    1979-01-01

    Using the optimum technique of thermal analysis in carbon-containing shales and hornfels of ancient deposits of the Kyzylkum and Zirabulak-Ziaetdinsk mountains, four groups are revealed of mineral form of carbon, corresponding to the kerite-oxykeriteanthraxolite-shungite-graphite series. Interpretation of the thermograms obtained shows the varying degree of metamorphism of the carbon-containing rock of the areas studied.

  20. Quantification of Black Carbon and Other Pollutant Emissions from a Traditional and an Improved Cookstove

    Energy Technology Data Exchange (ETDEWEB)

    Kirchstetter, Thomas [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Environmental Energy Technologies Division; Preble, Chelsea [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Environmental Energy Technologies Division; Hadley, Odelle [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Environmental Energy Technologies Division; Gadgil, Ashok [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Environmental Energy Technologies Division

    2010-11-05

    Traditional methods of cooking in developing regions of the world emit pollutants that endanger the lives of billions of people and contribute to climate change. This study quantifies the emission of pollutants from the Berkeley-Darfur Stove and the traditional three-stone fire at the Lawrence Berkeley National Laboratory cookstove testing facility. The Berkeley-Darfur Stove was designed as a fuel efficient alternative to the three-stone fire to aid refugees in Darfur, who walk long distances from their camps and risk bodily harm in search of wood for cooking. A potential co-benefit of the more fuel efficient stove may be reduced pollutant emissions. This study measured emissions of carbon dioxide, carbon monoxide, particulate matter, and sunlight-absorbing black carbon. It also measured climate-relevant optical properties of the emitted particulate matter. Pollutant monitors were calibrated specifically for measuring cookstove smoke.

  1. Source attribution of Arctic black carbon constrained by aircraft and surface measurements

    Science.gov (United States)

    Xu, Jun-Wei; Martin, Randall V.; Morrow, Andrew; Sharma, Sangeeta; Huang, Lin; Leaitch, W. Richard; Burkart, Julia; Schulz, Hannes; Zanatta, Marco; Willis, Megan D.; Henze, Daven K.; Lee, Colin J.; Herber, Andreas B.; Abbatt, Jonathan P. D.

    2017-10-01

    Black carbon (BC) contributes to Arctic warming, yet sources of Arctic BC and their geographic contributions remain uncertain. We interpret a series of recent airborne (NETCARE 2015; PAMARCMiP 2009 and 2011 campaigns) and ground-based measurements (at Alert, Barrow and Ny-Ålesund) from multiple methods (thermal, laser incandescence and light absorption) with the GEOS-Chem global chemical transport model and its adjoint to attribute the sources of Arctic BC. This is the first comparison with a chemical transport model of refractory BC (rBC) measurements at Alert. The springtime airborne measurements performed by the NETCARE campaign in 2015 and the PAMARCMiP campaigns in 2009 and 2011 offer BC vertical profiles extending to above 6 km across the Arctic and include profiles above Arctic ground monitoring stations. Our simulations with the addition of seasonally varying domestic heating and of gas flaring emissions are consistent with ground-based measurements of BC concentrations at Alert and Barrow in winter and spring (rRMSE effect on the Arctic BC column burden both in spring (56 %) and annually (37 %), with the largest contribution in the middle troposphere (400-700 hPa). Anthropogenic emissions from northern Asia contribute considerable BC (27 % in spring and 43 % annually) to the lower troposphere (below 900 hPa). Biomass burning contributes 20 % to the Arctic BC column annually.At the Arctic surface, anthropogenic emissions from northern Asia (40-45 %) and eastern and southern Asia (20-40 %) are the largest BC contributors in winter and spring, followed by Europe (16-36 %). Biomass burning from North America is the most important contributor to all stations in summer, especially at Barrow.Our adjoint simulations indicate pronounced spatial heterogeneity in the contribution of emissions to the Arctic BC column concentrations, with noteworthy contributions from emissions in eastern China (15 %) and western Siberia (6.5 %). Although uncertain, gas flaring

  2. Daily black carbon emissions from fires in northern Eurasia for 2002-2015

    Science.gov (United States)

    Hao, Wei Min; Petkov, Alexander; Nordgren, Bryce L.; Corley, Rachel E.; Silverstein, Robin P.; Urbanski, Shawn P.; Evangeliou, Nikolaos; Balkanski, Yves; Kinder, Bradley L.

    2016-12-01

    Black carbon (BC) emitted from fires in northern Eurasia is transported and deposited on ice and snow in the Arctic and can accelerate its melting during certain times of the year. Thus, we developed a high spatial resolution (500 m × 500 m) dataset to examine daily BC emissions from fires in this region for 2002-2015. Black carbon emissions were estimated based on MODIS (Moderate Resolution Imaging Spectroradiometer) land cover maps and detected burned areas, the Forest Inventory Survey of the Russian Federation, the International Panel on Climate Change (IPCC) Tier-1 Global Biomass Carbon Map for the year 2000, and vegetation specific BC emission factors. Annual BC emissions from northern Eurasian fires varied greatly, ranging from 0.39 Tg in 2010 to 1.82 Tg in 2015, with an average of 0.71 ± 0.37 Tg from 2002 to 2015. During the 14-year period, BC emissions from forest fires accounted for about two-thirds of the emissions, followed by grassland fires (18 %). Russia dominated the BC emissions from forest fires (92 %) and central and western Asia was the major region for BC emissions from grassland fires (54 %). Overall, Russia contributed 80 % of the total BC emissions from fires in northern Eurasia. Black carbon emissions were the highest in the years 2003, 2008, and 2012. Approximately 58 % of the BC emissions from fires occurred in spring, 31 % in summer, and 10 % in fall. The high emissions in spring also coincide with the most intense period of ice and snow melting in the Arctic.

  3. Soot on snow in Iceland: First results on black carbon and organic carbon in Iceland 2016 snow and ice samples, including the glacier Solheimajökull

    Science.gov (United States)

    Meinander, Outi; Dagsson-Waldhauserova, Pavla; Gritsevich, Maria; Aurela, Minna; Arnalds, Olafur; Dragosics, Monika; Virkkula, Aki; Svensson, Jonas; Peltoniemi, Jouni; Kontu, Anna; Kivekäs, Niku; Leppäranta, Matti; de Leeuw, Gerrit; Laaksonen, Ari; Lihavainen, Heikki; Arslan, Ali N.; Paatero, Jussi

    2017-04-01

    New results on black carbon (BC) and organic carbon (OC) on snow and ice in Iceland in 2016 will be presented in connection to our earlier results on BC and OC on Arctic seasonal snow surface, and in connection to our 2013 and 2016 experiments on effects of light absorbing impurities, including Icelandic dust, on snow albedo, melt and density. Our sampling included the glacier Solheimajökull in Iceland. The mass balance of this glacier is negative and it has been shrinking during the last 20 years by 900 meters from its southwestern corner. Icelandic snow and ice samples were not expected to contain high concentrations of BC, as power generation with domestic renewable water and geothermal power energy sources cover 80 % of the total energy consumption in Iceland. Our BC results on filters analyzed with a Thermal/Optical Carbon Aerosol Analyzer (OC/EC) confirm this assumption. Other potential soot sources in Iceland include agricultural burning, industry (aluminum and ferroalloy production and fishing industry), open burning, residential heating and transport (shipping, road traffic, aviation). On the contrary to low BC, we have found high concentrations of organic carbon in our Iceland 2016 samples. Some of the possible reasons for those will be discussed in this presentation. Earlier, we have measured and reported unexpectedly low snow albedo values of Arctic seasonally melting snow in Sodankylä, north of Arctic Circle. Our low albedo results of melting snow have been confirmed by three independent data sets. We have explained these low values to be due to: (i) large snow grain sizes up to 3 mm in diameter (seasonally melting snow); (ii) meltwater surrounding the grains and increasing the effective grain size; (iii) absorption caused by impurities in the snow, with concentration of elemental carbon (black carbon) in snow of 87 ppb, and organic carbon 2894 ppb. The high concentrations of carbon were due to air masses originating from the Kola Peninsula, Russia

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

    Science.gov (United States)

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

    2015-01-01

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

  5. Release of Black Carbon From Thawing Permafrost Estimated by Sequestration Fluxes in the East Siberian Arctic Shelf Recipient

    NARCIS (Netherlands)

    Salvadó, Joan A.; Bröder, Lisa; Andersson, August; Semiletov, Igor P.; Gustafsson, Örjan

    2017-01-01

    Black carbon (BC) plays an important role in carbon burial in marine sediments globally. Yet the sequestration of BC in the Arctic Ocean is poorly understood. Here we assess the concentrations, fluxes, and sources of soot BC (SBC)—the most refractory component of BC—in sediments from the East

  6. The relationship between carbon stable isotope ratios of hatchling down and egg yolk in Black-headed Gulls

    NARCIS (Netherlands)

    Klaassen, M.R.J.; Baarspul, T.; Dekkers, T.; Van Tienen, P.

    2004-01-01

    We reconstructed the nutrient source for egg synthesis by sampling Black-headed Gull (Larus ridibundus) eggs for yolk, analyzing their carbon stable isotope ratio, and comparing that to hatchling down. Most of the variation in carbon stable isotope ratio was explained by differences between nests,

  7. The effect of surfactant on stability and thermal conductivity of carbon nanotube based nanofluids

    Directory of Open Access Journals (Sweden)

    Leong Kin Yuen

    2016-01-01

    Full Text Available The addition of highly conductive substance such as carbon nanotubes into a traditional heat transfer fluid will enhance the fluids’ thermal conductivity. However, dispersion process of carbon nanotubes into base fluids is not an easy task due to hydrophobic characteristic of its surface. This study attempts to investigate the stability and thermal conductivity of carbon nanotube based ethylene glycol/water nanofluids with and without surfactants. Stability investigation was conducted through observation and zeta potential measurement methods. As for the thermal conductivity, the samples were measured based on transient line heat source. The results showed that 0.01 wt.% of carbon nanotube based nanofluid, containing 0.01wt.% hexadecyltrimethylammonium bromide possess highest zeta potential value compared to the other tested samples. 0.5 wt. % of carbon nanotube based nanofluids with gum arabic exhibit 25.7% thermal conductivity enhancement.

  8. In vitro toxicity of carbon nanotubes, nano-graphite and carbon black, similar impacts of acid functionalization.

    Science.gov (United States)

    Figarol, Agathe; Pourchez, Jérémie; Boudard, Delphine; Forest, Valérie; Akono, Céline; Tulliani, Jean-Marc; Lecompte, Jean-Pierre; Cottier, Michèle; Bernache-Assollant, Didier; Grosseau, Philippe

    2015-12-25

    Carbon nanotubes (CNT) and nano-graphite (NG) are graphene-based nanomaterials which share exceptional physicochemical properties, but whose health impacts are unfortunately still not well understood. On the other hand, carbon black (CB) is a conventional and widely studied material. The comparison of these three carbon-based nanomaterials is thus of great interest to improve our understanding of their toxicity. An acid functionalization was carried out on CNT, NG and CB so that, after a thorough characterization, their impacts on RAW 264.7 macrophages could be compared for a similar surface chemistry (15 to 120 μg·mL(-1) nanomaterials, 90-min to 24-h contact). Functionalized nanomaterials triggered a weak cytotoxicity similar to the pristine nanomaterials. Acid functionalization increased the pro-inflammatory response except for CB which did not trigger any TNF-α production before or after functionalization, and seemed to strongly decrease the oxidative stress. The toxicological impact of acid functionalization appeared thus to follow a similar trend whatever the carbon-based nanomaterial. At equivalent dose expressed in surface and equivalent surface chemistry, the toxicological responses from murine macrophages to NG were higher than for CNT and CB. It seemed to correspond to the hypothesis of a platelet and fiber paradigm. Copyright © 2015. Published by Elsevier Ltd.

  9. EFFECT OF HEAT TREATMENT ON THERMAL PROPERTIES OF PITCH-BASED AND PAN-BASED CARBON-CARBON COMPOSITES

    Energy Technology Data Exchange (ETDEWEB)

    Iqbal, Sardar S. [Southern Illinois University; Dinwiddie, Ralph Barton [ORNL; Porter, Wallace D [ORNL; Lance, Michael J [ORNL; Fillip, Peter [Southern Illinois University

    2011-01-01

    Thermal properties of two directional (2D) pitch-based carbon fiber with charred resin and three directional (3D) PAN-based carbon fiber with CVI carbon matrix C/C composite were investigated for non-heat treated (NHT) and heat treated (HT) materials through the thickness (z-direction). Heat treatment was performed at 1800, 2100 and 2400 oC for 1-hr in inert argon atmosphere. Thermal diffusivity, heat capacity and bulk density were measured to calculate thermal conductivity. Thermal diffusivity and conductivity was the highest for 3D C/C heat treated at maximum temperature with non-heat treated one exhibiting the lowest one. Similarly, 2D C/C heat treated at maximum temperature exhibited the highest thermal diffusivity and thermal conductivity. Polarized light microscopy (PLM) images of HTT C/C show a progressive improvement in microstructure when compared to NHT C/C. However, HTT 2D and 3D C/C composites exhibited extensive shrinkage of charred resin and CVI carbon matrix, respectively, from fibers resulting in intra and inter-bundles cracking when compared to NHT one. Raman spectroscopy and XRD results of NHT and HTT C/C indicated increased ordering of structure. A progressive improvement in thermal properties was observed with increased heat treatment temperatures.

  10. The electrical properties of epoxy resin composites filled with Cnts and carbon black.

    Science.gov (United States)

    Bellucci, S; Coderoni, L; Micciulla, F; Rinaldi, G; Sacco, I

    2011-10-01

    This work introduces an experimental activity related to the realization of an epossidic nanostructured material that develops the function of covering for electronic circuits in aeronautical field. This covering meets the demand of protection of these circuits from possible troubles of electromagnetic nature. In order to realize this covering we used an epoxy resin as matrix (Epon 828) loaded with conductive nanofillers or carbon nanotubes (Cnts). To check the efficiency of the coating we have considered the carbon black, filler widely used as a conductive covering for screenings. We have considered different percentages of the different fillers, precisely 0.1%, 0.25% and 0.5% wt (% valued in comparison to the weight of the resin). From every mixture 12 samples have been obtained (the size of every sample is 10 mm x 10 mm x 10 mm). Every sample has been subjected to electrical measurements, that have concerned the measurement of current intensity and resistance (so as to allow the evaluation of the enhancement of the conductivity), through the application of different values of voltage. The results have demonstrated that the epoxy matrix loaded with Cnts yields higher values of electrical conductivity than the same matrix loaded with carbon black.

  11. 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.

  12. Preparation, characterization and evaluation of electrocatalysts supported on functionalized carbon black for polymer exchange membrane fuel cell applications; Preparacao, caracterizacao e avaliacao de eletrocatalisadores suportados em carbono funcionalizado para aplicacao em celulas a combustivel tipo PEM

    Energy Technology Data Exchange (ETDEWEB)

    Carmo, Marcelo do

    2008-12-18

    The fuel cell technology associated with the growing exigency of low environmental impact energy became prosperous in the world energy scenery. The fuel cell is basically a device that converts directly the chemical energy of a fuel into electrical and thermal energy with a continuous operation by the constant feed of a fuel. Especially, the carbon black Vulcan XC72 is usually employed as an electro catalyst support, and some factors as an accessible and high surface area in order to get maximum particles dispersion, pore size, adequate pore distribution and the presence of functional groups in the carbon black surface are considered fundamental characteristics for an innovative materials development. However, the Vulcan XC72 still reveals insufficient conditions for these purposes. This study consists in the preparation and in the physical chemical characterization of functionalized carbon black by hydrogen peroxide and by polymeric chains with proton conduction properties, and its posterior utilization as electro catalyst support for PEMFC and DMFC application. After the carbon functionalization, an improvement in the carbon black dispersion in water media was observed, a beneficial effect for electro catalyst preparation. It was also observed, that the functional groups and the polymeric chains worked as stabilizers in the particle growing, producing much more homogeneous electrocatalysts, exhibiting smaller average particle size. Especially, in the case of polymeric chains functionalization, a decrease in the ohmic drop was observed for this system, attributed to an improvement in the proton transference. (author)

  13. 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.

  14. 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.

  15. 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

  16. Ni-P alloy-carbon black composite films fabricated by electrodeposition

    OpenAIRE

    Suzuki, Yosuke; Arai, Susumu; Endo, Morinobu

    2010-01-01

    Ni-P alloy-carbon black (CB) composite films were fabricated by electroplating and their microstructures and properties were examined. The CB and phosphorus contents of the composite films were also investigated. The CB particles were found to be embedded in the Ni-P alloy matrix. The CB content in the deposits increased, reached a maximum value of 0.77 mass% with increasing CB concentration in the bath up to 10 g dm(-3), and then decreased with a further increase in the CB concentration in t...

  17. 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

  18. 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

    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...

  19. PM2.5 and aerosol black carbon in Suva, Fiji

    Science.gov (United States)

    Isley, C. F.; Nelson, P. F.; Taylor, M. P.; Mani, F. S.; Maata, M.; Atanacio, A.; Stelcer, E.; Cohen, D. D.

    2017-02-01

    Concentrations of particulate air pollution in Suva, Fiji, have been largely unknown and consequently, current strategies to reduce health risk from air pollution in Suva are not targeted effectively. This lack of air quality data is common across the Pacific Island Countries. A monitoring study, during 2014 and 2015, has characterised the fine particulate air quality in Suva, representing the most detailed study to date of fine aerosol air pollutants for the Pacific Islands; with sampling at City, Residential (Kinoya) and Background (Suva Point) sites. Meteorology for Suva, as it relates to pollutant dispersion for this period of time, has also been analysed. The study design enables the contribution of maritime air and the anthropogenic emissions to be carefully distinguished from each other and separately characterised. Back trajectory calculations show that a packet of air sampled at the Suva City site has typically travelled 724 km in the 24-h prior to sampling, mainly over open ocean waters; inferring that pollutants would also be rapidly transported away from Suva. For fine particulates, Suva City reported a mid-week PM2.5 of 8.6 ± 0.4 μg/m3, averaged over 13-months of gravimetric sampling. Continuous monitoring (Osiris laser photometer) suggests that some areas of Suva may experience levels exceeding the WHO PM2.5 guideline of 10 μg/m3, however, compared to other countries, Fiji's PM2.5 is low. Peak aerosol particulate levels, at all sites, were experienced at night-time, when atmospheric conditions were least favourable to dispersion of air pollutants. Suva's average ambient concentrations of black carbon in PM2.5, 2.2 ± 0.1 μg/m3, are, however, similar to those measured in much larger cities. With any given parcel of air spending only seven minutes, on average, over the land area of Suva Peninsula, these black carbon concentrations are indicative that significant combustion emissions occur within Suva. Many other communities in the Pacific Islands

  20. Thermally Conductive Tape Based on Carbon Nanotube Array Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Future NASA missions require thermal control systems that can accommodate large changes in ambient temperature. The two essential aspects of an effective thermal...

  1. 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.

  2. Microwave Absorption Properties of Double-Layer RADAR Absorbing Materials Based on Doped Barium Hexaferrite/TiO2/Conducting Carbon Black

    National Research Council Canada - National Science Library

    Sukanta Das; G. C. Nayak; S. K. Sahu; P. C. Routray; A. K. Roy; H. Baskey

    2014-01-01

      In this report, we demonstrate microwave absorption properties of barium hexaferrite, doped barium hexaferrite, titanium dioxide and conducting carbon black based RADAR absorbing material for stealth application...

  3. Elastomeric thermal interface materials with high through-plane thermal conductivity from carbon fiber fillers vertically aligned by electrostatic flocking.

    Science.gov (United States)

    Uetani, Kojiro; Ata, Seisuke; Tomonoh, Shigeki; Yamada, Takeo; Yumura, Motoo; Hata, Kenji

    2014-09-03

    Electrostatic flocking is applied to create an array of aligned carbon fibers from which an elastomeric thermal interface material (TIM) can be fabricated with a high through-plane thermal conductivity of 23.3 W/mK. A high thermal conductivity can be achieved with a significantly low filler level (13.2 wt%). As a result, this material retains the intrinsic properties of the matrix, i.e., elastomeric behavior. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Low percolation threshold carbon-black/ nitrile-butadiene-rubber composites and their electromagnetic shielding effects.

    Science.gov (United States)

    Zeng, Min; Zhao, Dongliang; Yu, Ronghai; Feng, Meng; Yang, Bai; Liu, Xiaofang; Zhang, Yanghuan; Wang, Xinlin

    2013-02-01

    Nitrile-butadiene-rubber composites, filled with super conducting carbon black, are successfully prepared with low percolation threshold, high conductivity and electromagnetic shielding effectiveness. Percolation theory is used to represent the system's conductivity, and the corresponding result is close to the experimental value. The fitting curve also gives the weight fraction threshold and conductivity exponent of the conducting polymer. The percolation threshold of the composite is 9.2 phr, which is much smaller than previous homologous findings and lower than the value of short carbon fiber counterparts reported. The volume resistivity becomes 3.17 omega x cm for the 20 phr sample and decreases to 0.66 omega x cm for the 40 phr sample. At 1.8 GHz for 40 phr sample, the shielding effectiveness is -43 dB.

  5. Production of thermally conductive carbon foams and their application in automobile transport

    Science.gov (United States)

    Samoylov, V. M.; Danilov, E. A.; Galimov, E. R.; Fedyaev, V. L.; Galimova, N. Ya; Orlov, M. A.

    2017-09-01

    The report examines the possible methods of synthesis and properties of a new class of carbon materials - thermally conductive foams based on mesophase pitches and their application in automobiles to control the heat flow.

  6. Evaluation of bioactive compounds of black mulberry juice after thermal, microwave, ultrasonic processing, and storage at different temperatures.

    Science.gov (United States)

    Jiang, Bo; Mantri, Nitin; Hu, Ya; Lu, Jiayin; Jiang, Wu; Lu, Hongfei

    2015-07-01

    The effect of different sterilization methods (thermal, microwave, and ultrasonic processing) on the main bioactive compounds and antioxidant activity of black mulberry juice during selected storage time (8 days) and temperatures (5, 15, and 25 ℃) was investigated. The antioxidant activity of thermal-treated juice depleted with storage time, whilst both ultrasound- and microwave-treated juices showed transient increase in antioxidant activity during the first 2 days that later decreased with storage time. Lower temperature storage preserved more bioactive compounds and antioxidant activity, especially in ultrasound sterilized samples. The activation energy values were 15.99, 13.07, and 12.81 kJ/mol for ultrasonic, microwave, and thermal pasteurization processes, respectively. In general, ultrasound-sterilized samples showed higher total phenolics, anthocyanin, and antioxidant activity compared to the microwave- and thermal-processed juice during the storage time especially at lower temperatures. © The Author(s) 2014.

  7. Modeling the Role of Bulk and Surface Characteristics of Carbon Fiber on Thermal Conductance across the Carbon Fiber/Matrix Interface (Postprint)

    Science.gov (United States)

    2015-11-09

    dependent on the thermal transport between the fiber and resin interfaces. Using atomistic molecular dynamics simulations, the thermal conductance across...features of the carbon fiber. The surface of the carbon fiber is modeled as sheets of graphitic carbon with (a) varying degrees of surface functionality, (b...varying defect concentrations in the surface-carbon model (pure graphitic vs partially graphitic ), (c) varying orientation of graphitic carbon at the

  8. Magnetic field induced tunability on the thermal conductivity of ferrofluids loaded with carbon nanofibers

    Science.gov (United States)

    Ortiz-Salazar, M.; Pech-May, N. W.; Vales-Pinzon, C.; Medina-Esquivel, R.; Alvarado-Gil, J. J.

    2018-02-01

    In this paper, it is shown that the thermal conductivity of magnetic fluids, formed by a ferrofluid loaded with carbon nanofibers, can be tuned by applying a moderate intensity magnetic field. The tuning is generated by orienting the nanoparticles in the ferrofluid, which in turn partially align the carbon nanofibers, favoring or hindering heat flow along a given direction. Thermal diffusivity at several volume concentrations of nanofibers (0, 0.25, 0.50, 1, 2 and 5%) was measured using the thermal wave resonant cavity technique, located inside a uniform moderate intensity magnetic field. Measurements were performed for random and aligned carbon nanofibers, oriented in the parallel and perpendicular directions with respect to the heat flux. The experimental results show that for 5% volume concentration of carbon nanofibers in the ferrofluid, in random configuration, i.e. without external magnetic field applied, the effective thermal conductivity increased 3 times compared to that of the ferrofluid matrix. Moreover, for parallel alignment of the carbon nanofibers with respect to the heat flux direction, the effective thermal conductivity increased 5 times. However, for perpendicular alignment of the carbon nanofibers with respect to the heat flux direction only a 2 times increment in the effective thermal conductivity is obtained. A 750 G intensity magnetic field is used for both alignment configurations. Additionally, the effect of the concentration of carbon nanofibers on the thermal time-response of the magnetic fluids was studied by switching on/off the magnetic field. The Lewis–Nielsen model was used to interpret the dependence of the thermal conductivity results as a function the concentration and orientation of the carbon nanofibers.

  9. Thermal Expansion and Diffusion Coefficients of Carbon Nanotube-Polymer Composites

    OpenAIRE

    Wei, Chenyu; Srivastava, Deepak; Cho, Kyeongjae

    2002-01-01

    Classical molecular dynamics (MD) simulations employing Brenner potential for intra-nanotube interactions and Van der Waals forces for polymer-nanotube interfaces are used to invetigate the thermal expansion and diffusion characteristics of carbon nanotube-polyethylene composites. Additions of carbon nanotubes to polymer matrix are found to increase the glass transition temperature Tg, and thermal expansion and diffusion coefficients in the composite above Tg. These findings could have implic...

  10. Azobenzene-functionalized carbon nanotubes as high-energy density solar thermal fuels.

    Science.gov (United States)

    Kolpak, Alexie M; Grossman, Jeffrey C

    2011-08-10

    Solar thermal fuels, which reversibly store solar energy in molecular bonds, are a tantalizing prospect for clean, renewable, and transportable energy conversion/storage. However, large-scale adoption requires enhanced energy storage capacity and thermal stability. Here we present a novel solar thermal fuel, composed of azobenzene-functionalized carbon nanotubes, with the volumetric energy density of Li-ion batteries. Our work also demonstrates that the inclusion of nanoscale templates is an effective strategy for design of highly cyclable, thermally stable, and energy-dense solar thermal fuels.

  11. Dielectric and Microwave Properties of Siloxane Rubber/Carbon Black Nanocomposites and Their Correlation

    Directory of Open Access Journals (Sweden)

    Omar A. Al-Hartomy

    2011-01-01

    Full Text Available In this paper, the dielectric and microwave properties of carbon black/siloxane rubber-based nanocomposites have been investigated in the frequency range from 1 GHz till 12 GHz according to the content of carbon black and the frequency. It has been established that the increasing frequency and filler content lead to an increase in the relative permittivity and tangent of dielectric loss angle. At higher filler content, the effects become more pronounced, especially those upon dielectric loss. It has been also established that there are two well-distinguished areas in all dependences of microwave properties on frequency and filler content increasing. The first is between 1 and 8 GHz wherein the reflection and attenuation of microwaves do not change considerably with frequency and filler content alternation while shielding effectiveness worsens. The second area is between 8 and 12 GHz wherein the reflection and attenuation of microwaves increase drastically with the increasing frequency and filler content. Shielding effectiveness improves, too. It has been established that in all cases the degree of correlation between dielectric and microwave properties evaluated on the basis of the coefficients of correlation calculation is perfect.

  12. BLACK Carbon Emissions from Diesel Sources in the Largest Arctic City: Case Study of Murmansk

    Science.gov (United States)

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

    2014-12-01

    Russia has very little data on its black carbon (BC) emissions. Because Russia makes up such a large share of the Arctic, understanding Russian emissions will improve our understanding of overall BC levels, BC in the Arctic and the link between BC and climate change. This paper provides a detailed, bottom-up inventory of BC emissions from diesel sources in Murmansk, Russia, along with uncertainty estimates associated with these emissions. The research team developed a detailed data collection methodology. The methodology involves assessing the vehicle fleet and activity in Murmansk using traffic, parking lot and driver surveys combined with an existing database from a vehicle inspection station and statistical data. The team also assessed the most appropriate emission factors, drawing from both Russian and international inventory methodologies. The researchers also compared fuel consumption using statistical data and bottom-up fuel calculations. They then calculated emissions for on-road transportation, off-road transportation (including mines), diesel generators, fishing and other sources. The article also provides a preliminary assessment of Russia-wide emissions of black carbon from diesel sources.

  13. Nanoparticulate carbon black in cigarette smoke induces DNA cleavage and Th17-mediated emphysema.

    Science.gov (United States)

    You, Ran; Lu, Wen; Shan, Ming; Berlin, Jacob M; Samuel, Errol Lg; Marcano, Daniela C; Sun, Zhengzong; Sikkema, William Ka; Yuan, Xiaoyi; Song, Lizhen; Hendrix, Amanda Y; Tour, James M; Corry, David B; Kheradmand, Farrah

    2015-10-05

    Chronic inhalation of cigarette smoke is the major cause of sterile inflammation and pulmonary emphysema. The effect of carbon black (CB), a universal constituent of smoke derived from the incomplete combustion of organic material, in smokers and non-smokers is less known. In this study, we show that insoluble nanoparticulate carbon black (nCB) accumulates in human myeloid dendritic cells (mDCs) from emphysematous lung and in CD11c(+) lung antigen presenting cells (APC) of mice exposed to smoke. Likewise, nCB intranasal administration induced emphysema in mouse lungs. Delivered by smoking or intranasally, nCB persisted indefinitely in mouse lung, activated lung APCs, and promoted T helper 17 cell differentiation through double-stranded DNA break (DSB) and ASC-mediated inflammasome assembly in phagocytes. Increasing the polarity or size of CB mitigated many adverse effects. Thus, nCB causes sterile inflammation, DSB, and emphysema and explains adverse health outcomes seen in smokers while implicating the dangers of nCB exposure in non-smokers.

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

    Directory of Open Access Journals (Sweden)

    M. D. Willis

    2016-04-01

    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 (HOA in two distinct particle types: HOA-rich and BC-rich particles. The average mass fraction of black carbon in HOA-rich and BC-rich particle classes was  < 0.1 and 0.8, respectively. Notably, approximately 90 % of BC mass resides in BC-rich particles. This new measurement capability provides quantitative insight into the physical and chemical nature of BC-containing particles and is used to drive a particle-resolved aerosol box model. Significant differences in calculated single scattering albedo (an increase of 0.1 arise from accurate treatment of initial particle mixing state as compared to the assumption of uniform aerosol composition at the point of BC injection into the atmosphere.

  15. 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.

  16. Black Carbon Aerosols in the Marine Boundary Layer on the West Coast of Southern Africa

    Science.gov (United States)

    Piketh, S.; Formenti, P.; Namwoonde, A.; Feron, A.; Gaimoz, C.; Cazaunau, M.; Hanghome, M.; Broccardo, S. P.; Walton, N.; Klopper, D.; Burger, R.; Desboeufs, K. V.; Siour, G.; Junkermann, W.; Maenhaut, W.

    2016-12-01

    Continuous measurements, since 2012, at the Henties Bay Aerosol Observatory (HBAO; 22°S, 14°05'E), Namibia, show that, during the austral wintertime, transport of black carbon aerosols occurs at low-level into the marine boundary layer towards the South East Atlantic coast. This is ahead of the dry season peak for southern Africa (August to October), when biomass burning aerosols outflow into the free troposphere above the stratocumulus clouds. The concentration of black carbon equivalent associated with this low-level transport is of the order of 100-150 ng m-3. Assuming that they are related to biomass burning, a particle mass concentration of 5-7 µg m-3 and to a number concentration of 300-400 cm-3 is estimated. These values are sufficiently high to enable them, by entrainment, to cause an almost doubling of the cloud optical depth as well as an increase of approximately 40% in cloud reflectivity with respect to pristine conditions. Their direct radiative effect is negligible.

  17. 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.

  18. 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.

  19. 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..

  20. Measured black carbon deposition on the Sierra Nevada snow pack and implication for snow pack retreat

    Directory of Open Access Journals (Sweden)

    O. L. Hadley

    2010-08-01

    Full Text Available 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.

  1. Modeling the Role of Bulk and Surface Characteristics of Carbon Fiber on Thermal Conductance across the Carbon-Fiber/Matrix Interface.

    Science.gov (United States)

    Varshney, Vikas; Roy, Ajit K; Baur, Jeffery W

    2015-12-09

    The rapid heating of carbon-fiber-reinforced polymer matrix composites leads to complex thermophysical interactions which not only are dependent on the thermal properties of the constituents and microstructure but are also dependent on the thermal transport between the fiber and resin interfaces. Using atomistic molecular dynamics simulations, the thermal conductance across the interface between a carbon-fiber near-surface region and bismaleimide monomer matrix is calculated as a function of the interface and bulk features of the carbon fiber. The surface of the carbon fiber is modeled as sheets of graphitic carbon with (a) varying degrees of surface functionality, (b) varying defect concentrations in the surface-carbon model (pure graphitic vs partially graphitic), (c) varying orientation of graphitic carbon at the interface, (d) varying interface saturation (dangling vs saturated bonds), (e) varying degrees of surface roughness, and (f) incorporating high conductive fillers (carbon nanotubes) at the interface. After combining separately equilibrated matrix system and different surface-carbon models, thermal energy exchange is investigated in terms of interface thermal conductance across the carbon fiber and the matrix. It is observed that modifications in the studied parameters (a-f) often lead to significant modulation of thermal conductance across the interface and, thus, showcases the role of interface tailoring and surface-carbon morphology toward thermal energy exchange. More importantly, the results provide key bounds and a realistic degree of variation to the interface thermal conductance values at fiber/matrix interfaces as a function of different surface-carbon features.

  2. Assessment of chars from black coal carbonization for adsorption treatment of waste water from coking plants

    Energy Technology Data Exchange (ETDEWEB)

    Wolany, B.; Szkuta-Pochopien, T.; Malczyk, R.; Sekula, M.

    1985-06-01

    The Institute for Chemical Coal Processing investigated efficiency of carbon adsorption in treatment of waste water from a coking plant in Poland. Four types of adsorption media were used: a coarse-grained non-activated char, a fine-grained non-activated char, a coarse-grained activated char and Carbopol Z-4 activated carbon produced on a commercial scale. The chars were produced by carbonization of black coal from Poland in a rotary chamber using semicoke as heat carrier. Sorptive properties of 4 types of chars were compared. All the tested chars were characterized by sorptive properties in relation to chemical compounds from waste water. The coarse-grained activated char was superior to other chars. The working sorptive capacity of the coarse-grained activated char amounted to 86% of the capacity of Carbopol Z-4 activated carbon (when 2 chars were used for reducing chemical oxygen demand of waste water to about 35% of the initial level, treatment efficiency amounted to 65%). Use of the coarse-grained activated char for waste water treatment in coking plants on a commercial scale is recommended. 13 references.

  3. Molecular Dynamics Simulations of the Thermal Conductivity of Single-Wall Carbon Nanotubes

    Science.gov (United States)

    Osman, M.; Srivastava, Deepak; Govindan,T. R. (Technical Monitor)

    2000-01-01

    Carbon nanotubes (CNT) have very attractive electronic, mechanical. and thermal properties. Recently, measurements of thermal conductivity in single wall CNT mats showed estimated thermal conductivity magnitudes ranging from 17.5 to 58 W/cm-K at room temperature. which are better than bulk graphite. The cylinderical symmetry of CNT leads to large thermal conductivity along the tube axis, additionally, unlike graphite. CNTs can be made into ropes that can be used as heat conducting pipes for nanoscale applications. The thermal conductivity of several single wall carbon nanotubes has been calculated over temperature range from l00 K to 600 K using non-equilibrium molecular dynamics using Tersoff-Brenner potential for C-C interactions. Thermal conductivity of single wall CNTs shows a peaking behavior as a function of temperature. Dependence of the peak position on the chirality and radius of the tube will be discussed and explained in this presentation.

  4. Thermal characterization of carbon nanotube foam using MEMS microhotplates and thermographic analysis

    NARCIS (Netherlands)

    Silvestri, C.; Riccio, M.; Poelma, R.H.; Morana, B.; Vollebregt, S.; Santagata, F.; Irace, A.; Zhang, G.Q.; Sarro, P.M.

    2016-01-01

    Thermal material properties play a fundamental role in the thermal management of microelectronic systems. The porous nature of carbon nanotube (CNT) arrays results in a very high surface area to volume ratio, which makes the material attractive for surface driven heat transfer mechanisms. Here, we

  5. Black carbon and other refractory forms in recent sediments from the Gulf of Cadiz, Spain

    Science.gov (United States)

    González-Vila, F. J.; de la Rosa, J. M.; González-Pérez, J. A.

    2009-01-01

    Black carbon (BC) produced by incomplete combustion of fossil fuels and vegetation is a ubiquitous form of refractory organic matter (ROM) widely distributed in the environment. The stable non-reactive, mainly aromatic, BC has received special interest in recent years as a possible carbon sink in soils and sediments. At present, several methods have been used, with applications for soil and sediments, although no single method has been accepted to detect BC forms, and therefore providing the analytical data required to estimate BC contribution to terrestrial and sedimentary carbon fluxes and the global carbon cycle. This study considers the potential of the combined use of analytical pyrolysis (Py-GC/MS) and solid state 13C NMR to determine the presence of BC and to characterize the refractory organic matter in a set of recent marine sediments from the Southwest Atlantic coast of Spain (Gulf of Cadiz). The content of BC-like material found in sediments (3.0 - 16.5 % of total organic carbon) was in the range previously reported for this kind of samples and decreases from coast to offshore. Solid state CP-MAS 13C NMR and Py-GC/MS analysis of the isolated ROM revealed a conspicuous aliphatic domain remained in the samples after chlorite oxidation. Our results suggests that, in recent sediments from fluvial and marine environments, not only BC and refractory carbon forms with aromatic nature may be sequestered in a stable form; it also seems probable that the ROM pool contains a significant amount of C immobilized in the form of alkylic compounds.

  6. 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.)

  7. 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

  8. Thermal cooking changes the profile of phenolic compounds, but does not attenuate the anti-inflammatory activities of black rice

    Directory of Open Access Journals (Sweden)

    Sassy Bhawamai

    2016-09-01

    Full Text Available Background: Evidence on biological activities of cooked black rice is limited. This study examined the effects of washing and cooking on the bioactive ingredients and biological activities of black rice. Methods: Cooked rice was prepared by washing 0–3 times followed by cooking in a rice cooker. The acidic methanol extracts of raw and cooked rice were used for the analyses. Results: Raw black rice, both washed and unwashed, had higher contents of polyphenols, anthocyanins, and cyanidin-3-glucoside (C3G, but lower protocatechuic acid (PA, than did cooked samples. Similarly, raw rice extracts were higher in ferric-reducing antioxidant power (FRAP activities than extracts of cooked samples. Nonetheless, extracts of raw and cooked rice showed similar inhibitory potencies on nitric oxide, tumor necrosis factor-α, and interleukin-6 productions in lipopolysaccharide-activated macrophages, whereas equivalent amounts of C3G and PA did not possess such inhibitory effects. Conclusions: Thermal cooking decreased total anthocyanin and C3G contents and the FRAP antioxidative capacity, but did not affect anti-inflammatory activities of black rice. Neither C3G nor PA contributed to the anti-inflammatory activity of black rice.

  9. The effects of permafrost thaw on soil hydrologic, thermal, and carbon dynamics in an Alaskan peatland

    Science.gov (United States)

    Jonathan A. O' Donnell; M.Torre Jorgenson; Jennifer W. Harden; A.David McGuire; Mikhail Z. Kanevskiy; Kimberly P. Wickland

    2012-01-01

    Recent warming at high-latitudes has accelerated permafrost thaw in northern peatlands, and thaw can have profound effects on local hydrology and ecosystem carbon balance. To assess the impact of permafrost thaw on soil organic carbon (OC) dynamics, we measured soil hydrologic and thermal dynamics and soil OC stocks across a collapse-scar bog chronosequence in interior...

  10. Evaluation of a 2-step thermal method for separating organic and elemental carbon for radiocarbon analysis

    NARCIS (Netherlands)

    Dusek, U.; Monaco, M.; Prokopiou, M.; Gongriep, F.; Hitzenberger, R.; Meijer, H. A. J.; Röckmann, T.

    2014-01-01

    We thoroughly characterized a system for thermal separation of organic carbon (OC) and elemental carbon (EC) for subsequent radiocarbon analysis. Different organic compounds as well as ambient aerosol filter samples were introduced into an oven system and combusted to CO2 in pure O2. The main

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

    Directory of Open Access Journals (Sweden)

    Ramin Zafarmehrabian

    2012-01-01

    Full Text Available 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 resistance, rolling resistance and heat buildup of the tire. Tensile strength and modulus and wet grip of tire tread decrease with increasing of silica in rubber compound formulation.

  12. 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

    2015-03-03

    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

  13. 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.

  14. Carbon hybrid fillers composed of carbon nanotubes directly grown on graphene nanoplatelets for effective thermal conductivity in epoxy composites.

    Science.gov (United States)

    Yu, Lan; Park, Ji Sun; Lim, Yun-Soo; Lee, Churl Seung; Shin, Kwonwoo; Moon, Ho Jun; Yang, Cheol-Min; Lee, Young Sil; Han, Jong Hun

    2013-03-26

    Carbon nanomaterials are generally used to promote the thermal conductivity of polymer composites. However, individual graphene nanoplatelets (GNPs) or carbon nanotubes (CNTs) limit the realization of the desirable thermal conductivity of the composite in both through- and in-plane directions. In this work, we present the thermal conductivity enhancement of the epoxy composite with carbon hybrid fillers composed of CNTs directly grown on the GNP support. The composite with 20 wt% hybrid filler loading showed 300% and 50% through-plane thermal conductivity improvements in comparison with the individual CNTs and GNPs, respectively. Moreover, it showed an enhanced thermal conductivity of up to 12% higher than that of the simply mixed GNP and CNT fillers. In more detail, hybrid fillers, whose CNTs were synthesized on the GNP support (Support C, Fe/Mo-MgO:GNP=1:0.456) for 60 min via chemical vapor deposition process, presented the highest through-plane thermal conductivity of 2.41 W m(-1) K(-1) in an epoxy composite.

  15. Measurements and Analysis of Black Carbon Aerosols in the Eastern Mediterranean Megacity

    Science.gov (United States)

    Unal, A.; Ozdemir, H.; Kindap, T.; Demir, G.; Karaca, M.; Khan, M. N.

    2010-12-01

    In a world where at least 50 percent of the population is living in urban environments, air pollution and specifically particulate matter became one of the most critical issues. There have been many studies that focused on mass concentration measurements of PM10 and PM2.5. Recent studies suggest that chemical composition is critical in understanding the effects of PM on health as well as climate. For example, public health studies reveal that, components of the atmospheric aerosols have different impacts on human health. Smith et al. (2009) stated that; on the basis of the 1μg/m3 contrast, the percentage increase in all-cause mortality for PM2.5 was 0.58; sulfate effects were about twice those of PM2.5, and effects of elemental carbon (an indicator of black carbon mass) about ten times greater. To date, many studies and national inventories have been based on particulate matter (PM10 and PM2.5), and the major greenhouse pollutants, but not speciated emissions, especially in the developing world (Smith et al., 2009; Chow et al., 2010). But air quality standards will soon need to include particulate black carbon (BC), as it directly afffects climate, visibility, and human health. Anthropogenic emissions are increasing dramatically worldwide and recent estimates of global BC emissions range from 8 to 24 Tg (1012 g) per year. In this study, we investigated BC pollution for the first time in Istanbul, Turkey. Istanbul is a megacity of over 15 million inhabitants (OECD, 2008). On-road traffic is also increasing rapidly in the city (over 3 million vehicles on the road). Hence, the city has a potential to be an important source for both local and regional pollution in the Eastern Mediterranean. In our study, an Aethalometer (health risks associated with it.

  16. Two black carbon pools transported by the Changjiang and Huanghe Rivers in China

    Science.gov (United States)

    Wang, Xuchen; Xu, Caili; Druffel, Ellen M.; Xue, Yuejun; Qi, Yuanzhi

    2016-12-01

    Major rivers play important roles in transporting large amounts of terrestrial organic matter from land to the ocean each year, and the organic matter carried by rivers contains a significant fraction of black carbon (BC). A recent study estimated that 0.027 Gt of BC is transported in the dissolved phase by rivers each year, which accounts for 10% of the global flux of dissolved organic carbon. The relative sources of this large amount of riverine dissolved black carbon (DBC) from biomass burning (young, modern 14C) and fossil fuel (old, 14C free) combustion are not known. We present radiocarbon measurements of BC in both dissolved and particulate phases transported by the Changjiang and Huanghe Rivers, the two largest rivers in China, during 2015. We show that two, distinct BC pools (young and old) were carried by the rivers. The DBC pool was much younger than the particulate BC (PBC) pool. Mass balance calculations indicate that most (78-85%) of the DBC in the Changjiang and Huanghe Rivers was derived from biomass burning, and only 15-22% was from fossil fuel combustion. In contrast, PBC from biomass burning and fossil fuel combustion were approximately equal in these two rivers. Export of PBC and DBC by the rivers are decoupled, and fluxes of PBC were 4.1 and 6.7 times higher than DBC in the Changjiang and Huanghe Rivers, respectively. The 14C age differences of the two BC pools suggest that BC derived from biomass burning and fossil fuel combustion are mobilized in different phases and on different time scales in these rivers.

  17. Black carbon contributes to organic matter in young soils in the Morteratsch proglacial area (Switzerland

    Directory of Open Access Journals (Sweden)

    E. Eckmeier

    2013-03-01

    Full Text Available Most glacier forefields of the European Alps are being progressively exposed since the glaciers reached their maximum expansion in the 1850s. Global warming and climate changes additionally promote the exposure of sediments in previously glaciated areas. In these proglacial areas, initial soils have started to develop so that they may offer a continuous chronosequence from 0 to 150-yr-old soils. The build-up of organic matter is an important factor of soil formation, and not only autochthonous but also distant sources might contribute to its accumulation in young soils and surfaces of glacier forefields. Only little is known about black carbon in soils that develop in glacier forefields, although charred organic matter could be an important component of organic carbon in Alpine soils. The aim of our study was to examine whether black carbon (BC is present in the initial soils of a proglacial area, and to estimate its relative contribution to soil organic matter. We investigated soil samples from 35 sites distributed over the whole proglacial area of Morteratsch (Upper Engadine, Switzerland, covering a chronosequence from 0 to 150 yr. BC concentrations were determined in fine earth using the benzene polycarboxylic acid (BPCA marker method. We found that charred organic matter occurred in the whole area, and that it was a main compound of soil organic matter in the youngest soils, where total Corg concentrations were very low. The absolute concentrations of BC in fine earth were generally low but increased in soils that had been exposed for more than 40 yr. Specific initial microbial communities may profit from this additional C source during the first years of soil evolution and potentially promote soil development in its early stage.

  18. 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.

  19. A High Temperature Kinetic Study for the Thermal Unimolecular Decomposition of Diethyl Carbonate

    KAUST Repository

    Alabbad, Mohammed

    2017-07-08

    Thermal unimolecular decomposition of diethyl carbonate (DEC) was investigated in a shock tube by measuring ethylene concentration with a CO2 gas laser over 900 - 1200 K and 1.2 – 2.8 bar. Rate coefficients were extracted using a simple kinetic scheme comprising of thermal decomposition of DEC as initial step followed by rapid thermal decomposition of the intermediate ethyl-hydrogen-carbonate. Our results were further analysed using ab initio and master equation calculations to obtain pressure- and temperature- dependence of rate coefficients. Similar to alkyl esters, unimolecular decomposition of DEC is found to undergo six-center retro-ene elimination of ethylene in a concerted manner.

  20. Source attribution of Arctic black carbon constrained by aircraft and surface measurements

    Directory of Open Access Journals (Sweden)

    J.-W. Xu

    2017-10-01

    Full Text Available Black carbon (BC contributes to Arctic warming, yet sources of Arctic BC and their geographic contributions remain uncertain. We interpret a series of recent airborne (NETCARE 2015; PAMARCMiP 2009 and 2011 campaigns and ground-based measurements (at Alert, Barrow and Ny-Ålesund from multiple methods (thermal, laser incandescence and light absorption with the GEOS-Chem global chemical transport model and its adjoint to attribute the sources of Arctic BC. This is the first comparison with a chemical transport model of refractory BC (rBC measurements at Alert. The springtime airborne measurements performed by the NETCARE campaign in 2015 and the PAMARCMiP campaigns in 2009 and 2011 offer BC vertical profiles extending to above 6 km across the Arctic and include profiles above Arctic ground monitoring stations. Our simulations with the addition of seasonally varying domestic heating and of gas flaring emissions are consistent with ground-based measurements of BC concentrations at Alert and Barrow in winter and spring (rRMSE  < 13 % and with airborne measurements of the BC vertical profile across the Arctic (rRMSE  = 17 % except for an underestimation in the middle troposphere (500–700 hPa.Sensitivity simulations suggest that anthropogenic emissions in eastern and southern Asia have the largest effect on the Arctic BC column burden both in spring (56 % and annually (37 %, with the largest contribution in the middle troposphere (400–700 hPa. Anthropogenic emissions from northern Asia contribute considerable BC (27 % in spring and 43 % annually to the lower troposphere (below 900 hPa. Biomass burning contributes 20 % to the Arctic BC column annually.At the Arctic surface, anthropogenic emissions from northern Asia (40–45 % and eastern and southern Asia (20–40 % are the largest BC contributors in winter and spring, followed by Europe (16–36 %. Biomass burning from North America is the most important

  1. Development of a thermal method for the measurement of elemental carbon

    Energy Technology Data Exchange (ETDEWEB)

    Lavanchy, V.M.H. [Bern Univ. (Switzerland); Baltensperger, U.; Gaeggeler, H.W. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1997-09-01

    A thermal method was developed to measure the organic carbon (OC) and elemental carbon (EC) content of atmospheric aerosols. OC is first oxidized under an O{sub 2} flow during a precombustion step and measured with an Non-Dispersive Infrared Analyzer (NDIR). The remaining carbon, defined as EC, is then oxidized at 650{sup o}C. (author) 1 fig., 1 tab., 3 refs.

  2. Black carbon aerosol and its radiative impact at a high-altitude remote site on the southeastern Tibet Plateau

    Science.gov (United States)

    Zhao, Zhuzi; Wang, Qiyuan; Xu, Baiqing; Shen, Zhenxing; Huang, Rujin; Zhu, Chongshu; Su, Xiaoli; Zhao, Shuyu; Long, Xin; Liu, Suixin; Cao, Junji

    2017-05-01

    Aerosol black carbon (BC) was measured with an Aethalometer™ at Lulang, a high-altitude station in southeastern Tibetan Plateau (TP), from July 2008 to August 2009. Daily mean BC loadings varied from 57.7 to 5368.9 ng m-3 (grand average ± standard deviation = 496.5 ± 521.2 ng m-3), indicating a significant BC burden even at free tropospheric altitudes. BC loadings were highest during the premonsoon and lowest during the monsoon, and peaks in BC were coincident with high atmospheric boundary layers. Daily peaks in BC occurred from 08:00 to 10:00 local time with minor fluctuations at other times. The BC mass absorption efficiency (MAE) was calculated from elemental carbon concentrations obtained from a thermal/optical reflectance method and absorption coefficients from the Aethalometer™, and values ranged from 6.1 to 31.7 m2 g-1 (average = 16.6 ± 5.7 m2 g-1). Strong variations in the MAEs during the monsoon can be ascribed to large uncertainties due to low BC and babs and possibly coatings on the BC. High MAEs during premonsoon pollution events were likely due to internal mixing during transport. The mean direct surface radiative forcing (DRF) estimated from a radiation model was -19.9 (±7.4) W m-2 for the full aerosol population and -3.9 (±1.8) W m-2 for a BC only scenario. The BC DRF during a case study (-36.0 W m-2) was much stronger than the typical, and the BC contribution to the forcing was higher ( 50%) than usual ( 20%). These results show that BC can at times account for a relatively large fraction of the aerosol surface heating over the southeast TP, which may affect both climate and hydrological cycles.

  3. Effects of biomass burning on climate, accounting for heat and moisture fluxes, black and brown carbon, and cloud absorption effects

    Science.gov (United States)

    Jacobson, Mark Z.

    2014-07-01

    This paper examines the effects on climate and air pollution of open biomass burning (BB) when heat and moisture fluxes, gases and aerosols (including black and brown carbon, tar balls, and reflective particles), cloud absorption effects (CAEs) I and II, and aerosol semidirect and indirect effects on clouds are treated. It also examines the climate impacts of most anthropogenic heat and moisture fluxes (AHFs and AMFs). Transient 20 year simulations indicate BB may cause a net global warming of 0.4 K because CAE I ( 32% of BB warming), CAE II, semidirect effects, AHFs ( 7%), AMFs, and aerosol absorption outweigh direct aerosol cooling and indirect effects, contrary to previous BB studies that did not treat CAEs, AHFs, AMFs, or brown carbon. Some BB warming can be understood in terms of the anticorrelation between instantaneous direct radiative forcing (DRF) changes and surface temperature changes in clouds containing absorbing aerosols. BB may cause 250,000 (73,000-435,000) premature mortalities/yr, with >90% from particles. AHFs from all sources and AMFs + AHFs from power plants and electricity use each may cause a statistically significant +0.03 K global warming. Solar plus thermal-IR DRFs were +0.033 (+0.027) W/m2 for all AHFs globally without (with) evaporating cooling water, +0.009 W/m2 for AMFs globally, +0.52 W/m2 (94.3% solar) for all-source BC outside of clouds plus interstitially between cloud drops at the cloud relative humidity, and +0.06 W/m2 (99.7% solar) for BC inclusions in cloud hydrometeor particles. Modeled post-1850 biomass, biofuel, and fossil fuel burning, AHFs, AMFs, and urban surfaces accounted for most observed global warming.

  4. 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.

  5. 40 CFR 721.10080 - Carbon black, 4-[(17-substituted-3,6,9,12,15-pentaazaheptadec-1-yl) substituted] phenyl-modified...

    Science.gov (United States)

    2010-07-01

    ... generically as carbon black, 4- phenyl-modified, hydrochlorides (PMN P-06-8) is subject to reporting under... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Carbon black, 4- phenyl-modified, hydrochlorides (generic). 721.10080 Section 721.10080 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY...

  6. 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,...

  7. Geological and geomechanical properties of the carbonate rocks at the eastern Black Sea Region (NE Turkey)

    Science.gov (United States)

    Ersoy, Hakan; Yalçinalp, Bülent; Arslan, Mehmet; Babacan, Ali Erden; Çetiner, Gözde

    2016-11-01

    Turkey located in the Alpine-Himalayan Mountain Belt has 35% of the natural stone reserves of the world and has good quality marble, limestone, travertine and onyx reserves especially in the western regions of the country. The eastern Black Sea Region with a 1.4 million meters cubes reserve has a little role on the natural stone production in the country. For this reason, this paper deals with investigation on the potential of carbonate stone in the region and determination of the geological and geo-mechanical properties of these rocks in order to provide economic contribution to the national economy. While the study sites are selected among the all carbonate rock sites, the importance as well as the representative of the sites were carefully considered for the region. After representative samples were analyzed for major oxide and trace element compositions to find out petrochemical variations, the experimental program conducted on rock samples for determination of both physical and strength properties of the carbonate rocks. The results of the tests showed that there are significant variations in the geo-mechanical properties of the studied rock groups. The density values vary from 2.48 to 2.70 gr/cm3, water absorption by weight values range from 0.07 to 1.15% and the apparent porosity of the carbonate rocks are between 0.19 and 3.29%. However, the values of the UCS shows variation from 36 to 80 MPa. Tensile and bending strength values range from 3.2 to 7.5 MPa and 6.0-9.2 MPa respectively. Although the onyx samples have the lowest values of apparent porosity and water absorption by weight, these samples do not have the highest values of UCS values owing to occurrence of the micro-cracks. The UCS values of the rock samples were also found after cycling tests However, the limestone samples have less than 5% deterioration after freezing-thawing and wetting-drying tests, but travertine and onyx samples have more than 15% deterioration. Exception of the apparent

  8. Spatial, temporal and source contribution assessments of black carbon over the northern interior of South Africa

    Science.gov (United States)

    Euphinia Chiloane, Kgaugelo; Beukes, Johan Paul; Gideon van Zyl, Pieter; Maritz, Petra; Vakkari, Ville; Josipovic, Miroslav; Derick Venter, Andrew; Jaars, Kerneels; Tiitta, Petri; Kulmala, Markku; Wiedensohler, Alfred; Liousse, Catherine; Vuyisile Mkhatshwa, Gabisile; Ramandh, Avishkar; Laakso, Lauri

    2017-05-01

    After carbon dioxide (CO2), aerosol black carbon (BC) is considered to be the second most important contributor to global warming. This paper presents equivalent black carbon (eBC) (derived from an optical absorption method) data collected from three sites in the interior of South Africa where continuous measurements were conducted, i.e. Elandsfontein, Welgegund and Marikana, as well elemental carbon (EC) (determined by evolved carbon method) data at five sites where samples were collected once a month on a filter and analysed offline, i.e. Louis Trichardt, Skukuza, Vaal Triangle, Amersfoort and Botsalano.Analyses of eBC and EC spatial mass concentration patterns across the eight sites indicate that the mass concentrations in the South African interior are in general higher than what has been reported for the developed world and that different sources are likely to influence different sites. The mean eBC or EC mass concentrations for the background sites (Welgegund, Louis Trichardt, Skukuza, Botsalano) and sites influenced by industrial activities and/or nearby settlements (Elandsfontein, Marikana, Vaal Triangle and Amersfoort) ranged between 0.7 and 1.1, and 1.3 and 1.4 µg m-3, respectively. Similar seasonal patterns were observed at all three sites where continuous measurement data were collected (Elandsfontein, Marikana and Welgegund), with the highest eBC mass concentrations measured from June to October, indicating contributions from household combustion in the cold winter months (June-August), as well as savannah and grassland fires during the dry season (May to mid-October). Diurnal patterns of eBC at Elandsfontein, Marikana and Welgegund indicated maximum concentrations in the early mornings and late evenings, and minima during daytime. From the patterns it could be deduced that for Marikana and Welgegund, household combustion, as well as savannah and grassland fires, were the most significant sources, respectively.Possible contributing sources were

  9. 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.

  10. Carbon black nanoparticles film electrode prepared by using substrate-induced deposition approach

    Energy Technology Data Exchange (ETDEWEB)

    Svegl, Irena Grabec; Bele, Marjan [National Institute of Chemistry, P.O. Box 660, SI-1001 Ljubljana (Slovenia); Ogorevc, Bozidar [National Institute of Chemistry, P.O. Box 660, SI-1001 Ljubljana (Slovenia)], E-mail: bogorevc@ki.si

    2008-11-03

    A new type of carbon film electrode, composed of a thin layer of tightly packed carbon black (CB) nanoparticles deposited onto a gelatin-covered indium tin oxide/glass support using the surface-induced deposition (SID) approach, is presented. Some parameters of the novel SID method were optimized and the surface image and functionalization of the investigated carbon black film electrode (CBFE) was inspected by employing scanning electron microscopy and infrared spectroscopy. A cyclic voltammetry (CV) study was conducted in which the electron-transfer kinetics and CBFE interfacial characteristics were evaluated employing several selected reference redox systems, such as [Ru(NH{sub 3}){sub 6}]{sup 3+/2+}, [Fe(CN){sub 6}]{sup 3-/4-} and Fe{sup 3+/2+} in aqueous, and ferrocene/ferrocenium in acetonitrile media. CV recordings were also performed in order to compare the electrochemical behavior of the CBFE with that of some well-known and established bare carbon-based electrodes. In order to confirm the validity of the CB film preparation method, the electroanalytical performance of the proposed CBFE was examined by carrying out linear sweep voltammetry of ascorbic acid (AA), anodic stripping square-wave voltammetry of Cu(II) in acidic medium, and amperometric measurements of hydrogen peroxide under flow injection conditions. The sensing characteristics of the novel carbon film electrode, demonstrated in this preliminary study, comprise: (i) a wide working potential window ranging from +1.0 to -1.3 V (depending on the solution pH), (ii) a wide applicable pH range (at least from 2 to 12), (iii) low voltammetric background (<5 {mu}A cm{sup -2}), (iv) a satisfactory linear voltammetric and amperometric response (r{sup 2} > 0.99) to various analytes, (v) good reproducibility (for example, r.s.d. of 2% in amperometric detection of H{sub 2}O{sub 2} and r.s.d. of 8.5% for electrode-to-electrode CV runs), and (vi) stable and fast current response (at least 100 CV runs with

  11. Carbon black nanoparticles film electrode prepared by using substrate-induced deposition approach.

    Science.gov (United States)

    Svegl, Irena Grabec; Bele, Marjan; Ogorevc, Bozidar

    2008-11-03

    A new type of carbon film electrode, composed of a thin layer of tightly packed carbon black (CB) nanoparticles deposited onto a gelatin-covered indium tin oxide/glass support using the surface-induced deposition (SID) approach, is presented. Some parameters of the novel SID method were optimized and the surface image and functionalization of the investigated carbon black film electrode (CBFE) was inspected by employing scanning electron microscopy and infrared spectroscopy. A cyclic voltammetry (CV) study was conducted in which the electron-transfer kinetics and CBFE interfacial characteristics were evaluated employing several selected reference redox systems, such as [Ru(NH(3))(6)](3+/2+), [Fe(CN)(6)](3-/4-) and Fe(3+/2+) in aqueous, and ferrocene/ferrocenium in acetonitrile media. CV recordings were also performed in order to compare the electrochemical behavior of the CBFE with that of some well-known and established bare carbon-based electrodes. In order to confirm the validity of the CB film preparation method, the electroanalytical performance of the proposed CBFE was examined by carrying out linear sweep voltammetry of ascorbic acid (AA), anodic stripping square-wave voltammetry of Cu(II) in acidic medium, and amperometric measurements of hydrogen peroxide under flow injection conditions. The sensing characteristics of the novel carbon film electrode, demonstrated in this preliminary study, comprise: (i) a wide working potential window ranging from +1.0 to -1.3 V (depending on the solution pH), (ii) a wide applicable pH range (at least from 2 to 12), (iii) low voltammetric background (0.99) to various analytes, (v) good reproducibility (for example, r.s.d. of 2% in amperometric detection of H(2)O(2) and r.s.d. of 8.5% for electrode-to-electrode CV runs), and (vi) stable and fast current response (at least 100 CV runs with negligible change in CV response). The main advantages of the proposed CBFE originate from the unique CB film formation procedure that

  12. Direct evidence for organic carbon preservation as clay-organic nanocomposites in a Devonian black shale; from deposition to diagenesis

    Science.gov (United States)

    Kennedy, Martin John; Löhr, Stefan Carlos; Fraser, Samuel Alex; Baruch, Elizabeth Teresa

    2014-02-01

    The burial of marine sourced organic carbon (OC) in continental margin sediments is most commonly linked to oceanographic regulation of bottom-water oxygenation (anoxia) and/or biological productivity. Here we show an additional influence in the Devonian Woodford Shale, in which OC occurs as nanometer intercalations with specific phyllosilicate minerals (mixed-layer illite/smectite) that we term organo-mineral nanocomposites. High resolution transmission electron microscopic (HRTEM) images provide direct evidence of this nano-scale relationship. While discrete micron-scale organic particles, such as Tasmanites algal cysts, are present in some lamina, a strong relation between total organic carbon (TOC) and mineral surface area (MSA) over a range of 15% TOC indicate that the dominant association of organic carbon is with mineral surfaces and not as discrete pelagic grains, consistent with HRTEM images of nanocomposites. Where periods of oxygenation are indicated by bioturbation, this relationship is modified by a shift to lower OC loading on mineral surfaces and reduced MSA variability likely resulting from biological mixing and homogenization of the sediment, oxidative burn down of OC and/or stripping of OC from minerals in animal guts. The TOC-MSA relationship extends across a range of burial depths and thermal maturities into the oil window and persists through partial illitization. Where illitization occurs, the loss of mineral surface area associated with the collapse of smectite interlayer space results in a systematic increase in TOC:MSA and reorganization of organic carbon and clays into nano-scale aggregates. While the Woodford Shale is representative of black shale deposits commonly thought to record heightened marine productivity and/or anoxia, our results point to the importance of high surface area clay minerals for OC enrichment. Given that the vast majority of these clay minerals are formed in soils before being transported to continental margin

  13. Carbon-Nanotube-Enhanced Thermal Contactor in Low Contact Pressure Region

    Science.gov (United States)

    Tsukamoto, Takashiro; Esashi, Masayoshi; Tanaka, Shuji

    2010-07-01

    We first demonstrated considerable reduction of thermal contact resistance (TCR) of a bending thermal contactor in microscale using carbon nanotubes (CNTs). TCR reduction using CNTs were previously reported with flat contact surface, but the thermal contact surfaces of actual microdevices often bend because of their residual and thermal stress. We evaluated both flat and bending contact surfaces to apply this method for a variety of applications. The TCR reduction is observed not only with a flat contact surface but also a bending surface. A bending micro thermal contactor with a plasma-enhanced chemical vapor deposition (PECVD)-grown 10 µm long “CNT carpet” shows a TCR of ca. 600 mm2 K/W at a contact pressure of 20 kPa, which is about 1/10 to the TCR of the reference contactor without “CNT carpet”. This technique is useful for micro thermal devices such as micro thermal switch.

  14. Ambient black carbon particulate matter in the coal region of Dhanbad, India.

    Science.gov (United States)

    Singh, S; Tiwari, S; Hopke, P K; Zhou, C; Turner, J R; Panicker, A S; Singh, P K

    2017-10-08

    Light-absorbing, atmospheric particles have gained greater attention in recent years because of their direct and indirect impacts on regional and global climate. Atmospheric black carbon (BC) aerosol is a leading climate warming agent, yet uncertainties in the global direct aerosol radiative forcing remain large. Based on a year of aerosol absorption measurements at seven wavelengths, BC concentrations were investigated in Dhanbad, the coal capital of India. Coal is routinely burned for cooking and residential heat as well as in small industries. The mean daily concentrations of ultraviolet-absorbing black carbon measured at 370nm (UVBC) and black carbon measured at 880nm (BC) were 9.8±5.7 and 6.5±3.8μgm(-3), respectively. The difference between UVBC and BC, Delta-C, is an indicator of biomass or residential coal burning and averaged 3.29±4.61μgm(-3). An alternative approach uses the Ǻngstrom Exponent (AE) to estimate the biomass/coal and traffic BC concentrations. Biomass/coal burning contributed ~87% and high temperature, fossil-fuel combustion contributed ~13% to the annual average BC concentration. The post-monsoon seasonal mean UVBC values were 10.9μgm(-3) and BC of 7.2μgm(-3). Potential source contribution function analysis showed that in the post-monsoon season, air masses came from the central and northwestern Indo-Gangetic Plains where there is extensive agricultural burning. The mean winter UVBC and BC concentrations were 15.0 and 10.1μgm(-3), respectively. These higher values were largely produced by local sources under poor dispersion conditions. The direct radiative forcing (DRF) due to UVBC and BC at the surface (SUR) and the top of the atmosphere (TOA) were calculated. The mean atmospheric heating rates due to UVBC and BC were estimated to be 1.40°Kday(-1) and 1.18°Kday(-1), respectively. This high heating rate may affect the monsoon circulation in this region. Copyright © 2017 Elsevier B.V. All rights reserved.

  15. Analysis and high resolution modelling of black carbon vertical profiles measured over three Italian valleys

    Science.gov (United States)

    Gandolfi, Ilaria; Curci, Gabriele; Falasca, Serena; Ferrero, Luca

    2017-04-01

    Analysis and high resolution modelling of black carbon vertical profiles measured over three Italian valleys Ilaria Gandolfi1,2, Gabriele Curci1,2, Serena Falasca1,2, Luca Ferrero3 1 Department of Physical and Chemical Sciences, University of L'Aquila, L'Aquila, Italy 2 Center of Excellence CETEMPS, University of L'Aquila, L'Aquila, Italy 3 POLARIS Research Centre, Department of Earth and Environmental Sciences, University of Milano-Bicocca, Piazza della Scienza 1, 20126, Milan, Italy Last decades were characterized by a growing interest in aerosols: mainly for their effect on human health and on the energy balance of solar and planetary radiation, thus their role in climate change. In this study, we analyze the evolution of vertical profile of black carbon (BC) through tethered balloon observations and chemistry-transport modelling. Black carbon is regarded as the second most important anthropogenic climate forcing agent and its concentration varies significantly depending on the altitude and the sources on the territory. In winter of 2010 University Of Milan Bicocca conducted three intensive measurements campaigns over three Italian basin valleys (Terni, Po Valley, Passiria Valley). The choice of the valleys was made taking into consideration the orography and the river basin structure. The measurement campaign was based on a helium-filled tethered balloon, on which the instrumentation for the analysis has been mounted; the instrumentation consisted on a meteorological station, an OPC, a cascade impactor and a micro-Aethalometer. Subsequently, at University of L'Aquila simulations were produced to help interpretation of these vertical aerosol profiles (mass, composition and distribution) and related optical properties (scattering, absorption) using a chemistry-transport model (WRF-CHIMERE) at high horizontal resolution (1 km). The analysis focused primarily on the calculation of the heating rate and of the Direct Radiative Effect (DRE), and on the analysis of the

  16. Black Carbon Emissions from Fires in Northern Eurasia from 2002 to 2012

    Science.gov (United States)

    Hao, W. M.; Petkov, A.; Corley, R.; Nordgren, B.; Silverstein, R.; Urbanski, S. P.

    2014-12-01

    Northern Eurasia covers 20% of the global land mass and contains 70% of the boreal forest. During certain times of the year, black carbon (BC) in smoke plumes in high latitudes may be transported and deposited on Arctic ice and accelerate ice melting. It is thus imperative to better understand daily sources, transport, and deposition of BC in Northern Eurasia. We examined daily BC emissions from fires over different land cover types in Northern Eurasia at a 500 m x 500 m resolution from 2002 to 2012. Black carbon emissions were estimated based on the MODIS land cover maps and detected burned areas, the Forest Inventory Survey of the Russian Federation, and emission factors of BC for different types of vegetation fires. Our estimated annual burned areas in Northern Eurasia varied considerably from 1.6 × 105 km2 (2011) to 4.9 × 105 km2 (2003) with an average of 2.6 × 105 km2. Grassland dominates the total burned area (61%) and followed by forest (27%). For grassland fires, about three-quarters of the burned area occurred in Central and Western Asia and about 17% in Russia. More than 90% of the forest burned area was in Russia. Annual BC emissions from fires varied enormously from 4.1 ×108 kg in 2010 to 2.1 × 109 kg in 2003 with an average of 8.5×108 kg. In contrast to burned area, BC emissions were dominated by forest fires which accounted for about two-thirds of the emissions, followed by grassland fires (15%). More than 90% of the BC emissions from forest fires occurred in Russia. Central and Western Asia is the major region for BC emissions from grassland fires (53%), followed by Russia (34%). There are no apparent trends in area burned or BC emissions from 2002 to 2012. Overall, Russia contributed 83% of the total BC emissions from fires in Northern Eurasia. These results are critical in understanding the future impacts of climate change on the fire dynamics in Northern Eurasia and the contribution of black carbon to accelerated melting of Arctic ice.

  17. Combining charcoal and elemental black carbon analysis in sedimentary archives: Implications for past fire regimes, the pyrogenic carbon cycle, and the human-climate interactions

    Science.gov (United States)

    Thevenon, Florian; Williamson, David; Bard, Edouard; Anselmetti, Flavio S.; Beaufort, Luc; Cachier, Hélène

    2010-07-01

    This paper addresses the quantification of combustion-derived products in oceanic and continental sediments by optical and chemical approaches, and the interest of combining such methods for reconstructing past biomass burning activity and the pyrogenic carbon cycle. In such context, the dark particles > 0.2 µm 2 remaining after the partial digestion of organic matter are optically counted by automated image analysis and defined as charcoal, while the elemental carbon remaining after thermal and chemical oxidative treatments is quantified as black carbon (BC). The obtained pyrogenic carbon records from three sediment core-based case studies, (i) the Late Pleistocene equatorial Pacific Ocean, (ii) the mid-Holocene European Lake Lucerne, and (iii) the Late Holocene African Lake Masoko, are interpreted as proxy records of regional transportation mechanisms and biomass burning activities. The results show that the burial of dark carbon-rich particles in the 360 kyr-long record from the west equatorial Pacific is controlled by the combination of sea-level changes and low-latitude atmospheric circulation patterns (summer monsoon dynamics). However, the three fold increases in charcoal and BC sediment influxes between 53-43 and 12-10 kyr BP suggest that major shifts in fire activity occur synchronously with human colonization in the Indo/Pacific region. The coarse charcoal distribution from a 7.2 kyr record from Lake Lucerne in Switzerland closely matches the regional timing of major technical, land-use, and socio-economic changes during the Neolithic (between ca. 5.7 and 5.2 kyr BP and 4.9-4.5 kyr BP), the Bronze and Iron Ages (at ca. 3.3 and 2.4 kyr BP, respectively), and the industrialization (after AD 1838), pointing to the key impact of human activities on the sources, transportation processes and reservoirs of refractory carbon during the Holocene. In the tropical Masoko maar lake in Tanzania, where charcoal and BC records are highly sensitive to the local climate

  18. Quantifying black carbon light absorption enhancement with a novel statistical approach

    Directory of Open Access Journals (Sweden)

    C. Wu

    2018-01-01

    Full Text Available Black carbon (BC particles in the atmosphere can absorb more light when coated by non-absorbing or weakly absorbing materials during atmospheric aging, due to the lensing effect. In this study, the light absorption enhancement factor, Eabs, was quantified using a 1-year measurement of mass absorption efficiency (MAE in the Pearl River Delta region (PRD. A new approach for calculating primary MAE (MAEp, the key for Eabs estimation, is demonstrated using the minimum R squared (MRS method, exploring the inherent source independency between BC and its coating materials. A unique feature of Eabs estimation with the MRS approach is its insensitivity to systematic biases in elemental carbon (EC and σabs measurements. The annual average Eabs550 is found to be 1.50 ± 0.48 (±1 SD in the PRD region, exhibiting a clear seasonal pattern with higher values in summer and lower in winter. Elevated Eabs in the summertime is likely associated with aged air masses, predominantly of marine origin, along with long-range transport of biomass-burning-influenced air masses from Southeast Asia. Core–shell Mie simulations along with measured Eabs and absorption Ångström exponent (AAE constraints suggest that in the PRD, the coating materials are unlikely to be dominated by brown carbon and the coating thickness is higher in the rainy season than in the dry season.

  19. 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.

  20. Field Emission of Thermally Grown Carbon Nanostructures on Silicon Carbide

    Science.gov (United States)

    2012-03-22

    acetylene (C2H2), ethylene (C2H4), or benzene (C6H6) for MWCNTs is flowed across the substrate reacting with the catalytic nanoparticles to synthesize... Vibration of Zigzag Single Walled Carbon Nanotubes using Nonlocal Timoshenko Beam Theory". Comput. Mater. Sci., (1), 2012. [14] S. Rai, "Carbon

  1. Studies on Enhancing Transverse Thermal Conductivity in Carbon/Carbon Composites

    National Research Council Canada - National Science Library

    Manocha, Lalit M

    2008-01-01

    ...) on a large scale in the form of aligned carbon nanotubes as arrays. Arrays of these carbon nanotubes were densified, like in carbon felt densification process by filling the space within the nanotube...

  2. On a possible bias in elemental carbon measurements with the Sunset thermal/optical carbon analyser caused by unstable laser signal

    NARCIS (Netherlands)

    Ammerlaan, B.A.J.; Jedynska, A.D.; Henzing, J.S.; Holzinger, R.

    2015-01-01

    We present results that demonstrate a possible bias in the fractioning of total carbon (TC) into elemental carbon (EC) and organic carbon (OC) for measurements with the Sunset Laboratory Inc. Thermal/Optical Carbon Aerosol Analyser. The bias is caused by an unstable laser transmission signal. The

  3. High-Conductance Thermal Interfaces Based on Carbon Nanotubes Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The new devices and missions to achieve the aims of the NASA's Science Mission Directorate (SMD) are creating increasingly demanding thermal environments and...

  4. 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.

  5. A pressure-sensitive carbon black cement composite for traffic monitoring

    KAUST Repository

    Monteiro, A.O.

    2017-08-17

    Recent advances in nanotechnology have guided the development of a new generation of multifunctional construction materials. An example of this are cement-based composites, some of which can be used not just to pave roads but also to monitor them. A cement composite, integrating a carbon black (CB) filler, was used as a piezoresistive sensor to identify different cyclic compressive loadings, at temperatures ranging from 15°C to 45°C. The mechanical essays were performed under realistic conditions using 600cm3 specimens and uniaxial loads typical of automobile traffic. A linear and reversible pressure-sensing performance was found with gauge factors ranging from 40 to 60. Overall, these results show that CB/cement composites can act as stress-sensitive materials for traffic monitoring.

  6. Differential Dynamic Modulus of Carbon Black Filled, Uncured SBR in Single-Step Large Shearing Deformations

    Science.gov (United States)

    Satoh, Youji; Fujii, Shuji; Kawahara, Seiichi; Isono, Yoshinobu; Kagami, Shigeru

    Correspondence between nonlinear viscoelastic properties and change in various networks in carbon black (CB) filled, uncured SBRs has been studied by using combined measurements of relaxation modulus, differential dynamic modulus, and volume resisitivity in wide range of filler concentrations at various shear strains. Volume resistivity at no deformation showed step-off like change which can be explained by the percolation theory. This indicates formation of contact filler network at high filler loading. In addition, change in volume resistivity showed clear correspondence with linear-nonlinear transition in viscoelasticity. By the use of simple three-network model, contributions of contact filler, bridged filler, and entanglement networks to relaxation modulus were estimated. It was found that contact filler and bridged filler networks were dominant at lower and at higher filler concentrations, respectively. It was proposed, furthermore, that differential dynamic modulus can be used as the probes for changes in contact filler and bridged filler networks, respectively.

  7. Self-sensing piezoresistive cement composite loaded with carbon black particles

    KAUST Repository

    Monteiro, André O.

    2017-04-27

    Strain sensors can be embedded in civil engineering infrastructures to perform real-time service life monitoring. Here, the sensing capability of piezoresistive cement-based composites loaded with carbon black (CB) particles is investigated. Several composite mixtures, with a CB filler loading up to 10% of binder mass, were mechanically tested under cyclic uniaxial compression, registering variations in electrical resistance as a function of deformation. The results show a reversible piezoresistive behaviour and a quasi-linear relation between the fractional change in resistivity and the compressive strain, in particular for those compositions with higher amount of CB. Gage factors of 30 and 24 were found for compositions containing 7 and 10% of binder mass, respectively. These findings suggest that the CB-cement composites may be a promising active material to monitor compressive strain in civil infrastructures such as concrete bridges and roadways.

  8. Modeling plumes containing black-carbon from Siberian sources to the Arctic

    Science.gov (United States)

    Raut, J.; Fast, J. D.; Law, K.; Weinzierl, B.; Rose, M.; Kim, J.; Thomas, J. L.; Marelle, L.; Roiger, A.; Schlager, H.; Reiter, A.; Quennehen, B.; Ma, P.; Singh, B.; Rasch, P. J.

    2013-12-01

    There are currently large uncertainties in global climate model predictions of black carbon (BC) in the Arctic. These differences are in part due to uncertainties in anthropogenic and biomass burning emissions, errors arising from model parameterizations, and inadequate spatial resolution in large scale models. In addition to the contribution to aerosol radiative forcing, black carbon deposited on snow alters its albedo and consequently the rate of melting. Our study presents the main pollution transport pathways from Siberia to the Arctic and how they impact the Arctic air composition in summer and spring. We focus on two periods (summer 2012 and spring 2008) when field campaigns took place in the Arctic. As part of the Arctic Climate Change, Economy and Society (ACCESS) project, an aircraft campaign was conducted in July 2012 in Andøya, Norway. The main focus of the campaign was to investigate the role of current and future anthropogenic activities in and near the Arctic on regional air pollution and to analyze potential connections to Arctic climate. To put the emerging local pollution within a broader context, biomass burning plumes containing black carbon imported from Siberian wildfires were sampled during the campaign. Two flights north of Norway into the Arctic, with a refueling stop in Spitsbergen focused specifically on biomass burning pollution transported across the North Pole from Siberia. To simulate the emission, transport, and fate of black carbon, we use a regional chemical transport model, the Weather Research and Forecasting model with chemistry (WRF-Chem), with a model domain that encompasses most of the northern hemisphere. The model is able to represent the most intense plumes sampled during the flights in the North of Spitsbergen, with ~120 ppb CO enhancement. The simulations show a clear connection of these plumes to fires in Siberia and Central Russia and are complemented by a more detailed comparison to airborne observations and satellite

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

    DEFF Research Database (Denmark)

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

    2016-01-01

    Inflammation and oxidative stress are considered the main drivers of vasomotor dysfunction and progression of atherosclerosis after inhalation of particulate matter. In addition, new studies have shown that particle exposure can induce the level of bioactive mediators in serum, driving vascular......-and systemic toxicity. We aimed to investigate if pulmonary inflammation would accelerate nanoparticle-induced atherosclerotic plaque progression in Apolipoprotein E knockout (ApoE-/-) mice. ApoE-/- mice were exposed to vehicle, 8.53 or 25.6 mu g nanosized carbon black (CB) alone or spiked with LPS (0.2 mu g....../mouse/exposure; once a week for 10 weeks). Inflammation was determined by counting cells in bronchoalveolar lavage fluid. Serum Amyloid A3 (Saa3) expression and glutathione status were determined in lung tissue. Plaque progression was assessed in the aorta and the brachiocephalic artery. The effect of vasoactive...

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

    Science.gov (United States)

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

    2016-11-01

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

  11. Radiative absorption enhancements due to the mixing state of atmospheric black carbon.

    Science.gov (United States)

    Cappa, Christopher D; Onasch, Timothy B; Massoli, Paola; Worsnop, Douglas R; Bates, Timothy S; Cross, Eben S; Davidovits, Paul; Hakala, Jani; Hayden, Katherine L; Jobson, B Tom; Kolesar, Katheryn R; Lack, Daniel A; Lerner, Brian M; Li, Shao-Meng; Mellon, Daniel; Nuaaman, Ibraheem; Olfert, Jason S; Petäjä, Tuukka; Quinn, Patricia K; Song, Chen; Subramanian, R; Williams, Eric J; Zaveri, Rahul A

    2012-08-31

    Atmospheric black carbon (BC) warms Earth's climate, and its reduction has been targeted for near-term climate change mitigation. Models that include forcing by BC assume internal mixing with non-BC aerosol components that enhance BC absorption, often by a factor of ~2; such model estimates have yet to be clearly validated through atmospheric observations. Here, direct in situ measurements of BC absorption enhancements (E(abs)) and mixing state are reported for two California regions. The observed E(abs) is small-6% on average at 532 nm-and increases weakly with photochemical aging. The E(abs) is less than predicted from observationally constrained theoretical calculations, suggesting that many climate models may overestimate warming by BC. These ambient observations stand in contrast to laboratory measurements that show substantial E(abs) for BC are possible.

  12. Catalytic Activity of Oxidized Carbon Black and Graphene Oxide for the Crosslinking of Epoxy Resins

    Directory of Open Access Journals (Sweden)

    Maria Rosaria Acocella

    2017-04-01

    Full Text Available This article compares the catalytic activities of oxidized carbon black (oCB and graphene oxide (eGO samples on the kinetics of a reaction of diglycidyl ether of bisphenol A (DGEBA with a diamine, leading to crosslinked insoluble networks. The study is mainly conducted by rheometry and Differential Scanning Calorimetry (DSC. Following the same oxidation procedure, CB samples are more efficiently oxidized than graphite samples. For instance, CB and graphite samples with high specific surface areas (151 and 308 m2/g, as oxidized by the Hummers’ method, exhibit O/C wt/wt ratios of 0.91 and 0.62, respectively. Due to the higher oxidation levels, these oCB samples exhibit a higher catalytic activity toward the curing of epoxy resins than fully exfoliated graphene oxide.

  13. Tensile properties of carbon black-filled natural rubber latex films using two different approaches of film preparation

    Science.gov (United States)

    Jarkasi, Siti Aisyah; Samsuri, Azemi; Hashim, M. Y. Amir; Kamarun, Dzaraini

    2017-09-01

    A study was structured to investigate the effects of two different approaches of black-filled NRL films preparation on tensile strengths and tensile stress at 100% strain (M100). In the "First Approach", carbon black dispersion was added into the NRL and mixed using mechanical stirrer. Then the black-filled NRL was coagulated with acetic acid and dried to form NR black-filled masterbatch. This black-filled NR masterbatch was then masticated and mixed with other compounding ingredients on the 2-roll mill. In the "Second Approach", carbon black dispersion was mixed with NRL plus all other compounding ingredients using a mechanical stirrer at high mechanical stirring speed (200 rpm) for 3 hrs. Tensile test-pieces from these two rubber specimens were tested according to ISO37. It was observed that the tensile strengths are affected by both methods. In the case of masticated latex masterbatch, the black-filled NRL films gave higher tensile strength (25-27 MPa) as compared to un-masticated black-filled NRL films (11-17 MPa). The optimum amount of filler loading for highest tensile strength in both approaches was 20 phr of carbon black. However these different approaches did not give significant effect to the elongation at break, EB and M100. SEM images of samples prepared from both approaches suggested that the dispersion of filler in the rubber matrix was better in the masticated samples compared to the un-masticated samples. The reason for the difference in the tensile strength between the two black-filled rubbers might be associated with the degree of dispersions and the uniformity of the dispersions within the rubber matrix. The first mixing approach involved high mechanical shearing action during mastication and mixing process on the 2-roll mill. The high shearing actions were able to breakdown filler aggregates efficiently and distributed the dispersed filler uniformly within the rubber matrix. In the second approach, the breakdown of filler aggregates relied on

  14. Black carbon emissions in the United Kingdom during the past four decades: An empirical analysis

    Energy Technology Data Exchange (ETDEWEB)

    Novakov, T.; Hansen, J.E.

    2004-04-22

    We use data from a unique 40-year record of 150 urban and rural stations in the ''Black Smoke and SO2 Network'' in Great Britain to infer information about sources of atmospheric black carbon (BC). The data show a rapid decline of ambient atmospheric BC between 1962 and the early 1990s that exceeds the decline in official estimates of BC emissions based only on amount of fuel use and mostly fixed emission factors. This provides empirical confirmation of the existence and large impact of a time-dependent ''technology factor'' that must multiply the rate of fossil fuel use. Current ambient BC amounts in Great Britain comparable to those in western and central Europe, with diesel engines being the principal present source. From comparison of BC and SO2 data we infer that current BC emission inventories understate true emissions in the U.K. by about a factor of two. The results imply that there is the potential for improved technology to achieve large reduction of global ambient BC. There is a need for comparable monitoring of BC in other countries.

  15. Seasonality of global and Arctic black carbon processes in the Arctic Monitoring and Assessment Programme models: Global and Arctic Black Carbon Processes

    Energy Technology Data Exchange (ETDEWEB)

    Mahmood, Rashed [School of Earth and Ocean Sciences, University of Victoria, Victoria British Columbia Canada; Department of Meteorology, COMSATS Institute of Information Technology, Islamabad Pakistan; von Salzen, Knut [School of Earth and Ocean Sciences, University of Victoria, Victoria British Columbia Canada; Canadian Center for Climate Modelling and Analysis, Environment and Climate Change Canada, University of Victoria, Victoria British Columbia Canada; Flanner, Mark [Department of Atmospheric, Oceanic and Space Sciences, University of Michigan, Ann Arbor Michigan USA; Sand, Maria [Center for International Climate and Environmental Research-Oslo, Oslo Norway; Langner, Joakim [Swedish Meteorological and Hydrological Institute, Norrköping Sweden; Wang, Hailong [Atmospheric Sciences and Global Change Division, Pacific Northwest National Laboratory, Richland Washington USA; Huang, Lin [Climate Chemistry Measurements and Research, Environment and Climate Change Canada, Toronto Ontario Canada

    2016-06-22

    This study quantifies black carbon (BC) processes in three global climate models and one chemistry transport model, with focus on the seasonality of BC transport, emissions, wet and dry deposition in the Arctic. In the models, transport of BC to the Arctic from lower latitudes is the major BC source for this region while Arctic emissions are very small. All models simulated a similar annual cycle of BC transport from lower latitudes to the Arctic, with maximum transport occurring in July. Substantial differences were found in simulated BC burdens and vertical distributions, with CanAM (NorESM) producing the strongest (weakest) seasonal cycle. CanAM also has the shortest annual mean residence time for BC in the Arctic followed by SMHI-MATCH, CESM and NorESM. The relative contribution of wet and dry deposition rates in removing BC varies seasonally and is one of the major factors causing seasonal variations in BC burdens in the Arctic. Overall, considerable differences in wet deposition efficiencies in the models exist and are a leading cause of differences in simulated BC burdens. Results from model sensitivity experiments indicate that scavenging of BC in convective clouds acts to substantially increase the overall efficiency of BC wet deposition in the Arctic, which leads to low BC burdens and a more pronounced seasonal cycle compared to simulations without convective BC scavenging. In contrast, the simulated seasonality of BC concentrations in the upper troposphere is only weakly influenced by wet deposition in stratiform (layer) clouds whereas lower tropospheric concentrations are highly sensitive.

  16. In utero exposure to nanosized carbon black (Printex90) does not induce tandem repeat mutations in female murine germ cells

    DEFF Research Database (Denmark)

    Boisen, Anne Mette Zenner; Shipley, Thomas; Jackson, Petra

    2013-01-01

    cell division, which occurs during fetal development in females. We investigated the effects of prenatal exposure to carbon black nanoparticles (CB) on induction of mutations in the female mouse germline during fetal development, spanning the critical developmental stages of oogenesis. Pregnant C57BL/6...

  17. 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 K.; 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.

  18. 40 CFR 721.10075 - Carbon black, 4-[[2-(Sulfooxy) ethyl]substituted] phenyl- modified, sodium salts (generic).

    Science.gov (United States)

    2010-07-01

    ...) The chemical substance identified generically as carbon black, 4- substituted] phenyl-modified, sodium...- modified, sodium salts (generic). 721.10075 Section 721.10075 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) TOXIC SUBSTANCES CONTROL ACT SIGNIFICANT NEW USES OF CHEMICAL SUBSTANCES...

  19. Mutation spectrum in FE1-MUTA(TM) Mouse lung epithelial cells exposed to nanoparticulate carbon black

    DEFF Research Database (Denmark)

    Jacobsen, Nicklas Raun; White, Paul A; Gingerich, John

    2011-01-01

    It has been shown previously that carbon black (CB), Printex 90 exposure induces cII and lacZ mutants in the FE1-Muta(TM) Mouse lung epithelial cell line and causes oxidatively damaged DNA and the production of reactive oxygen species (ROS). The purpose of this study was to determine the mutation...

  20. Particulate matter and black carbon optical properties and emission factors from prescribed fires in the southeastern United States

    Science.gov (United States)

    The aerosol emissions from prescribed fires in the Southeastern United States were measured and compared to emissions from laboratory burns with fuels collected from the site. Fine particulate matter (PM2.5), black carbon, and aerosol light scattering and absorption were characte...

  1. Black carbon concentrations and sources in the marine boundary layer of the tropical Atlantic Ocean using four methodologies

    Science.gov (United States)

    Combustion-derived aerosols in the marine boundary layer have been poorly studied, especially in remote environments such as the open Atlantic Ocean. The tropical Atlantic has the potential to contain a high concentration of aerosols, such as black carbon, due to the African emis...

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

    DEFF Research Database (Denmark)

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

    2012-01-01

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

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

    DEFF Research Database (Denmark)

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

    2009-01-01

    phase responses, including C-reactive protein (CRP) and serum amyloid A (SAA) in humans. In this study we test the hypothesis that diesel exhaust particles (DEP) - or carbon black (CB)-induced lung inflammation initiates an acute phase response in the liver. RESULTS: Mice were exposed to filtered air...

  4. Using Black Carbon as a Tracer of Human Impact in the McMurdo Dry Valleys, Antarctica

    Science.gov (United States)

    Khan, A. L.; Ding, Y.; Jaffe, R.; McKnight, D. M.

    2013-12-01

    This study focuses on quantifying human impact in the McMurdo Dry Valleys through studying black carbon in the dissolved phase in water. Robust efforts and policies exist to minimize human impact in Antarctica, the most remote and pristine continent. Previous studies have been conducted to quantify various tracers of human impact from McMurdo Station, however, no known studies have looked at Black Carbon, soot particles, or products of in-complete combustion of fossil fuels, in the dissolved phase in the lakes of the Dry Valleys. One might expect the lakes to be completely void of black carbon; however, preliminary samples from Lake Fryxell and Lake Hoare show that some BC is present in the lakes, at approximately 4-6 mg/L, one-third of the concentration of temperate lakes. Potential local sources include field camps, relatively heavy helicopter traffic, especially compared to other regions of the Antarctic, as well as generator use. During the height of the austral summer, the edges of these perennially frozen lakes thaw, enabling wind deposition of debris and particles including black carbon, onto the surface of the water. Long range transport is also potential, though previous studies have shown that few particles have the ability to make it through the strong polar vortex, additionally the southern hemisphere has much less industrial production than the north. Therefore, our assumption is that most of the BC we find in the lakes, could be traced to human impact.

  5. Black carbon trends in southwestern Iberia in the context of the financial and economic crisis. The role of bioenergy.

    Science.gov (United States)

    Malico, Isabel; Pereira, Sérgio Nepomuceno; Costa, Maria João

    2017-01-01

    Since black carbon concentrations are useful to reveal changes in anthropogenic activities, measurements taken from 2007 to 2015 in a Portuguese city are used to assess to which extent the ambient air was impacted by the economic crisis. The average black carbon concentrations are representative of an urban area of small size (1.3 ± 1.3 μg m-3). The highest concentrations are observed in the heating season, being biomass combustion one of the causes for the high values. The daily cycle of black carbon concentrations presents both morning and evening peaks, mainly due to road traffic and, in the heating season, to domestic heating as well. The yearly averaged black carbon mass concentrations decreased 33 % from 2007 to 2015, possibly due to a combination of the economic recession and environmental legislation. The reduction in road traffic led to a decrease in the daily morning peak from 2007 to 2015. This reduction was not followed by a decrease in the evening peak, explained by an increase in biomass burning. Biomass is the cheapest heating fuel in Portugal, and its consumption increased in the aftermath of the economic crisis. The use of bioenergy is an alternative to fossil fuels and presents many advantages. However, energy policies should discourage inefficient biomass burning and promote better ways of exploiting the available energy resources and emission air pollution mitigation strategies.

  6. Atmospheric Black Carbon: Chemical Bonding and Structural Information of Individual Aerosol Particles

    Science.gov (United States)

    Gilles, M. K.; Tivanski, A. V.; Hopkins, R. J.; Marten, B. D.

    2006-12-01

    The formation of aerosols from both natural and anthropogenic sources affects the Earth's temperature and climate by altering the radiative properties of the atmosphere. Aerosols containing black carbon (BC) that are released into the atmosphere from the burning of biomass, natural fires and the combustion of coals, diesel and jet fuels, contribute a large positive component to this radiative forcing, thus causing a heating of the atmosphere. A distinct type of biomass burn aerosol referred to as "tar balls" has recently been reported in the literature and is characterized by a spherical morphology, high carbon content and ability to efficiently scatter and absorb light. At present, very little is known about the exact nature and variation of the range of BC aerosols in the atmosphere with regards to optical, chemical and physical properties. Additionally, the similarity of these aerosols to surrogates used in the laboratory as atmospheric mimics remains unclear. The local chemical bonding, structural ordering and carbon-to-oxygen ratios of a plethora of black carbon standard reference materials (BC SRMs), high molecular mass humic-like substances (HULIS) and atmospheric aerosols from a variety of sources are examined using scanning transmission X-ray microscopy (STXM) coupled with near edge X-ray absorption fine structure (NEXAFS) spectroscopy. STXM/NEXAFS enables single aerosol particles of diameter upwards of 100 nm to be studied, which allows the diversity of atmospheric aerosol collected during a variety of field missions to be assessed. We apply a semi-quantitative peak fitting method to the recorded NEXAFS spectral fingerprints allowing comparison of BC SRMs and HULIS to BC aerosol originating from anthropogenic combustion and biomass burning events. This method allows us to distinguish between anthropogenic combustion and biomass burn aerosol using both chemical bonding and structural ordering information. The STXM/NEXAFS technique has also been utilized to

  7. [Response of black soil organic carbon, nitrogen and its availability to longterm fertilization].

    Science.gov (United States)

    Luo, Kun; Hu, Rong-Gui; Zhang, Wen-Ju; Zhou, Bao-Ku; Xu, Ming-Gang; Zhang, Jing-Ye; Xia, Ping-Ping

    2013-02-01

    Based on the long-term fertilization experiments, effects of various fertilization practices on the soil organic carbon (SOC) and total nitrogen (TN) in the surface (0-20 cm) and subsurface (20-40 cm) black soil in northeast China were studied. Results showed that, compared with the CK, long-term application of organic manure, especially the combination of mineral fertilizers and organic manure significantly increased the organic SOC and TN in the surface soil. Application of mineral fertilizers plus organic manure with conventional (NPM) and high application (N2P2M2) rate increased SOC significantly by 24. 6% and 25.1% , and TN by 29.5% and 32.8%, respectively. However, there was no significant difference among the treatments for SOC and TN at the subsurface. Compared with the CK (CKh), mineral fertilizer plus organic manure (NPM and N2P2M2) did not only increase the soil microbial biomass carbon (SMBC) and nitrogen (SMBN) , dissolved organic carbon (DOC) and nitrogen (DN), but also significantly increased the ratio of SMBC and DOC to SOC, SMBN and TN to TN. Application of the NPM and N2P2M2 increased the value of SMBC/SOC by 0.36 to 0.59 and SMBN/TN by 1.21 to 1.95 percentage points, respectively. The value of DOC/SOC and DN/TN ranged from 0.53% to 0.72% and 1.41% to 1.78%, respectively. This result indicated that SMBC, SMBN, DOC, DN and SMBC/ SOC, SMBN/TN, DOC/SOC, DN/TN were more sensitive than SOC and TN to long-term fertilization in the soil profile, and were better indicators for the impact of long-term fertilization soil fertility. The concluded that the application of manure especially manure plus mineral fertilizers can increase soil nutrients activity in the surface and subsurface black soil, acting as a helpful practice to improve soil fertility and the ability of nutrient supply, while it may cause potential environment pollution on carbon and nitrogen loss in the agroecosystem.

  8. Central Asian supra-glacier snow melt enhanced by anthropogenic black carbon

    Science.gov (United States)

    Schmale, Julia; Flanner, Mark; Kang, Shichang; Sprenger, Michael; Farinotti, Daniel; Zhang, Qianggong; Guo, Junming; Li, Yang; Lawrence, Mark; Schwikowski, Margit

    2016-04-01

    In Central Asia, more than 60 % of the population depends on water stored in glaciers and mountain snow. Densely populated areas near lower-lying mountain ranges are particularly vulnerable and a recent study showed that the region might lose 50 % of its glacier mass by 2050. While temperature, precipitation and dynamic processes are key drivers of glacial change, deposition of light absorbing impurities such as mineral dust and black carbon can lead to accelerated melting through surface albedo reduction. Here, we discuss the origin of deposited mineral dust and black carbon and their impacts on albedo change and snow melt. 218 snow samples were taken on 4 glaciers, Abramov (Pamir), Suek, Glacier No. 354 and Golubin (Tien Shan), representing deposition between summer 2012 and 2014. They were analyzed for elemental carbon, mineral dust and iron among other parameters. We find the elemental carbon concentration to be at the higher end of the range reported for neighboring mountain ranges between 70 and 502 ng g-1 (interquartile range). To investigate the origin of the snow impurities, we used a Lagrangian particle dispersion model, LAGRANTO. Back trajectory ensembles of 40 members with varied starting points to capture the meteorological spread were released every 6 hours for the covered period at all sites. "Footprints" were calculated and combined with emission inventories to estimate the relative contribution of anthropogenic and natural BC to deposited aerosol on the glaciers. We find that more than 94 % of BC is of anthropogenic origin and the major source region is Central Asia followed by the Middle East. Further exploring the implications of mineral dust and BC deposition, we calculate the snow albedo reduction with the Snow-Ice-Aerosol-Radiative model (SNICAR). Even though mineral dust concentrations were up to a factor of 50 higher than BC concentrations, BC dominates the albedo reduction. Using these results we calculate the snow melt induced by

  9. 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.

  10. 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. Copyright © 2015 Elsevier B.V. All rights reserved.

  11. 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.

  12. 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.

  13. Real-time indoor and outdoor measurements of black carbon at primary schools

    Science.gov (United States)

    Reche, C.; Rivas, I.; Pandolfi, M.; Viana, M.; Bouso, L.; Àlvarez-Pedrerol, M.; Alastuey, A.; Sunyer, J.; Querol, X.

    2015-11-01

    Epidemiological and toxicological studies have demonstrated the association between Black Carbon in indoor and outdoor air and the occurrence of health risks. Data on air quality in schools is of special interest, as children are more vulnerable to health hazards. In this context, indoor and outdoor measurements of real-time Equivalent Black Carbon (EBC) were collected at 39 primary schools located in Barcelona (Spain), with classrooms naturally ventilated under warm weather conditions. A main contribution of road traffic emissions to indoor and outdoor EBC levels was evidenced through different approaches. Simultaneous measurements of EBC levels at schools under different traffic conditions revealed concentrations by 30-35% higher at schools exposed to higher vehicles intensities. Moreover, a significant correlation was obtained between average outdoor EBC levels at different districts of the city and the percentage of surface area in each district used for the road network (R2 = 0.61). Higher indoor than outdoor levels were recorded at some instances when the indoor sampling location was relatively closer to road traffic, even under low outdoor temperatures. Indeed, the average indoor/outdoor EBC ratios for each school correlate moderately between campaigns in spite of significant differences in temperature between sampling periods. These two facts highlight the strong dependency of the EBC levels on the distance to traffic. The peaks of exposure inside the classrooms seemed to be determined by outdoor concentrations, as shown by the parallelism between indoor and outdoor mean EBC daily cycles and the similar contribution of traffic rush hours to indoor and outdoor daily mean levels. The airtightness of the classroom was suggested as the responsible for the indoor/outdoor ratios of EBC higher than 1 recorded at nights.

  14. 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.

  15. Exposure to fine particulate, black carbon, and particle number concentration in transportation microenvironments

    Science.gov (United States)

    Morales Betancourt, R.; Galvis, B.; Balachandran, S.; Ramos-Bonilla, J. P.; Sarmiento, O. L.; Gallo-Murcia, S. M.; Contreras, Y.

    2017-05-01

    This research determined intake dose of fine particulate matter (PM2.5), equivalent black carbon (eBC), and number of sub-micron particles (Np) for commuters in Bogotá, Colombia. Doses were estimated through measurements of exposure concentration, a surrogate of physical activity, as well as travel times and speeds. Impacts of travel mode, traffic load, and street configuration on dose and exposure were explored. Three road segments were selected because of their different traffic loads and composition, and dissimilar street configuration. The transport modes considered include active modes (walking and cycling) and motorized modes (bus, car, taxi, and motorcycle). Measurements were performed simultaneously in the available modes at each road segment. High average eBC concentrations were observed throughout the campaign, ranging from 20 to 120 μgm-3 . Commuters in motorized modes experienced significantly higher exposure concentrations than pedestrians and bicyclists. The highest average concentrations of PM2.5, eBC , and Np were measured inside the city's Bus Rapid Transit (BRT) system vehicles. Pedestrians and bicycle users in an open street configuration were exposed to the lowest average concentrations of PM2.5 and eBC , six times lower than those experienced by commuters using the BRT in the same street segment. Pedestrians experienced the highest particulate matter intake dose in the road segments studied, despite being exposed to lower concentrations than commuters in motorized modes. Average potential dose of PM2.5 and eBC per unit length traveled were nearly three times higher for pedestrians in a street canyon configuration compared to commuters in public transport. Slower travel speed and elevated inhalation rates dominate PM dose for pedestrians. The presence of dedicated bike lanes on sidewalks has a significant impact on reducing the exposure concentration for bicyclists compared to those riding in mixed traffic lanes. This study proposes a simple

  16. Polycyclic aromatic hydrocarbon (PAH) sorption process to the "black carbon" (BC) component in river sediments

    Science.gov (United States)

    Zhang, Jing; Séquaris, Jean-Marie; Narres, Hans-Dieter; Vereecken, Harry; Klumpp, Erwin

    2010-05-01

    The importance of BC for the long term sequestration of organic carbon is actually discussed for mitigating climate change. In this context, the role of BC as a filter or source of nutrients or toxic chemicals is questioned. The fate of polycyclic aromatic hydrocarbons (PAHs) is especially concerned. In this study, we have investigated the binding of PAH compounds, pyrene and phenanthrene, to Yangtze River sediments. For this purpose, the PAHs sorption to pristine and preheated sediments at 375°C was studied, which allow discriminating the contributions of amorphous organic carbon (AOC) and black carbon (BC) fractions to the PAH sorption extent. An analytical procedure for the determination of PAHs in the solution phase of the batch experiments has been developed with fluorescence spectroscopy. The PAHs sorption isotherms to pristine sediments were fitted by Freundlich and composite models as linear Langmuir model (LLM) and linear Polanyi-Dubinin-Manes model (LPDMM). The sequential application of composite models LLM and LPDMM to the sorption isotherms allows assessing the partition of PAHs into AOC and its nonlinear adsorption in the porous structure of BC. The modelling results indicate that the PAHs sorption to minor BC component of sediments (molecular sieving plays an important role in the competitive PAHs sorption in a multi-solute system. J. Zhang, Ph.D. Dissertation, RWTH Aachen, Germany, 2010 J. Zhang et al., Effects of organic carbon and clay fractions on the pyrene sorption and distribution in Yangtze River sediments (submitted). J. Zhang et al., Pyrene and phenanthrene sorptions to Yangtze River sediments and their components in single and binary solute systems (submitted)

  17. Synthesis of Mesoporous Metal Oxides by Structure Replication: Thermal Analysis of Metal Nitrates in Porous Carbon Matrices

    National Research Council Canada - National Science Library

    Christian Weinberger; Jan Roggenbuck; Jan Hanss; Michael Tiemann

    2015-01-01

    .... Thermal conversion of the metal nitrates into the respective metal oxides, and subsequent removal of the carbon matrix by thermal combustion, provides a versatile means to prepare mesoporous metal oxides...

  18. Thermal Resistance across Interfaces Comprising Dimensionally Mismatched Carbon Nanotube-Graphene Junctions in 3D Carbon Nanomaterials

    Directory of Open Access Journals (Sweden)

    Jungkyu Park

    2014-01-01

    Full Text Available In the present study, reverse nonequilibrium molecular dynamics is employed to study thermal resistance across interfaces comprising dimensionally mismatched junctions of single layer graphene floors with (6,6 single-walled carbon nanotube (SWCNT pillars in 3D carbon nanomaterials. Results obtained from unit cell analysis indicate the presence of notable interfacial thermal resistance in the out-of-plane direction (along the longitudinal axis of the SWCNTs but negligible resistance in the in-plane direction along the graphene floor. The interfacial thermal resistance in the out-of-plane direction is understood to be due to the change in dimensionality as well as phonon spectra mismatch as the phonons propagate from SWCNTs to the graphene sheet and then back again to the SWCNTs. The thermal conductivity of the unit cells was observed to increase nearly linearly with an increase in cell size, that is, pillar height as well as interpillar distance, and approaches a plateau as the pillar height and the interpillar distance approach the critical lengths for ballistic thermal transport in SWCNT and single layer graphene. The results indicate that the thermal transport characteristics of these SWCNT-graphene hybrid structures can be tuned by controlling the SWCNT-graphene junction characteristics as well as the unit cell dimensions.

  19. Production of hydrogen from methane decomposition using nanosized carbon black as catalyst in a fluidized-bed reactor

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Jiuling [Tianjin Key Laboratory of Applied Catalysis Science and Technology, School of Chemical Engineering, Tianjin University, Tianjin 300072 (China); Division of Chemical Engineering, the University of Queensland, St Lucia, Brisbane, QLD 4072 (Australia); He, Miao; Wang, Gaowei; Li, Yongdan [Tianjin Key Laboratory of Applied Catalysis Science and Technology, School of Chemical Engineering, Tianjin University, Tianjin 300072 (China); Zhu, Zhonghua John [Division of Chemical Engineering, the University of Queensland, St Lucia, Brisbane, QLD 4072 (Australia)

    2009-12-15

    Nanosized carbon black (NCB) was employed as catalyst for methane decomposition to produce hydrogen in a fluidized-bed reactor. The carbon atoms of the surface defects of NCB act as active sites in this reaction. The activity of NCB is improved after more defects in the surface of NCB are generated after the treatment in nitric acid and calcination in nitrogen gas. The loading of small amounts of Ni and Co can obviously increase the initial activity of NCB, however, their activity deceases very quickly after the reaction begins due to the encapsulation of the corresponding metal particles inside amorphous carbon produced from methane decomposition. After reaction, the formed carbon was found to grow into carbon flakes and cover the surface of NCB. The investigation with TEM and SEM indicates that they may form from a new carbon crystallite, not build upon the existing hexagon layer in the surface defects of NCB. (author)

  20. Shot Noise Thermometry for Thermal Characterization of Templated Carbon Nanotubes

    OpenAIRE

    Sayer, Robert A; Kim, Sunkook; Franklin, Aaron D; Mohammadi, Saeed; Fisher, Timothy

    2010-01-01

    A carbon nanotube (CNT) thermometer that operates on the principles of electrical shot noise is reported. Shot noise thermometry is a self-calibrating measurement technique that relates statistical fluctuations in dc current across a device to temperature. A structure consisting of vertical, top, and bottom-contacted single-walled carbon nanotubes in a porous anodic alumina template was fabricated and used to measure shot noise. Frequencies between 60 and 100 kHz were observed to preclude sig...

  1. Surface Response of Brominated Carbon Media on Laser and Thermal Excitation: Optical and Thermal Analysis Study

    OpenAIRE

    Volodymyr V. Multian; Kinzerskyi, Fillip E.; Anna V. Vakaliuk; Grishchenko, Liudmyla M.; Diyuk, Vitaliy E.; Boldyrieva, Olga Yu; Kozhanov, Vadim O.; Oleksandr V. Mischanchuk; Vladyslav V. Lisnyak; Gayvoronsky, Volodymyr Ya.

    2017-01-01

    The present study is objected to develop an analytical remote optical diagnostics of the functionalized carbons surface. Carbon composites with up to 1 mmol g?1 of irreversibly adsorbed bromine were produced by the room temperature plasma treatment of an activated carbon fabric (ACF) derived from polyacrylonitrile textile. The brominated ACF (BrACF) was studied by elastic optical scattering indicatrix analysis at wavelength 532 nm. The obtained data were interpreted within results of the ther...

  2. 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

  3. Thermal characteristics of spent activated carbon generated from air cleaning units in Korean nuclear power plants

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Hang Rae; So, Ji Yang [KHNP Central Research Institute, Daejeon (Korea, Republic of)

    2017-06-15

    To identify the feasibility of disposing of spent activated carbon as a clearance level waste, we performed characterization of radioactive pollution for spent activated carbon through radioisotope analysis; results showed that the C-14 concentrations of about half of the spent activated carbon samples taken from Korean NPPs exceeded the clearance level limit. In this situation, we selected thermal treatment technology to remove C-14 and analyzed the moisture content and thermal characteristics. The results of the moisture content analysis showed that the moisture content of the spent activated carbon is in the range of 1.2–23.9 wt% depending on the operation and storage conditions. The results of TGA indicated that most of the spent activated carbon lost weight in 3 temperature ranges. Through py-GC/MS analysis based on the result of TGA, we found that activated carbon loses weight rapidly with moisture desorption reaching to 100°C and desorbs various organic and inorganic carbon compounds reaching to 200°C. The result of pyrolysis analysis showed that the experiment of C-14 desorption using thermal treatment technology requires at least 3 steps of heat treatment, including a heat treatment at high temperature over 850°C, in order to reduce the C-14 concentration below the clearance level.

  4. Thermal characteristics of spent activated carbon generated from air cleaning units in korean nuclear power plants

    Directory of Open Access Journals (Sweden)

    Ji-Yang So

    2017-06-01

    Full Text Available To identify the feasibility of disposing of spent activated carbon as a clearance level waste, we performed characterization of radioactive pollution for spent activated carbon through radioisotope analysis; results showed that the C-14 concentrations of about half of the spent activated carbon samples taken from Korean NPPs exceeded the clearance level limit. In this situation, we selected thermal treatment technology to remove C-14 and analyzed the moisture content and thermal characteristics. The results of the moisture content analysis showed that the moisture content of the spent activated carbon is in the range of 1.2–23.9 wt% depending on the operation and storage conditions. The results of TGA indicated that most of the spent activated carbon lost weight in 3 temperature ranges. Through py-GC/MS analysis based on the result of TGA, we found that activated carbon loses weight rapidly with moisture desorption reaching to 100°C and desorbs various organic and inorganic carbon compounds reaching to 200°C. The result of pyrolysis analysis showed that the experiment of C-14 desorption using thermal treatment technology requires at least 3 steps of heat treatment, including a heat treatment at high temperature over 850°C, in order to reduce the C-14 concentration below the clearance level.

  5. Effect of accelerated thermal ageing on the selective solar thermal harvesting properties of multiwall carbon nanotube/nickel oxide nanocomposite coatings

    CSIR Research Space (South Africa)

    Roro, Kittessa T

    2012-05-01

    Full Text Available intensity in the D and G bands of disordered and graphitic carbon, respectively but an enhancement of the NiO bands indicating loss of carbon atoms due to thermal ageing tests. Simple equations are derived determining the proportion of carbon atoms...

  6. Modelling of thermal shock experiments of carbon based materials in JUDITH

    Science.gov (United States)

    Ogorodnikova, O. V.; Pestchanyi, S.; Koza, Y.; Linke, J.

    2005-03-01

    The interaction of hot plasma with material in fusion devices can result in material erosion and irreversible damage. Carbon based materials are proposed for ITER divertor armour. To simulate carbon erosion under high heat fluxes, electron beam heating in the JUDITH facility has been used. In this paper, carbon erosion under energetic electron impact is modeled by the 3D thermomechanics code 'PEGASUS-3D'. The code is based on a crack generation induced by thermal stress. The particle emission observed in thermal shock experiments is a result of breaking bonds between grains caused by thermal stress. The comparison of calculations with experimental data from JUDITH shows good agreement for various incident power densities and pulse durations. A realistic mean failure stress has been found. Pre-heating of test specimens results in earlier onset of brittle destruction and enhanced particle loss in agreement with experiments.

  7. 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.

  8. Thermal and pH degradation kinetics of anthocyanins in natural food colorant prepared from black rice bran.

    Science.gov (United States)

    Loypimai, Patiwit; Moongngarm, Anuchita; Chottanom, Pheeraya

    2016-01-01

    The study of the stability of anthocyanins in food colorant powder is important to predict the quality changes occurring as the food products are processed, to prevent and control the degradation of the anthocyanins. The objectives of this study were to identify anthocyanin components in natural food colorants obtained from black rice bran, and investigate their thermal stability at 60, 80, and 100 °C, pH stability from 2.0 to 5.0 and also their correlation with visual color, L (*), C (*), and h°. Results showed that only six types of anthocyanins, cyanidin-3-O-glucoside, cyanidin-3-O-rutinoside, delphinidin, cyanidin, pelargonidin and malvidin were present in raw black rice bran (BRB) and black rice bran colorant powder (BCP). The thermal degradation of both the visual color and the anthocyanin content in the BCP followed a first-order kinetic reaction model. The temperature-dependent degradation was adequately fitted to the Arrhenius equation. In terms of the pH stability, increasing pH values resulted in lower activation energies (E a ) and higher half-life (t 1/2 ) values for both color parameters and individual anthocyanins when heating from 60 to 100 °C. Moreover, the degradation rate constant (k) increased with increasing temperature and pH value. The degradation of cyanidin-3-O-glucoside and total anthocyanins showed a strong positive correlation with C (*). The changes in visual color may be used as an on-line quality control indicator during thermal processing of food products containing rice bran colorants which have high anthocyanin content.

  9. A global gas flaring black carbon emission rate dataset from 1994 to 2012

    Science.gov (United States)

    Huang, Kan; Fu, Joshua S.

    2016-01-01

    Global flaring of associated petroleum gas is a potential emission source of particulate matters (PM) and could be notable in some specific regions that are in urgent need of mitigation. PM emitted from gas flaring is mainly in the form of black carbon (BC), which is a strong short-lived climate forcer. However, BC from gas flaring has been neglected in most global/regional emission inventories and is rarely considered in climate modeling. Here we present a global gas flaring BC emission rate dataset for the period 1994–2012 in a machine-readable format. We develop a region-dependent gas flaring BC emission factor database based on the chemical compositions of associated petroleum gas at various oil fields. Gas flaring BC emission rates are estimated using this emission factor database and flaring volumes retrieved from satellite imagery. Evaluation using a chemical transport model suggests that consideration of gas flaring emissions can improve model performance. This dataset will benefit and inform a broad range of research topics, e.g., carbon budget, air quality/climate modeling, and environmental/human exposure. PMID:27874852

  10. Laser-initiated decomposition products of indocyanine green (ICG) and carbon black sensitized biological tissues

    Science.gov (United States)

    Kokosa, John M.; Przyjazny, Andrzej; Bartels, Kenneth E.; Motamedi, Massoud; Hayes, Donald J.; Wallace, David B.; Frederickson, Christopher J.

    1997-05-01

    Organic dyes have found increasing use a s sensitizers in laser surgical procedures, due to their high optical absorbances. Little is known, however, about the nature of the degradation products formed when these dyes are irradiated with a laser. Previous work in our laboratories has shown that irradiation of polymeric and biological tissues with CO2 and Nd:YAG lasers produces a host of volatile and semivolatile by-products, some of which are known to be potential carcinogens. This work focuses on the identification of the chemical by-products formed by diode laser and Nd:YAG laser irradiation of indocyanine green (ICG) and carbon black based ink sensitized tissues, including bone, tendon and sheep's teeth. Samples were mounted in a 0.5-L Pyrex sample chamber equipped with quartz optical windows, charcoal filtered air inlet and an outlet attached to an appropriate sample trap and a constant flow pump. By-products were analyzed by GC/MS and HPLC. Volatiles identified included benzene and formaldehyde. Semi-volatiles included traces of polycyclic aromatics, arising from the biological matrix and inks, as well as fragments of ICG and the carbon ink components. The significance of these results will be discussed, including the necessity of using appropriate evacuation devices when utilizing lasers for surgical procedures.

  11. Kinetics and Equilibrium Study of Black Krom KJR Dye Sorption by Bone-based Activated Carbon

    Directory of Open Access Journals (Sweden)

    Aparecido Nivaldo Módenes

    2014-09-01

    Full Text Available In this work, the sorption capacity of a bone-based activated carbon for the Black Krom KJR dye removal was investigated in a batch system. Preliminary sorption tests were performed in order to assess the effects of initial pH, sorption temperature, stirring speed and the particle size on the sorption process. The most reliable conditions were used to perform the kinetic and equilibrium tests in duplicate. From the kinetic sorption experiments, an equilibrium time of 24 h was achieved with a sorption capacity of 53 mg·g-1. Kinetic dye sorption data was well represented by both the pseudo second order and Elovich models. Among used isotherm models, the Langmuir model exhibited best fit to the equilibrium sorption data, showing a maximum sorption capacity value of 154 ± 8 mg·g-1 and affinity constant value of 0.0114 ± 0.0012 g·L-1, respectively. Based on these results, it is remarkable the great potential exhibited by the bone-based activated carbon adsorbent for its application in industrial wastewater treatment systems.

  12. Facile preparation of carbon microcapsules containing phase-change material with enhanced thermal properties.

    Science.gov (United States)

    Tahan Latibari, Sara; Mehrali, Mohammad; Mehrali, Mehdi; Mahlia, Teuku Meurah Indra; Metselaar, Hendrik Simon Cornelis

    2014-01-01

    This study describes the hydrothermal synthesis of a novel carbon/palmitic acid (PA) microencapsulated phase change material (MEPCM). The field emission scanning electron microscopy (FESEM) and high resolution transmission electron microscopy (HRTEM) images confirm that spherical capsules of uniform size were formed with a mean diameter of 6.42 μm. The melting and freezing temperature were found to be slightly lower than those of pure PA with little undercooling. The composite retained 75% of the latent heat of pure PA. Thermal stability of the MEPCM was found to be better than that of pure PA. The thermal conductivity of MEPCM was increased by as much as 41% at 30°C. Due to its good thermal properties and chemical and mechanical stability, the carbon/PA MEPCM displays a good potential for thermal energy storage systems.

  13. Equilibrium Limit of Boundary Scattering in Carbon Nanostructures: Molecular Dynamics Calculations of Thermal Transport

    Science.gov (United States)

    Haskins, Justin; Kinaci, Alper; Sevik, Cem; Cagin, Tahir

    2012-01-01

    It is widely known that graphene and many of its derivative nanostructures have exceedingly high reported thermal conductivities (up to 4000 W/mK at 300 K). Such attractive thermal properties beg the use of these structures in practical devices; however, to implement these materials while preserving transport quality, the influence of structure on thermal conductivity should be thoroughly understood. For graphene nanostructures, having average phonon mean free paths on the order of one micron, a primary concern is how size influences the potential for heat conduction. To investigate this, we employ a novel technique to evaluate the lattice thermal conductivity from the Green-Kubo relations and equilibrium molecular dynamics in systems where phonon-boundary scattering dominates heat flow. Specifically, the thermal conductivities of graphene nanoribbons and carbon nanotubes are calculated in sizes up to 3 microns, and the relative influence of boundary scattering on thermal transport is determined to be dominant at sizes less than 1 micron, after which the thermal transport largely depends on the quality of the nanostructure interface. The method is also extended to carbon nanostructures (fullerenes) where phonon confinement, as opposed to boundary scattering, dominates, and general trends related to the influence of curvature on thermal transport in these materials are discussed.

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

    Science.gov (United States)

    Buffaloe, G. M.; Lack, D. A.; Williams, E. J.; Coffman, D.; Hayden, K. L.; Lerner, B. M.; Li, S.-M.; Nuaaman, I.; Massoli, P.; Onasch, T. B.; Quinn, P. K.; Cappa, C. D.

    2014-02-01

    Black carbon (BC) mass emission factors (EFBC; g BC(kg fuel)) 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 (average fuel sulphur content of 0.4%, 0.09% and 0.03% for vessels operating slow-speed, medium-speed and high-speed diesel engines, respectively). 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. These measurements have been used to assess the level of agreement between these different techniques for the determination of BC emission factors from ship plumes. Also, these measurements greatly expand upon the number of individual ships for which BC emission factors have been determined during real-world operation. The measured EFBC's have been divided into vessel type categories and engine type categories, from which averages have been determined. The geometric average EFBC (excluding outliers) determined from over 71 vessels and 135 plumes encountered was 0.31 ± 0.31 g BC (kg fuel)-1, where the standard deviation represents the variability between individual vessels. 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

  15. Modelling of deposited black carbon with the Lagrangian particle dispersion model FLEXPART in backward mode

    Science.gov (United States)

    Eckhardt, Sabine; Cassiani, Massimo; Sollum, Espen; Evangeliou, Nikolaos; Stohl, Andreas

    2017-04-01

    Lagrangian particle dispersion models are popular tools to simulate the dispersion of trace gases, aerosols or radionuclides in the atmosphere. If they consider only linear processes, they are self-adjoint, i.e., they can be run forward and backward in time without changes to the source code. Backward simulations are very efficient if the number of receptors is smaller than the number of sources, and they are well suited to establish source-receptor (s-r) relationships for measurements of various trace substances in air. However, not only the air concentrations are of interest, but also the s-r relationships for deposition are important for interpreting measurement data. E.g., deposition of dust is measured regularly in ice cores, partly also as a proxy to understand changes in aridity in dust source regions. Contamination of snow by black carbon (BC) aerosols has recently become a hot topic because of the potential impact of BC on the snow albedo. To interpret such deposition measurements and study the sources of the deposited substance, it would be convenient to have a model that is capable of efficient s-r relationship calculations for such types of measurements. We present here the implementation of such an algorithm into the Lagrangian particle dispersion model FLEXPART, and test the new scheme by comparisons with results from forward simulations as well as comparisons with measurements. As an application, we analyse source regions for elemental carbon (EC) measured in snow over the years 2014-2016 in the Russian Arctic. Simulations using an annual constant black carbon inventory based on ECLIPSE V5 and GFED (Global Fire Emission Database), have been performed. The meteorological data used in the simulation are 3 hourly operational data from the European Centre of Medium Range Weather Forecast (ECMWF) on a 1 degree grid resolution and 138 vertical levels. The model is able to capture very well the measured concentrations. Gas flaring and residential

  16. 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 mixing of boundary layer and free tropospheric air by the formation of clouds that dilutes the concentration of the SLCPs, the decreased actinic flux that reduces the production of ozone by photochemical reactions and the heavy, almost daily rain that removes particulate 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

  17. 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, Pmixing 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 result of the balancing effects of lower precursor gases, i.e. VOCs, offset by lower NOx that is an O3 inhibitor. A comparison of average, maximum values of eBC measured during the one year period of the current study with maximum values measured in short field campaigns in 2000 and

  18. Thermal and pH degradation kinetics of anthocyanins in natural food colorant prepared from black rice bran

    OpenAIRE

    Loypimai, Patiwit; Moongngarm, Anuchita; Chottanom, Pheeraya

    2015-01-01

    The study of the stability of anthocyanins in food colorant powder is important to predict the quality changes occurring as the food products are processed, to prevent and control the degradation of the anthocyanins. The objectives of this study were to identify anthocyanin components in natural food colorants obtained from black rice bran, and investigate their thermal stability at 60, 80, and 100 °C, pH stability from 2.0 to 5.0 and also their correlation with visual color, L*, C*, and h°. ...

  19. 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.

  20. Thermal Reactivity and Structure of Carbonized Binder Pitches

    OpenAIRE

    Madshus, Stian

    2005-01-01

    Pitches are used on a large scale in the manufacture of carbon anodes for the production of primary aluminium. The role of the pitch is to act as a binder between the petroleum coke grains. The structure of the carbonized pitch binder (pitch coke) has an important impact on the overall performance of the anode. Even though the binder pitch is the minor constituent in an anode, it is impossible to make a good quality anode without a good quality binder pitch. Pitch is an extremely complex ...