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Sample records for aerosol coating product

  1. 40 CFR 59.507 - What are the labeling requirements for aerosol coatings?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... aerosol coatings? 59.507 Section 59.507 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... COMMERCIAL PRODUCTS National Volatile Organic Compound Emission Standards for Aerosol Coatings § 59.507 What are the labeling requirements for aerosol coatings? (a) The labels of all aerosol...

  2. 40 CFR 59.507 - What are the labeling requirements for aerosol coatings?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... aerosol coatings? 59.507 Section 59.507 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... COMMERCIAL PRODUCTS National Volatile Organic Compound Emission Standards for Aerosol Coatings § 59.507 What are the labeling requirements for aerosol coatings? (a) The labels of all aerosol...

  3. 40 CFR 59.507 - What are the labeling requirements for aerosol coatings?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... aerosol coatings? 59.507 Section 59.507 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... COMMERCIAL PRODUCTS National Volatile Organic Compound Emission Standards for Aerosol Coatings § 59.507 What are the labeling requirements for aerosol coatings? (a) The labels of all aerosol...

  4. 40 CFR 59.507 - What are the labeling requirements for aerosol coatings?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... aerosol coatings? 59.507 Section 59.507 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... COMMERCIAL PRODUCTS National Volatile Organic Compound Emission Standards for Aerosol Coatings § 59.507 What are the labeling requirements for aerosol coatings? (a) The labels of all aerosol...

  5. 40 CFR 59.507 - What are the labeling requirements for aerosol coatings?

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... aerosol coatings? 59.507 Section 59.507 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... COMMERCIAL PRODUCTS National Volatile Organic Compound Emission Standards for Aerosol Coatings § 59.507 What are the labeling requirements for aerosol coatings? (a) The labels of all aerosol...

  6. TOPICAL REVIEW: Nucleation and aerosol processing in atmospheric pressure electrical discharges: powders production, coatings and filtration

    NASA Astrophysics Data System (ADS)

    Borra, Jean-Pascal

    2006-01-01

    This review addresses the production of nano-particles and the processing of particles injected in atmospheric pressure electrical discharges (APED). The mechanisms of formation and the evolution of particles suspended in gases are first presented, with numerical and experimental facilities. Different APED and related properties are then introduced for dc corona, streamer and spark filamentary discharges (FD), as well as for ac filamentary and homogeneous dielectric barrier discharges (DBD). Two mechanisms of particle production are depicted in APED: when FD interact with the surface of electrodes or dielectrics and when filamentary and homogeneous DBD induce reactions with gaseous precursors in volume. In both cases, condensable gaseous species are produced, leading to nano-sized particles by physical and chemical routes of nucleation. The evolution of the so-formed nano-particles, i.e. the growth by coagulation/condensation, the charging and the collection are detailed for each APED, with respect to fine powders production and thin films deposition. Finally, when particles are injected in APED, they undergo interfacial processes. Non-thermal plasmas charge particles for electro-collection and trigger heterogeneous chemical reactions for organic and inorganic films deposition. Heat exchanges in thermal plasmas enable powder purification, shaping, melting for hard coatings and fine powders production by reactive evaporation.

  7. Design of Aerosol Coating Reactors: Precursor Injection

    PubMed Central

    Buesser, Beat; Pratsinis, Sotiris E.

    2013-01-01

    Particles are coated with thin shells to facilitate their processing and incorporation into liquid or solid matrixes without altering core particle properties (coloristic, magnetic, etc.). Here, computational fluid and particle dynamics are combined to investigate the geometry of an aerosol reactor for continuous coating of freshly-made titanium dioxide core nanoparticles with nanothin silica shells by injection of hexamethyldisiloxane (HMDSO) vapor downstream of TiO2 particle formation. The focus is on the influence of HMDSO vapor jet number and direction in terms of azimuth and inclination jet angles on process temperature and coated particle characteristics (shell thickness and fraction of uncoated particles). Rapid and homogeneous mixing of core particle aerosol and coating precursor vapor facilitates synthesis of core-shell nanoparticles with uniform shell thickness and high coating efficiency (minimal uncoated core and free coating particles). PMID:23658471

  8. Design of Aerosol Particle Coating: Thickness, Texture and Efficiency

    PubMed Central

    Buesser, B.; Pratsinis, S.E.

    2013-01-01

    Core-shell particles preserve the performance (e.g. magnetic, plasmonic or opacifying) of a core material while modifying its surface with a shell that facilitates (e.g. by blocking its reactivity) their incorporation into a host liquid or polymer matrix. Here coating of titania (core) aerosol particles with thin silica shells (films or layers) is investigated at non-isothermal conditions by a trimodal aerosol dynamics model, accounting for SiO2 generation by gas phase and surface oxidation of hexamethyldisiloxane (HMDSO) vapor, coagulation and sintering. After TiO2 particles have reached their final primary particle size (e.g. upon completion of sintering during their flame synthesis), coating starts by uniformly mixing them with HMDSO vapor that is oxidized either in the gas phase or on the particles’ surface resulting in SiO2 aerosols or deposits, respectively. Sintering of SiO2 deposited onto the core TiO2 particles takes place transforming rough into smooth coating shells depending on process conditions. The core-shell characteristics (thickness, texture and efficiency) are calculated for two limiting cases of coating shells: perfectly smooth (e.g. hermetic) and fractal-like. At constant TiO2 core particle production rate, the influence of coating weight fraction, surface oxidation and core particle size on coating shell characteristics is investigated and compared to pertinent experimental data through coating diagrams. With an optimal temperature profile for complete precursor conversion, the TiO2 aerosol and SiO2-precursor (HMDSO) vapor concentrations have the strongest influence on product coating shell characteristics. PMID:23729833

  9. Radiative absorption enhancement from coatings on black carbon aerosols.

    PubMed

    Cui, Xinjuan; Wang, Xinfeng; Yang, Lingxiao; Chen, Bing; Chen, Jianmin; Andersson, August; Gustafsson, Örjan

    2016-05-01

    The radiative absorption enhancement of ambient black carbon (BC), by light-refractive coatings of atmospheric aerosols, constitutes a large uncertainty in estimates of climate forcing. The direct measurements of radiative absorption enhancement require the experimentally-removing the coating materials in ambient BC-containing aerosols, which remains a challenge. Here, the absorption enhancement of the BC core by non-absorbing aerosol coatings was quantified using a two-step removal of both inorganic and organic matter coatings of ambient aerosols. The mass absorption cross-section (MAC) of decoated/pure atmospheric BC aerosols of 4.4±0.8m(2)g(-1) was enhanced to 9.6±1.8m(2)g(-1) at 678-nm wavelength for ambiently-coated BC aerosols at a rural Northern China site. The enhancement of MAC (EMAC) rises from 1.4±0.3 in fresh combustion emissions to ~3 for aged ambient China aerosols. The three-week high-intensity campaign observed an average EMAC of 2.25±0.55, and sulfates were primary drivers of the enhanced BC absorption. PMID:26874760

  10. The MODIS Aerosol Algorithm, Products and Validation

    NASA Technical Reports Server (NTRS)

    Remer, L. A.; Kaufman, Y. J.; Tanre, D.; Mattoo, S.; Chu, D. A.; Martins, J. V.; Li, R.-R.; Ichoku, C.; Levy, R. C.; Kleidman, R. G.

    2003-01-01

    The MODerate resolution Imaging Spectroradiometer (MODIS) aboard both NASA's Terra and Aqua satellites is making near global daily observations of the earth in a wide spectral range. These measurements are used to derive spectral aerosol optical thickness and aerosol size parameters over both land and ocean. The aerosol products available over land include aerosol optical thickness at three visible wavelengths, a measure of the fraction of aerosol optical thickness attributed to the fine mode and several derived parameters including reflected spectral solar flux at top of atmosphere. Over ocean, the aerosol optical thickness is provided in seven wavelengths from 0.47 microns to 2.13 microns. In addition, quantitative aerosol size information includes effective radius of the aerosol and quantitative fraction of optical thickness attributed to the fine mode. Spectral aerosol flux, mass concentration and number of cloud condensation nuclei round out the list of available aerosol products over the ocean. The spectral optical thickness and effective radius of the aerosol over the ocean are validated by comparison with two years of AERONET data gleaned from 133 AERONET stations. 8000 MODIS aerosol retrievals colocated with AERONET measurements confirm that one-standard deviation of MODIS optical thickness retrievals fall within the predicted uncertainty of delta tauapproximately equal to plus or minus 0.03 plus or minus 0.05 tau over ocean and delta tay equal to plus or minus 0.05 plus or minus 0.15 tau over land. 271 MODIS aerosol retrievals co-located with AERONET inversions at island and coastal sites suggest that one-standard deviation of MODIS effective radius retrievals falls within delta r_eff approximately equal to 0.11 microns. The accuracy of the MODIS retrievals suggests that the product can be used to help narrow the uncertainties associated with aerosol radiative forcing of global climate.

  11. Multi-Sensor Aerosol Products Sampling System

    NASA Technical Reports Server (NTRS)

    Petrenko, M.; Ichoku, C.; Leptoukh, G.

    2011-01-01

    Global and local properties of atmospheric aerosols have been extensively observed and measured using both spaceborne and ground-based instruments, especially during the last decade. Unique properties retrieved by the different instruments contribute to an unprecedented availability of the most complete set of complimentary aerosol measurements ever acquired. However, some of these measurements remain underutilized, largely due to the complexities involved in analyzing them synergistically. To characterize the inconsistencies and bridge the gap that exists between the sensors, we have established a Multi-sensor Aerosol Products Sampling System (MAPSS), which consistently samples and generates the spatial statistics (mean, standard deviation, direction and rate of spatial variation, and spatial correlation coefficient) of aerosol products from multiple spacebome sensors, including MODIS (on Terra and Aqua), MISR, OMI, POLDER, CALIOP, and SeaWiFS. Samples of satellite aerosol products are extracted over Aerosol Robotic Network (AERONET) locations as well as over other locations of interest such as those with available ground-based aerosol observations. In this way, MAPSS enables a direct cross-characterization and data integration between Level-2 aerosol observations from multiple sensors. In addition, the available well-characterized co-located ground-based data provides the basis for the integrated validation of these products. This paper explains the sampling methodology and concepts used in MAPSS, and demonstrates specific examples of using MAPSS for an integrated analysis of multiple aerosol products.

  12. 77 FR 14279 - National Volatile Organic Compound Emission Standards for Aerosol Coatings-Addition of Dimethyl...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-03-09

    ...The EPA is taking direct final action to amend the National Volatile Organic Compound Emission Standards for Aerosol Coatings final rule, which is a rule that establishes national reactivity-based emission standards for the aerosol coatings category (aerosol spray paints) under the Clean Air Act, published elsewhere in the Federal Register. This direct final action adds three compounds:......

  13. Osteogenic responses to zirconia with hydroxyapatite coating by aerosol deposition.

    PubMed

    Cho, Y; Hong, J; Ryoo, H; Kim, D; Park, J; Han, J

    2015-03-01

    Previously, we found that osteogenic responses to zirconia co-doped with niobium oxide (Nb2O5) or tantalum oxide (Ta2O5) are comparable with responses to titanium, which is widely used as a dental implant material. The present study aimed to evaluate the in vitro osteogenic potential of hydroxyapatite (HA)-coated zirconia by an aerosol deposition method for improved osseointegration. Surface analysis by scanning electron microscopy and x-ray diffraction proved that a thin as-deposited HA film on zirconia showed a shallow, regular, crater-like surface. Deposition of dense and uniform HA films was measured by SEM, and the contact angle test demonstrated improved wettability of the HA-coated surface. Confocal laser scanning microscopy indicated that MC3T3-E1 pre-osteoblast attachment did not differ notably between the titanium and zirconia surfaces; however, cells on the HA-coated zirconia exhibited a lower proliferation than those on the uncoated zirconia late in the culture. Nevertheless, ALP, alizarin red S staining, and bone marker gene expression analysis indicated good osteogenic responses on HA-coated zirconia. Our results suggest that HA-coating by aerosol deposition improves the quality of surface modification and is favorable to osteogenesis. PMID:25586588

  14. Osteogenic Responses to Zirconia with Hydroxyapatite Coating by Aerosol Deposition

    PubMed Central

    Cho, Y.; Hong, J.; Ryoo, H.; Kim, D.; Park, J.

    2015-01-01

    Previously, we found that osteogenic responses to zirconia co-doped with niobium oxide (Nb2O5) or tantalum oxide (Ta2O5) are comparable with responses to titanium, which is widely used as a dental implant material. The present study aimed to evaluate the in vitro osteogenic potential of hydroxyapatite (HA)-coated zirconia by an aerosol deposition method for improved osseointegration. Surface analysis by scanning electron microscopy and x-ray diffraction proved that a thin as-deposited HA film on zirconia showed a shallow, regular, crater-like surface. Deposition of dense and uniform HA films was measured by SEM, and the contact angle test demonstrated improved wettability of the HA-coated surface. Confocal laser scanning microscopy indicated that MC3T3-E1 pre-osteoblast attachment did not differ notably between the titanium and zirconia surfaces; however, cells on the HA-coated zirconia exhibited a lower proliferation than those on the uncoated zirconia late in the culture. Nevertheless, ALP, alizarin red S staining, and bone marker gene expression analysis indicated good osteogenic responses on HA-coated zirconia. Our results suggest that HA-coating by aerosol deposition improves the quality of surface modification and is favorable to osteogenesis. PMID:25586588

  15. Molecular dynamics studies of organic-coated nano aerosols

    NASA Astrophysics Data System (ADS)

    Chakraborty, Purnendu

    2008-10-01

    Atmospheric aerosols play an important role in atmospheric processes. These aerosol particles can affect climate through scattering, transmission and absorption of radiation as well as acting as cloud condensation nuclei. It has recently been found that fatty acids reside on the surfaces of marine and continental aerosols. In this research, an attempt has been made to understand the structures and properties of such organic coated aerosols using Molecular Dynamics simulation. The model particle consisted of a water droplet coated with fatty acid. The density profile (using both Coarse-Grained and Atomistic/United atom models) demonstrated that such aerosol particles have an inverted micelle structure consisting of an aqueous core and with the hydrophobic hydrocarbon tails exposed to the atmosphere. For smaller chains, with the organic molecules directed radially outwards from the water---organic interface) the normal pressure profile showed that the organic coating is under tension resulting in a 'negative' surface tension. As a result, such particles would have an inverse Kelvin vapor pressure effect and would be able to process water vapor despite the hydrophobic surface. Following the work on surface tension, the rate of water uptake by coated aerosols was computed. It was found that the sticking coefficient of water vapor on such particles was about a sixth of that on pure water droplets. This may seem to imply that the net condensation rate is lower, but we also need to take into account the evaporation of water from such particles. With a significant reduction in the evaporation rate (the coating lends greater stability to the particle resulting in reduced evaporation rate), the equilibrium vapor pressure of water on such particles reduced, resulting in a "net water attractor". Thus if such structures were created in sufficient concentration, they might be important contributors in the cloud condensation process. Next the effect of longer Fatty acid molecules

  16. Soot aggregate restructuring due to coatings of secondary organic aerosol derived from aromatic precursors.

    PubMed

    Schnitzler, Elijah G; Dutt, Ashneil; Charbonneau, André M; Olfert, Jason S; Jäger, Wolfgang

    2014-12-16

    Restructuring of monodisperse soot aggregates due to coatings of secondary organic aerosol (SOA) derived from hydroxyl radical-initiated oxidation of toluene, p-xylene, ethylbenzene, and benzene was investigated in a series of photo-oxidation (smog) chamber experiments. Soot aggregates were generated by combustion of ethylene using a McKenna burner, treated by denuding, size-selected by a differential mobility analyzer, and injected into a smog chamber, where they were exposed to low vapor pressure products of aromatic hydrocarbon oxidation, which formed SOA coatings. Aggregate restructuring began once a threshold coating mass was reached, and the degree of the subsequent restructuring increased with mass growth factor. Although significantly compacted, fully processed aggregates were not spherical, with a mass-mobility exponent of 2.78, so additional SOA was required to fill indentations between collapsed branches of the restructured aggregates before the dynamic shape factor of coated particles approached 1. Trends in diameter growth factor, effective density, and dynamic shape factor with increasing mass growth factor indicate distinct stages in soot aggregate processing by SOA coatings. The final degree and coating mass dependence of soot restructuring were found to be the same for SOA coatings from all four aromatic precursors, indicating that the surface tensions of the SOA coatings are similar. PMID:25390075

  17. Characterisation of coated aerosols using optical tweezers and neutron reflectometry

    NASA Astrophysics Data System (ADS)

    Jones, S. H.; Ward, A.; King, M. D.

    2013-12-01

    Thin organic films are believed to form naturally on the surface of aerosols [1,2] and influence aerosol properties. Cloud condensation nuclei formation and chemical reactions such as aerosol oxidation are effected by the presence of thin films [3]. There is a requirement to characterise the physical properties of both the core aerosol and its organic film in order to fully understand the contribution of coated aerosols to the indirect effect. Two complementary techniques have been used to study the oxidation of thin organic films on the surface of aerosols; laser optical tweezers and neutron reflectometry. Micron sized polystyrene beads coated in oleic acid have been trapped in air using two counter propagating laser beams. Polystyrene beads are used as a proxy for solid aerosol. The trapped aerosol is illuminated with a white LED over a broadband wavelength range and the scattered light collected to produce a Mie spectrum [4]. Analysis of the Mie spectrum results in determination of the core polystyrene bead radius, the oleic acid film thickness and refractive index dispersion of the core and shell [5]. A flow of ozone gas can then be introduced into the aerosol environment to oxidise the thin film of oleic acid and the reaction followed by monitoring the changes in the Mie spectrum. The results demonstrate complete removal of the oleic acid film. We conclude that the use of a counter propagating optical trap combined with white light Mie spectroscopy can be used to study a range of organic films on different types of aerosols and their oxidation reactions. Neutron reflectometry has been used as a complementary technique to study the oxidation of monolayer films at the air-water interface in order to gain information on reaction kinetics. The oxidation of an oleic acid film at the air-water interface by the common tropospheric oxidant ozone has been studied using a Langmuir trough. Results indicate complete removal of the oleic acid film with ozone in agreement

  18. Critical evaluation of cloud contamination in MISR aerosol product using collocated MODIS aerosol and cloud products

    NASA Astrophysics Data System (ADS)

    Shi, Y.; Zhang, J.; Reid, J. S.; Liu, B.; Deshmukh, R.

    2012-12-01

    Unique in its ability of observing the atmospheric state in nine angles nearly simultaneously, the Multi-angle Imaging Spectroradiometer (MISR) instrument has been successfully used for various applications including remote sensing of aerosol properties. However, MISR has limited spectral channels compared with other multi-spectral sensors such as the Moderate Resolution Imaging Spectroradiometer (MODIS), which poses a challenge to cloud screening for applications using MISR. This is particularly important for aerosol property retrievals as cloud contamination and cloud artifacts are one of the larger error sources in satellite aerosol products. Using collocated MODIS and MISR data sets, the potential effects of cloud contamination on the MISR aerosol product are studied. Over global oceans, for non-glint regions, the cloud mask from the level 2 MODIS aerosol products (MOD04) is used. Over ocean glint regions as well as land, the level 2 MODIS cloud mask products (MOD35) are used. The relations between cloud coverage and the bias of MISR AOD are examined using collocated the MODIS cloud information and MISR AOD data. In particular, the suspicious high AOD loading band reported by the MISR aerosol product over high latitude southern oceans is investigated. Finally, a level 3 MISR aerosol product with a new cloud screening method is developed and the potential usage of such a product in satellite aerosol data assimilation is explored.

  19. Aerosol Best Estimate Value-Added Product

    SciTech Connect

    Flynn, C; Turner, D; Koontz, A; Chand, D; Sivaraman, C

    2012-07-19

    The objective of the Aerosol Best Estimate (AEROSOLBE) value-added product (VAP) is to provide vertical profiles of aerosol extinction, single scatter albedo, asymmetry parameter, and Angstroem exponents for the atmospheric column above the Central Facility at the ARM Southern Great Plains (SGP) site. We expect that AEROSOLBE will provide nearly continuous estimates of aerosol optical properties under a range of conditions (clear, broken clouds, overcast clouds, etc.). The primary requirement of this VAP was to provide an aerosol data set as continuous as possible in both time and height for the Broadband Heating Rate Profile (BBHRP) VAP in order to provide a structure for the comprehensive assessment of our ability to model atmospheric radiative transfer for all conditions. Even though BBHRP has been completed, AEROSOLBE results are very valuable for environmental, atmospheric, and climate research.

  20. Introducing... The MODIS Collection 6 Aerosol Products

    NASA Astrophysics Data System (ADS)

    Levy, R. C.; Remer, L. A.; Mattoo, S.; Kleidman, R. G.

    2010-12-01

    As evidenced by more than 1000 publications to date, the MODIS aerosol products are indispensable to research as well as operational applications. The products are used independently, but also in conjunction with other remote sensing instruments and serve as the basis for intercomparisons with models of all scales. In collaboration with our data users, we have made a number of changes to the algorithm and product list, and expect to begin processing “Collection 6” (C006) beginning in early 2011. In addition to more robust means of dealing with degraded or missing reflectance observations, and new protocol for Quality Assurance (QA) characterization and reporting structure, C006 offers new scientific products. C006 will explicitly identify clouds within the aerosol scene, determine distance to nearest cloud for each non-cloudy pixel and provide statistics to help quantify cloud/aerosol interactions. In addition to the traditional retrieval at 10 km resolution focused on climate applications, C006 will provide a 3 km product aimed at characterizing regional and local air quality. The range of valid solar zenith is increased from 72° to 84°, thus increasing retrieval coverage in mid and high latitudes over both land and ocean. Over land, C006 will provide a merged “Dark-target” and “Deep-blue” aerosol product. As for the retrieval over traditional dark targets (land and ocean), the C006 product will benefit from better physical constraints. The lookup tables (central wavelengths, Rayleigh optical depth) are more consistent in C006, and the over-ocean retrieval now includes dependence on wind speed. The dark-land retrieval is improved with adjusted aerosol map boundaries. Finally, the entire C006 archive will be produced utilizing collective knowledge of the MODIS instrument behavior over time. Impacts from calibration drifts and instrument response will be minimized such that C006 will be ever closer to characterizing a global aerosol climate data record.

  1. Silicon production in an aerosol reactor

    NASA Technical Reports Server (NTRS)

    Wu, J. J.; Flagan, R. C.

    1986-01-01

    An aerosol reactor system was developed in which large particles of silicon can be grown by silane pyrolysis. To grow particles to sizes larger than one micron, vapor deposition must be used to grow a relatively small number of seed particles. Suppression of nucleation is achieved by limiting the rate of gas phase chemical reactions such that the condensible products of the gas phase chemical reactions diffuse to the surface of the seed particles as rapidly as they are produced. This prevents high degrees of supersaturation and runaway nucleation during the growth process. Particles on the order of 10 microns were grown repeatedly with the present aersol reactor. The nucleation controlled aerosol reactor is, therefore, a suitable system for the production of powders that can readily be separated from the gas by aerodynamic means.

  2. Production flux of sea spray aerosol

    SciTech Connect

    de Leeuw, G.; Lewis, E.; Andreas, E. L.; Anguelova, M. D.; Fairall, C. W.; O’Dowd, C.; Schulz, M.; Schwartz, S. E.

    2011-05-07

    Knowledge of the size- and composition-dependent production flux of primary sea spray aerosol (SSA) particles and its dependence on environmental variables is required for modeling cloud microphysical properties and aerosol radiative influences, interpreting measurements of particulate matter in coastal areas and its relation to air quality, and evaluating rates of uptake and reactions of gases in sea spray drops. This review examines recent research pertinent to SSA production flux, which deals mainly with production of particles with r{sub 80} (equilibrium radius at 80% relative humidity) less than 1 {micro}m and as small as 0.01 {micro}m. Production of sea spray particles and its dependence on controlling factors has been investigated in laboratory studies that have examined the dependences on water temperature, salinity, and the presence of organics and in field measurements with micrometeorological techniques that use newly developed fast optical particle sizers. Extensive measurements show that water-insoluble organic matter contributes substantially to the composition of SSA particles with r{sub 80} < 0.25 {micro}m and, in locations with high biological activity, can be the dominant constituent. Order-of-magnitude variation remains in estimates of the size-dependent production flux per white area, the quantity central to formulations of the production flux based on the whitecap method. This variation indicates that the production flux may depend on quantities such as the volume flux of air bubbles to the surface that are not accounted for in current models. Variation in estimates of the whitecap fraction as a function of wind speed contributes additional, comparable uncertainty to production flux estimates.

  3. Improving aerosolization of drug powders by reducing powder intrinsic cohesion via a mechanical dry coating approach.

    PubMed

    Zhou, Qi Tony; Qu, Li; Larson, Ian; Stewart, Peter J; Morton, David A V

    2010-07-15

    The aim of this study was to investigate the effect of coating on the aerosolization of three model micronized powders. Three model powder materials (salbutamol sulphate, salmeterol xinafoate, triamcinolone acetonide) were chosen not only for their different chemical properties but also for their different physical properties such as shape and size distribution. Each powder was coated with 5% (w/w) magnesium stearate using two different dry mechanofusion approaches. After mechanofusion, both poured and tapped densities for all three model drug powders significantly increased. There were significant improvements in aerosolization behavior from an inhaler device for all model powders after mechanofusion. Such improvements in aerosolization were attributed to the reduction in agglomerate strength caused by decreasing powder intrinsic cohesion via surface modification. The work also indicated that the effect of the coating was dependant on the initial particle properties. PMID:20435112

  4. The MODIS Aerosol Algorithm, Products, Validation and Applications

    NASA Technical Reports Server (NTRS)

    Remer, L. A.; Kaufman, Y. J.; Tanre, D.

    2003-01-01

    The MODerate resolution Imaging Spectroradiometer (MODIS) currently aboard both the Terra and Aqua satellites produces a suite of products designed to characterize global aerosol distribution, optical thickness and particle size. Never before has a space-borne instrument been able to provide such detailed information, complementing field and modeling efforts to produce a comprehensive picture of aerosol characteristics. The three years of Terra-MODIS data have been validated by comparing with co-located AERONET observations of aerosol optical thickness and derivations of aerosol size parameters. Some 8000 comparison points located at 133 AERONET sites around the globe show that the MODIS aerosol optical thickness retrievals are accurate to within the pre-launch expectations. MODIS-derived size parameters are also compared with AERONET retrievals and found to agree well for fine-mode dominated aerosol regimes. Aerosol regimes dominated by dust aerosol are less accurate, attributed to what is thought to be nonsphericity. Errors due to nonsphericity will be reduced by introducing a new set of empirical phase functions, derived without any assumptions of particle shape. The major innovation that MODIS bring to the field of remote sensing of aerosol is the measure of particle size and the separation of finemode and coarsemode dominated aerosol regimes. Particle size can separate finemode man-made aerosols created during combustion, from larger natural aerosols originating from salt spray or wind erosion. This separation allows for the calculation of aerosol radiative effect and the estimation of the man-made aerosol radiative forcing. MODIS can also be used in regional studies of aerosol-cloud interaction that affect the global radiative and hydrological cycles.

  5. Susceptibility of stored-product psocids to aerosol insecticides

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The efficacies of commercial methoprene and esfenvalerate aerosols for control of stored-product psocid pests were evaluated in simulated field studies. The efficacies of methoprene, esfenvalerate EC, the carrier Isopar-M™, and a combination of methoprene and esfenvalerate aerosols for control of Li...

  6. 77 FR 14324 - National Volatile Organic Compound Emission Standards for Aerosol Coatings-Addition of Dimethyl...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-03-09

    ... (65 FR 67249, November 9, 2000). This action adds compounds to Table 2A of the aerosol coatings rule... 12866 (58 FR 51735 October 4, 1993) and is, therefore, not subject to review under the Executive Orders 12866 and 13563 (76 FR 3821, January 21, 2011). B. Paperwork Reduction Act This action does not...

  7. MODIS 3km Aerosol Product: Algorithm and Global Perspective

    NASA Technical Reports Server (NTRS)

    Remer, L. A.; Mattoo, S.; Levy, R. C.; Munchak, L.

    2013-01-01

    After more than a decade of producing a nominal 10 km aerosol product based on the dark target method, the MODIS aerosol team will be releasing a nominal 3 km product as part of their Collection 6 release. The new product differs from the original 10 km product only in the manner in which reflectance pixels are ingested, organized and selected by the aerosol algorithm. Overall, the 3 km product closely mirrors the 10 km product. However, the finer resolution product is able to retrieve over ocean closer to islands and coastlines, and is better able to resolve fine aerosol features such as smoke plumes over both ocean and land. In some situations, it provides retrievals over entire regions that the 10 km product barely samples. In situations traditionally difficult for the dark target algorithm, such as over bright or urban surfaces the 3 km product introduces isolated spikes of artificially high aerosol optical depth (AOD) that the 10 km algorithm avoids. Over land, globally, the 3 km product appears to be 0.01 to 0.02 higher than the 10 km product, while over ocean, the 3 km algorithm is retrieving a proportionally greater number of very low aerosol loading situations. Based on collocations with ground-based observations for only six months, expected errors associated with the 3 km land product are determined to be greater than for the 10 km product: 0.05 0.25 AOD. Over ocean, the suggestion is for expected errors to be the same as the 10 km product: 0.03 0.05 AOD. The advantage of the product is on the local scale, which will require continued evaluation not addressed here. Nevertheless, the new 3 km product is expected to provide important information complementary to existing satellite-derived products and become an important tool for the aerosol community.

  8. Effect of surface coating with magnesium stearate via mechanical dry powder coating approach on the aerosol performance of micronized drug powders from dry powder inhalers.

    PubMed

    Zhou, Qi Tony; Qu, Li; Gengenbach, Thomas; Larson, Ian; Stewart, Peter J; Morton, David A V

    2013-03-01

    The objective of this study was to investigate the effect of particle surface coating with magnesium stearate on the aerosolization of dry powder inhaler formulations. Micronized salbutamol sulphate as a model drug was dry coated with magnesium stearate using a mechanofusion technique. The coating quality was characterized by X-ray photoelectron spectroscopy. Powder bulk and flow properties were assessed by bulk densities and shear cell measurements. The aerosol performance was studied by laser diffraction and supported by a twin-stage impinger. High degrees of coating coverage were achieved after mechanofusion, as measured by X-ray photoelectron spectroscopy. Concomitant significant increases occurred in powder bulk densities and in aerosol performance after coating. The apparent optimum performance corresponded with using 2% w/w magnesium stearate. In contrast, traditional blending resulted in no significant changes in either bulk or aerosolization behaviour compared to the untreated sample. It is believed that conventional low-shear blending provides insufficient energy levels to expose host micronized particle surfaces from agglomerates and to distribute guest coating material effectively for coating. A simple ultra-high-shear mechanical dry powder coating step was shown as highly effective in producing ultra-thin coatings on micronized powders and to substantially improve the powder aerosolization efficiency. PMID:23196863

  9. Recent Improvements to CALIOP Level 3 Aerosol Profile Product for Global 3-D Aerosol Extinction Characterization

    NASA Astrophysics Data System (ADS)

    Tackett, J. L.; Getzewich, B. J.; Winker, D. M.; Vaughan, M. A.

    2015-12-01

    With nine years of retrievals, the CALIOP level 3 aerosol profile product provides an unprecedented synopsis of aerosol extinction in three dimensions and the potential to quantify changes in aerosol distributions over time. The CALIOP level 3 aerosol profile product, initially released as a beta product in 2011, reports monthly averages of quality-screened aerosol extinction profiles on a uniform latitude/longitude grid for different cloud-cover scenarios, called "sky conditions". This presentation demonstrates improvements to the second version of the product which will be released in September 2015. The largest improvements are the new sky condition definitions which parse the atmosphere into "cloud-free" views accessible to passive remote sensors, "all-sky" views accessible to active remote sensors and "cloudy-sky" views for opaque and transparent clouds which were previously inaccessible to passive remote sensors. Taken together, the new sky conditions comprehensively summarize CALIOP aerosol extinction profiles for a broad range of scientific queries. In addition to dust-only extinction profiles, the new version will include polluted-dust and smoke-only extinction averages. A new method is adopted for averaging dust-only extinction profiles to reduce high biases which exist in the beta version of the level 3 aerosol profile product. This presentation justifies the new averaging methodology and demonstrates vertical profiles of dust and smoke extinction over Africa during the biomass burning season. Another crucial advancement demonstrated in this presentation is a new approach for computing monthly mean aerosol optical depth which removes low biases reported in the beta version - a scenario unique to lidar datasets.

  10. Development of synthetic GOES-R ABI aerosol products

    NASA Astrophysics Data System (ADS)

    Hoff, R. M.; Kondragunta, S.; Ciren, P.; Xu, C.; Zhang, H.; Huff, A.

    2014-09-01

    An Observing Systems Simulation Experiment (OSSE) for GOES-R Advanced Baseline Imager (ABI) aerosol products has been carried out. The generation of simulated data involves prediction of aerosol chemical composition fields at one-hour resolution and 12 km × 12 km spacing. These data are then fed to a radiative transfer model to simulate the on-orbit radiances that the GOES-R ABI will see in six channels. This allows the ABI aerosol algorithm to be tested to produce products that will be available after launch. In cooperation with a user group of 40+ state and local air quality forecasters, the system has been tested in real-time experiments where the results mimic what the forecasters will see after 2016 when GOES-R launches. Feedback from this group has allowed refinement of the web display system for the ABI aerosol products and has creatively called for new products that were not envisaged by the satellite team.

  11. Polymer coating of carrier excipients modify aerosol performance of adhered drugs used in dry powder inhalation therapy.

    PubMed

    Traini, Daniela; Scalia, Santo; Adi, Handoko; Marangoni, Elisabetta; Young, Paul M

    2012-11-15

    The potential of excipient coating to enhance aerosol performance of micronized drugs in carrier excipient-drug blends, used in dry powder inhalers, was investigated. Both EC (ethyl cellulose) and PVP (polyvinylpyrrolidone) were used as coating agents. Carriers were prepared via sieve fractioning followed by spray drying, with and without polymer additive. Each uncoated and coated carrier salbutamol sulphate (SS) blended systems were evaluated for particle size, morphology, drug carrier adhesion and aerosolisation performance, after blending and storage for 24h. All carrier-based systems prepared had similar particle sizes and morphologies. The surface chemistries of the carriers were significantly different, as was drug-carrier adhesion and aerosolisation performance. Particle adhesion between SS and aerosol performance (fine particle fraction; FPF) followed the rank: PVP coated>un-coated>EC coated lactose. This rank order could be attributed to the surface energy measured by contact goniometry and related to the chemistry of lactose and each polymer. Storage did not significantly affect aerosol performance, however a rank increase in mean FPF value was observed for uncoated and EC coated lactose. Finally, the net electrostatic charge across the aerosol cloud indicated that the EC coated lactose transferred less charge to SS particles. The performance of each carrier system could be attributed to the carrier surface chemistry and, in general, by careful selection of the coating polymer, drug-carrier adhesion, electrostatic charge and aerosol performance could be controlled. PMID:22964399

  12. Aerosol Production in a Mixed Deciduous/Coniferous Forest

    NASA Astrophysics Data System (ADS)

    Slade, N.; Mielke, L.; Alaghmand, M.; Galloway, M.; Kammrath, A.; Keutsch, F.; Hansen, R.; Griffith, S.; Dusanter, S.; Stevens, P.; Carroll, M.; Bertman, S.; Shepson, P.

    2008-12-01

    Aerosols are of fundamental concern because of their impacts on air quality, human health and radiative forcing. Recent studies have focused on secondary organic aerosol (SOA) production due to oxidation of volatile organic compounds (VOCs), and more importantly biogenic-VOCs (BVOCs), in particular, isoprene. However, the SOA precursors are not well understood because the mechanisms have shown that isoprene oxidation can contribute to aerosol production through multiple generation oxidation products. For terpenes, it is more likely that primary or secondary oxidation products lead to particle formation. In the present study, we measured the aerosol size distribution, along with O3, HOx, NOx, NOy and BVOCs, in a mixed deciduous forest that is undergoing successional transition to a conifer-dominated species mix. This study was conducted in a rural forest environment in northern Michigan as a part of the summer 2008 PROPHET campaign at the University of Michigan Biological Station (UMBS). We examine here the potential BVOC contribution to aerosol formation. A TSI, inc. Scanning Mobility Particle Sizer (SMPS) was used to measure aerosol number density in the size range, 15 nm < x < 711 nm and a Proton Transfer Reaction - Linear Ion Trap (PTR-LIT) mass spectrometer for quantifying isoprene and other BVOCs, including methyl vinyl ketone and methacrolein, and total monoterpenes. Preliminary results show periods of new particle production. Here we use a unique set of BVOC, HOx, NOx, NOy, O3 and meteorological data to examine conditions leading to new particle production.

  13. Thick-Film Yttrium Iron Garnet Coatings via Aerosol Deposition

    NASA Astrophysics Data System (ADS)

    Johnson, Scooter D.; Glaser, Evan R.; Cheng, Shu-Fan; Eddy, Charles R.; Kub, Fritz; Gorzkowski, Edward P.

    2016-03-01

    Aerosol deposition is a thick-film deposition process that can produce layers up to several hundred micrometers thick with densities greater than 95 pct of the theoretical value. The primary advantage of aerosol deposition is that the deposition takes place entirely at room temperature, thereby enabling film growth in material systems with disparate melting temperatures. We show representative characterization results of yttrium iron garnet thick films deposited onto a <111> gadolinium gallium garnet substrate by aerosol deposition using scanning electron microscopy, X-ray diffraction, profilometry, vibrating sample magnetometry, and ferromagnetic resonance. To further elucidate the effect of density and grain size on the magnetic properties, we perform post-deposition annealing of the films to study the effect on the structural and magnetic properties of the films. Our results indicate that our system can successfully deposit dense, thick yttrium iron garnet films and that with moderate annealing the films can achieve a ferromagnetic resonance linewidth comparable to that reported for polycrystalline films deposited by other higher temperature growth techniques.

  14. Silicon production in an aerosol reactor

    NASA Technical Reports Server (NTRS)

    Wu, J. J.; Alam, M. K.; Johnson, B. E.; Flagan, R. C.

    1984-01-01

    An aerosol reactor for the growth of large silicon particles by silane pyrolysis was shown to demonstrate the following properties: (1) generate seed particles by pyrolysis of a small amount of silane; (2) mix seed aerosol with primary silane flow, limiting number concentration such that the amount of silane is sufficient to grow the desired size of particles from the seed; and (3) react the silane at a rate which is controlled such that the seed particles scavenge the condensible vapors rapidly enough to inhibit further nucleation.

  15. Effect of ceramic coating by aerosol deposition on abrasion resistance of a resin composite material.

    PubMed

    Taira, Yohsuke; Hatono, Hironori; Mizukane, Masahiro; Tokita, Masahiro; Atsuta, Mitsuru

    2006-12-01

    Aerosol deposition (AD coating) is a novel technique to coat solid substances with a ceramic film. The purpose of the present study was to investigate the effect of AD coating on abrasion resistance of a resin composite material. A 5-microm-thick aluminum oxide layer was created on the polymerized resin composite. The specimen was cyclically abraded using a toothbrush abrasion simulator for 100,000 cycles. Abraded surface was then measured with a profilometer to determine the average roughness (Ra) and maximum roughness (Rmax). It was found that abrasion cycling increased the Ra value of the No-AD-coating group, but decreased the Ra and Rmax values of the AD coating group. Moreover, the AD coating group showed significantly smaller Ra and Rmax values after 100,000 abrasion cycles as compared to the No-coating control group. Microscopic observation supported these findings. In conclusion, the resistance of the resin composite against toothbrush abrasion was improved by AD coating. PMID:17338303

  16. Organic Aerosol Component (OACOMP) Value-Added Product Report

    SciTech Connect

    Fast, J; Zhang, Q; Tilp, A; Shippert, T; Parworth, C; Mei, F

    2013-08-23

    Significantly improved returns in their aerosol chemistry data can be achieved via the development of a value-added product (VAP) of deriving OA components, called Organic Aerosol Components (OACOMP). OACOMP is primarily based on multivariate analysis of the measured organic mass spectral matrix. The key outputs of OACOMP are the concentration time series and the mass spectra of OA factors that are associated with distinct sources, formation and evolution processes, and physicochemical properties.

  17. Production of Highly Charged Pharmaceutical Aerosols Using a New Aerosol Induction Charger

    PubMed Central

    Golshahi, Laleh; Longest, P. Worth; Holbrook, Landon; Snead, Jessica; Hindle, Michael

    2015-01-01

    Purpose Properly charged particles can be used for effective lung targeting of pharmaceutical aerosols. The objective of this study was to characterize the performance of a new induction charger that operates with a mesh nebulizer for the production of highly charged submicrometer aerosols to bypass the mouth-throat and deliver clinically relevant doses of medications to the lungs. Methods Variables of interest included combinations of model drug (i.e. albuterol sulfate) and charging excipient (NaCl) as well as strength of the charging field (1–5 kV/cm). Aerosol charge and size were measured using a modified electrical low pressure impactor system combined with high performance liquid chromatography. Results At the approximate mass median aerodynamic diameter (MMAD) of the aerosol (~ 0.4 μm), the induction charge on the particles was an order of magnitude above the field and diffusion charge limit. The nebulization rate was 439.3 ± 42.9 μl/min, which with a 0.1 % w/v solution delivered 419.5 ± 34.2 μg of medication per minute. A new correlation was developed to predict particle charge produced by the induction charger. Conclusions The combination of the aerosol induction charger and predictive correlations will allow for the practical generation and control of charged submicrometer aerosols for targeting deposition within the lungs. PMID:25823649

  18. Identification of an organic coating on marine aerosol particles by TOF-SIMS

    NASA Astrophysics Data System (ADS)

    Tervahattu, Heikki; Juhanoja, Jyrki; Kupiainen, Kaarle

    2002-08-01

    Marine aerosol particles play an important role in atmospheric processes. It has been suggested that as marine aerosol particles form, they acquire a coating of organic surfactants. This theory has been supported only by indirect evidence. Recently, we gave new morphological indication of such organic coating without however providing molecular speciation. Here we have studied the surface of marine aerosol particles by time-of-flight secondary ion mass spectrometry (TOF-SIMS), which is very suitable for surface research due to its unique combination of surface sensitivity and the detailed molecular information obtained. Spectra from the outermost surface gave high intensity for palmitic acid and lower peaks for other fatty acids. According to TOF-SIMS images, palmitic acid was distributed on small particles, similar with the marine particles. Sputtering stripped palmitic acid and revealed the inner core of the sea-salt particles. Our results show that fatty acids are important ingredients of the outermost surface layer of the studied aerosol particles.

  19. MISR Aerosol Product Attributes and Statistical Comparisons with MODIS

    NASA Technical Reports Server (NTRS)

    Kahn, Ralph A.; Nelson, David L.; Garay, Michael J.; Levy, Robert C.; Bull, Michael A.; Diner, David J.; Martonchik, John V.; Paradise, Susan R.; Hansen, Earl G.; Remer, Lorraine A.

    2009-01-01

    In this paper, Multi-angle Imaging SpectroRadiometer (MISR) aerosol product attributes are described, including geometry and algorithm performance flags. Actual retrieval coverage is mapped and explained in detail using representative global monthly data. Statistical comparisons are made with coincident aerosol optical depth (AOD) and Angstrom exponent (ANG) retrieval results from the Moderate Resolution Imaging Spectroradiometer (MODIS) instrument. The relationship between these results and the ones previously obtained for MISR and MODIS individually, based on comparisons with coincident ground-truth observations, is established. For the data examined, MISR and MODIS each obtain successful aerosol retrievals about 15% of the time, and coincident MISR-MODIS aerosol retrievals are obtained for about 6%-7% of the total overlap region. Cloud avoidance, glint and oblique-Sun exclusions, and other algorithm physical limitations account for these results. For both MISR and MODIS, successful retrievals are obtained for over 75% of locations where attempts are made. Where coincident AOD retrievals are obtained over ocean, the MISR-MODIS correlation coefficient is about 0.9; over land, the correlation coefficient is about 0.7. Differences are traced to specific known algorithm issues or conditions. Over-ocean ANG comparisons yield a correlation of 0.67, showing consistency in distinguishing aerosol air masses dominated by coarse-mode versus fine-mode particles. Sampling considerations imply that care must be taken when assessing monthly global aerosol direct radiative forcing and AOD trends with these products, but they can be used directly for many other applications, such as regional AOD gradient and aerosol air mass type mapping and aerosol transport model validation. Users are urged to take seriously the published product data-quality statements.

  20. MISR Global Aerosol Product Assessment by Comparison with AERONET

    NASA Astrophysics Data System (ADS)

    Gaitley, B. J.; Kahn, R. A.

    2010-12-01

    Barbara J. Gaitley1, Ralph Kahn2, 1Jet Propulsion Laboratory, California Institute of Technology, Pasadena CA 91109; 818-354-0552; 2NASA Goddard Space Flight Center; e-mail: barbara.gaitley@jpl.nasa.gov As a further step in validating the NASA Earth Observing System Terra satellite’s Multi-angle Imaging SpectroRadiometer (MISR) aerosol products, an extensive statistical comparison between MISR optical depth and Angstrom exponent and Aerosol Robotic Network (AERONET) retrievals has been completed. Angstrom exponent was interpreted in terms of components and mixtures used by the retrieval algorithm. Specific examples illustrating the analysis approach will be shown. Eight years of data from 81 geographically diverse sites having good long-term measurement records were first stratified based on locations where six broad aerosol air mass type categories are likely to occur: maritime, biomass burning, desert dust, urban pollution, continental and mixed dust+smoke aerosols. The number of actual coincident measurements was constrained by requiring that the AERONET direct sun aerosol optical depth (AOD) data was obtained within a two-hour window centered on the MISR overpass time. 5156 coincident observations are included in this AOD data set. AERONET direct sun data were averaged over the measurements obtained within this window, and were then interpolated to the MISR characteristic wavelengths to facilitate comparison. All AERONET measurements are Level 2.0, Version 2 data. A previous, systematic comparison of MISR and AERONET aerosol optical depth data [Kahn, Gaitley et al., JGR 110, 2005] identified specific, suggested improvements to the early post-launch MISR Standard Aerosol retrieval algorithms. Most of these suggestions were implemented in the uniformly reprocessed MISR Version 22 aerosol products used in the current study. We documented the performance of the current MISR products based on the comparison statistics. For example, agreement between AERONET and

  1. A New Stratospheric Aerosol Product from CALIPSO Lidar Measurements

    NASA Astrophysics Data System (ADS)

    Kar, J.; Vaughan, M.; Trepte, C. R.; Winker, D. M.; Vernier, J. P.; Pitts, M. C.; Young, S. A.; Liu, Z.; Lucker, P.; Tackett, J. L.; Omar, A. H.

    2014-12-01

    Stratospheric aerosols are derived from precursor SO2 and OCS gases transported from the lower troposphere. Volcanic injections can also enhance aerosol loadings far above background levels. The latter can exert a significant influence on the Earth's radiation budget for major and even minor eruptions. Careful measurements are needed, therefore, to monitor the distribution and evolution of stratospheric aerosols for climate related studies. The Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) mission has been acquiring profile measurements of clouds and aerosols since 2006, leading to major advances in our understanding of tropospheric aerosol and cloud properties and the processes that control them. The CALIPSO products have also enabled new insights into polar stratospheric clouds and stratospheric aerosols. Vernier et al (2009,JGR,114,D00H10) reported on the construction of a modified CALIPSO lidar product that corrected minor artifacts with the original lidar calibration that affected stratospheric aerosol investigations. A significantly improved CALIPSO Lidar Version 4 Level 1 product has been recently released addressing these calibration issues and has resulted in enhanced signal levels and a highly stable record over the span of the mission. Based on this product, a new 3D gridded stratospheric CALIPSO data product is under development and being targeted for release in 2015. A key emphasis of this new product is to bridge the measurement gap between the SAGE II and SAGE III data record (1984-2005) and the start of measurements from the new SAGE III instrument to be deployed on the International Space Station in 2016. The primary parameters delivered in the CALIPSO stratospheric data products will be attenuated scattering ratio and aerosol extinction profiles, both averaged over one month intervals and binned into an equal angle grid of constant latitude and longitude with a vertical resolution of 900m. We will present the overall

  2. Susceptibility of Stored-Product Psocids to Aerosol Insecticides

    PubMed Central

    Opit, George P.; Arthur, Frank H.; Throne, James E.; Payton, Mark E.

    2012-01-01

    The efficacies of commercial methoprene and esfenvalerate aerosols for control of stored-product psocid pests were evaluated in simulated field studies. The efficacies of methoprene, esfenvalerate EC, the carrier Isopar-M™, and a combination of methoprene and esfenvalerate aerosols for control of Liposcelis decolor (Pearman) (Psocoptera: Liposcelididae) and Liposcelis entomophila (Enderlein) nymphs were assessed, and the effects of direct and indirect exposure of Liposcelis bostrychophila Badonnel, L. decolor, and Liposcelis paeta Pearman adults to esfenvalerate EC aerosol were evaluated. The greatest nymphal mortality attained was 76%, indicating that the four aerosols tested were ineffective against L. decolor and L. entomophila nymphs. In the direct and indirect exposure studies, the greatest adult mortalities attained for the three psocid species were 62 and 32%, respectively. Based on these data, esfenvalerate aerosol is ineffective for control of L. bostrychophila, L. decolor, L. entomophila, and L. paeta psocid species. This study shows that methoprene, esfenvalerate EC, and a combination of methoprene and esfenvalerate aerosols were ineffective against the four psocid species tested when applied at rates that are usually effective against other stored-product insect pests. PMID:23463916

  3. Susceptibility of stored-product psocids to aerosol insecticides.

    PubMed

    Opit, George P; Arthur, Frank H; Throne, James E; Payton, Mark E

    2012-01-01

    The efficacies of commercial methoprene and esfenvalerate aerosols for control of stored-product psocid pests were evaluated in simulated field studies. The efficacies of methoprene, esfenvalerate EC, the carrier Isopar-M™, and a combination of methoprene and esfenvalerate aerosols for control of Liposcelis decolor (Pearman) (Psocoptera: Liposcelididae) and Liposcelis entomophila (Enderlein) nymphs were assessed, and the effects of direct and indirect exposure of Liposcelis bostrychophila Badonnel, L. decolor, and Liposcelis paeta Pearman adults to esfenvalerate EC aerosol were evaluated. The greatest nymphal mortality attained was 76%, indicating that the four aerosols tested were ineffective against L. decolor and L. entomophila nymphs. In the direct and indirect exposure studies, the greatest adult mortalities attained for the three psocid species were 62 and 32%, respectively. Based on these data, esfenvalerate aerosol is ineffective for control of L. bostrychophila, L. decolor, L. entomophila, and L. paeta psocid species. This study shows that methoprene, esfenvalerate EC, and a combination of methoprene and esfenvalerate aerosols were ineffective against the four psocid species tested when applied at rates that are usually effective against other stored-product insect pests. PMID:23463916

  4. Organic Aerosol Component (OACOMP) Value-Added Product

    SciTech Connect

    Fast, J; Zhang, Q; tilp, A; Shippert, T; Parworth, C; Mei, F

    2013-08-23

    Organic aerosol (OA, i.e., the organic fraction of particles) accounts for 10–90% of the fine aerosol mass globally and is a key determinant of aerosol radiative forcing. But atmospheric OA is poorly characterized and its life cycle insufficiently represented in models. As a result, current models are unable to simulate OA concentrations and properties accurately. This deficiency represents a large source of uncertainty in quantification of aerosol effects and prediction of future climate change. Evaluation and development of aerosol models require data products generated from field observations. Real-time, quantitative data acquired with aerosol mass spectrometers (AMS) (Canagaratna et al. 2007) are critical to this need. The AMS determines size-resolved concentrations of non-refractory (NR) species in submicrometer particles (PM1) with fast time resolution suitable for both ground-based and aircraft deployments. The high-resolution AMS (HR-AMS), which is equipped with a high mass resolution time-of-flight mass spectrometer, can be used to determine the elemental composition and oxidation degrees of OA (DeCarlo et al. 2006).

  5. A theoretical study on gas-phase coating of aerosol particles

    SciTech Connect

    Jain, S.; Fotou, G.P.; Kodas, T.T.

    1997-01-01

    In situ coating of aerosol particles by gas-phase and surface reaction in a flow reactor is modeled accounting for scavenging (capture of small particles by large particles) and simultaneous surface reaction along with the finite sintering rate of the scavenged particles. A log-normal size distribution is assumed for the host and coating particles to describe coagulation and a monodisperse size distribution is used for the coating particles to describe sintering. As an example, coating of titania particles with silica in a continuous flow hot-wall reactor was modeled. High temperatures, low reactant concentrations, and large host particle surface areas favored smoother coatings in the parameter range: temperature 1,700--1,800 K, host particle number concentration 1 {times} 10{sup 5}--1 {times} 10{sup 7} No./cm{sup 3}, average host particle size 1 {micro}m, inlet coating reactant concentration (SiCl{sub 4}) 2 {times} 10{sup {minus}7}--2 {times} 10{sup {minus}10} mol/cm{sup 3}, and various surface reaction rates. The fraction of silica deposited on the TiO{sub 2} particles decreased by more than seven times with a hundredfold increase in SiCl{sub 4} inlet concentration because of the resulted increase in the average SiO{sub 2} particle size under the assumed coating conditions. Increasing the TiO{sub 2} particle number concentration resulted in higher scavenging efficiency of SiO{sub 2}. In the TiO{sub 2}/SiO{sub 2} system it is likely that surface reaction as well as scavenging play important roles in the coating process. The results agree qualitatively with experimental observations of TiO{sub 2} particles coated in situ with silica.

  6. Pulmonary toxicity following exposure to a tile coating product containing alkylsiloxanes. A clinical and toxicological evaluation

    PubMed Central

    Nørgaard, A. W.; Hansen, J. S.; Sørli, J. B.; Jacobsen, P.; Lynggard, F.; Levin, M.; Nielsen, G. D.; Wolkoff, P.; Ebbehøj, N. E.; Larsen, S. T.

    2014-01-01

    Context Coating products are widely used for making surfaces water and dirt repellent. However, on several occasions the use of these products has been associated with lung toxicity. Objective In the present study, we evaluated the toxic effects of an aerosolized tile-coating product. Methods Thirty-nine persons, who reported respiratory and systemic symptoms following exposure to the tile-coating product, were clinically examined. The product was analysed chemically and furthermore, the exposure scenario was reconstructed using a climate chamber and the toxicological properties of the product were studied using in vivo and by in vitro surfactometry. Results The symptoms developed within few hours and included coughing, tachypnoea, chest pain, general malaise and fever. The physical examination revealed perihilar lung infiltrates on chest radiograph and reduced blood oxygen saturation. The acute symptoms resolved gradually within 1–3 days and no delayed symptoms were observed. By means of mass spectrometry and X-ray spectroscopy, it was shown that the product contained non-fluorinated alkylsiloxanes. The exposure conditions in the supermarket were reconstructed under controlled conditions in a climate chamber and particle and gas exposure levels were monitored over time allowing estimation of human exposure levels. Mice exposed to the product developed symptoms of acute pulmonary toxicity in a concentration-and time-dependent manner. The symptoms of acute pulmonary toxicity likely resulted from inhibition of the pulmonary surfactant function as demonstrated by in vitro surfactometry. Among these patients only a partial association between the level of exposure and the degree of respiratory symptoms was observed, which could be because of a high inter-individual difference in sensitivity and time-dependent changes in the chemical composition of the aerosol. Conclusion Workers need to cautiously apply surface coating products because the contents can be highly

  7. In situ aerosol optics in Reno, NV, USA during and after the summer 2008 California wildfires and the influence of aerosol coatings

    NASA Astrophysics Data System (ADS)

    Gyawali, M.; Arnott, W. P.; Lewis, K.; Moosmüller, H.

    2009-06-01

    Hundreds of wildfires in Northern California were sparked by lightning during the summer of 2008, resulting in downwind smoke for the months of June and July. Comparisons are reported for aerosol optics measurements in Reno Nevada made during the very smoky summer month of July and the relatively clean month of August. Photoacoustic instruments equipped with integrating nephelometers were used to measure aerosol light scattering and absorption at wavelengths of 405 nm and 870 nm, revealing a strong variation of the aerosol light absorption with wavelength. Coated sphere calculations were used to show that Ångström exponents of absorption (AEA) as large as 1.6 are possible even with non-absorbing organic coatings on black carbon cores, suggesting care be exercised when diagnosing AEA. Insight on fuels burned is gleaned from comparison of AEA versus single scattering albedo (SSA) of the ambient measurements with laboratory biomass smoke measurements for many fuels. Measurements during the month of August, which were largely unaffected by fire smoke, exhibit surprisingly low AEA for aerosol light absorption when the SSA is highest, again likely as a consequence of the underappreciated wavelength dependence of aerosol light absorption by particles coated with non absorbing organic and inorganic matter.

  8. Current Status of Suomi NPP VIIRS Aerosol Products

    NASA Astrophysics Data System (ADS)

    Kondragunta, S.; Laszlo, I.; Liu, H.; Zhang, H.; Huang, J.; Remer, L. A.; Ciren, P.; Huang, H.

    2013-12-01

    The Suomi National Polar-orbiting Partnership (NPP) Visible Infrared Imaging Radiometer Suite (VIIRS) instrument was launched on October 28, 2011. It provides Aerosol Optical Thickness (AOT) at two different spatial resolutions: a pixel level (~750 m at nadir) product called the Intermediate Product (IP) and an aggregated (~6 km at nadir) product called the Environmental Data Record (EDR). The VIIRS AOT is expected to provide continuity to the 10-km Aqua and Terra MODIS (Moderate resolution Imaging Spectroradiometer) AOT products that the air quality and public health community has been using. The VIIRS aerosol product suite also includes less mature products such as Suspended Matter (SM) and Aerosol Particle Size Parameter (APSP). An extensive validation of VIIRS best quality aerosol products with ground based L1.5 AERONET data shows that the AOT EDR product has an accuracy/precision of -0.01/0.11 and 0.01/0.08 over land and ocean respectively. Globally, VIIRS mean AOT EDR (0.20) is similar to Aqua MODIS (0.16) with some important regional and seasonal differences. Analysis of SM shows that the algorithm predominantly picks smoke both over land and ocean which is not in agreement with retrievals from Multi-angle Imaging SpectroRadiometer (MISR) and Cloud Aerosol Lidar and Infrared Pathfinder Space Observations (CALIPSO). Similarly, the Angstrom Exponent (AE) retrieval used as a proxy for particle size has no skill over land and only a marginal skill over ocean when compared to AERONET; although a bias of ~0.2 for over ocean retrievals meets specification (0.3), the correlation is low and the standard deviation is ~0.6 and does not meet specification (0.3). This evaluation places the VIIRS AOT product at the provisional maturity level (product is validated, may contain some errors, and ready for operational evaluation). However, several algorithm updates which include a better approach to retrieve surface reflectance are forthcoming. Current status of the aerosol

  9. Structure and dissolution of L-leucine-coated salbutamol sulphate aerosol particles.

    PubMed

    Raula, Janne; Seppälä, Jukka; Malm, Jari; Karppinen, Maarit; Kauppinen, Esko I

    2012-06-01

    L-Leucine formed different crystalline coatings on salbutamol sulphate aerosol particles depending on the saturation conditions of L-leucine. The work emphasizes a careful characterization of powders where structural compartments such as crystal size and particle coating may affect the performance of drug when administered. The sublimation of L-leucine from the aerosol particles took place 90°C lower temperature than the bulk L-leucine which was attributed to result from the sublimation of L-leucine from nano-sized crystalline domains. The dissolution slowed down and initial dissolution rate decreased with increasing L-leucine content. Decreasing crystalline domains to nano-scale improve heat and mass transfer which was observed as the lowered decomposition temperature of the drug salbutamol sulphate and the sublimation temperature of surface material L-leucine as well as the altered dissolution characteristics of the drug. The structure of the coated drug particles was studied by means of thermal analysis techniques (DSC and TG), and the dissolution of salbutamol sulphate was studied as an on-line measurement in a diffusion cell. PMID:22562614

  10. Effect of Organic Coatings, Humidity and Aerosol Acidity on Multiphase Chemistry of Isoprene Epoxydiols.

    PubMed

    Riva, Matthieu; Bell, David M; Hansen, Anne-Maria Kaldal; Drozd, Greg T; Zhang, Zhenfa; Gold, Avram; Imre, Dan; Surratt, Jason D; Glasius, Marianne; Zelenyuk, Alla

    2016-06-01

    Multiphase chemistry of isomeric isoprene epoxydiols (IEPOX) has been shown to be the dominant source of isoprene-derived secondary organic aerosol (SOA). Recent studies have reported particles composed of ammonium bisulfate (ABS) mixed with model organics exhibit slower rates of IEPOX uptake. In the present study, we investigate the effect of atmospherically relevant organic coatings of α-pinene (AP) SOA on the reactive uptake of trans-β-IEPOX onto ABS particles under different conditions and coating thicknesses. Single particle mass spectrometry was used to characterize in real-time particle size, shape, density, and quantitative composition before and after reaction with IEPOX. We find that IEPOX uptake by pure sulfate particles is a volume-controlled process, which results in particles with uniform concentration of IEPOX-derived SOA across a wide range of sizes. Aerosol acidity was shown to enhance IEPOX-derived SOA formation, consistent with recent studies. The presence of water has a weaker impact on IEPOX-derived SOA yield, but significantly enhanced formation of 2-methyltetrols, consistent with offline filter analysis. In contrast, IEPOX uptake by ABS particles coated with AP-derived SOA is lower compared to that of pure ABS particles, strongly dependent on particle composition, and therefore on particle size. PMID:27176464

  11. N(2)O(5) reaction on submicron sea salt aerosol: kinetics, products, and the effect of surface active organics.

    PubMed

    Thornton, Joel A; Abbatt, Jonathan P D

    2005-11-10

    The reaction of N(2)O(5) on sea salt aerosol is a sink for atmospheric nitrogen oxides and a source of the Cl radical. We present room-temperature measurements of the N(2)O(5) loss rate on submicron artificial seawater (ASW) aerosol, performed with an entrained aerosol flow tube coupled to a chemical ionization mass spectrometer, as a function of aerosol phase (aqueous or partially crystalline), liquid water content, and size. We also present an analysis of the product growth kinetics showing that ClNO(2) is produced at a rate equal to N(2)O(5) loss, with an estimated lower limit yield of 50% at 50% relative humidity (RH). The reaction probability for N(2)O(5), gamma(N(2)(O)(5)), depends strongly on the particle phase, being 0.005 +/- 0.004 on partially crystalline ASW aerosol at 30% RH and 0.03 +/- 0.008 on aqueous ASW aerosol at 65% RH. At 50% RH, N(2)O(5) loss is relatively insensitive to particle size for radii greater than 100 nm, and gamma(N(2)(O)(5)) displays a statistically insignificant increase from 0.022 to approximately 0.03 for aqueous ASW aerosol over the RH range of 43-70%. We find that the presence of millimolar levels of hexanoic acid in the aerosol bulk decreases the gamma(N(2)(O)(5)) at 70% RH by a factor of 3-4 from approximately 0.025 to 0.008 +/- 0.004. This reduction is likely due to the partitioning of hexanoic acid to the gas-aerosol interface at a surface coverage that we estimate to be equivalent to a monolayer. This result is the first evidence that a monolayer coating of aqueous organic surfactant can slow the reactive uptake of atmospheric trace gases to aerosol. PMID:16838918

  12. PRODUCTION OF SECONDARY ORGANIC AEROSOL FROM MULTIPHASE TERPENE PHOTOOXIDATION

    EPA Science Inventory

    This project involves a field and laboratory study of the production of aerosol from the atmospheric photooxidation of biogenic volatile organic compounds (BVOCs), specifically the terpenes α- and β-pinene, using a unique combination of approaches that rely on produ...

  13. Characterization of Fe–Cr alloy metallic interconnects coated with LSMO using the aerosol deposition process

    SciTech Connect

    Huang, Jian-Jia; Fu, Yen-Pei; Wang, Jian-Yih; Cheng, Yung-Neng; Lee, Shyong; Hsu, Jin-Cherng

    2014-03-01

    Graphical abstract: - Highlights: • Lanthanum strontium manganite (LSMO) as the protective layer for metallic interconnects was successfully prepared by aerosol deposition method (AD). • The microstructure, electrical resistance and composition for LSMO-coated Fe–Cr alloys undergoing high temperature, long-hour oxidation were investigated. • The denser protective layer prepared by AD might effectively prohibit the growth of oxidized scale after long time running at 800 °C in air. - Abstract: A Fe–Cr alloy, used for metallic interconnects, was coated with a protective layer of lanthanum strontium manganite (LSMO) using the aerosol deposition method (AD). The effects of the LSMO protective layer, which was coated on the Fe–Cr interconnects using AD, on the area specific resistance (ASR) during high temperature oxidation and the Cr evaporation behaviors were systematically investigated in this paper. The microstructures, morphologies, and compositions of the oxidized scales that appeared on the LSMO-coated Fe–Cr alloy after annealing at 800 °C for 750 h in air were examined using SEM equipped with EDS. The EPMA mapping of the LSMO-coated Fe–Cr interconnects undergoing long term, high-temperature oxidation was used to explain the formation layers of the oxidized scale, which consists of (Mn,Cr){sub 3}O{sub 4} and Cr{sub 2}O{sub 3} layers. Moreover, the experimental results revealed that the AD process is a potential method for preparing denser protective layers with highly desirable electrical properties for metallic interconnects.

  14. Towards an improved aerosol product from SCIAMACHY limb measurements

    NASA Astrophysics Data System (ADS)

    Rozanov, Alexei; Burrows, John; Hommel, Rene

    2015-04-01

    Stratospheric aerosols are of a great scientific interest because of their crucial role in the Earth's radiative budget as well as their contribution to chemical processes resulting in ozone depletion. While the permanent aerosol background in the stratosphere is determined by the tropical injection of SO2, COS and sulphate particles from the troposphere, major perturbations of the stratospheric aerosol layer result form an uplift of SO2 after strong volcanic eruptions. Satellite measurements in the visible spectral range represent one of the most important sources of information about the vertical distribution of the stratospheric aerosol on the global scale. This study employs measurements of the scattered solar light performed in the limb viewing geometry from the space borne spectrometer SCIAMACHY, which operated onboard the ENVISAT satellite from August 2002 to April 2012. A progress in the development of SCIAMACHY aerosol data product within the ROSA/ROMIC project including the improvements in the extinction coefficient data base and steps towards the retrieval of particle size distribution parameters is reported.

  15. Chemical compositions of black carbon particle cores and coatings via soot particle aerosol mass spectrometry with photoionization and electron ionization.

    PubMed

    Canagaratna, Manjula R; Massoli, Paola; Browne, Eleanor C; Franklin, Jonathan P; Wilson, Kevin R; Onasch, Timothy B; Kirchstetter, Thomas W; Fortner, Edward C; Kolb, Charles E; Jayne, John T; Kroll, Jesse H; Worsnop, Douglas R

    2015-05-14

    Black carbon is an important constituent of atmospheric aerosol particle matter (PM) with significant effects on the global radiation budget and on human health. The soot particle aerosol mass spectrometer (SP-AMS) has been developed and deployed for real-time ambient measurements of refractory carbon particles. In the SP-AMS, black carbon or metallic particles are vaporized through absorption of 1064 nm light from a CW Nd:YAG laser. This scheme allows for continuous "soft" vaporization of both core and coating materials. The main focus of this work is to characterize the extent to which this vaporization scheme provides enhanced chemical composition information about aerosol particles. This information is difficult to extract from standard SP-AMS mass spectra because they are complicated by extensive fragmentation from the harsh 70 eV EI ionization scheme that is typically used in these instruments. Thus, in this work synchotron-generated vacuum ultraviolet (VUV) light in the 8-14 eV range is used to measure VUV-SP-AMS spectra with minimal fragmentation. VUV-SP-AMS spectra of commercially available carbon black, fullerene black, and laboratory generated flame soots were obtained. Small carbon cluster cations (C(+)-C5(+)) were found to dominate the VUV-SP-AMS spectra of all the samples, indicating that the corresponding neutral clusters are key products of the SP vaporization process. Intercomparisons of carbon cluster ratios observed in VUV-SP-AMS and SP-AMS spectra are used to confirm spectral features that could be used to distinguish between different types of refractory carbon particles. VUV-SP-AMS spectra of oxidized organic species adsorbed on absorbing cores are also examined and found to display less thermally induced decomposition and fragmentation than spectra obtained with thermal vaporization at 200 °C (the minimum temperature needed to quantitatively vaporize ambient oxidized organic aerosol with a continuously heated surface). The particle cores

  16. Changes in the optical properties of benzo[a]pyrene-coated aerosols upon heterogeneous reactions with NO2 and NO3.

    PubMed

    Lu, Jessica W; Flores, J Michel; Lavi, Avi; Abo-Riziq, Ali; Rudich, Yinon

    2011-04-14

    Chemical reactions can alter the chemical, physical, and optical properties of aerosols. It has been postulated that nitration of aerosols can account for atmospheric absorbance over urban areas. To study this potentially important process, the change in optical properties of laboratory-generated benzo[a]pyrene (BaP)-coated aerosols following exposure to NO(2) and NO(3) was investigated at 355 nm and 532 nm by three aerosol analysis techniques. The extinction coefficient was determined at 355 nm and 532 nm from cavity ring-down aerosol spectroscopy (CRD-AS); the absorption coefficient was measured by photoacoustic spectroscopy (PAS) at 532 nm, while an on-line aerosol mass spectrometer (AMS) supplied real-time quantitative information about the chemical composition of aerosols. In this study, 240 nm polystyrene latex (PSL) spheres were thinly coated with BaP to form 300 or 310 nm aerosols that were exposed to high concentrations of NO(2) and NO(3) and measured with CRD-AS, PAS, and the AMS. The extinction efficiencies (Q(ext)) changed after exposure to NO(2) and NO(3) at both wavelengths. Prior to reaction, Q(ext) for the 355 nm and 532 nm wavelengths were 4.36 ± 0.04 and 2.39 ± 0.05, respectively, and Q(ext) increased to 5.26 ± 0.04 and 2.79 ± 0.05 after exposure. The absorption cross-section at 532 nm, determined with PAS, reached σ(abs) = (0.039 ± 0.001) × 10(-8) cm(2), indicating that absorption increased with formation of nitro-BaP, the main reaction product detected by the AMS. The single-scattering albedo (SSA), a measure of particle scattering efficiency, decreased from 1 to 0.85 ± 0.03, showing that changes in the optical properties of BaP-covered aerosols due to nitration may have implications for regional radiation budget and, hence, climate. PMID:21373662

  17. 21 CFR 700.16 - Use of aerosol cosmetic products containing zirconium.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 7 2010-04-01 2010-04-01 false Use of aerosol cosmetic products containing... SERVICES (CONTINUED) COSMETICS GENERAL Requirements for Specific Cosmetic Products § 700.16 Use of aerosol... in cosmetics and/or cosmetics that are also drugs, as, for example, aerosol antiperspirants....

  18. The Collection 6 MODIS aerosol products over land and ocean

    NASA Astrophysics Data System (ADS)

    Levy, R. C.; Mattoo, S.; Munchak, L. A.; Remer, L. A.; Sayer, A. M.; Hsu, N. C.

    2013-01-01

    The twin Moderate Imaging resolution Spectroradiometer (MODIS) sensors have been flying on Terra since 2000 and Aqua since 2002, creating an incredible dataset of global Earth observations. Here, we introduce the Collection 6 (C6) algorithm to retrieve aerosol optical depth (AOD) and aerosol size parameters from MODIS-observed spectral reflectance. While not a major overhaul from the previous Collection 5 (C5) version, there are enough changes that there is significant impact on the products and their interpretation. The C6 algorithm is comprised of three sub-algorithms for retrieving aerosol properties (1) over ocean (dark in visible and near-IR wavelengths), (2) over vegetated/dark-soiled land (dark in the visible) and (3) over desert/arid land (bright in the visible). Here, we focus on the changes to both "dark target" algorithms (#1 and #2; DT-ocean and DT-land). Affecting both DT algorithms, we have updated assumptions for central wavelengths, Rayleigh optical depths and gas (H2O, O3, CO2, etc.) absorption corrections, and relaxed the solar zenith angle limit (up to ≤ 84°) to increase pole-ward coverage. For DT-land, we have updated the cloud mask to allow heavy smoke retrievals, fine-tuned the assignments for aerosol type as function of season/location, corrected bugs in the Quality Assurance (QA) logic, and added diagnostic parameters such topographic altitude. For DT-ocean, improvements include a revised cloud mask for thin-cirrus detection, inclusion of wind speed dependence in the retrieval, updates to logic of QA Confidence flag (QAC) assignment, and additions of important diagnostic information. All together, the changes to the DT algorithms result in reduced global AOD (by 0.02) over ocean and increased AOD (by 0.01) over land, along with some changes in spatial coverage. Preliminary validation shows that compared to surface-based sunphotometer data, the C6 DT-products should compare at least as well as those from C5. However, at the same time as we

  19. The Collection 6 'dark-target' MODIS Aerosol Products

    NASA Technical Reports Server (NTRS)

    Levy, Robert C.; Mattoo, Shana; Munchak, Leigh A.; Kleidman, Richard G.; Patadia, Falguni; Gupta, Pawan; Remer, Lorraine

    2013-01-01

    Aerosol retrieval algorithms are applied to Moderate resolution Imaging Spectroradiometer (MODIS) sensors on both Terra and Aqua, creating two streams of decade-plus aerosol information. Products of aerosol optical depth (AOD) and aerosol size are used for many applications, but the primary concern is that these global products are comprehensive and consistent enough for use in climate studies. One of our major customers is the international modeling comparison study known as AEROCOM, which relies on the MODIS data as a benchmark. In order to keep up with the needs of AEROCOM and other MODIS data users, while utilizing new science and tools, we have improved the algorithms and products. The code, and the associated products, will be known as Collection 6 (C6). While not a major overhaul from the previous Collection 5 (C5) version, there are enough changes that there are significant impacts to the products and their interpretation. In its entirety, the C6 algorithm is comprised of three sub-algorithms for retrieving aerosol properties over different surfaces: These include the dark-target DT algorithms to retrieve over (1) ocean and (2) vegetated-dark-soiled land, plus the (3) Deep Blue (DB) algorithm, originally developed to retrieve over desert-arid land. Focusing on the two DT algorithms, we have updated assumptions for central wavelengths, Rayleigh optical depths and gas (H2O, O3, CO2, etc.) absorption corrections, while relaxing the solar zenith angle limit (up to 84) to increase pole-ward coverage. For DT-land, we have updated the cloud mask to allow heavy smoke retrievals, fine-tuned the assignments for aerosol type as function of season location, corrected bugs in the Quality Assurance (QA) logic, and added diagnostic parameters such as topographic altitude. For DT-ocean, improvements include a revised cloud mask for thin-cirrus detection, inclusion of wind speed dependence in the retrieval, updates to logic of QA Confidence flag (QAC) assignment, and

  20. An investigation of a potential low bias in the MODIS aerosol products over Asia

    NASA Astrophysics Data System (ADS)

    McHardy, T. M.; Shi, Y.; Zhang, J.; Reid, J. S.; Campbell, J. R.; Hsu, N. Y. C.

    2015-12-01

    Heavy aerosol plumes can be misidentified as clouds in passive satellite-based aerosol retrievals due to their relatively high visible reflectivity. Thus, over regions such as China, where a higher frequency of heavy aerosol plumes is expected, regional aerosol optical depth analyses reported from passive satellite-based aerosol products may biased low. This fundamental error can be suppressed under certain conditions. In this study, with a synergistic use of satellite observations from MODIS, OMI and CALIOP, a low bias in the MODIS Dark Target (DT) and Deep Blue (DB) aerosol products is studied over Asia for the influence of dense aerosol plume undersampling. A new scheme has been developed for detecting heavy aerosol plumes by coupling OMI aerosol index retrievals with available CALIOP level 1B and cloud and aerosol profile data. Collocated CALIOP, MODIS and OMI data are then used to further investigate the potential low bias in the MODIS DT and DB aerosol products, in an attempt to quantify the measure of undersampling in the regional DT and DB archive. Our preliminary results show that DT and DB aerosol algorithms detect about half heavy aerosol loading when CALIPSO and OMI AI believe there are heavy absorbing aerosols.

  1. The Collection 6 MODIS aerosol products over land and ocean

    NASA Astrophysics Data System (ADS)

    Levy, R. C.; Mattoo, S.; Munchak, L. A.; Remer, L. A.; Sayer, A. M.; Patadia, F.; Hsu, N. C.

    2013-11-01

    The twin Moderate resolution Imaging Spectroradiometer (MODIS) sensors have been flying on Terra since 2000 and Aqua since 2002, creating an extensive data set of global Earth observations. Here, we introduce the Collection 6 (C6) algorithm to retrieve aerosol optical depth (AOD) and aerosol size parameters from MODIS-observed spectral reflectance. While not a major overhaul from the previous Collection 5 (C5) version, there are enough changes that there are significant impacts to the products and their interpretation. The C6 aerosol data set will be created from three separate retrieval algorithms that operate over different surface types. These are the two "Dark Target" (DT) algorithms for retrieving (1) over ocean (dark in visible and longer wavelengths) and (2) over vegetated/dark-soiled land (dark in the visible), plus the "Deep Blue" (DB) algorithm developed originally for retrieving (3) over desert/arid land (bright in the visible). Here, we focus on DT-ocean and DT-land (#1 and #2). We have updated assumptions for central wavelengths, Rayleigh optical depths and gas (H2O, O3, CO2, etc.) absorption corrections, while relaxing the solar zenith angle limit (up to ≤ 84°) to increase poleward coverage. For DT-land, we have updated the cloud mask to allow heavy smoke retrievals, fine-tuned the assignments for aerosol type as function of season/location, corrected bugs in the Quality Assurance (QA) logic, and added diagnostic parameters such topographic altitude. For DT-ocean, improvements include a revised cloud mask for thin-cirrus detection, inclusion of wind speed dependence on the surface reflectance, updates to logic of QA Confidence flag (QAC) assignment, and additions of important diagnostic information. At the same time, we quantified how "upstream" changes to instrument calibration, land/sea masking and cloud masking will also impact the statistics of global AOD, and affect Terra and Aqua differently. For Aqua, all changes will result in reduced

  2. What is the "Clim-Likely" aerosol product?

    Atmospheric Science Data Center

    2014-12-08

    The "Clim-Likely" aerosol climatology data set was developed as an initial step in identifying a range of ... mixtures for the MISR Standard Aerosol Retrieval Algorithm climatology, and as one standard against which to compare MISR aerosol air mass ...

  3. MISR Global Aerosol Product Assessment by Comparison with AERONET

    NASA Technical Reports Server (NTRS)

    Kahn, Ralph A.; Gaitley, Barbara J.; Garay, Michael J.; Diner, David J.; Eck, Thomas F.; Smirnov, Alexander; Holben, Brent N.

    2010-01-01

    A statistical approach is used to assess the quality of the MISR Version 22 (V22) aerosol products. Aerosol Optical Depth (AOD) retrieval results are improved relative to the early post- launch values reported by Kahn et al. [2005a], varying with particle type category. Overall, about 70% to 75% of MISR AOD retrievals fall within 0.05 or 20% AOD of the paired validation data, and about 50% to 55% are within 0.03 or 10% AOD, except at sites where dust, or mixed dust and smoke, are commonly found. Retrieved particle microphysical properties amount to categorical values, such as three groupings in size: "small," "medium," and "large." For particle size, ground-based AERONET sun photometer Angstrom Exponents are used to assess statistically the corresponding MISR values, which are interpreted in terms of retrieved size categories. Coincident Single-Scattering Albedo (SSA) and fraction AOD spherical data are too limited for statistical validation. V22 distinguishes two or three size bins, depending on aerosol type, and about two bins in SSA (absorbing vs. non-absorbing), as well as spherical vs. non-spherical particles, under good retrieval conditions. Particle type sensitivity varies considerably with conditions, and is diminished for mid-visible AOD below about 0.15 or 0.2. Based on these results, specific algorithm upgrades are proposed, and are being investigated by the MISR team for possible implementation in future versions of the product.

  4. Formulation and production of intumescent coating systems

    NASA Technical Reports Server (NTRS)

    Hoffman, J.; Schwartz, H. R.

    1973-01-01

    Methods for manufacturing and producing fire protective intumescent coatings are described. The coatings consist of three reactive parts mixed together at the time of use. The chemical composition of the reactive parts is discussed. The characteristics of the coatings which are obtained by three types of processing are analyzed. Qualification tests of the materials to determine acceptability are reported.

  5. A merged aerosol dataset based on MODIS and MISR Aerosol Optical Depth products

    NASA Astrophysics Data System (ADS)

    Singh, Manoj K.; Gautam, Ritesh; Venkatachalam, Parvatham

    2016-05-01

    Aerosol Optical Depth (AOD) products available from MODIS and MISR observations are widely used for aerosol characterization, and global/environmental change studies. These products are based on different retrieval-algorithms, resolutions, sampling, and cloud-screening schemes, which have led to global/regional biases. Thus a merged product is desirable which bridges this gap by utilizing strengths from each of the sensors. In view of this, we have developed a "merged" AOD product based on MODIS and MISR AOD datasets, using Bayesian principles which takes error distributions from ground-based AOD measurements (from AERONET). Our methodology and resulting dataset are especially relevant in the scenario of combining multi-sensor retrievals for satellite-based climate data records; particularly for long-term studies involving AOD. Specifically for MISR AOD product, we also developed a methodology to produce a gap-filled dataset, using geostatistical methods (e.g. Kriging), taking advantage of available MODIS data. Merged and spatially-complete AOD datasets are inter-compared with other satellite products and with AERONET data at three stations- Kanpur, Jaipur and Gandhi College, in the Indo-Gangetic Plains. The RMSE of merged AOD (0.08-0.09) is lower than MISR (0.11-0.20) and MODIS (0.15-0.27). It is found that merged AOD has higher correlation with AERONET data (r within 0.92-0.95), compared to MISR (0.74-0.86) and MODIS (0.69-0.84) data. In terms of Expected Error, the accuracy of valid merged AOD is found to be superior as percent of merged AOD within error envelope are larger (71-92%), compared to MISR (43-61%) and MODIS (50-70%).

  6. Classification of Dust Days by Satellite Remotely Sensed Aerosol Products

    NASA Technical Reports Server (NTRS)

    Sorek-Hammer, M.; Cohen, A.; Levy, Robert C.; Ziv, B.; Broday, D. M.

    2013-01-01

    Considerable progress in satellite remote sensing (SRS) of dust particles has been seen in the last decade. From an environmental health perspective, such an event detection, after linking it to ground particulate matter (PM) concentrations, can proxy acute exposure to respirable particles of certain properties (i.e. size, composition, and toxicity). Being affected considerably by atmospheric dust, previous studies in the Eastern Mediterranean, and in Israel in particular, have focused on mechanistic and synoptic prediction, classification, and characterization of dust events. In particular, a scheme for identifying dust days (DD) in Israel based on ground PM10 (particulate matter of size smaller than 10 nm) measurements has been suggested, which has been validated by compositional analysis. This scheme requires information regarding ground PM10 levels, which is naturally limited in places with sparse ground-monitoring coverage. In such cases, SRS may be an efficient and cost-effective alternative to ground measurements. This work demonstrates a new model for identifying DD and non-DD (NDD) over Israel based on an integration of aerosol products from different satellite platforms (Moderate Resolution Imaging Spectroradiometer (MODIS) and Ozone Monitoring Instrument (OMI)). Analysis of ground-monitoring data from 2007 to 2008 in southern Israel revealed 67 DD, with more than 88 percent occurring during winter and spring. A Classification and Regression Tree (CART) model that was applied to a database containing ground monitoring (the dependent variable) and SRS aerosol product (the independent variables) records revealed an optimal set of binary variables for the identification of DD. These variables are combinations of the following primary variables: the calendar month, ground-level relative humidity (RH), the aerosol optical depth (AOD) from MODIS, and the aerosol absorbing index (AAI) from OMI. A logistic regression that uses these variables, coded as binary

  7. Light-enhanced primary marine aerosol production from biologically productive seawater

    NASA Astrophysics Data System (ADS)

    Long, M. S.; Keene, W. C.; Kieber, D. J.; Frossard, A. A.; Russell, L. M.; Maben, J. R.; Kinsey, J. D.; Quinn, P. K.; Bates, T. S.

    2014-04-01

    Physical and biogeochemical processes in seawater controlling primary marine aerosol (PMA) production and composition are poorly understood and associated with large uncertainties in estimated fluxes into the atmosphere. PMA production was investigated in the biologically productive NE Pacific Ocean and in biologically productive and oligotrophic regions of the NW Atlantic Ocean. Physicochemical properties of model PMA, produced by aeration of fresh seawater under controlled conditions, were quantified. Diel variability in model PMA mass and number fluxes was observed in biologically productive waters, increasing following sunrise and decreasing to predawn levels overnight. Such variability was not seen in oligotrophic waters. During daytime, surfactant scavenging by aeration in the aerosol generator without replenishing the seawater in the reservoir reduced the model PMA production in productive waters to nighttime levels but had no influence on production from oligotrophic waters. Results suggest bubble plume interactions with sunlight-mediated biogenic surfactants in productive seawater significantly enhanced model PMA production.

  8. Production, Organic Characterization, and Phase Transformations of Marine Particles Aerosolized from a Laboratory Mesocosm Phytoplankton Bioreactor

    NASA Astrophysics Data System (ADS)

    Alpert, P. A.; Knopf, D. A.; Aller, J. Y.; Radway, J.; Kilthau, W.

    2012-12-01

    artificial seawater show agreement with previous studies. As the phytoplankton population grows, particle production increases, with particles smaller than 200 nm in diameter primarily contributing to this increase. CCSEM/EDAX and STXM/NEXAFS analysis shows that phytoplankton presence can result in purely organic airborne particles, NaCl particles coated with organic material and organic particles containing phytoplankton frustule fragments. We also have observed that submicrometer particles can efficiently nucleate ice and that the same ice nucleating particles examined with CCSEM/EDAX and STXM/NEXAFS contain significant organic material by mass. These results will aid in understanding the effects of biological activity on the composition and mixing state of ocean derived aerosol particles and their potential impact on cold cloud formation.

  9. The Multi-Sensor Aerosol Products Sampling System (MAPSS) for Integrated Analysis of Satellite Retrieval Uncertainties

    NASA Technical Reports Server (NTRS)

    Ichoku, Charles; Petrenko, Maksym; Leptoukh, Gregory

    2010-01-01

    Among the known atmospheric constituents, aerosols represent the greatest uncertainty in climate research. Although satellite-based aerosol retrieval has practically become routine, especially during the last decade, there is often disagreement between similar aerosol parameters retrieved from different sensors, leaving users confused as to which sensors to trust for answering important science questions about the distribution, properties, and impacts of aerosols. As long as there is no consensus and the inconsistencies are not well characterized and understood ', there will be no way of developing reliable climate data records from satellite aerosol measurements. Fortunately, the most globally representative well-calibrated ground-based aerosol measurements corresponding to the satellite-retrieved products are available from the Aerosol Robotic Network (AERONET). To adequately utilize the advantages offered by this vital resource,., an online Multi-sensor Aerosol Products Sampling System (MAPSS) was recently developed. The aim of MAPSS is to facilitate detailed comparative analysis of satellite aerosol measurements from different sensors (Terra-MODIS, Aqua-MODIS, Terra-MISR, Aura-OMI, Parasol-POLDER, and Calipso-CALIOP) based on the collocation of these data products over AERONET stations. In this presentation, we will describe the strategy of the MAPSS system, its potential advantages for the aerosol community, and the preliminary results of an integrated comparative uncertainty analysis of aerosol products from multiple satellite sensors.

  10. Toward a Coherent Detailed Evaluation of Aerosol Data Products from Multiple Satellite Sensors

    NASA Technical Reports Server (NTRS)

    Ichoku, Charles; Petrenko, Maksym; Leptoukh, Gregory

    2011-01-01

    Atmospheric aerosols represent one of the greatest uncertainties in climate research. Although satellite-based aerosol retrieval has practically become routine, especially during the last decade, there is often disagreement between similar aerosol parameters retrieved from different sensors, leaving users confused as to which sensors to trust for answering important science questions about the distribution, properties, and impacts of aerosols. As long as there is no consensus and the inconsistencies are not well characterized and understood, there will be no way of developing reliable climate data records from satellite aerosol measurements. Fortunately, the most globally representative well-calibrated ground-based aerosol measurements corresponding to the satellite-retrieved products are available from the Aerosol Robotic Network (AERONET). To adequately utilize the advantages offered by this vital resource, an online Multi-sensor Aerosol Products Sampling System (MAPSS) was recently developed. The aim of MAPSS is to facilitate detailed comparative analysis of satellite aerosol measurements from different sensors (Terra-MODIS, Aqua-MODIS, TerraMISR, Aura-OMI, Parasol-POLDER, and Calipso-CALIOP) based on the collocation of these data products over AERONET stations. In this presentation, we will describe the strategy of the MASS system, its potential advantages for the aerosol community, and the preliminary results of an integrated comparative uncertainly analysis of aerosol products from multiple satellite sensors.

  11. Kinetics, products, and mechanisms of secondary organic aerosol formation.

    PubMed

    Ziemann, Paul J; Atkinson, Roger

    2012-10-01

    Secondary organic aerosol (SOA) is formed in the atmosphere when volatile organic compounds (VOCs) emitted from anthropogenic and biogenic sources are oxidized by reactions with OH radicals, O(3), NO(3) radicals, or Cl atoms to form less volatile products that subsequently partition into aerosol particles. Once in particles, these organic compounds can undergo heterogenous/multiphase reactions to form more highly oxidized or oligomeric products. SOA comprises a large fraction of atmospheric aerosol mass and can have significant effects on atmospheric chemistry, visibility, human health, and climate. Previous articles have reviewed the kinetics, products, and mechanisms of atmospheric VOC reactions and the general chemistry and physics involved in SOA formation. In this article we present a detailed review of VOC and heterogeneous/multiphase chemistry as they apply to SOA formation, with a focus on the effects of VOC molecular structure on the kinetics of initial reactions with the major atmospheric oxidants, the subsequent reactions of alkyl, alkyl peroxy, and alkoxy radical intermediates, and the composition of the resulting products. Structural features of reactants and products discussed include compound carbon number; linear, branched, and cyclic configurations; the presence of C[double bond, length as m-dash]C bonds and aromatic rings; and functional groups such as carbonyl, hydroxyl, ester, hydroxperoxy, carboxyl, peroxycarboxyl, nitrate, and peroxynitrate. The intention of this review is to provide atmospheric chemists with sufficient information to understand the dominant pathways by which the major classes of atmospheric VOCs react to form SOA products, and the further reactions of these products in particles. This will allow reasonable predictions to be made, based on molecular structure, about the kinetics, products, and mechanisms of VOC and heterogeneous/multiphase reactions, including the effects of important variables such as VOC, oxidant, and NO

  12. 21 CFR 700.16 - Use of aerosol cosmetic products containing zirconium.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 7 2011-04-01 2010-04-01 true Use of aerosol cosmetic products containing... SERVICES (CONTINUED) COSMETICS GENERAL Requirements for Specific Cosmetic Products § 700.16 Use of aerosol cosmetic products containing zirconium. (a) Zirconium-containing complexes have been used as an...

  13. 21 CFR 700.16 - Use of aerosol cosmetic products containing zirconium.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 7 2012-04-01 2012-04-01 false Use of aerosol cosmetic products containing... SERVICES (CONTINUED) COSMETICS GENERAL Requirements for Specific Cosmetic Products § 700.16 Use of aerosol cosmetic products containing zirconium. (a) Zirconium-containing complexes have been used as an...

  14. 21 CFR 700.16 - Use of aerosol cosmetic products containing zirconium.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 7 2014-04-01 2014-04-01 false Use of aerosol cosmetic products containing... SERVICES (CONTINUED) COSMETICS GENERAL Requirements for Specific Cosmetic Products § 700.16 Use of aerosol cosmetic products containing zirconium. (a) Zirconium-containing complexes have been used as an...

  15. Evaluating MODIS Collection 6 Dark Target Over Water Aerosol Products for Multi-sensor Data Fusion

    NASA Astrophysics Data System (ADS)

    Shi, Y.; Zhang, J.; Reid, J. S.; Hyer, E. J.; McHardy, T. M.; Lee, L.

    2014-12-01

    The Moderate Resolution Imaging Spectroradiometer (MODIS) aerosol products have been widely used in aerosol related climate, visibility, and air quality studies for more than a decade. Recently, the MODIS collection 6 (c6) aerosol products from MODIS-Aqua have been released. The reported changes between Collection 5 and Collection 6 include updates in the retrieving algorithms and a new cloud filtering process for the over-ocean products. Thus it is necessary to fully evaluate the collection 6 products for applications that require high quality MODIS aerosol optical depth data, such as operational aerosol data assimilation. The uncertainties in the MODIS c6 DT over ocean products are studied through both inter-comparing with the Multi-angle Imaging Spectroradiometer (MISR) aerosol products and by evaluation against ground truth. Special attention is given to the low bias in MODIS DT products due to the misclassifications of heavy aerosol plumes as clouds. Finally, a quality assured data assimilation grade aerosol optical product is constructed for aerosol data assimilation related applications.

  16. Production of satellite-derived aerosol climate data records: current status of the ESA Aerosol_cci project

    NASA Astrophysics Data System (ADS)

    de Leeuw, Gerrit; Holzer-Popp, Thomas; Pinnock, Simon

    2015-04-01

    and the Aerosol_cci team Within the ESA Climate Change Initiative (CCI) project Aerosol_cci (Phase 1: 2010 -2014; Phase 2: 2014-2017) intensive work has been conducted to improve algorithms for the retrieval of aerosol information from European sensors ATSR (3 algorithms), PARASOL, MERIS (3 algorithms), synergetic AATSR/SCIAMACHY, OMI and GOMOS. Whereas OMI and GOMOS were used to derive absorbing aerosol index and stratospheric extinction profiles, respectively, Aerosol Optical Depth (AOD) and Ångström coefficient were retrieved from the other sensors. The cooperation between the project partners, including both the retrieval teams and independent validation teams, has resulted in a strong improvement of most algorithms. In particular the AATSR retrieved AOD is qualitatively similar to that from MODIS, usually taken as the standard, MISR and SeaWiFS. This conclusion has been reached form several different ways of validation of the L2 and L3 products, using AERONET sun photometer data as the common ground-truth for the application of both 'traditional' statistical techniques and a 'scoring' technique using spatial and temporal correlations. Quantitatively, the limited AATSR swath width of 500km results in a smaller amount of data. Nevertheless, the assimilation of AATSR-retrieved AOD, together with MODIS data, contributes to improving the in the ECMWF climate model results. In addition to the multi-spectral AOD, and thus the Ångström Exponent, also a per-pixel uncertainty is provided and validated. By the end of Aerosol_cci Phase 1 the ATSR algorithms have been applied to both ATSR-2 and AATSR resulting in an AOD time series of 17 years. In phase 2 this work is continued with a focus on the further improvement of the ATSR algorithms as well as those for the other instruments and algorithms, mentioned above, which in phase 1 were considered less mature. The first efforts are on the further characterization of the uncertainties and on better understanding of the

  17. Secondary organic material formed by methylglyoxal in aqueous aerosol mimics - Part 2: Product identification using Aerosol-CIMS

    NASA Astrophysics Data System (ADS)

    Sareen, N.; Shapiro, E. L.; Schwier, A. N.; McNeill, V. F.

    2009-07-01

    We used chemical ionization mass spectrometry with a volatilization flow tube inlet (Aerosol-CIMS) to characterize secondary organic material formed by methylglyoxal with ammonium sulfate in aqueous aerosol mimics. Bulk reaction mixtures were diluted and atomized to form submicron aerosol particles. Organics were detected using Aerosol-CIMS in positive and negative ion mode using I- and H3O+·(H2O)n as reagent ions. The results are consistent with aldol condensation products, carbon-nitrogen species, sulfur-containing compounds, and oligomeric species up to 759 amu. These results support previous observations by us and others that ammonium sulfate plays a critical role in the SOA formation chemistry of dicarbonyl compounds.

  18. Oxygenated products of sesquiterpenes in secondary organic aerosol

    NASA Astrophysics Data System (ADS)

    van Eijck, A.; Kampf, C.; Hoffmann, T.

    2012-04-01

    Secondary organic aerosol (SOA) has a huge impact on air quality and climate change. It influences the Earth radiative budget through absorbing, scattering and reflecting radiation as well as the formation of clouds because the particulates can act as cloud condensation nuclei (CCN). Furthermore, it plays an important role for human health. SOA is formed from gaseous precursors which get oxidized by ozone, OH- and NO3-radicals in the atmosphere. Due to their low vapor pressure these degradation products can nucleate to form new particles or they can condense on existing aerosol particles. Despite the major progress in research during the last few years the actual chemical composition as well as the contribution of various volatile organic compounds (VOCs) to the formation of secondary organic aerosol is still partially unknown. Recent studies indicate that sesquiterpenes play an important role in the formation of SOA because of the low volatility of their oxygenated products (Lee et al., 2006). Their emission is estimated to be about 14,8 Tg per year (Henze et al., 2008), however, these emission rates remain highly uncertain due to the lack of quantitative emission rate measurements. In addition, the knowledge about the actual atmospheric degradation mechanism and the main oxidation products of sesquiterpenes is quite limited. β-Caryophyllene, α-humulene, α-farnesene and β-farnesene are the most abundant sequiterpenes in many sesquiterpene emission profiles. But also aromadendren, α-bergamotene and δ-cadinene and germacrene-D can contribute significantly to some emission profiles (Duhl et al., 2008). To determine the major oxygenated products of sesquiterpenes in SOA, reaction chamber experiments with different sesquiterpenes and ozone were performed in a 100 L reaction chamber. To measure the time dependent formation of initial oxidation products, an APCI-IT-MS was directly connected to the reaction chamber. After 2 hours the APCI-IT-MS was replaced by a

  19. Explosion risk evaluation during production of coating powder.

    PubMed

    Li, Gang; Yuan, Chunmiao; Chen, Baozhi

    2007-10-22

    Powder coating is widely used in industry to prevent equipment corrosion. More than 600 companies produce coating powder in China, but most do not understand the explosion hazard of such products. In the present investigation the explosibility parameters of a coating powder were determined. Results showed that the coating powder is explosible, though the ignition energy is higher than those of normal dusts such as coal powder and corn starch. Based on these experimental findings, a systematic explosion protection method is proposed, with explosion isolation and explosion venting being adopted as the main protective methods. PMID:17574336

  20. Resolution and Content Improvements to MISR Aerosol and Land Surface Products

    NASA Astrophysics Data System (ADS)

    Garay, M. J.; Bull, M. A.; Diner, D. J.; Hansen, E. G.; Kalashnikova, O. V.

    2015-12-01

    Since early 2000, the Multi-angle Imaging SpectroRadiometer (MISR) instrument on NASA's Terra satellite has been providing operational Level 2 (swath-based) aerosol optical depth (AOD) and particle property retrievals at 17.6 km spatial resolution and atmospherically corrected land surface products at 1.1 km resolution. The performance of the aerosol product has been validated against ground-based Aerosol Robotic Network (AERONET) observations, model comparisons, and climatological assessments. This product has played a major role in studies of the impacts of aerosols on climate and air quality. The surface product has found a variety of uses, particularly at regional scales for assessing vegetation and land surface change. A major development effort has led to the release of an update to the operational (Version 22) MISR Level 2 aerosol and land surface retrieval products, which has been in production since December 2007. The new release is designated Version 23. The resolution of the aerosol product has been increased to 4.4 km, allowing more detailed characterization of aerosol spatial variability, especially near local sources and in urban areas. The product content has been simplified and updated to include more robust measures of retrieval uncertainty and other fields to benefit users. The land surface product has also been updated to incorporate the Version 23 aerosol product as input and to improve spatial coverage, particularly over mountainous terrain and snow/ice-covered surfaces. We will describe the major upgrades incorporated in Version 23 and present validation of the aerosol product against both the standard AERONET historical database, as well as high spatial density AERONET-DRAGON deployments. Comparisons will also be shown relative to the Version 22 aerosol and land surface products. Applications enabled by these product updates will be discussed.

  1. Two MODIS Aerosol Products Over Ocean on the Terra and Aqua CERES SSF Datasets

    NASA Technical Reports Server (NTRS)

    Ignatov, Alexander; Minnis, Patrick; Loeb, Norman; Wielicki, Bruce; Miller, Walter; Sun-Mack, Sunny; Tanre, Didier; Remer, Lorraine; Laszlo, Istvan; Geier, Erika

    2004-01-01

    Over ocean, two aerosol products are reported on the Terra and Aqua CERES SSFs. Both are derived from MODIS, but using different sampling and aerosol algorithms. This study briefly summarizes these products, and compares using 2 weeks of global Terra data from 15-21 December 2000, and 1-7 June 2001.

  2. Assessment of 10-Year Global Record of Aerosol Products from the OMI Near-UV Algorithm

    NASA Astrophysics Data System (ADS)

    Ahn, C.; Torres, O.; Jethva, H. T.

    2014-12-01

    Global observations of aerosol properties from space are critical for understanding climate change and air quality applications. The Ozone Monitoring Instrument (OMI) onboard the EOS-Aura satellite provides information on aerosol optical properties by making use of the large sensitivity to aerosol absorption and dark surface albedo in the UV spectral region. These unique features enable us to retrieve both aerosol extinction optical depth (AOD) and single scattering albedo (SSA) successfully from radiance measurements at 354 and 388 nm by the OMI near UV aerosol algorithm (OMAERUV). Recent improvements to algorithms in conjunction with the Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) and Atmospheric Infrared Sounder (AIRS) carbon monoxide data also reduce uncertainties due to aerosol layer heights and types significantly in retrieved products. We present validation results of OMI AOD against space and time collocated Aerosol Robotic Network (AERONET) measured AOD values over multiple stations representing major aerosol episodes and regimes. We also compare the OMI SSA against the inversion made by AERONET as well as an independent network of ground-based radiometer called SKYNET in Japan, China, South-East Asia, India, and Europe. The outcome of the evaluation analysis indicates that in spite of the "row anomaly" problem, affecting the sensor since mid-2007, the long-term aerosol record shows remarkable sensor stability. The OMAERUV 10-year global aerosol record is publicly available at the NASA data service center web site (http://disc.sci.gsfc.nasa.gov/Aura/data-holdings/OMI/omaeruv_v003.shtml).

  3. VIIRS Aerosol Optical Depth (AOD) Products for Air Quality Applications

    NASA Astrophysics Data System (ADS)

    Huff, A. K.; Zhang, H.; Kondragunta, S.; Laszlo, I.

    2014-12-01

    The air quality community uses satellite aerosol optical depth (AOD) for a variety of applications, including daily air quality forecasting, retrospective event analysis, and justification for Exceptional Events. AOD is suitable for ambient air quality applications because is related to particulate matter (e.g., PM2.5) concentrations in the atmosphere; higher values of AOD correspond to higher concentrations of particulate matter. AOD is useful for identifying and tracking areas of high PM2.5 concentrations that correspond to air quality events, such as wildfires, dust storms, or haze episodes. Currently, the air quality community utilizes AOD from the MODIS instrument on NASA's polar-orbiting Terra and Aqua satellites and from NOAA's GOES geostationary satellites (e.g, GASP). The Visible Infrared Imaging Radiometer Suite (VIIRS) instrument on the Suomi-NPP satellite is making AOD measurements that are similar to MODIS AOD, but with higher spatial resolution. Two AOD products are available from VIIRS: the 750 m nadir resolution Intermediate Product (IP) and the 6 km resolution Environmental Data Record (EDR) product, which is aggregated from IP measurements. These VIIRS AOD products offer a substantial increase in spatial resolution compared to the MODIS AOD 3 km and 10 km AOD products, respectively. True color (RGB) imagery is also available from VIIRS as a decision aid for air quality applications. It serves as a complement to AOD measurements by providing visible information about areas of smoke, haze, and blowing dust in the atmosphere. Case studies of VIIRS AOD and RGB data for recent air quality events will be presented, with a focus on wildfires, and the relative pros and cons of the VIIRS AOD IP and EDR for air quality applications will be discussed in comparison to MODIS AOD products. Improvements to VIIRS aerosol products based on user feedback as part of the NOAA Satellite Air Quality Proving Ground (AQPG) will be outlined, and an overview of future

  4. Production of porous coating on a prosthesis

    DOEpatents

    Sump, Kenneth R.

    1987-01-01

    Preselected surface areas of a prosthesis are covered by a blend of matching primary metallic particles and expendable particles. The particles are compressed and heated to assure that deformation and metallurgical bonding occurs between them and between the primary particles and the surface boundaries of the prosthesis. Porosity is achieved by removal of the expendable material. The result is a coating including discrete bonded particles separated by a network of interconnected voids presenting a homogeneous porous coating about the substrate. It has strength suitable for bone implant usage without intermediate adhesives, and adequate porosity to promote subsequent bone ingrowth.

  5. IRON COATED URANIUM AND ITS PRODUCTION

    DOEpatents

    Gray, A.G.

    1960-03-15

    A method of applying a protective coating to a metallic uranium article is given. The method comprises etching the surface of the article with an etchant solution containlng chloride ions, such as a solution of phosphoric acid and hydrochloric acid, cleaning the etched surface, electroplating iron thereon from a ferrous ammonium sulfate electroplating bath, and soldering an aluminum sheath to the resultant iron layer.

  6. Influence of anthropogenic aerosol deposition on the relationship between oceanic productivity and warming

    NASA Astrophysics Data System (ADS)

    Wang, Rong; Balkanski, Yves; Bopp, Laurent; Aumont, Olivier; Boucher, Olivier; Ciais, Philippe; Gehlen, Marion; Peñuelas, Josep; Ethé, Christian; Hauglustaine, Didier; Li, Bengang; Liu, Junfeng; Zhou, Feng; Tao, Shu

    2015-12-01

    Satellite data and models suggest that oceanic productivity is reduced in response to less nutrient supply under warming. In contrast, anthropogenic aerosols provide nutrients and exert a fertilizing effect, but its contribution to evolution of oceanic productivity is unknown. We simulate the response of oceanic biogeochemistry to anthropogenic aerosols deposition under varying climate from 1850 to 2010. We find a positive response of observed chlorophyll to deposition of anthropogenic aerosols. Our results suggest that anthropogenic aerosols reduce the sensitivity of oceanic productivity to warming from -15.2 ± 1.8 to -13.3 ± 1.6 Pg C yr-1 °C-1 in global stratified oceans during 1948-2007. The reducing percentage over the North Atlantic, North Pacific, and Indian Oceans reaches 40, 24, and 25%, respectively. We hypothesize that inevitable reduction of aerosol emissions in response to higher air quality standards in the future might accelerate the decline of oceanic productivity per unit warming.

  7. Surface coatings and catalyst production by electrodeposition

    NASA Technical Reports Server (NTRS)

    May, Chester B.; Riley, Clyde; Coble, H. Dwain; Loo, Boon H.

    1987-01-01

    Electrodeposition and electrocodeposition in low gravity are discussed. The goal is to provide a better understanding of the role of convection and buoyancy in the mechanisms of formation of some electrodeposited surfaces, fluid flow in the vicinity of electrodepositing surfaces, the influence of a moving medium upon codeposition, the effect of gravity upon the dispersion (coagulation) of neutral particles that are desired for codeposition and preparation of improved surface coatings and metal catalysts.

  8. Occupational exposure to inhalable and total aerosol in the primary nickel production industry.

    PubMed Central

    Tsai, P J; Vincent, J H; Wahl, G; Maldonado, G

    1995-01-01

    OBJECTIVES--This paper describes a study that was carried out in the primary nickel production industry to investigate the levels of personal exposure to aerosols containing nickel and the impact on exposure assessment of introducing new personal sampling techniques with performance consistent with the latest particle size-selective criteria. METHODS--Experiments were carried out at workplaces in mining, milling, smelting, and refining works to investigate the effect of changing from the current method of total aerosol (with the widely used 37 mm filter holder) to the new method of measuring inhalable aerosol (with the Institute of Occupational Medicine (IOM) inhalable aerosol sampler). RESULTS--The results show that inhalable aerosol exposure concentrations--for both overall aerosol and for total nickel--were consistently and significantly higher than the corresponding total aerosol concentrations. Weighted least squares linear regression yielded IOM/37 mm factors ranging from about 1.2 to 4.0. The exposure data for each company process were found to be log-normally distributed. CONCLUSIONS--The results suggest the possibility of generating a single pragmatic factor for each company process for converting current total aerosol exposures to new exposures based on the inhalability concept contained in the latest particle size-selective criteria for aerosol exposure assessment. Such data may be important in determining new occupational exposure limits for nickel. PMID:8563841

  9. MODIS 3 Km Aerosol Product: Applications over Land in an Urban/suburban Region

    NASA Technical Reports Server (NTRS)

    Munchak, L. A.; Levy, R. C.; Mattoo, S.; Remer, L. A.; Holben, B. N.; Schafer, J. S.; Hostetler, C. A.; Ferrare, R. A.

    2013-01-01

    MODerate resolution Imaging Spectroradiometer (MODIS) instruments aboard the Terra and Aqua satellites have provided a rich dataset of aerosol information at a 10 km spatial scale. Although originally intended for climate applications, the air quality community quickly became interested in using the MODIS aerosol data. However, 10 km resolution is not sufficient to resolve local scale aerosol features. With this in mind, MODIS Collection 6 is including a global aerosol product with a 3 km resolution. Here, we evaluate the 3 km product over the Baltimore/Washington D.C., USA, corridor during the summer of 2011, by comparing with spatially dense data collected as part of the DISCOVER-AQ campaign these data were measured by the NASA Langley Research Center airborne High Spectral Resolution Lidar (HSRL) and a network of 44 sun photometers (SP) spaced approximately 10 km apart. The HSRL instrument shows that AOD can vary by up to 0.2 within a single 10 km MODIS pixel, meaning that higher resolution satellite retrievals may help to characterize aerosol spatial distributions in this region. Different techniques for validating a high-resolution aerosol product against SP measurements are considered. Although the 10 km product is more statistically reliable than the 3 km product, the 3 km product still performs acceptably, with more than two-thirds of MODIS/SP collocations falling within the expected error envelope with high correlation (R > 0.90). The 3 km product can better resolve aerosol gradients and retrieve closer to clouds and shorelines than the 10 km product, but tends to show more significant noise especially in urban areas. This urban degradation is quantified using ancillary land cover data. Overall, we show that the MODIS 3 km product adds new information to the existing set of satellite derived aerosol products and validates well over the region, but due to noise and problems in urban areas, should be treated with some degree of caution.

  10. A production parylene coating process for hybrid microcircuits

    NASA Technical Reports Server (NTRS)

    Kale, V. S.; Riley, T. J.

    1977-01-01

    The real impetus for developing a production parylene coating process for internal hybrid passivation came as a result of the possibility of loose conductive particles in hybrid microelectronic circuits, causing intermittent and sometimes permanent failures. Because of the excellent mechanical properties of parylene, it is capable of securing the loose particles in place and prevent such failures. The process of coating described consists of (1) vaporizing the initial charge, which is in the form of a dimer; (2) conversion of the dimer into a reactive monomer; and (3) deposition and subsequent polymerization of the monomer in the deposition chamber which forms a uniform parylene film over all the cold surfaces in contact. Experimental results are discussed in terms of wire bond reliability, resistor drift, high-temperature storage characteristics of parylene, and coating acceptance standards. It is concluded that internal cavities of microelectronic circuits can be successfully coated with parylene provided appropriate tooling is used to protect external leads from the parylene monomer.

  11. Aerosols and their influence on radiation partitioning and savanna productivity in northern Australia

    SciTech Connect

    Kanniah, K. D.; Beringer, J.; Tapper, N. J.; Long, Charles N.

    2010-05-01

    We investigated the effect of aerosols and clouds on the Net Ecosystem Productivity (NEP) of savannas in northern Australia using aerosol optical depth, clouds and radiation data from the Atmospheric Radiation Measurement (ARM) site in Darwin and carbon flux data measured from eddy covariance techniques from a site at Howard Springs, 35km southeast of Darwin. Generally we found that the concentration of aerosols in this region was relatively low than observed at other sites, therefore the proportion of diffuse radiation reaching the earths surface was only ~ 30%. As a result, we observed only a modest change in carbon uptake under aerosol laden skies and there was no significant difference for dry season Radiation Use Efficiency (RUE) between clear sky, aerosols or thin clouds. On the other hand thick clouds in the wet season produce much more diffuse radiation than aerosols or thin clouds and therefore the initial canopy quantum efficiency was seen to increase 45 and 2.5 times more than under thin clouds and aerosols respectively. The normalized carbon uptake under thick clouds is 57% and 50% higher than under aerosols and thin clouds respectively even though the total irradiance received under thick clouds was reduced 59% and 50% than under aerosols and thin clouds respectively. However, reduction in total irradiance decreases the mean absolute carbon uptake as much as 22% under heavy cloud cover compared to thin clouds or aerosols. Thus, any increase in aerosol concentration or cloud cover that can enhance the diffuse component may have large impacts on productivity in this region.

  12. Method and device for producing and delivering an aerosol for remote sealing and coating

    DOEpatents

    Modera, M.P.; Carrie, F.R.

    1996-06-04

    The invention is a method and device for sealing leaks remotely by means of injecting a previously prepared aerosol into the enclosure being sealed. Specifically the invention is a method and device for preparing, transporting, and depositing and solid phase aerosol to the interior surface of the enclosure. 1 fig.

  13. Method and device for producing and delivering an aerosol for remote sealing and coating

    DOEpatents

    Modera, Mark P.; Carrie, Francois R.

    1996-01-01

    The invention is a method and device for sealing leaks remotely by means of injecting a previously prepared aerosol into the enclosure being sealed. Specifically the invention is a method and device for preparing, transporting, and depositing and solid phase aerosol to the interior surface of the enclosure.

  14. Aerosol Optical Depth Value-Added Product Report

    SciTech Connect

    Koontz, A; Hodges, G; Barnard, J; Flynn, C; Michalsky, J

    2013-03-17

    This document describes the process applied to retrieve aerosol optical depth (AOD) from multifilter rotating shadowband radiometers (MFRSR) and normal incidence multifilter radiometers (NIMFR) operated at the ARM Climate Research Facility’s ground-based facilities.

  15. Controls on aerosol wet deposition from satellite-based (re-)analysis products

    NASA Astrophysics Data System (ADS)

    Chuang, P. Y.

    2015-12-01

    Aerosol wet deposition is the key aerosol loss mechanism globally, yet is not well-understood relative to aerosol sources and transformations. The difficulty in generating appropriate observational data sets is one important barrier to the study of aerosol wet removal. In this study, we combine two independent products based on satellite measurements. Aerosol optical depth (AOD) is obtained from the ECMWF Monitoring Atmospheric Composition and Climate (MACC) project, which is a re-analysis product that assimilates MODIS-retrieved aerosol optical depth. Rainfall is obtained from the Tropical Rainfall Measurement Mission (TRMM) Multi-satellite Precipitation Analysis version 7 (TMPA-7). The latter product is available only from 50°N to 50°S, which sets our region of study. The data used is from 2011-12, is averaged to 6-hr intervals and has a horizontal resolution of 0.25°x0.25°. Our approach involves constructing a Lagrangian advection scheme that predicts aerosol AOD at the next time step (i.e. 6 hr in the future) based on current time step AOD and winds, and neglecting all aerosol sources and sinks. Predicted AOD is then compared with MACC reanalysis AOD conditioned on Lagrangian parcels that experienced rainfall during that interval, with AOD decreases attributed to wet deposition. Aerosol wet deposition is often parameterized in models as a function of rainfall rate using a power law. We evaluate the validity of such a power law relationship, and, when valid, compute the power law exponent globally, and by region (including continental and maritime locations) to reveal seasonal and geographic variability. Assuming precipitation is modulated by aerosol, at least in some regimes, then it follows that wet deposition also depends on AOD, and we quantify the strength of this coupling. This same approach could be used to study wet deposition of trace gases such as CO and ozone, as these are also available from the MACC re-analysis.

  16. Characterization of particulate products for aging of ethylbenzene secondary organic aerosol in the presence of ammonium sulfate seed aerosol.

    PubMed

    Huang, Mingqiang; Zhang, Jiahui; Cai, Shunyou; Liao, Yingmin; Zhao, Weixiong; Hu, Changjin; Gu, Xuejun; Fang, Li; Zhang, Weijun

    2016-09-01

    Aging of secondary organic aerosol (SOA) particles formed from OH- initiated oxidation of ethylbenzene in the presence of high mass (100-300μg/m(3)) concentrations of (NH4)2SO4 seed aerosol was investigated in a home-made smog chamber in this study. The chemical composition of aged ethylbenzene SOA particles was measured using an aerosol laser time-of-flight mass spectrometer (ALTOFMS) coupled with a Fuzzy C-Means (FCM) clustering algorithm. Experimental results showed that nitrophenol, ethyl-nitrophenol, 2,4-dinitrophenol, methyl glyoxylic acid, 5-ethyl-6-oxo-2,4-hexadienoic acid, 2-ethyl-2,4-hexadiendioic acid, 2,3-dihydroxy-5-ethyl-6-oxo-4-hexenoic acid, 1H-imidazole, hydrated N-glyoxal substituted 1H-imidazole, hydrated glyoxal dimer substituted imidazole, 1H-imidazole-2-carbaldehyde, N-glyoxal substituted hydrated 1H-imidazole-2-carbaldehyde and high-molecular-weight (HMW) components were the predominant products in the aged particles. Compared to the previous aromatic SOA aging studies, imidazole compounds, which can absorb solar radiation effectively, were newly detected in aged ethylbenzene SOA in the presence of high concentrations of (NH4)2SO4 seed aerosol. These findings provide new information for discussing aromatic SOA aging mechanisms. PMID:27593289

  17. Air Quality Monitoring and Forecasting Applications of Suomi NPP VIIRS Aerosol Products

    NASA Astrophysics Data System (ADS)

    Kondragunta, Shobha

    The Suomi National Polar-orbiting Partnership (NPP) Visible Infrared Imaging Radiometer Suite (VIIRS) instrument was launched on October 28, 2011. It provides Aerosol Optical Thickness (AOT) at two different spatial resolutions: a pixel level (~750 m at nadir) product called the Intermediate Product (IP) and an aggregated (~6 km at nadir) product called the Environmental Data Record (EDR), and a Suspended Matter (SM) EDR that provides aerosol type (dust, smoke, sea salt, and volcanic ash) information. An extensive validation of VIIRS best quality aerosol products with ground based L1.5 Aerosol Robotic NETwork (AERONET) data shows that the AOT EDR product has an accuracy/precision of -0.01/0.11 and 0.01/0.08 over land and ocean respectively. Globally, VIIRS mean AOT EDR (0.20) is similar to Aqua MODIS (0.16) with some important regional and seasonal differences. The accuracy of the SM product, however, is found to be very low (20 percent) when compared to Cloud Aerosol Lidar with Orthogonal Polarization (CALIOP) and AERONET. Several algorithm updates which include a better approach to retrieve surface reflectance have been developed for AOT retrieval. For dust aerosol type retrieval, a new approach that takes advantage of spectral dependence of Rayleigh scattering, surface reflectance, dust absorption in the deep blue (412 nm), blue (440 nm), and mid-IR (2.2 um) has been developed that detects dust with an accuracy of ~80 percent. For smoke plume identification, a source apportionment algorithm that combines fire hot spots with AOT imagery has been developed that provides smoke plume extent with an accuracy of ~70 percent. The VIIRS aerosol products will provide continuity to the current operational use of aerosol products from Aqua and Terra MODIS. These include aerosol data assimilation in Naval Research Laboratory (NRL) global aerosol model, verification of National Weather Service (NWS) dust and smoke forecasts, exceptional events monitoring by different states

  18. MODIS aerosol products in Collection 6:Moving towards multisensor fusion and interdisciplinary studies

    NASA Astrophysics Data System (ADS)

    Mattoo, S.; Levy, R. C.; Remer, L. A.

    2009-12-01

    As the Terra satellite turns 10, so do the MODIS aerosol products. During the past ten years the MODIS products have evolved and expanded to include opportunities and capabilities nonexistent in the at-launch version. We are anticipating the next step, Collection 6, becoming available in late 2010. The new products in the Collection 6 MODIS aerosol suite of products will include: 1) Fine mode aerosol optical depth over land from the PARASOL POLDER data set, merged into the MODIS data product. This is a direct capture of the PARASOL product that will be placed in the MODIS data files. It is not a separate derivation using PARASOL radiances and polarization. The incorporation of the PARASOL product over land is collocated to the MODIS 10 km product pixel, and is provided as a convenience to MODIS users. 2) Aerosol optical depth over land at 3 km resolution for Air Quality monitoring. 3) Cloud mask and distance to the nearest cloud calculated and presented for every 500 m “cloud-free” pixel that allows better control of cloud contamination in the basic aerosol products. This information is also summarized statistically at the 10 km product resolution, and will be available for both land and ocean. 4) A Quality Assurance (QA) flag in simple plain integers that does not require a binary reader to decode.

  19. Fission product partitioning in aerosol release from simulated spent nuclear fuel

    NASA Astrophysics Data System (ADS)

    Di Lemma, F. G.; Colle, J. Y.; Rasmussen, G.; Konings, R. J. M.

    2015-10-01

    Aerosols created by the vaporization of simulated spent nuclear fuel (simfuel) were produced by laser heating techniques and characterised by a wide range of post-analyses. In particular attention has been focused on determining the fission product behaviour in the aerosols, in order to improve the evaluation of the source term and consequently the risk associated with release from spent fuel sabotage or accidents. Different simulated spent fuels were tested with burn-up up to 8 at. %. The results from the aerosol characterisation were compared with studies of the vaporization process by Knudsen Effusion Mass Spectrometry and thermochemical equilibrium calculations. These studies permit an understanding of the aerosol gaseous precursors and the gaseous reactions taking place during the aerosol formation process.

  20. The Remote Sensing of Mineral Aerosols and their Impact on Phytoplankton Productivity

    NASA Technical Reports Server (NTRS)

    Tindale, Neil W.

    1997-01-01

    The overall objective of this experiment was to test the iron hypothesis does the addition of iron to nutrient rich surface waters enhance productivity? Our specific objectives in this experiment included sampling and studying the marine aerosol size and type (which are related to chemical reactivity) during the PlumEx cruise to determine the importance of local (Galapagos Islands) versus long-range sources of atmospheric material. Detailed results of single particle analysis of our samples are being prepared for publication in two papers. We collect aerosol samples and they have been analyzed for trace metals and other elements. We are mapped aerosol distribution and the desert source areas around the Arabian Sea region. We did record a clear relationship between the aerosol radiance and synoptic weather patterns with distinct signals over the ocean northwest and southwest of Australia. While the interpretation was limited an aerosol climatology pattern was presented.

  1. COATING ALTERNATIVES GUIDE (CAGE) FOR METAL PARTS AND PRODUCTS PAINTING

    EPA Science Inventory

    The paper discusses the initial development of a Coating Alternatives Guide (CAGE) for metal parts and products painting. t is an innovative technology transfer approach that provides a tool to improve technology diffusion and assistance. t will provide vital, user-accessible inf...

  2. Development and Applications of a New, High-Resolution, Operational MISR Aerosol Product

    NASA Astrophysics Data System (ADS)

    Garay, M. J.; Diner, D. J.; Kalashnikova, O.

    2014-12-01

    Since early 2000, the Multi-angle Imaging SpectroRadiometer (MISR) instrument on NASA's Terra satellite has been providing aerosol optical depth (AOD) and particle property retrievals at 17.6 km spatial resolution. Capitalizing on the capabilities provided by multi-angle viewing, the operational MISR algorithm performs well, with about 75% of MISR AOD retrievals falling within 0.05 or 20% × AOD of the paired validation data from the ground-based Aerosol Robotic Network (AERONET), and is able to distinguish aerosol particles by size and sphericity, over both land and water. These attributes enable a variety of applications, including aerosol transport model validation and global air quality assessment. Motivated by the adverse impacts of aerosols on human health at the local level, and taking advantage of computational speed advances that have occurred since the launch of Terra, we have implemented an operational MISR aerosol product with 4.4 km spatial resolution that maintains, and sometimes improves upon, the quality of the 17.6 km resolution product. We will describe the performance of this product relative to the heritage 17.6 km product, the global AERONET validation network, and high spatial density AERONET-DRAGON sites. Other changes that simplify product content, and make working with the data much easier for users, will also be discussed. Examples of how the new product demonstrates finer spatial variability of aerosol fields than previously retrieved, and ways this new dataset can be used for studies of local aerosol effects, will be shown.

  3. Products of BVOC oxidation: ozone and organic aerosols

    NASA Astrophysics Data System (ADS)

    Wildt, Jürgen; Andres, Stefanie; Carriero, Giulia; Ehn, Mikael; Fares, Silvano; Hoffmann, Thorsten; Hacker, Lina; Kiendler-Scharr, Astrid; Kleist, Einhard; Paoletti, Elena; Pullinen, Iida; Rohrer, Franz; Rudich, Yinon; Springer, Monika; Tillmann, Ralf; Wahner, Andreas; Wu, Cheng; Mentel, Thomas

    2015-04-01

    Biogenic Volatile Organic Compounds (BVOC) are important precursors in photochemical O3 and secondary organic aerosol (SOA) formation. We conducted a series of laboratory experiments with OH-induced oxidation of monoterpenes to elucidate pathways and efficiencies of O3 and SOA formation. At high NOx conditions ([BVOC] / [NOx] < 7 ppbC / ppb) photochemical ozone formation was observed. For -pinene as individual BVOC as well as for the monoterpene mixes emitted from different plant species we observed increasing ozone formation with increasing [NOX]. Between 2 and 3 O3-molecules were formed from 1 monoterpene when ozone formation was BVOC limited. Under such high NOX conditions, new particle formation was suppressed. Increasing [BVOC] / [NOX] ratios caused increasing efficiency of new particle formation indicating that peroxy radicals are the key intermediates in both, photochemical ozone- and new particle formation. The classical chemistry of peroxy radicals is well established (e.g. Master Chemical Mechanism). Peroxy radicals are produced by addition of molecular oxygen to the alkyl radical formed after OH attack at the BVOC. They either react with NO which leads to ozone formation or they react with other peroxy radicals and form chemically stable products (hydroperoxides, alkoholes and ketones). Much less knowledge exists on such reactions for Highly Oxidized Peroxy Radicals, (HOPR). Such HOPR were observed during ozonolysis of several volatiles and, in case of monoterpenes as precursors, they can contain more than 12 Oxygen atoms (Mentel et al., 2015). Although the OH-initiated formation of HOPR is yet not fully understood, their basic gas phase reactions seem to follow classical photochemical rules. In reactions with NO they can act as precursor for O3 and in reactions with other HOPR or with classical less oxidized peroxy radicals they can form highly oxidized stable products and alkoxy radicals. In addition, HOPR-HOPR reactions lead to the formation of

  4. Aerosol Production from Charbroiled and Wet-Fried Meats

    NASA Astrophysics Data System (ADS)

    Niedziela, R. F.; Blanc, L. E.

    2012-12-01

    Previous work in our laboratory focused on the chemical and optical characterization of aerosols produced during the dry-frying of different meat samples. This method yielded a complex ensemble of particles composed of water and long-chain fatty acids with the latter dominated by oleic, stearic, and palmitic acids. The present study examines how wet-frying and charbroiling cooking methods affect the physical and chemical properties of their derived aerosols. Samples of ground beef, salmon, chicken, and pork were subject to both cooking methods in the laboratory, with their respective aerosols swept into a laminar flow cell where they were optically analyzed in the mid-infrared and collected through a gas chromatography probe for chemical characterization. This presentation will compare and contrast the nature of the aerosols generated in each cooking method, particularly those produced during charbroiling which exposes the samples, and their drippings, to significantly higher temperatures. Characterization of such cooking-related aerosols is important because of the potential impact of these particles on air quality, particularly in urban areas.

  5. Production Mechanism, Number Concentration, Size Distribution, Chemical Composition, and Optical Properties of Sea Spray Aerosols Workshop, Summer 2012

    SciTech Connect

    Meskhidze, Nicholas

    2013-10-21

    The objective of this workshop was to address the most urgent open science questions for improved quantification of sea spray aerosol-radiation-climate interactions. Sea spray emission and its influence on global climate remains one of the most uncertain components of the aerosol-radiation-climate problem, but has received less attention than other aerosol processes (e.g. production of terrestrial secondary organic aerosols). Thus, the special emphasis was placed on the production flux of sea spray aerosol particles, their number concentration and chemical composition and properties.

  6. Validation of the NOAA/NESDIS satellite aerosol product over the North Atlantic in 1989

    NASA Astrophysics Data System (ADS)

    Ignatov, Aleksandr M.; Stowe, Larry L.; Sakerin, Sergey M.; Korotaev, Gennady K.

    1995-03-01

    A validation experiment and resulting potential improvements to the operational satellite optical thickness product at the National Oceanic and Atmospheric Administration/National Environmental Satellite Data and Information Service (NOAA/NESDIS) are presented. An earlier paper described a set of Sun photometer measurements collected from the Soviet R/V Akademik Vernadsky during its cruise in the Atlantic Ocean and Mediterranean Sea from September to December 1989. The accuracy of the Sun photometer aerosol optical thickness was proven acceptable of use as a ground truth standard for validation of the NOAA product. This paper describes the validation methodology and the results of its application to the NOAA 11 satellite product. A systematic underestimation in the operational values by about 35%, relative to the ship truth, is found. Causes for this discrepancy are examined, emphasizing the importance of careful satellite instrument calibration, and a revision of the oceanic reflectance model used in the retrieval algorithm. It is shown that the remaining systematic underestimate in satellite aerosol optical thickness can be attributed only to the aerosol model used in the retrieval. Additional checks of this conclusion using independent data sets are underway. If confirmed, a fundamental revision of the presently used aerosol model would be required. An example of a simple adjustment to the present aerosol model which successfully removes the bias is given, based on the assumption of an absorbing aerosol.

  7. Characterization of potential impurities and degradation products in electronic cigarette formulations and aerosols.

    PubMed

    Flora, Jason W; Meruva, Naren; Huang, Chorng B; Wilkinson, Celeste T; Ballentine, Regina; Smith, Donna C; Werley, Michael S; McKinney, Willie J

    2016-02-01

    E-cigarettes are gaining popularity in the U.S. as well as in other global markets. Currently, limited published analytical data characterizing e-cigarette formulations (e-liquids) and aerosols exist. While FDA has not published a harmful and potentially harmful constituent (HPHC) list for e-cigarettes, the HPHC list for currently regulated tobacco products may be useful to analytically characterize e-cigarette aerosols. For example, most e-cigarette formulations contain propylene glycol and glycerin, which may produce aldehydes when heated. In addition, nicotine-related chemicals have been previously reported as potential e-cigarette formulation impurities. This study determined e-liquid formulation impurities and potentially harmful chemicals in aerosols of select commercial MarkTen(®) e-cigarettes manufactured by NuMark LLC. The potential hazard of the identified formulation impurities and aerosol chemicals was also estimated. E-cigarettes were machine puffed (4-s duration, 55-mL volume, 30-s intervals) to battery exhaustion to maximize aerosol collection. Aerosols analyzed for carbonyls were collected in 20-puff increments to account for analyte instability. Tobacco specific nitrosamines were measured at levels observed in pharmaceutical grade nicotine. Nicotine-related impurities in the e-cigarette formulations were below the identification and qualification thresholds proposed in ICH Guideline Q3B(R2). Levels of potentially harmful chemicals detected in the aerosols were determined to be below published occupational exposure limits. PMID:26617410

  8. If the MODIS Aerosol Product is so Infested with Cloud Contamination, Why Does Everybody Use the Product?

    NASA Technical Reports Server (NTRS)

    Remeer, Lorraine A.

    2011-01-01

    The MODIS aerosol cloud mask is based on a spatial variability test, using the assumption that aerosols are more homogeneous than clouds. On top of this first line of defense are a series of additional tests based on threshold values and ratios of various MODIS channels. The goal is to eliminate clouds and keep the aerosol. How well have we succeeded? There have been several studies showing cloud contamination in the MODIS aerosol product and several alternative cloud masks proposed. There are even "competing" MODIS aerosol products that offer an alternative "cloud free" world. Are these alternative products an improvement to the old standard product? We find there is a trade-off between retrieval availability and cloud contamination, and for many applications it is better to have a little bit of cloud in the product than to not have enough product. I will review the decisions that led us to the present MODIS cloud mask, and show how it is simultaneously too liberal and too conservative, some ideas on how to make it better and why in the end it doesn't matter. I hope to inspire a spirited discussion and will be very willing to take your complaints and suggestions.

  9. The Impact of Organic Surfactants and Coatings in Regulating Heterogeneous N2O5 Reaction Kinetics on Nascent Marine Aerosol

    NASA Astrophysics Data System (ADS)

    Ryder, O. S.; Campbell, N.; Schill, S.; Pöhlker, C.; Andreae, M. O.; Bertram, T. H.

    2013-12-01

    The heterogeneous reaction of N2O5 on aerosol particles impacts both the lifetime of nitrogen oxides, and the production rate of chlorine radicals following the activation of particulate chloride to nitryl chloride in both coastal and continental regions. The extent to which N2O5 reactivity impacts oxidant loadings depends on the heterogeneous reaction rate, which is directly influenced by aerosol chemical composition, morphology, and physical phase state. In the marine environment, the chemical composition of aerosol particles produced via wave induced bubble bursting mechanisms varies greatly and is influenced by the composition of the sea surface microlayer . Here, we present direct measurements of N2O5 reaction kinetics determined using model sea-spray particles generated in a novel Marine Aerosol Reference Tank (MART), capable of generating accurate mimics of ambient sea spray particles, in a lab environment. Here, a synthetic sea salt ocean was sequentially doped with organic molecules chosen to mimic organic species present in natural sea water over the course of a phytoplankton bloom in the open ocean. These included sterol, galactose, lippolysaccharide, BSA protein, and 1,2-dipalmitoyl-sn-glycero-3-phosphate (DPPA). These observations permit discussion of the role of marine organics in regulating heterogeneous reaction kinetics, as well a re-evaluation of potential organic lab proxies for marine organics.

  10. The uncertainty of MODIS C6 aerosol optical depth product over land

    NASA Astrophysics Data System (ADS)

    Wu, Yerong; de Graaf, Martin; Menenti, Massimo

    2015-04-01

    Aerosol Optical Depth (AOD) has an important impact on climate change and air quality. A number of AOD satellite data products have been released, like Moderate Resolution Imaging Spectroradiometer (MODIS) AOD product, which are further applied for monitoring PM2.5, for long-term aerosol trend analysis, and for estimating aerosol radiative forcing. However, the accuracy of MODIS AOD product with ±0.03 or 15-20% of global mean value over land is still low for extensive scientific research. To investigate the accuracy of the product, a synthetic experiment was designed where the errors introduced by both radiometry and algorithm, e.g. instrument calibration, gas correction and cloud mask, and some assumptions on aerosol properties can be removed. Through analysis of the mean value of retrieved AOD over 1520 observational configurations, the algorithm performs very well with small errors (up to 0.2%) for most cases, while for some extreme cases (eg., AOD=5.0), it performs less accurately (> 3%). The uncertainty also shows a trend related to the geometry of observations (e.g., scattering angle). The results suggest higher accuracy at large scattering angles, and lower accuracy at small scattering angles. The main reason for the uncertainty is an inappropriate assumption on surface reflectance, where surface reflectance is regarded as a function of aerosol loading and mixing ratio. Therefore, a more accurate representation of the surface reflectance will increase the accuracy of the MODIS AOD product.

  11. Optimization of Laser Cladding for Al Coating Production

    NASA Astrophysics Data System (ADS)

    Riveiro, A.; Mejías, A.; Lusquiños, F.; del Val, J.; Comesaña, R.; Pardo, J.; Pou, J.

    The production of aluminum based coatings on a stainless steel (AISI 304) substrate by side laser cladding, and using a high power diode laser was experimentally studied. Relevant processing parameters were found and correlations between them were determined. Furthermore, the influence of the processing parameters on the costs associated to the process was examined. These relationships can be used as a guideline for the selection of proper processing parameters for laser cladding of this kind of materials.

  12. ALTERNATIVE FORMULATIONS TO REDUCE CFC USE IN U.S. EXEMPTED AND EXCLUSED AEROSOL PRODUCTS

    EPA Science Inventory

    The report examines products exempted and excluded from those affected by the 1978 ban on the use of chlorofluorocarbons (CFCs) as aerosol propellants, the present consumption of CFCs still utilized for these products in the U.S., and alternative formulations which may be used to...

  13. ALTERNATIVE FORMULATIONS TO REDUCE CFC USE IN U.S. EXEMPTED AND EXCLUDED AEROSOL PRODUCTS

    EPA Science Inventory

    The report examines products exempted and excluded from those affected by the 1978 ban on the use of chlorofluorocarbons (CFCs) as aerosol propellants, the present consumption of CFCs still utilized for these products in the U.S., and alternative formulations which may be used to...

  14. Aerosol Products from The Future Space Lidar AEOLUS

    NASA Astrophysics Data System (ADS)

    Martinet, Pauline; Dabas, Alain; Lever, Vincent; Flamant, Pierre; Huber, Dorit

    2016-06-01

    Ready for launch by the end of 2016, the Doppler lidar mission AEOLUS from the European Space Agency (ESA) will be the first High-Spectral Resolution Lidar (HSRL) in space. Operating in the UV, it implements two detection channels for aerosol and molecular backscatter. The system is primarily designed for the measurement of winds, but the HSRL capability enables the measurement of the particulate backscatter and extinction coefficients without any a priori assumption on the aerosol type. The level-2A (L2A) processor has been developed for these measurements and tested with synthetic data. The results show good aerosol backscatter profiles can be retrieved. Extinction coefficients are reasonable but do not reach the quality of backscatter coefficients. A precise, full, radiometric calibration of the lidar is required. A major limitation of the system is a single polarization component of the light is detected leading to an underestimation of backscatter coefficients when the atmospheric particles are depolarizing. The vertical resolution goes from 250 meters in the lowest part of the atmosphere, to 2 km in the lower stratosphere. The maximum altitude can reach above 20km. The basic horizontal averaging is 90km. Averaging on shorter distances (down to a few km) are possible but require a sufficient signal to noise ratio.

  15. Evidence of Aerosols as a Media for Rapid Daytime HONO Production over China

    SciTech Connect

    Liu, Zhen; Wang, Yuhang; Costabile, Francesa; Amoroso, Antonio; Zhao, Chun; Huey, L. G.; Stickel, Robert; Liao, Jin; Zhu, Tong

    2014-12-16

    Current knowledge of daytime HONO sources remains incomplete. A large missing daytime HONO source has been found in many places around the world, including polluted regions in China. Conventional understanding and recent studies attributed this missing source mainly to ground surface processes or gas-phase chemistry, while assuming aerosols to be an insignificant media for HONO production. We analyze in situ observations of HONO and its precursors at an urban site in Beijing, China, and report an apparent dependence of the missing HONO source strength on aerosol surface area and solar ultraviolet radiation. Based on extensive correlation analysis and process-modeling, we propose that the rapid daytime HONO production in Beijing can be explained by enhanced hydrolytic disproportionation of NO2 on aqueous aerosol surfaces due to catalysis by dicarboxylic acid anions. The combination of high abundance of NO2, aromatic hydrocarbons, and aerosols over broad regions in China likely leads to elevated HONO levels, rapid OH production, and enhanced oxidizing capacity on a regional basis. Our findings call for attention to aerosols as a media for daytime heterogeneous HONO production in polluted regions like Beijing. This study also highlights the complex and uncertain heterogeneous chemistry in China, which merits future efforts of reconciling regional modeling and laboratory experiments, in order to understand and mitigate the regional particulate and O3 pollutions over China.

  16. On direct passive microwave remote sensing of sea spray aerosol production

    NASA Astrophysics Data System (ADS)

    Savelyev, I. B.; Anguelova, M. D.; Frick, G. M.; Dowgiallo, D. J.; Hwang, P. A.; Caffrey, P. F.; Bobak, J. P.

    2014-11-01

    This study addresses and attempts to mitigate persistent uncertainty and scatter among existing approaches for determining the rate of sea spray aerosol production by breaking waves in the open ocean. The new approach proposed here utilizes passive microwave emissions from the ocean surface, which are known to be sensitive to surface roughness and foam. Direct, simultaneous, and collocated measurements of the aerosol production and microwave emissions were collected aboard the FLoating Instrument Platform (FLIP) in deep water ~ 150 km off the coast of California over a period of ~ 4 days. Vertical profiles of coarse-mode aerosol (0.25-23.5 μm) concentrations were measured with a forward-scattering spectrometer and converted to surface flux using dry deposition and vertical gradient methods. Back-trajectory analysis of eastern North Pacific meteorology verified the clean marine origin of the sampled air mass over at least 5 days prior to measurements. Vertical and horizontal polarization surface brightness temperature were measured with a microwave radiometer at 10.7 GHz frequency. Data analysis revealed a strong sensitivity of the brightness temperature polarization difference to the rate of aerosol production. An existing model of microwave emission from the ocean surface was used to determine the empirical relationship and to attribute its underlying physical basis to microwave emissions from surface roughness and foam within active and passive phases of breaking waves. A possibility of and initial steps towards satellite retrievals of the sea spray aerosol production are briefly discussed in concluding remarks.

  17. On direct passive microwave remote sensing of sea spray aerosol production

    NASA Astrophysics Data System (ADS)

    Savelyev, I. B.; Anguelova, M. D.; Frick, G. M.; Dowgiallo, D. J.; Hwang, P. A.; Caffrey, P. F.; Bobak, J. P.

    2014-06-01

    This study addresses and attempts to mitigate persistent uncertainty and scatter among existing approaches for determining the rate of sea spray aerosol production by breaking waves in the open ocean. The new approach proposed here utilizes passive microwave emissions from the ocean surface, which are known to be sensitive to surface roughness and foam. Direct, simultaneous, and collocated measurements of the aerosol production and microwave emissions were collected on-board FLoating Instrument Platform (FLIP) in deep water ∼150 km off the coast of California over a period of ∼4 days. Vertical profiles of coarse-mode aerosol (0.25-23.5 μm) concentrations were measured with a forward scattering spectrometer and converted to surface flux using dry deposition and vertical gradient methods. Back trajectory analysis of Northeast Pacific meteorology verified the clean marine origin of the sampled air mass over at least 5 days prior to measurements. Vertical and horizontal polarization surface brightness temperatures were measured with a microwave radiometer at 10.7 GHz frequency. Data analysis revealed a strong sensitivity of the brightness temperature polarization difference to the rate of aerosol production. An existing model of microwave emission from the ocean surface was used to determine the empirical relationship and to attribute its underlying physical basis to microwave emissions from surface roughness and foam within active and passive phases of breaking waves. A possibility of and initial steps towards satellite retrievals of the sea spray aerosol production are briefly discussed in concluding remarks.

  18. Bioequivalence for locally acting nasal spray and nasal aerosol products: standard development and generic approval.

    PubMed

    Li, Bing V; Jin, Feiyan; Lee, Sau L; Bai, Tao; Chowdhury, Badrul; Caramenico, Hoainhon T; Conner, Dale P

    2013-07-01

    Demonstrating bioequivalence (BE) for nasal spray/aerosol products for local action has been very challenging because the relationship between the drug in systemic circulation and the drug reaching the nasal site of action has not been well established. Thus, the current BE standard for these drug/device combination products is based on a weight-of-evidence approach, which contains three major elements: equivalent in vitro performance, equivalent systemic exposure, and equivalent local delivery. In addition, formulation sameness and device similarity are evidences to support BE. This paper presents a comprehensive review of the scientific rationale of the current BE standard and their development history for nasal spray/aerosol products, as well as the Food and Drug Administration's review and approval status of generic nasal sprays/aerosols with the application of these BE standard. PMID:23686396

  19. Analysis of reversibility and reaction products of glyoxal uptake onto ammonium sulfate aerosol

    NASA Astrophysics Data System (ADS)

    Galloway, M. M.; Chhabra, P. S.; Chan, A. W.; Surratt, J. D.; Kwan, A. J.; Wennberg, P. O.; Flagan, R. C.; Seinfeld, J. H.; Keutsch, F. N.

    2009-04-01

    Glyoxal, the smallest alpha-dicarbonyl, is an oxidation product of both biogenic and anthropogenic volatile organic compounds (Fu et al. JGR 113, D15303, 2008). Despite its low molecular weight, its role in secondary organic aerosol (SOA) formation has gained interest and a recent study suggested that it accounts for more than 15% of SOA in Mexico City (Volkamer et al. GRL 34, L19807, 2007). Despite numerous previous studies, questions remain regarding the processes controlling glyoxal uptake onto aerosol, including the role of acid catalysis, degree of reversibility, and identity of aerosol phase reaction products. We present results of chamber aerosol studies (Galloway et al. ACPD 8, 20799, 2008) and laboratory studies of bulk samples aimed at improving the understanding of these processes, in particular formation of oligomers and organosulfates of glyoxal, as well as the formation of imidazoles (carbon-nitrogen containing heterocyclic aromatic compounds) under dark and irradiated conditions. The relevance of these classes of reaction products extends beyond glyoxal, as evidence of oligomers and organosulfates other than those of glyoxal have been found in ambient aerosol (Surratt et al. JPCA 112, 8345, 2008; Denkenberger et al. Environ. Sci. Technol. 41, 5439, 2007). Experiments in which a chamber air mass was diluted after equilibration of glyoxal uptake onto ammonium sulfate seed aerosol (relative humidity 60% and glyoxal mixing ratios of 25-200 ppbv) shows that under these conditions uptake is reversible. The most important condensed phase products are hydrated oligomers of glyoxal, which are also formed reversibly under these conditions. Our studies show that organosulfates were not formed under dark conditions for neutral or acidified aerosol; similarly, Minerath et al. have recently shown that formation of a different class of organosulfates (alkyl sulfates) also proceeds very slowly even under acidic conditions (Environ. Sci. Technol. 42, 4410, 2008). The

  20. Forecasting Plant Productivity and Health Using Diffuse-to-Global Irradiance Ratios Extracted from the OMI Aerosol Product

    NASA Technical Reports Server (NTRS)

    Knowlton, Kelly; Andrews, Jane C.; Ryan, Robert E.

    2007-01-01

    Atmospheric aerosols are a major contributor to diffuse irradiance. This Candidate Solution suggests using the OMI (Ozone Monitoring Instrument) aerosol product as input into a radiative transfer model, which would calculate the ratio of diffuse to global irradiance at the Earth s surface. This ratio can significantly influence the rate of photosynthesis in plants; increasing the ratio of diffuse to global irradiance can accelerate photosynthesis, resulting in greater plant productivity. Accurate values of this ratio could be useful in predicting crop productivity, thereby improving forecasts of regional food resources. However, disagreements exist between diffuse-to-global irradiance values measured by different satellites and ground sensors. OMI, with its unique combination of spectral bands, high resolution, and daily global coverage, may be able to provide more accurate aerosol measurements than other comparable sensors.

  1. Near-Cloud Aerosol Properties from the 1 Km Resolution MODIS Ocean Product

    NASA Technical Reports Server (NTRS)

    Varnai, Tamas; Marshak, Alexander

    2014-01-01

    This study examines aerosol properties in the vicinity of clouds by analyzing high-resolution atmospheric correction parameters provided in the MODIS (Moderate Resolution Imaging Spectroradiometer) ocean color product. The study analyzes data from a 2 week long period of September in 10 years, covering a large area in the northeast Atlantic Ocean. The results indicate that on the one hand, the Quality Assessment (QA) flags of the ocean color product successfully eliminate cloud-related uncertainties in ocean parameters such as chlorophyll content, but on the other hand, using the flags introduces a sampling bias in atmospheric products such as aerosol optical thickness (AOT) and Angstrom exponent. Therefore, researchers need to select QA flags by balancing the risks of increased retrieval uncertainties and sampling biases. Using an optimal set of QA flags, the results reveal substantial increases in optical thickness near clouds-on average the increase is 50% for the roughly half of pixels within 5 km from clouds and is accompanied by a roughly matching increase in particle size. Theoretical simulations show that the 50% increase in 550nm AOT changes instantaneous direct aerosol radiative forcing by up to 8W/m2 and that the radiative impact is significantly larger if observed near-cloud changes are attributed to aerosol particles as opposed to undetected cloud particles. These results underline that accounting for near-cloud areas and understanding the causes of near-cloud particle changes are critical for accurate calculations of direct aerosol radiative forcing.

  2. Contribution of airborne microbes to bacterial production and N2 fixation in seawater upon aerosol deposition

    NASA Astrophysics Data System (ADS)

    Rahav, Eyal; Ovadia, Galit; Paytan, Adina; Herut, Barak

    2016-01-01

    Aerosol deposition may supply a high diversity of airborne microbes, which can affect surface microbial composition and biological production. This study reports a diverse microbial community associated with dust and other aerosol particles, which differed significantly according to their geographical air mass origin. Microcosm bioassay experiments, in which aerosols were added to sterile (0.2 µm filtered and autoclaved) SE Mediterranean Sea (SEMS) water, were performed to assess the potential impact of airborne bacteria on bacterial abundance, production, and N2 fixation. Significant increase was observed in all parameters within a few hours, and calculations suggest that airborne microbes can account for one third in bacterial abundance and 50-100% in bacterial production and N2-fixation rates following dust/aerosol amendments in the surface SEMS. We show that dust/aerosol deposition can be a potential source of a wide array of microorganisms, which may impact microbial composition and food web dynamics in oligotrophic marine systems such as the SEMS.

  3. Capabilities and Limitations of MISR Aerosol Products in Dust-Laden Regions

    NASA Technical Reports Server (NTRS)

    Kalashnikova, Olga V.; Garay, Michael J.; Sokolik, Irina N.; Diner, David J.; Kahn, Ralph A.; Martonchcik, John V.; Lee, Jae N.; Torres, Omar; Yang, Weidong; Marshak, Alexander; Kassabian, Sero; Chodas, Mark

    2011-01-01

    Atmospheric mineral dust particles have significant effects on climate and the environment, and despite notable advances in modeling and satellite and ground-based measurements, remain one of the major factors contributing to large uncertainty in aerosol radiative forcing. We examine the Multi-angle Imaging SpectroRadiometer (MISR) 11+ year aerosol data record to demonstrate MISR's unique strengths and assess potential biases of MISR products for dust study applications. In particular, we examine MISR's unique capabilities to 1) distinguish dust aerosol from spherical aerosol types, 2) provide aerosol optical depths over bright desert source regions, and 3) provide high-resolution retrievals of dust plume heights and associated winds. We show examples of regional and global MISR data products in dusty regions together with quantitative evaluations of product accuracies through comparisons with independent data sources, and demonstrate applications of MISR data to dust regional and climatological studies, such as dust property evolution during transport, dust source climatology in relation to climatic factors, and dust source dynamics. The potential use of MISR radiance data to study dust properties is also discussed.

  4. Laser Remote Sensing from ISS: CATS Cloud and Aerosol Level 2 Data Products (Heritage Edition)

    NASA Astrophysics Data System (ADS)

    Rodier, Sharon; Palm, Steve; Vaughan, Mark; Yorks, John; McGill, Matt; Jensen, Mike; Murray, Tim; Trepte, Chip

    2016-06-01

    With the recent launch of the Cloud-Aerosol Transport System (CATS) we have the opportunity to acquire a continuous record of space based lidar measurements spanning from the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) era to the start of the EarthCARE mission. Utilizing existing well-validated science algorithms from the CALIPSO mission, we will ingest the CATS data stream and deliver high-quality lidar data sets to the user community at the earliest possible opportunity. In this paper we present an overview of procedures necessary to generate CALIPSO-like lidar level 2 data products from the CATS level 1 data products.

  5. Evaluation of Ag nanoparticle coated air filter against aerosolized virus: Anti-viral efficiency with dust loading.

    PubMed

    Joe, Yun Haeng; Park, Dae Hoon; Hwang, Jungho

    2016-01-15

    In this study, the effect of dust loading on the anti-viral ability of an anti-viral air filter was investigated. Silver nanoparticles approximately 11 nm in diameter were synthesized via a spark discharge generation system and were used as anti-viral agents coated onto a medium air filter. The pressure drop, filtration efficiency, and anti-viral ability of the filter against aerosolized bacteriophage MS2 virus particles were tested with dust loading. The filtration efficiency and pressure drop increased with dust loading, while the anti-viral ability decreased. Theoretical analysis of anti-viral ability with dust loading was carried out using a mathematical model based on that presented by Joe et al. (J. Hazard. Mater.; 280: 356-363, 2014). Our model can be used to compare anti-viral abilities of various anti-viral agents, determine appropriate coating areal density of anti-viral agent on a filter, and predict the life cycle of an anti-viral filter. PMID:26434534

  6. Effect of fatty acid coatings on ozone uptake to deliquesced KI/NaCl aerosol particles

    NASA Astrophysics Data System (ADS)

    Ammann, M.; Rouvière, A.

    2009-12-01

    Phase transfer kinetics of gas phase oxidants may limit oxidative aging of aerosol particles. The aim of this work is to study the role of amphiphilic organic aerosol constituents on the kinetics of phase transfer of gaseous species to the bulk aqueous phase. The effect of (C9-C20) fatty acid surfactants on the phase transfer of ozone to deliquesced potassium iodide and sodium chloride have been investigated. Some other experiments of ozone uptake have been performed with different mixtures and proportions of fatty acids. The kinetic experiments were performed in an aerosol flow tube at room temperature and atmospheric pressure. To obtain deliquesced inorganic particles, the relative humidity was adjusted in the range of 75% to 80%. It is shown that the fatty acids in monolayer quantities may substantially inhibit the phase transfer of ozone to deliquesced particles. The results showed that especially the C15-C20 limit the mass transfer of ozone to the aqueous phase, whereby the magnitude of this effect was following the monolayer properties of the fatty acids. It was also possible to determine a resistance of such films to the transfer of ozone to the bulk phase.

  7. Aerosol Precursor Emissions, Secondary Aerosol Production, and Climate-Forcing Gas Exchange in the Midwestern United States

    NASA Astrophysics Data System (ADS)

    Doskey, P. V.

    2009-12-01

    Aerosol precursors in the Midwest are generated from a myriad of sources including biogenic emissions of terpenes from the Ozarks region, anthropogenic emissions of volatile and semivolatile aliphatic and aromatic hydrocarbons from the St. Louis airshed, and agricultural emissions of ammonia (NH3), amines, and nitrogen oxides (NOx) from animal husbandry and cropping systems of the Midwest Corn Belt. The deciduous and coniferous forests of the Ozarks region are significant sources of isoprene, monoterpenes, and sesquiterpenes that are sensitive to rising CO2 levels and temperature and generate light-scattering, secondary organic aerosol (SOA). Application of nitrogen fertilizers stimulates emissions of ammonia (NH3), nitric oxide (NO), and nitrous oxide (N2O) from agricultural soils and crops. Nitric acid, generated through photooxidation of NO emissions from fossil fuel combustion in urban air and from soil emissions in agroecosystems, reacts rapidly with NH3 to generate light-scattering, secondary inorganic aerosol (SIA). The atmospheric lifetime of N2O is about 120 years, making the substance a potent greenhouse gas with a global warming potential of 290 for a time horizon of 20 years relative to CO2. Emissions of CO2, N2O, and SIA precursors from the Midwest Corn Belt and surrounding areas are likely to increase in the near future as pastureland and prairie is converted to grow corn and other biofuel crops to meet the demand for renewable fuels. Several large river systems transport nutrients from fertilized fields of the Midwest agroecosystem to the Gulf of Mexico where plankton growth is accelerated. Microbial decomposition of plankton detritus consumes oxygen and creates a hypoxic zone, which might be a significant source of N2O.The presentation will discuss gaps in our knowledge of the production of climate-forcing species in the Midwestern United States.

  8. Uncertainty Analysis And Synergy Of Aerosol Products From Multiple Satellite Sensors For Advanced Atmospheric Research

    NASA Astrophysics Data System (ADS)

    Ichoku, C. M.; Petrenko, M.

    2013-05-01

    Aerosols are tiny particles suspended in the air, and can be made up of wind-blown dust, smoke from fires, and particulate emissions from automobiles, industries, and other natural and man-made sources. Aerosols can have significant impacts on the air quality, and can interact with clouds and solar radiation in such a way as to affect the water cycle and climate. However, the extent and scale of these impacts are still poorly understood, and this represents one of the greatest uncertainties in climate research to date. To fill this gap in our knowledge, the global and local properties of atmospheric aerosols are being extensively observed and measured, especially during the last decade, using both satellite and ground-based instruments, including such spaceborne sensors as MODIS on the Terra and Aqua satellites, MISR on Terra, OMI on Aura, POLDER on PARASOL, CALIOP on CALIPSO, SeaWiFS on SeaStar, and the ground-based Aerosol Robotic Network (AERONET) of sunphotometers. The aerosol measurements collected by these instruments over the last decade contribute to an unprecedented availability of the most complete set of complimentary aerosol measurements ever acquired. Still, to be able to utilize these measurements synergistically, they have to be carefully and uniformly analyzed and inter-compared, in order to understand the uncertainties and limitations of the products - a process that is greatly complicated by the diversity of differences that exist among them. In this presentation, we will show results of a coherent comparative uncertainty analysis of aerosol measurements from the above-named satellite sensors relative to AERONET. We use these results to demonstrate how these sensors perform in different parts of the world over different landcover types as well as their performance relative to one another, thereby facilitating product selection and integration for specific research and applications needs.

  9. Aerus-GEO: newly available satellite-derived aerosol optical depth product over Europe and Africa

    NASA Astrophysics Data System (ADS)

    Carrer, D.; Roujean, J. L.; Ceamanos, X.; Six, B.; Suman, S.

    2015-12-01

    The major difficulty in detecting the aerosol signal from visible and near-infrared remote sensing observations is to reach the proper separation of the components related to the atmosphere and the surface. A method is proposed to circumvent this issue by exploiting the directional and temporal dimensions of the satellite signal through the use of a semi-empirical kernel-driven model for the surface/atmosphere coupled system. This algorithm was implemented by the ICARE Data Center (http://www.icare.univ-lille1.fr), which operationally disseminates a daily AOD product at 670 nm over the MSG disk since 2014. The proposed method referred to as AERUS-GEO (Aerosol and surface albEdo Retrieval Using a directional Splitting method - application to GEO data) is applied to three spectral bands (0.6 mm, 0.8 mm, and 1.6 mm) of MSG (Meteosat Second Generation) observations, which scan Europe, Africa, and the Eastern part of South America every 15 minutes. The daily AOD estimates at 0.63μm has been extensively validated. In contrast, the Angstrom coefficient is still going through validation and we will show the differences between the MSG derived Angstrom exponent with that of CAMS (Copernicus Atmosphere Monitoring Service) near-real time aerosol product. The impact of aerosol type on the aerosol radiative forcing will be presented as a part of future development plan.

  10. A Marine Aerosol Reference Tank system as a breaking wave analogue for the production of foam and sea-spray aerosols

    NASA Astrophysics Data System (ADS)

    Stokes, M. D.; Deane, G. B.; Prather, K.; Bertram, T. H.; Ruppel, M. J.; Ryder, O. S.; Brady, J. M.; Zhao, D.

    2013-04-01

    In order to better understand the processes governing the production of marine aerosols a repeatable, controlled method for their generation is required. The Marine Aerosol Reference Tank (MART) has been designed to closely approximate oceanic conditions by producing an evolving bubble plume and surface foam patch. The tank utilizes an intermittently plunging sheet of water and large volume tank reservoir to simulate turbulence, plume and foam formation, and the water flow is monitored volumetrically and acoustically to ensure the repeatability of conditions.

  11. Biochemical Controls on the Production and Composition of Primary Marine Aerosol

    NASA Astrophysics Data System (ADS)

    Keene, W. C.; Kieber, D. J.; Frossard, A. A.; Long, M. S.; Russell, L. M.; Maben, J. R.; Kinsey, J. D.; Tyssebotn, I. M.; Quinn, P. K.; Bates, T. S.

    2013-12-01

    Nascent marine aerosols were produced by bursting bubbles from both flowing and fixed volumes of fresh surface seawater under controlled conditions in a high-capacity shipboard generator deployed in the eastern North Pacific Ocean during CalNex and in the western North Atlantic Ocean during the Western Atlantic Climate Study (WACS). Seawater conditions ranged from highly productive (chl a = 12 μg L-1) to oligotrophic (chl a = 0.03 μg L-1). Aerosols were also produced from fresh flowing seawater sampled at 2500 m depth (chl a = 0.00 μg L-1). Bubble sizes, bubble surface tension, and size-resolved aerosol chemical compositions and number production fluxes were quantified. Number fluxes were dominated by particles less than100-nm dry diameter that were composed primarily of organic matter (OM). Production fluxes of particulate OM corresponded to <0.01% of dissolved OM (DOC) in flowing seawater. Aerosol number fluxes from flowing productive waters were greater by factors of 2 to 3 compared to oligotrophic waters but corresponding organic enrichments (EFocs) relative to seawater were similar. Bubble scavenging from fixed-volume reservoirs of productive waters rapidly depleted dominant but small surfactants pools leading to lower bubble surface tensions and number production fluxes that converged to those for oligotrophic waters. Bubble scavenging from fixed-volume oligotrophic waters had no influence on aerosol fluxes suggesting the presence of a large background pool of surfactants. Number production fluxes and EFocs from flowing deep seawater were within the ranges of those from surface waters indicating that significant particulate OM is produced by bursting bubbles at the ocean surface in the absence of recent biological activity. Taken together, these results suggest that surfactant material associated with the large pool of recalcitrant DOC in surface seawater contributes to particulate OM in marine air.

  12. A new method of satellite-based haze aerosol monitoring over the North China Plain and a comparison with MODIS Collection 6 aerosol products

    NASA Astrophysics Data System (ADS)

    Yan, Xing; Shi, Wenzhong; Luo, Nana; Zhao, Wenji

    2016-05-01

    With worldwide urbanization, hazy weather has been increasingly frequent, especially in the North China Plain. However, haze aerosol monitoring remains a challenge. In this paper, MODerate resolution Imaging Spectroradiometer (MODIS) measurements were used to develop an enhanced haze aerosol retrieval algorithm (EHARA). This method can work not only on hazy days but also on normal weather days. Based on 12-year (2002-2014) Aerosol Robotic Network (AERONET) aerosol property data, empirical single scattering albedo (SSA) and asymmetry factor (AF) values were chosen to assist haze aerosol retrieval. For validation, EHARA aerosol optical thickness (AOT) values, along with MODIS Collection 6 (C6) dark-pixel and deep blue aerosol products, were compared with AERONET data. The results show that the EHARA can achieve greater AOT spatial coverage under hazy conditions with a high accuracy (73% within error range) and work a higher resolution (1-km). Additionally, this paper presents a comprehensive discussion of the differences between and limitations of the EHARA and the MODIS C6 DT land algorithms.

  13. Markers of heterogeneous reaction products in α-pinene ozone secondary organic aerosol

    NASA Astrophysics Data System (ADS)

    Czoschke, Nadine M.; Jang, Myoseon

    A gas chromatograph iontrap mass spectrometer (GC-ITMS) was used to analyze the gas-and particle-phase products of α-pinene ozone oxidation in the presence of three different inorganic seed aerosols: sodium chloride, ammonium sulfate only, and ammonium sulfate with sulfuric acid. Products of α-pinene ozone oxidation common to the literature showed little difference in gas or particle-phase concentrations between seed types within the precision of the measurements even though significantly different aerosol yields were found between seed types. Small amounts of ring-opening products of four-membered cyclic oxygenates and markers of aldol condensation products were tentatively identified in the particle-phase for all seed types. These tentatively identified products are thought to be the result of acid-catalyzed heterogeneous reactions in the particle-phase or during sampling processes or analysis. The mechanisms for their formation are also proposed in this study.

  14. Photochemical production of aerosols from real plant emissions

    NASA Astrophysics Data System (ADS)

    Mentel, Th. F.; Wildt, J.; Kiendler-Scharr, A.; Kleist, E.; Tillmann, R.; Dal Maso, M.; Fisseha, R.; Hohaus, Th.; Spahn, H.; Uerlings, R.; Wegener, R.; Griffiths, P. T.; Dinar, E.; Rudich, Y.; Wahner, A.

    2009-07-01

    Emission of biogenic volatile organic compounds (VOC) which on oxidation form secondary organic aerosols (SOA) can couple the vegetation with the atmosphere and climate. Particle formation from tree emissions was investigated in a new setup: a plant chamber coupled to a reaction chamber for oxidizing the plant emissions and for forming SOA. Emissions from the boreal tree species birch, pine, and spruce were studied. In addition, α-pinene was used as reference compound. Under the employed experimental conditions, OH radicals were essential for inducing new particle formation, although O3 (≤80 ppb) was always present and a fraction of the monoterpenes and the sesquiterpenes reacted with ozone before OH was generated. Formation rates of 3 nm particles were linearly related to the VOC carbon mixing ratios, as were the maximum observed volume and the condensational growth rates. For all trees, the threshold of new particle formation was lower than for α-pinene. It was lowest for birch which emitted the largest fraction of oxygenated VOC (OVOC), suggesting that OVOC may play a role in the nucleation process. Incremental mass yields were ≍5% for pine, spruce and α-pinene, and ≍10% for birch. α-Pinene was a good model compound to describe the yield and the growth of SOA particles from coniferous emissions. The mass fractional yields agreed well with observations for boreal forests. Despite the somewhat enhanced VOC and OH concentrations our results may be up-scaled to eco-system level. Using the mass fractional yields observed for the tree emissions and weighting them with the abundance of the respective trees in boreal forests SOA mass concentration calculations agree within 6% with field observations. For a future VOC increase of 50% we predict a particle mass increase due to SOA of 19% assuming today's mass contribution of pre-existing aerosol and oxidant levels.

  15. Photochemical production of aerosols from real plant emissions

    NASA Astrophysics Data System (ADS)

    Mentel, Th. F.; Wildt, J.; Kiendler-Scharr, A.; Kleist, E.; Tillmann, R.; Dal Maso, M.; Fisseha, R.; Hohaus, Th.; Spahn, H.; Uerlings, R.; Wegener, R.; Griffiths, P. T.; Dinar, E.; Rudich, Y.; Wahner, A.

    2009-01-01

    By emission of volatile organic compounds (VOC) which on oxidation form secondary organic aerosols (SOA) the vegetation is coupled to atmosphere and climate. New particle formation from tree emissions was investigated in a new setup: a plant chamber coupled to a reaction chamber for oxidizing the plant emissions and for forming SOA. The boreal tree species birch, pine, and spruce were studied and α-pinene was used as reference compound. Under the experimental conditions OH radicals were essential for inducing new particle formation, although O3 (≤80 ppb) was always present and a part of the monoterpenes and the sesquiterpenes reacted already with ozone before OH was generated. Formation rates of 3 nm particles were linearly related to the carbon mixing ratios of the VOC, as were the maximum observed volume and the condensational growth rates. The threshold of new particle formation was lower for the tree emissions than for α-pinene. It was lowest for birch with the largest fraction of oxygenated VOC (OVOC) suggesting that OVOC may play a pivotal role in new particle formation. Incremental mass yields were ≍5% for pine, spruce and α-pinene, and ≍10% for birch. α-Pinene was a good model compound to describe the yield and the growth of SOA particles from coniferous emissions. The mass fractional yields agreed well with observations for boreal forests. Despite our somewhat enhanced VOC and OH concentrations our results may thus be up-scaled to eco-system level. Using the mass fractional yields observed for the tree emissions and weighting them with the abundance of the respective trees in boreal forests we calculate SOA mass concentrations which agree within 6% with field observations. For a future VOC increase of 50% we predict a particle mass increase due to SOA of 19% assuming today's mass contribution of pre-existing aerosol.

  16. Observation of aerosol parameters at Saga using GOSAT product validation lidar

    NASA Astrophysics Data System (ADS)

    Takubo, Shoichiro; Okumura, Hiroshi; Kawasaki, Takeru; Abdullah, Indra Nugraha; Uchino, Osamu; Morino, Isamu; Yokota, Tatsuya; Nagai, Tomohiro; Sakai, Tetsu; Maki, Takashi; Arai, Kohei

    2012-11-01

    Greenhouse gases Observation SATellite (GOSAT) was launched to enable the precise monitoring of the density of carbon dioxide by combining global observation data sent from space with data obtained on land, and with simulation models. In addition, observation of methane, another greenhouse gas, has been considered. For validation of GOSAT data products, ground-base observation with Fourier Transform Spectrometer (FTS), aerosol lidar and ozone-DIAL (DIfferencial Absorption Lidar) at Saga University, JAPAN has been continued since March, 2011. In this article, observation results obtained from aerosol lidar are reported.

  17. On the Physics of Fizziness: How liquid properties control bursting bubble aerosol production?

    NASA Astrophysics Data System (ADS)

    Ghabache, Elisabeth; Antkowiak, Arnaud; Josserand, Christophe; Seon, Thomas

    2014-11-01

    Either in a champagne glass or at the oceanic scales, the tiny capillary bubbles rising at the surface burst in ejecting myriads of droplets. Focusing on the ejected droplets produced by a single bubble, we investigate experimentally how liquid properties and bubble size affect their characteristics: number, ejection velocities, sizes and ejection heights. These results allow us to finely tune the bursting bubble aerosol production. In the context of champagne industry, aerosols play a major role by spreading wine aroma above the glass. We demonstrate that this champagne fizz can be enhanced by selecting the wine viscosity and the bubble size, thanks to specially designed glass.

  18. Enteric coating of soft gelatin capsules by spouted bed: effect of operating conditions on coating efficiency and on product quality.

    PubMed

    Pissinati, Rafael; Oliveira, Wanderley Pereira

    2003-05-01

    The present study was conducted in order to analyze the viability of the spouted bed process for application of a gastric-resistant coating to soft gelatin capsules. The variables investigated were: included angle of conical base, (gamma), the relation between the feed mass flow rate of the coating suspension and the feed mass flow rate of spouting gas (W(s)/W(g)); the ratio between the flow rate of the spouting gas and the flow rate at minimum spouting condition (Q/Q(ms)); the mass of capsules in the bed (M(0)), and the capsule's size. The product quality was measured by disintegration tests, traction x deformation tests, image analysis and by the evaluation of the coating mass distribution and shape factor variation during the coating operation. The experiments were performed in a spouted bed with a column diameter of 200 mm and included a conical base angle of 40 degrees. The best coating efficiency values were obtained for M(0)=300 g. Coating efficiency tended to increase with increasing W(s)/W(g) ratio. Disintegration tests showed that the gastric-resistant effect was obtained with a coating mass of 3.86 mg/cm(2). The shape factor increase during the coating operation. The capsule's coating mass distribution tended to maintain the original distribution. PMID:12754006

  19. A decadal regional and global trend analysis of the aerosol optical depth using a data-assimilation grade over-water MODIS and Level 2 MISR aerosol products

    NASA Astrophysics Data System (ADS)

    Zhang, J.; Reid, J. S.

    2010-08-01

    Using the ten-year (2000-2009) DA quality Terra MODIS and MISR aerosol products, as well as 7 years of Aqua MODIS, we studied both regional and global aerosol trends over oceans. This included both natural and data assimilation grade versions of the products. Contrary to some of the previous studies that showed a decreasing trend in aerosol optical depth (AOD) over global oceans, after correcting for what appears to be aerosol signal drift from the radiometric calibration of both MODIS instruments, we found MODIS and MISR agreed on a statistically negligible global trend of 0.0003/per year. Our study also suggests that AODs over the Indian Bay of Bengal, east coast of Asia, and Arabian Sea show statistically significant increasing trends of 0.07, 0.06, and 0.06 per ten years for MODIS, respectively. Similar increasing trends were found from MISR, but with less relative magnitude. These trends reflect respective increases in the optical intensity of aerosol events in each region: anthropogenic aerosols over the east coast of China and Indian Bay of Bengal; and a stronger influence from dust events over the Arabian Sea. Negative AOD trends are found off Central America, the east coast of North America, and the west coast of Africa. However, confidence levels are low in these regions, which indicate that longer periods of observation are necessary to be conclusive.

  20. Observed aerosol-induced radiative effect on plant productivity in the eastern United States

    NASA Astrophysics Data System (ADS)

    Strada, S.; Unger, N.; Yue, X.

    2015-12-01

    We apply satellite observations of aerosol optical depth (AOD) in conjunction with flux tower-derived estimates of gross primary productivity (GPP) to probe the relationship between atmospheric aerosol loading and carbon uptake rate at 10 select sites (4 deciduous broadleaf, 3 cropland, 1 evergreen needle leaf, 1 mixed forest and 1 grassland) on hourly time scales in the growing season in the eastern United States. For deciduous and mixed forests, the aerosol light scattering increases GPP with a maximum effect observed under polluted conditions (AOD >0.6), when diffuse radiation is 40-60%. During midday hours, high AOD conditions (>0.4) enhance plant productivity by ∼13% in deciduous forests. In contrast, we find that high diffuse light fraction does not increase the carbon uptake rate in croplands and grasslands; for these ecosystems, we estimate that high AOD conditions reduce GPP by ∼17% during midday hours. Our findings are consistent with previous studies that have attributed these contrasting response sensitivities to the complex and closed canopy architecture of forests versus crops and grasslands. C4 but not C3 crops may benefit from pollution-induced changes in diffuse and direct light. Further research is needed to investigate the role of local meteorology as a possible confounder in the connection between atmospheric aerosols and plant productivity.

  1. Hygroscopicity of dicarbonyl-amine secondary organic aerosol products investigated with HTDMA

    NASA Astrophysics Data System (ADS)

    Hawkins, L. N.; de Haan, D. O.

    2010-12-01

    Recent studies have shown the importance of amine-dicarbonyl chemistry as a secondary organic aerosol (SOA) formation pathway, producing imines, imidazoles, and N-containing oligomers. Preliminary work in our group has suggested that some of these products may be surface active. Therefore, the presence of these products may result in important changes to submicron particle hygroscopicity that affect aerosol scattering and cloud condensation nuclei (CCN) activity, especially in regions with significant amine-containing particles. To investigate their hygroscopicity, we have designed a hygroscopicity tandem differential mobility analyzer (HTDMA) system around a 300 L Teflon chamber that allows for longer humidification times needed for some organic aerosol components that are only slightly hygroscopic. This modification provides a range of residence times from 2.5 minutes up to 1 hour, unlike previously published systems that vary from 2-30 seconds. Using the modified hygroscopicity tandem differential mobility analyzer (HTDMA), we have measured the hygroscopic growth factor (HGF) of SOA formed from reactions of glyoxal (and methylglyoxal) with methylamine, ammonium sulfate, and several amino acids. Changes to inorganic aerosol HGF in response to the presence of SOA products are also investigated.

  2. Continuous flame aerosol synthesis of carbon-coated nano-LiFePO4 for Li-ion batteries

    PubMed Central

    Waser, Oliver; Büchel, Robert; Hintennach, Andreas; Novák, Petr; Pratsinis, Sotiris E.

    2013-01-01

    Core-shell, nanosized LiFePO4-carbon particles were made in one step by scalable flame aerosol technology at 7 g/h. Core LiFePO4 particles were made in an enclosed flame spray pyrolysis (FSP) unit and were coated in-situ downstream by auto thermal carbonization (pyrolysis) of swirl-fed C2H2 in an O2-controlled atmosphere. The formation of acetylene carbon black (ACB) shell was investigated as a function of the process fuel-oxidant equivalence ratio (EQR). The core-shell morphology was obtained at slightly fuel-rich conditions (1.0 < EQR < 1.07) whereas segregated ACB and LiFePO4 particles were formed at fuel-lean conditions (0.8 < EQR < 1). Post-annealing of core-shell particles in reducing environment (5 vol% H2 in argon) at 700 °C for up to 4 hours established phase pure, monocrystalline LiFePO4 with a crystal size of 65 nm and 30 wt% ACB content. Uncoated LiFePO4 or segregated LiFePO4-ACB grew to 250 nm at these conditions. Annealing at 800 °C induced carbothermal reduction of LiFePO4 to Fe2P by ACB shell consumption that resulted in cavities between carbon shell and core LiFePO4 and even slight LiFePO4 crystal growth but better electrochemical performance. The present carbon-coated LiFePO4 showed superior cycle stability and higher rate capability than the benchmark, commercially available LiFePO4. PMID:23407817

  3. Comparison of Multi-angle Imaging SpectroRadiometer (MISR) joint aerosol product with high-resolution model output

    NASA Astrophysics Data System (ADS)

    Kalashnikova, O.; Lee, H.; Suzuki, K.; Braverman, A. J.

    2014-12-01

    The Multi-angle Imaging SpectroRadiometer (MISR) Level 3 Joint Aerosol product (JOINT_AS) provides global, descriptive summary of MISR Level 2 aerosol optical thickness (AOT) for eight different types of aerosols at 5 x 5 degrees of horizontal resolution in each month between March 2000 and present. Using Version 22 JOINT_AS, this study analyzed characteristics of the observed AOT distributions and compared various statistical moments of aerosol optical thickness derived from JOINT_AS with the results from Nonhydrostatic Icosahedral Atmospheric Model (NICAM) simulation. Overall, marginal distributions of AOT show highly positive skewness at many grid points. Some of the large skewness values are related to the problems in MISR's retrieval algorithm. For example, the positive skewness in AOT for strongly absorbing aerosols at mid- and high latitudes in winter results from few outlier values is due to cloud contamination over a wide area. Combined AOT for multiple MISR aerosol types is comparable to the AOT for carbonaceous, sulfate aerosols and dust particles from the NICAM simulation implemented with aerosol transport processes. NICAM's carbonaceous aerosols in the Southwest Africa show good agreement with MISR's strongly absorbing aerosols. The AOT of dust particles in MISR and NICAM exhibit similar spatial patterns over the Sahara desert. The AOT of nonabsorbing aerosols in MISR well represents spatial distributions of the sulfate aerosols originating from industrial complex over the Shandong Peninsula in China. Our results indicate that MISR's AOT for each aerosol type may be useful for monitoring biomass burning, dust storms and air pollution and evaluating chemistry climate models.

  4. Coatings.

    ERIC Educational Resources Information Center

    Anderson, Dennis G.

    1989-01-01

    This review covers analytical techniques applicable to the examination of coatings, raw materials, and substrates upon which coatings are placed. Techniques include chemical and electrochemical methods, chromatography, spectroscopy, thermal analysis, microscopy, and miscellaneous techniques. (MVL)

  5. Formation and evolution of molecular products in α-pinene secondary organic aerosol.

    PubMed

    Zhang, Xuan; McVay, Renee C; Huang, Dan D; Dalleska, Nathan F; Aumont, Bernard; Flagan, Richard C; Seinfeld, John H

    2015-11-17

    Much of our understanding of atmospheric secondary organic aerosol (SOA) formation from volatile organic compounds derives from laboratory chamber measurements, including mass yield and elemental composition. These measurements alone are insufficient to identify the chemical mechanisms of SOA production. We present here a comprehensive dataset on the molecular identity, abundance, and kinetics of α-pinene SOA, a canonical system that has received much attention owing to its importance as an organic aerosol source in the pristine atmosphere. Identified organic species account for ∼58-72% of the α-pinene SOA mass, and are characterized as semivolatile/low-volatility monomers and extremely low volatility dimers, which exhibit comparable oxidation states yet different functionalities. Features of the α-pinene SOA formation process are revealed for the first time, to our knowledge, from the dynamics of individual particle-phase components. Although monomeric products dominate the overall aerosol mass, rapid production of dimers plays a key role in initiating particle growth. Continuous production of monomers is observed after the parent α-pinene is consumed, which cannot be explained solely by gas-phase photochemical production. Additionally, distinct responses of monomers and dimers to α-pinene oxidation by ozone vs. hydroxyl radicals, temperature, and relative humidity are observed. Gas-phase radical combination reactions together with condensed phase rearrangement of labile molecules potentially explain the newly characterized SOA features, thereby opening up further avenues for understanding formation and evolution mechanisms of α-pinene SOA. PMID:26578760

  6. A consistent aerosol optical depth (AOD) dataset over mainland China by integration of several AOD products

    NASA Astrophysics Data System (ADS)

    Xu, H.; Guang, J.; Xue, Y.; de Leeuw, Gerrit; Che, Y. H.; Guo, Jianping; He, X. W.; Wang, T. K.

    2015-08-01

    The Moderate Resolution Imaging Spectroradiometer (MODIS), the Multiangle Imaging Spectroradiometer (MISR) and the Sea-viewing Wide Field-of-view Sensor (SeaWiFS) provide validated aerosol optical depth (AOD) products over both land and ocean. However, the values of the AOD provided by each of these satellites may show spatial and temporal differences due to the instrument characteristics and aerosol retrieval algorithms used for each instrument. In this article we present a method to produce an AOD data set over Asia for the year 2007 based on fusion of the data provided by different instruments and/or algorithms. First, the bias of each satellite-derived AOD product was calculated by comparison with ground-based AOD data derived from the AErosol RObotic NETwork (AERONET) and the China Aerosol Remote Sensing NETwork (CARSNET) for different values of the surface albedo and the AOD. Then, these multiple AOD products were combined using the maximum likelihood estimate (MLE) method using weights derived from the root mean square error (RMSE) associated with the accuracies of the original AOD products. The original and merged AOD dataset has been validated by comparison with AOD data from the CARSNET. Results show that the mean bias error (MBE) and mean absolute error (MAE) of the merged AOD dataset are not larger than that of any of the original AOD products. In addition, for the merged AOD dataset the fraction of pixels with no data is significantly smaller than that of any of the original products, thus increasing the spatial coverage. The fraction of retrievable area is about 50% for the merged AOD dataset and between 5% and 20% for the MISR, SeaWiFS, MODIS-DT and MODIS-DB algorithms.

  7. Polumeric electrode coated with reaction product of cyclic compound

    SciTech Connect

    Maxfield, M.; Elsenbaumer, R.L.; Shacklette, L.W.

    1984-09-18

    Batteries are disclosed with electrodes, especially cathodes, having a conjugated backbone polymer such as polyacetylene as electroactive material and a coating. The coating is formed by reaction between the oxidized polymer and a pyrrole, thiophene, azulene, furan or aniline compound.

  8. Monoterpene oxidation products and organosulfates in aerosols during BEARPEX 2007 and 2009

    NASA Astrophysics Data System (ADS)

    Glasius, Marianne; Kristensen, Kasper; Worton, David R.; Goldstein, Allen H.

    2010-05-01

    Organosulfate esters of oxidation products of monoterpenes and isoprene have been identified in aerosols from both laboratory and field studies. While the exact route of formation of organosulfates is still ambiguous, these compounds pose an interesting coupling between anthropogenic emissions and biogenic oxidation products in secondary organic aerosols (SOA). We present measurements of monoterpene oxidation products, organosulfates and nitroxy organosulfates in aerosols collected during the Biosphere Effects on Aerosols and Photochemistry Experiment (BEARPEX) in California during late summer 2007 and summer 2009. The study site was located in a Ponderosa pine plantation affected by regional transport of air pollutants. Particles (PM2.5) were collected as one night-time and two daytime samples per day using a high volume sampler. After extraction of filters, polar organic compounds were analysed by HPLC coupled through an electrospray inlet to a quadrupole time-of-flight mass spectrometer (qTOF-MS). Standards of adipic, cis-pinic and pinonic acids were used for quantification, while camphor sulphonic acid was used as a surrogate standard for organosulfate compounds. Organosulfate esters can be identified from their MS-fragments (HSO4- and SO3-) and the isotopic pattern of sulphur. Concentrations of adipic acid and the terpene oxidation products cis-pinic acid and pinonic acid (from α- and β-pinene) were quantified. The relative concentrations between samples of terpenylic acid, diterpenylic acid and 2-hydroxyterpenylic acid were also investigated. Organosulfate esters and nitroxy organosulfate esters of α-pinene, β-pinene, limonene and isoprene, as well as their oxidation products, were identified based on their molecular mass and fragmentation patterns. Concentrations of some nitroxy organosulfate esters generally increased during night compared to day-time. Their formation thus seems to be related to reactions involving nitrate radicals at night-time.

  9. A decadal regional and global trend analysis of the aerosol optical depth using a data-assimilation grade over-water MODIS and Level 2 MISR aerosol products

    NASA Astrophysics Data System (ADS)

    Zhang, J.; Reid, J. S.

    2010-11-01

    Using the ten-year (2000-2009) Data-Assimilation (DA) quality Terra MODIS and MISR aerosol products, as well as 7 years of Aqua MODIS, we studied both regional and global aerosol trends over oceans. This included both operational and data assimilation grade versions of the products. After correcting for what appears to be aerosol signal drift from the radiometric calibration of both MODIS instruments, we found MODIS and MISR agreed on a statistically negligible global trend of ±0.003/per decade. Our study also suggests that AODs over the Indian Bay of Bengal, east coast of Asia, and Arabian Sea show increasing trends of 0.07, 0.06, and 0.06 per decade for MODIS, respectively. These regional trends are considered as significant with a confidence level above 95%. Similar increasing trends were found from MISR, but with less relative magnitude. These trends reflect respective increases in the optical intensity of aerosol events in each region: anthropogenic aerosols over the east coast of China and Indian Bay of Bengal; and a stronger influence from dust events over the Arabian Sea. Negative AOD trends, low in confidence levels, are found off Central America, the east coast of North America, and the west coast of Africa, which indicate that longer periods of observation are necessary to be conclusive.

  10. Laboratory studies of oxidation of primary emissions: Oxidation of organic molecular markers and secondary organic aerosol production

    NASA Astrophysics Data System (ADS)

    Weitkamp, Emily A.

    Particulate matter (PM) is solid particles and liquid droplets of complex composition suspended in the atmosphere. In 1997, the National Ambient Air Quality Standards (NAAQS) for PM was modified to include new standards for fine particulate (particles smaller than 2.5mum, PM2.5) because of their association with adverse health effects, mortality and visibility reduction. Fine PM may also have large impacts on the global climate. Chemically, fine particulate is a complex mixture of organic and inorganic material, from both natural and anthropogenic sources. A large fraction of PM2.5 is organic. The first objective was to investigate heterogeneous oxidation of condensed-phase molecular markers for two major organic source categories, meat-cooking emissions and motor vehicle exhaust. Effective reaction rate constants of key molecular markers were measured over a range of atmospherically relevant experimental conditions, including a range of concentrations and relative humidities, and with SOA condensed on the particles. Aerosolized meat grease was reacted with ozone to investigate the oxidation of molecular markers for meat-cooking emissions. Aerosolized motor oil, which is chemically similar to vehicle exhaust aerosol and contains the molecular markers used in source apportionment, was reacted with the hydroxyl radical (OH) to investigate oxidation of motor vehicle molecular markers. All molecular markers of interest - oleic acid, palmitoleic acid, and cholesterol for meat-cooking emissions, and hopanes and steranes for vehicle exhaust - reacted at rates that are significant for time scales on the order of days assuming typical summertime oxidant concentrations. Experimental conditions influenced the reaction rate constants. For both systems, experiments conducted at high relative humidity (RH) had smaller reaction rate constants than those at low RH. SOA coating slowed the reaction rate constants for meat-cooking markers, but had no effect on the oxidation of

  11. Laser Remote Sensing from ISS: the CATS-CALIPSO Cloud and Aerosol Data Products

    NASA Astrophysics Data System (ADS)

    Rodier, S. D.; Palm, S. P.; Jensen, M. H.; Yorks, J. E.; McGill, M. J.; Vaughan, M.; Trepte, C. R.

    2014-12-01

    The NASA Cloud Aerosol Transport System (CATS) is a dual-beam, multi-wavelength (1064, 532 and 355 nm), polarization sensitive (1064 and 532 nm) lidar developed at NASA's Goddard Space Flight Center (GSFC) for deployment to the International Space Station (ISS) in late 2014. CATS will be mounted on the Japanese Experiment Module's Exposed Facility and will provide near-continuous, altitude-resolved measurements of clouds and aerosols in the Earth's atmosphere. The ISS orbit path provides a unique opportunity to capture the full diurnal cycle of cloud and aerosol development and transport, allowing for studies that are not possible with the lidar aboard the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) mission, which flies in the sun-synchronous A-Train orbit. One of the primary objectives of CATS is to continue the CALIPSO data record to provide continuity of aerosol and cloud lidar observations during the transition from CALIPSO to EarthCARE. To accomplish this, the CATS project at GSFC and the CALIPSO project at NASA's Langley Research Center are closely collaborating to develop and deliver a full suite of CALIPSO-like level 2 data products generated from the newly acquired CATS level 1B data. Now in its eighth year of on-orbit operations, the CALIPSO project has developed a robust set of mature and well-validated science algorithms to retrieve the spatial and optical properties of clouds and aerosols from multi-wavelength lidar backscatter signal. By leveraging both new and existing NASA technical resources, this joint effort by the CATS-CALIPSO team will enable rapid delivery of high-quality lidar data sets to the user community at the earliest possible opportunity. In this work we outline the development of the CALIPSO- CATS level 2 software and data products and describe the modifications made to the input CATS data stream and the CALIPSO processing algorithms in order to successfully interface two disparate data processing

  12. United role of radon decay products and nano-aerosols in radon dosimetry

    NASA Astrophysics Data System (ADS)

    Smerajec, M.; Vaupotič, J.

    2012-04-01

    The major part of human exposure to natural radiation originates from inhalation of radon (Rn) and radon short-lived decay products (RnDP: 218Po, 214Pb, 214Bi and 214Po). RnDP are formed as a result of α-transformation of radon. In the beginning they are positive ions which neutralize and form clusters with air molecules, and later partly attach to background aerosol particles in indoor air. Eventually, they appear as radioactive nano-aerosols with a bimodal size distribution in ranges of 1-10 nm (unattached RnDP) and of 200-800 nm (attached RnDP). When inhaled, they are deposited in the respiratory tract. Deposition is more efficient for smaller particles. Therefore, the fraction (fun) of the unattached RnDP, which appears to be influenced by the number concentration and size distribution of general (background) aerosols in the ambient air, has a crucial role in radon dosimetry. Radon, radon decay products and general aerosols have been monitored simultaneously in the kitchen of a typical rural house under real living conditions, also comprising four human activities generating particular matter: cooking and baking, as two typical activities in kitchen, and cigarette smoking and candle burning. In periods without any human activity, the total number concentration of general aerosol ranged from 1000 to 3000 cm-3,with the geometric mean of particle diameter in the range of 60-68 nm and with 0.1-1 % of particles smaller than 10 nm. Preparation of coffee changed the concentration to 193,000 cm-3, the geometric mean of diameter to 20 nm and fraction of particles smaller than 10 nm to 11 %. The respective changes were for baking cake: 503,000 cm-3, 17 nm and 19 %, for smoking:423,000 cm-3, 83 nm and 0.4 %, and forcandle burning: 945,000 cm-3, 8 nm and 85 %. While, as expected, a reduction of fun was observed during cooking, baking and smoking, when larger particles were emitted, fun did not increase during candle burning with mostly particles smaller than 10 nm

  13. Factors Regulating the Size-Resolved Production and Composition of Nascent Marine Aerosols (Invited)

    NASA Astrophysics Data System (ADS)

    Keene, W. C.; Frossard, A.; Long, M. S.; Maben, J. R.; Russell, L. M.; Kieber, D. J.; Kinsey, J.; Bates, T. S.; Quinn, P.

    2010-12-01

    Bursting bubbles generated by breaking wind waves at the ocean surface are a major but poorly constrained global source for aerosol mass, volume, and number and associated reactive constituents all of which significantly influence the multiphase physicochemical evolution of Earth’s troposphere and climate. During a spring 2010 cruise of the R/V Atlantis in the eastern North Pacific Ocean, marine aerosols were produced in a high-capacity glass and Teflon generator by artificially injecting zero air into fresh flowing seawater via coarse (A) and fine (D) frits at 1.2 m depth and seawater jets impinging upon the surface. Size-resolved number concentrations and organic and inorganic composition, organic functional groups, bubble-plume volumes, and near-surface bubble sizes were characterized over ranges of bubble and seawater flow rates and headspace RH. Seawater temperature, salinity, and chlorophyll a concentrations were measured in parallel. Relative to fine frits, bubble-plume volumes generated with coarse frits were three times smaller due to the higher initial rise velocity and shorting lifetimes of larger bubbles. However, bubbles produced by both coarse and fine frits evolved in response to surface tension to similar size (0.2- to 0.5-mm diameter) near the water-air interface. Consequently, the two frit sizes produced similar number fluxes of size-resolved aerosols per unit volume air flux. Production fluxes of supermicron- and submicron-diameter size fractions varied as linear functions of air detrainment. Ranges in centroids for number size distributions of aerosols produced with coarse (70- to 100-nm dry diameter) and fine frits (60- to 80-nm dry diameter) overlapped. Centroids for size distributions produced by a bubbler-type generator deployed in open seawater adjacent to the ship ranged from 55- 60-nm dry diameter. Number-size distributions produced by water jets were shifted towards larger particles with centroids of 100- to 150-nm dry diameter

  14. DETERMINATION OF SECONDARY ORGANIC AEROSOL PRODUCTS FROM THE PHOTOOXIDATION OF TOLUENE AND THEIR IMPLICATIONS IN AMBIENT PM2.5

    EPA Science Inventory

    Laboratory study was carried out to investigate the secondary organic aerosol products from photooxidation of the aromatic hydrocarbon toluene. The laboratory experiments consisted of irradiating toluene/propylene/NOX/air mixtures in a smog chamber operated in the dynamic mode...

  15. 3. Guidelines for efficacy testing of household insecticide products - Mosquito coils, vaporizer mats, liquid vaporizers, ambient emanators and aerosols

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This document provides specific and standardized procedures and criteria for efficacy testing and evaluation of specific household insecticide products intended for indoor use against mosquitoes, namely, mosquito coils, vaporizer mats, liquid vaporizers, ambient emanators and aerosols....

  16. Reactive processing of formaldehyde and acetaldehyde in aqueous aerosol mimics: surface tension depression and secondary organic products

    NASA Astrophysics Data System (ADS)

    Li, Z.; Schwier, A. N.; Sareen, N.; McNeill, V. F.

    2011-11-01

    The reactive uptake of carbonyl-containing volatile organic compounds (cVOCs) by aqueous atmospheric aerosols is a likely source of particulate organic material. The aqueous-phase secondary organic products of some cVOCs are surface-active. Therefore, cVOC uptake can lead to organic film formation at the gas-aerosol interface and changes in aerosol surface tension. We examined the chemical reactions of two abundant cVOCs, formaldehyde and acetaldehyde, in water and aqueous ammonium sulfate (AS) solutions mimicking tropospheric aerosols. Secondary organic products were identified using Aerosol Chemical Ionization Mass Spectrometry (Aerosol-CIMS), and changes in surface tension were monitored using pendant drop tensiometry. Hemiacetal oligomers and aldol condensation products were identified using Aerosol-CIMS. Acetaldehyde depresses surface tension to 65(±2) dyn cm-1 in pure water (a 10% surface tension reduction from that of pure water) and 62(±1) dyn cm-1 in AS solutions (a 20.6% reduction from that of a 3.1 M AS solution). Surface tension depression by formaldehyde in pure water is negligible; in AS solutions, a 9% reduction in surface tension is observed. Mixtures of these species were also studied in combination with methylglyoxal in order to evaluate the influence of cross-reactions on surface tension depression and product formation in these systems. We find that surface tension depression in the solutions containing mixed cVOCs exceeds that predicted by an additive model based on the single-species isotherms.

  17. Reactive processing of formaldehyde and acetaldehyde in aqueous aerosol mimics: surface tension depression and secondary organic products

    NASA Astrophysics Data System (ADS)

    Li, Z.; Schwier, A. N.; Sareen, N.; McNeill, V. F.

    2011-07-01

    The reactive uptake of carbonyl-containing volatile organic compounds (cVOCs) by aqueous atmospheric aerosols is a likely source of particulate organic material. The aqueous-phase secondary organic products of some cVOCs are surface-active. Therefore, cVOC uptake can lead to organic film formation at the gas-aerosol interface and changes in aerosol surface tension. We examined the chemical reactions of two abundant cVOCs, formaldehyde and acetaldehyde, in water and aqueous ammonium sulfate (AS) solutions mimicking tropospheric aerosols. Secondary organic products were identified using Aerosol Chemical Ionization Mass Spectrometry (Aerosol-CIMS), and changes in surface tension were monitored using pendant drop tensiometry. Hemiacetal oligomers and aldol condensation products were identified using Aerosol-CIMS. A hemiacetal sulfate ester was tentatively identified in the formaldehyde-AS system. Acetaldehyde depresses surface tension to 65(±2) dyn cm-1 in pure water and 62(±1) dyn cm-1 in AS solutions. Surface tension depression by formaldehyde in pure water is negligible; in AS solutions, a 9 % reduction in surface tension is observed. Mixtures of these species were also studied in combination with methylglyoxal in order to evaluate the influence of cross-reactions on surface tension depression and product formation in these systems. We find that surface tension depression in the solutions containing mixed cVOCs exceeds that predicted by an additive model based on the single-species isotherms.

  18. A new operational EUMETSAT product for the retrieval of aerosol optical properties over land (PMAp v2)

    NASA Astrophysics Data System (ADS)

    Grzegorski, Michael; Munro, Rosemary; Poli, Gabriele; Holdak, Andriy; Lang, Ruediger

    2016-04-01

    The retrieval of aerosol optical properties is an important task to provide data for industry and climate forecasting. An ideal instrument should include observations with moderate spectral and high spatial resolution for a wide range of wavelengths (from the UV to the TIR), measurements of the polarization state at different wavelengths and measurements of the same scene for different observation geometries. As such an ideal instrument is currently unavailable the usage of different instruments on one satellite platform is an alternative choice. Since February 2014, the Polar Multi sensor Aerosol product (PMAp) has been delivered as an operational GOME product to our customers. The algorithm retrieves aerosol optical properties over ocean (AOD, volcanic ash, aerosol type) using a multi-sensor approach (GOME, AVHRR, IASI). The product is now extended to pixels over land using a new release of the operational PMAp processor (PMAp v2). The pre-operational data dissemination of the new PMAp v2 data to our users is scheduled for March 2016. This presentation gives an overview on the new operational product PMAp v2 with a focus on the validation of the PMAp aerosol optical depth over land. The impact of different error sources on the results (e.g. surface contribution to the TOA reflectance) is discussed. We also show first results of upcoming extensions of our PMAp processor, in particular the improvement of the cloud/aerosol discrimination of thick aerosol events (e.g. volcanic ash plumes, desert dust outbreaks).

  19. The influence of marine microbial activities on aerosol production: A laboratory mesocosm study

    NASA Astrophysics Data System (ADS)

    Alpert, Peter A.; Kilthau, Wendy P.; Bothe, Dylan W.; Radway, JoAnn C.; Aller, Josephine Y.; Knopf, Daniel A.

    2015-09-01

    The oceans cover most of the Earth's surface, contain nearly half the total global primary biomass productivity, and are a major source of atmospheric aerosol particles. Here we experimentally investigate links between biological activity in seawater and sea spray aerosol (SSA) flux, a relationship of potential significance for organic aerosol loading and cloud formation over the oceans and thus for climate globally. Bubbles were generated in laboratory mesocosm experiments either by recirculating impinging water jets or glass frits. Experiments were conducted with Atlantic Ocean seawater collected off the eastern end of Long Island, NY, and with artificial seawater containing cultures of bacteria and phytoplankton Thalassiosira pseudonana, Emiliania huxleyi, and Nannochloris atomus. Changes in SSA size distributions occurred during all phases of bacterial and phytoplankton growth, as characterized by cell concentrations, dissolved organic carbon, total particulate carbon, and transparent exopolymer particles (gel-forming polysaccharides representing a major component of biogenic exudate material). Over a 2 week growth period, SSA particle concentrations increased by a factor of less than 2 when only bacteria were present and by a factor of about 3 when bacteria and phytoplankton were present. Production of jet-generated SSA particles of diameter less than 200 nm increased with time, while production of all particle diameters increased with time when frits were used. The implications of a marine biological activity dependent SSA flux are discussed.

  20. The optical, physical and chemical properties of the products of glyoxal uptake on ammonium sulfate seed aerosols

    NASA Astrophysics Data System (ADS)

    Trainic, M.; Riziq, A. A.; Lavi, A.; Flores, J. M.; Rudich, Y.

    2011-07-01

    The heterogeneous reaction between gas phase glyoxal and ammonium sulfate (AS) aerosols, a proxy for inorganic atmospheric aerosol, was studied in terms of the dependence of the optical, physical and chemical properties of the product aerosols on initial particle size and ambient RH. The reactions were studied under different relative humidity (RH) conditions, varying from dry conditions (~20 % RH) and up to 90 % RH, covering conditions prevalent in many atmospheric environments. At λ = 355 nm, the reacted aerosols demonstrate a substantial growth in optical extinction cross section, as well as in mobility diameter under a broad range of RH values (35-90 %). The ratio of the product aerosol to seed aerosol geometric cross section reached up to ~3.5, and the optical extinction cross-section up to ~250. The reactions show a trend of increasing physical and optical growth with decreasing seed aerosol size, from 100nm to 300 nm, as well as with decreasing RH values from 90 % to ~40 %. Optically inactive aerosols, at the limit of the Mie range (100 nm diameter) become optically active as they grow due to the reaction. AMS analyses of the reaction of 300 nm AS at RH values of 50 %, 75 % and 90 % show that the main products of the reaction are glyoxal oligomers, formed by acetal formation in the presence of AS. In addition, imidazole formation, which is a minor channel, is observed for all reactions, yielding a product which absorbs at λ = 290 nm, with possible implications on the radiative properties of the product aerosols. The ratio of absorbing substances (C-N compounds, including imidazoles) increases with increasing RH value. A core/shell model used for the investigation of the optical properties of the reaction products of AS 300nm with gas phase glyoxal, shows that the refractive index (RI) of the reaction products are in the range between 1.57-1.71 for the real part and between 0-0.02 for the imaginary part of the RI at 355 nm. The observed increase in the

  1. Mechanism for production of secondary organic aerosols and their representation in atmospheric models. Final report

    SciTech Connect

    Seinfeld, J.H.; Flagan, R.C.

    1999-06-07

    This document contains the following: organic aerosol formation from the oxidation of biogenic hydrocarbons; gas/particle partitioning of semivolatile organic compounds to model inorganic, organic, and ambient smog aerosols; and representation of secondary organic aerosol formation in atmospheric models.

  2. Development, Application, and Transition of Aerosol and Trace Gas Products Derived from Next-Generation Satellite Observations to Operations

    NASA Technical Reports Server (NTRS)

    Berndt, Emily; Naeger, Aaron; Zavodsky, Bradley; McGrath, Kevin; LaFontaine, Frank

    2016-01-01

    NASA Short-term Prediction Research and Transition (SPoRT) Center has a history of successfully transitioning unique observations and research capabilities to the operational weather community to improve short-term forecasts. SPoRTstrives to bridge the gap between research and operations by maintaining interactive partnerships with end users to develop products that match specific forecast challenges, provide training, and assess the products in the operational environment. This presentation focuses on recent product development, application, and transition of aerosol and trace gas products to operations for specific forecasting applications. Recent activities relating to the SPoRT ozone products, aerosol optical depth composite product, sulfur dioxide, and aerosol index products are discussed.

  3. Secondary organic aerosol formation from m-xylene photooxidation: The role of the phenolic product

    NASA Astrophysics Data System (ADS)

    Nakao, S.; Qi, L.; Clark, C.; Sato, K.; Tang, P.; Cocker, D.

    2009-12-01

    Aromatic hydrocarbons comprise a significant fraction of volatile organic compounds in the urban atmosphere and their importance as precursors to secondary organic aerosols (SOA) has been widely recognized. However, SOA formation from aromatics is one of the least understood processes among all the classes of volatile organic compounds (VOCs) due to its complex multi-generation reactions. Phenolic compounds have been identified as one of the significant products from OH-initiated reaction of aromatic hydrocarbons and are suggested to have a very high potential of SOA formation (e.g., cresol isomers having SOA yield 9~42%, Henry et al., Atmos. Environ., 2008). We examined the effect of extent of oxidation of m-xylene on chemical composition and physical properties using m-xylene and xylenol as reactants in environmental chamber experiments. Chemical composition of SOA was investigated by Liquid Chromatography / Time of Flight Mass Spectrometer (LC/ToF-MS), and Aerodyne High Resolution Time-of-Flight Aerosol Mass Spectrometer (HR-ToF-AMS). Physical properties of SOA such as density, volatility, and hygroscopicity were investigated by Aerosol Particle Mass Analyzer - Scanning Mobility Particle Sizer (APM-SMPS), Hygroscopicity/Volatility - Tandem Differential Mobility Analyzer (H/V-TDMA), respectively. Also SOA yields were obtained to evaluate the importance of xylenol as an intermediate product.

  4. Caffeine and theobromine levels in chocolate couverture and coating products.

    PubMed

    Ramli, N; Rahman, S; Hassan, O; Mohd Yatim, A; Said, M; Lim, L; Ng, W

    2000-03-01

    Thirty-two samples of chocolate products were analysed by HPLC for caffeine and theobromine contents. Defatted residues of samples were extracted with 80% aqueous acetone. After extraction into boiling water, the methylxanthines were identified and quantified with the use of μ-Bondapak column and mobile phase of methanol:water:acetic acid (20:79:1). Levels of caffein and theobromine in 32 samples of chocolate products averaged 0.62-1.14 mg/g and 0.026-0.153 mg/g respectively. Mean values for theobromine and caffeine content for chocolate coating were 0.82 and 0.07 mg/g respectively. The chocolate coating made from fat substitute had theobromine and caffeine levels ranging from 0.36-0.70 mg/g and 0.027-0.061 mg/g respectively, with mean values of 0.49 mg theobromine/g and 0.039 mg caffeine/g. In local chocolate, the mean theobromine and caffeine levels respectively were 0.72 mg/g and 0.04 mg/g in milk chocolate, and 0.85 mg/g and 0.06 mg/g in dark chocolate. Meanwhile, for imported chocolate, the mean theobromine and caffeine levels respectively were 1.05 mg/g and 0.12 mg/g in dark chocolate; 0.76 mg/g and 0.04 mg/g in milk chocolate; and 0.74 mg/g and 0.03 mg/g in white chocolate. Compared with the local chocolates, imported chocolates had higher levels of theobromine and caffeine at 1.141 mg/g and 0.1533mg/g. The average theobromine and caffeine concentrations in local chocolate were 0.082mg/g and 0.066mg/g. Theobromine concentration in chocolate samples is within the range of 0.62mg/g-1.141mg/g and the range of caffeine concentration is 0.026mg/g-0.153mg/g respectively. Bittersweet chocolates were found to have higher theobromine and caffeine concentrations than normal sweet chocolates and milk chocolates. PMID:22692392

  5. Laser Remote Sensing From ISS: CATS Cloud and Aerosol Level 2 Data Products (Heritage Edition)

    NASA Technical Reports Server (NTRS)

    Rodier, Sharon; Vaughan, Mark; Palm, Steve; Jensen, Mike; Yorks, John; McGill, Matt; Trepte, Chip; Murray, Tim; Lee, Kam-Pui

    2015-01-01

    The Cloud-Aerosol Transport System (CATS) instrument was developed at NASA's Goddard Space Flight Center (GSFC) and deployed to the International Space Station (ISS) on 10 January 2015. CATS is mounted on the Japanese Experiment Module's Exposed Facility (JEM_EF) and will provide near-continuous, altitude-resolved measurements of clouds and aerosols in the Earth's atmosphere. The CATS ISS orbit path provides a unique opportunity to capture the full diurnal cycle of cloud and aerosol development and transport, allowing for studies that are not possible with the lidar aboard the CALIPSO platform, which flies in the sun-synchronous A-Train orbit." " One of the primary science objectives of CATS is to continue the CALIPSO aerosol and cloud profile data record to provide continuity of lidar climate observations during the transition from CALIPSO to EarthCARE. To accomplish this, the CATS project at NASA's Goddard Space Flight Center (GSFC) and the CALIPSO project at NASA's Langley Research Center (LaRC) are closely collaborating to develop and deliver a full suite of CALIPSO-like level 2 data products that will be produced using the newly acquired CATS level 1B data whenever CATS is operating in science modes 1. The CALIPSO mission is now well into its ninth year of on-orbit operations, and has developed a robust set of mature and well-validated science algorithms to retrieve the spatial and optical properties of clouds and aerosols from multi-wavelength lidar backscatter signals. By leveraging both new and existing NASA technical resources, this joint effort by the CATS and CALIPSO teams will deliver validated lidar data sets to the user community at the earliest possible opportunity. The science community will have access to two sets of CATS Level 2 data products. The "Operational" data products will be produced by the GSFC CATS team utilizing the new instrument capabilities (e.g., multiple FOVs and 1064 nm depolarization), while the "Heritage" data products created

  6. A Novel Aerosol Method for the Production of Hydrogel Particles

    PubMed Central

    Guzman-Villanueva, Diana; Smyth, Hugh D. C.; Herrera-Ruiz, Dea; El-Sherbiny, Ibrahim M.

    2012-01-01

    A novel method of generating hydrogel particles for various applications including drug delivery purposes was developed. This method is based on the production of hydrogel particles from sprayed polymeric nano/microdroplets obtained by a nebulization process that is immediately followed by gelation in a crosslinking fluid. In this study, particle synthesis parameters such as type of nebulizer, type of crosslinker, air pressure, and polymer concentration were investigated for their impact on the mean particle size, swelling behavior, and morphology of the developed particles. Spherical alginate-based hydrogel particles with a mean particle size in the range from 842 to 886 nm were obtained. Using statistical analysis of the factorial design of experiment it was found that the main factors influencing the size and swelling values of the particles are the alginate concentration and the air pressure. Thus, it was demonstrated that the method described in the current study is promising for the generation of hydrogel particles and it constitutes a relatively simple and low-cost system. PMID:23687513

  7. Fast onset medications through thermally generated aerosols.

    PubMed

    Rabinowitz, Joshua D; Wensley, Martin; Lloyd, Peter; Myers, Daniel; Shen, William; Lu, Amy; Hodges, Craig; Hale, Ron; Mufson, Daniel; Zaffaroni, Alejandro

    2004-05-01

    Smoking involves heating a drug to form a mixture of drug vapor and gaseous degradation products. These gases subsequently cool and condense into aerosol particles that are inhaled. Here, we demonstrate rapid and reliable systemic delivery of pure pharmaceutical compounds without degradation products through a related process that also involves inhalation of thermally generated aerosol. Drug is coated as a thin film on a metallic substrate and vaporized by heating the metal. The thin nature of the drug coating minimizes the length of time during which the drug is exposed to elevated temperatures, thereby preventing its thermal decomposition. The vaporized, gas-phase drug rapidly condenses and coagulates into micrometer-sized aerosol particles. For the commonly prescribed antimigraine drug rizatriptan, inhalation of these particles results in nearly instantaneous systemic drug action. PMID:14752061

  8. Short term inhalation toxicity of a liquid aerosol of glutaraldehyde-coated CdS/Cd(OH)2 core shell quantum dots in rats.

    PubMed

    Ma-Hock, L; Farias, P M A; Hofmann, T; Andrade, A C D S; Silva, J N; Arnaud, T M S; Wohlleben, W; Strauss, V; Treumann, S; Chaves, C R; Gröters, S; Landsiedel, R; van Ravenzwaay, B

    2014-02-10

    Quantum dots exhibit extraordinary optical and mechanical properties, and the number of their applications is increasing. In order to investigate a possible effect of coating on the inhalation toxicity of previously tested non-coated CdS/Cd(OH)2 quantum dots and translocation of these very small particles from the lungs, rats were exposed to coated quantum dots or CdCl2 aerosol (since Cd(2+) was present as impurity), 6h/d for 5 consecutive days. Cd content was determined in organs and excreta after the end of exposure and three weeks thereafter. Toxicity was determined by examination of broncho-alveolar lavage fluid and microscopic evaluation of the entire respiratory tract. There was no evidence for translocation of particles from the respiratory tract. Evidence of a minimal inflammatory process was observed by examination of broncho-alveolar lavage fluid. Microscopically, minimal to mild epithelial alteration was seen in the larynx. The effects observed with coated quantum dots, non-coated quantum dots and CdCl2 were comparable, indicating that quantum dots elicited no significant effects beyond the toxicity of the Cd(2+) ion itself. Compared to other compounds with larger particle size tested at similarly low concentrations, quantum dots caused much less pronounced toxicological effects. Therefore, the present data show that small particle sizes with corresponding high surfaces are not the only factor triggering the toxic response or translocation. PMID:24296008

  9. Photooxidation Products of Isoprene Epoxydiols (IEPOX) and IEPOX-Derived Secondary Organic Aerosol

    NASA Astrophysics Data System (ADS)

    Bates, K. H.; Nguyen, T. B.; Coggon, M. M.; Lignell, H.; Stoltz, B.; Wennberg, P. O.; Seinfeld, J.

    2014-12-01

    Isoprene epoxydiol (IEPOX) has recently been identified as a key intermediate in the photooxidation of isoprene under low-NO conditions and in the formation of isoprene-derived secondary organic aerosol (SOA). IEPOX is generally expected to react with OH in the gas phase, where it has been found to form predominantly C4O3H8 products, or undergo reactive uptake onto particles, where it is converted into 2-methyltetrols or organosulfates by acid- or ammonium-catalyzed mechanisms. The subsequent chemistry of these gas- and particle-phase products has not yet been explored. Using synthetic standards of IEPOX and its gas-phase products, we have performed environmental chamber and flow tube experiments to investigate the fate of IEPOX in both the gas and particle phases. To explore the gas-phase chemistry of IEPOX, three potential isomers of the C4O3H8 products were synthesized and photooxidized by exposure to OH. Detection with CF3O- chemical ionization mass spectrometry (CIMS) allowed for determination of their oxidation rates, fractional yields from IEPOX oxidation, and major products. To explore the photooxidation of IEPOX-derived SOA, synthetic IEPOX was reacted with various salts and atomized into a flow tube, where it was photooxidized by exposure to OH. We will present results showing changes in gas- and particle-phase chemical composition, monitored during oxidation by CIMS and aerosol mass spectrometry, including their dependence on both seed particle composition and OH concentration. Preliminary data show that the photochemical loss of IEPOX-derived SOA mass may be an important consideration for predicting aerosol loading and gas phase oxidative chemistry in isoprene-rich environments.

  10. RESEARCH AND PRODUCT DEVELOPMENT OF LOW-VOC WOOD COATINGS

    EPA Science Inventory

    The report discusses a project, cofunded by the South Coast Air Quality Management District (SCAQMD) and the U.S. EPA, to develop a new, low volatile organic compound (VOC) wood coating. Traditional wood furniture coating technologies contain organic solvents which become air pol...

  11. New Global Deep Blue Aerosol Product over Land and Ocean from VIIRS, and Its comparisons with MODIS

    NASA Astrophysics Data System (ADS)

    Hsu, N. Y. C.; Bettenhausen, C.; Sayer, A. M.; Lee, J.; Tsay, S. C.; Carletta, N.

    2015-12-01

    The impacts of natural and anthropogenic sources of air pollution on climate and human health have continued to gain attention from the scientific community. In order to facilitate these effects, high quality consistent long-term global aerosol data records from satellites are essential. Several EOS-era instruments (e.g., SeaWiFS, MODIS, and MISR) are able to provide such information with a high degree of fidelity. However, with the aging MODIS sensors and the launch of the VIIRS instrument on Suomi NPP in late 2011, the continuation of long-term aerosol data records suitable for climate studies from MODIS to VIIRS is needed urgently. VIIRS was designed to have similar capabilities to MODIS, with similar visible/infrared spectral channels, and spatial/ temporal resolution. However, small but significant differences in several key channels used in aerosol retrievals between MODIS and VIIRS mean that significant effort is required to revise aerosol models and surface reflectance determination modules previously developed using MODIS data. In this study, we will show the global (land and ocean) distribution of aerosols from Version 1 of the VIIRS Deep Blue data set. The preliminary validation results of these new VIIRS Deep Blue aerosol products using data from AERONET sunphotometers over land and ocean will be discussed. We will also compare the monthly averaged Deep Blue aerosol optical thickness (AOT) from VIIRS with the MODIS C6 products to investigate if any systematic biases may exist between MODIS C6 and VIIRS AOT.

  12. Multiday production of condensing organic aerosol mass in urban and forest outflow

    NASA Astrophysics Data System (ADS)

    Lee-Taylor, J.; Hodzic, A.; Madronich, S.; Aumont, B.; Camredon, M.; Valorso, R.

    2015-01-01

    Secondary organic aerosol (SOA) production in air masses containing either anthropogenic or biogenic (terpene-dominated) emissions is investigated using the explicit gas-phase chemical mechanism generator GECKO-A. Simulations show several-fold increases in SOA mass continuing for multiple days in the urban outflow, even as the initial air parcel is diluted into the regional atmosphere. The SOA mass increase in the forest outflow is more modest (~50%) and of shorter duration (1-2 days). The multiday production in the urban outflow stems from continuing oxidation of gas-phase precursors which persist in equilibrium with the particle phase, and can be attributed to multigenerational reaction products of both aromatics and alkanes, especially those with relatively low carbon numbers (C4-15). In particular we find large contributions from substituted maleic anhydrides and multi-substituted peroxide-bicyclic alkenes. The results show that the predicted production is a robust feature of our model even under changing atmospheric conditions and different vapor pressure schemes, and contradict the notion that SOA undergoes little mass production beyond a short initial formation period. The results imply that anthropogenic aerosol precursors could influence the chemical and radiative characteristics of the atmosphere over an extremely wide region, and that SOA measurements near precursor sources may routinely underestimate this influence.

  13. Multiday production of condensing organic aerosol mass in urban and forest outflow

    NASA Astrophysics Data System (ADS)

    Lee-Taylor, J.; Hodzic, A.; Madronich, S.; Aumont, B.; Camredon, M.; Valorso, R.

    2014-07-01

    Secondary organic aerosol (SOA) production in air masses containing either anthropogenic or biogenic (terpene-dominated) emissions is investigated using the explicit gas-phase chemical mechanism generator GECKO-A. Simulations show several-fold increases in SOA mass continuing for several days in the urban outflow, even as the initial air parcel is diluted into the regional atmosphere. The SOA mass increase in the forest outflow is more modest (∼50%) and of shorter duration (1-2 days). The production in the urban outflow stems from continuing oxidation of gas-phase precursors which persist in equilibrium with the particle phase, and can be attributed to multigenerational reaction products of both aromatics and alkanes. In particular we find large contributions from substituted maleic anhydrides and multi-substituted peroxide-bicyclic alkenes. The results show that the predicted production is a robust feature of our model even under changing atmospheric conditions, and contradict the notion that SOA undergoes little mass production beyond a short initial formation period. The results imply that anthropogenic aerosol precursors could influence the chemical and radiative characteristics of the atmosphere over an extremely wide region, and that SOA measurements near precursor sources may routinely underestimate this influence.

  14. Multiday production of condensing organic aerosol mass in urban and forest outflow

    DOE PAGESBeta

    Lee-Taylor, J.; Hodzic, A.; Madronich, S.; Aumont, B.; Camredon, M.; Valorso, R.

    2014-07-03

    Secondary organic aerosol (SOA) production in air masses containing either anthropogenic or biogenic (terpene-dominated) emissions is investigated using the explicit gas-phase chemical mechanism generator GECKO-A. Simulations show several-fold increases in SOA mass continuing for several days in the urban outflow, even as the initial air parcel is diluted into the regional atmosphere. The SOA mass increase in the forest outflow is more modest (∼50%) and of shorter duration (1–2 days). The production in the urban outflow stems from continuing oxidation of gas-phase precursors which persist in equilibrium with the particle phase, and can be attributed to multigenerational reaction products ofmore » both aromatics and alkanes. In particular we find large contributions from substituted maleic anhydrides and multi-substituted peroxide-bicyclic alkenes. The results show that the predicted production is a robust feature of our model even under changing atmospheric conditions, and contradict the notion that SOA undergoes little mass production beyond a short initial formation period. The results imply that anthropogenic aerosol precursors could influence the chemical and radiative characteristics of the atmosphere over an extremely wide region, and that SOA measurements near precursor sources may routinely underestimate this influence.« less

  15. Gas-phase products and secondary aerosol yields from the ozonolysis of ten different terpenes

    NASA Astrophysics Data System (ADS)

    Lee, Anita; Goldstein, Allen H.; Keywood, Melita D.; Gao, Song; Varutbangkul, Varuntida; Bahreini, Roya; Ng, Nga L.; Flagan, Richard C.; Seinfeld, John H.

    2006-04-01

    The ozonolyses of six monoterpenes (α-pinene, β-pinene, 3-carene, terpinolene, α-terpinene, and myrcene), two sesquiterpenes (α-humulene and β-caryophyllene), and two oxygenated terpenes (methyl chavicol and linalool) were conducted individually in Teflon chambers to examine the gas-phase oxidation product and secondary organic aerosol (SOA) yields from these reactions. Particle size distribution and number concentration were monitored and allowed for the calculation of the SOA yield from each experiment, which ranged from 1 to 54%. A proton transfer reaction mass spectrometer (PTR-MS) was used to monitor the evolution of gas-phase products, identified by their mass to charge ratio (m/z). Several gas-phase oxidation products, formaldehyde, acetaldehyde, formic acid, acetone, acetic acid, and nopinone, were identified and calibrated. Aerosol yields, and the yields of these identified and calibrated oxidation products, as well as many higher m/z oxidation products observed with the PTR-MS, varied significantly between the different parent terpene compounds. The sum of measured oxidation products in the gas and particle phase ranged from 33 to 77% of the carbon in the reacted terpenes, suggesting there are still unmeasured products from these reactions. The observations of the higher molecular weight oxidation product ions provide evidence of previously unreported compounds and their temporal evolution in the smog chamber from multistep oxidation processes. Many of the observed ions, including m/z 111 and 113, have also been observed in ambient air above a Ponderosa pine forest canopy, and our results confirm they are consistent with products from terpene + O3 reactions. Many of these products are stable on the timescale of our experiments and can therefore be monitored in field campaigns as evidence for ozone oxidative chemistry.

  16. Secondary Organic Aerosol (SOA) production from the Aqueous Reactions of Phenols and Triplet Aromatic Carbonyls

    NASA Astrophysics Data System (ADS)

    Smith, J.; Sun, Y.; Lu, Y.; Zhang, Q.; Anastasio, C.

    2010-12-01

    The phenolic compounds guaiacol, syringol and phenol have recently been shown to produce secondary organic aerosol (SOA) at high yields in the aqueous phase upon exposure to simulated sunlight and hydroxyl radical. These phenols are significant products from wood combustion that can readily enter atmospheric waters, such as aqueous aerosol particles and cloud/fog droplets. Once in the aqueous phase, phenols can react with the triplet excited states of non-phenolic aromatic carbonyls (NPCs), particle-bound organics that are also emitted from wood combustion. In this study, we examined the aqueous-phase production of SOA from the reaction of phenolic compounds with triplet excited state organics. These aqueous phase reactions were tested by illuminating solutions containing a phenolic compound and NPC under simulated sunlight at various concentrations and pH values. The phenolic compound is consumed during these reactions, following a first-order decay that varies with phenol concentration, phenol identity, and pH. The non-volatile product mass formed in our illuminated solutions was determined gravimetrically and by analysis with High Resolution Time of Flight Aerosol Mass Spectrometry (HR-AMS). The SOA mass yield was determined as the mass of non-volatile product formed per mass of phenolic consumed during illumination. We also used HR-AMS to analyze for elemental composition, carbon oxidation state, and oligomers in the SOA produced. Our results to date indicate that phenols can be rapidly oxidized by triplet excited states under environmentally relevant conditions and that the accompanying SOA mass yields are very high.

  17. Gas phase emissions from cooking processes and their secondary aerosol production potential

    NASA Astrophysics Data System (ADS)

    Klein, Felix; Platt, Stephen; Bruns, Emily; Termime-roussel, Brice; Detournay, Anais; Mohr, Claudia; Crippa, Monica; Slowik, Jay; Marchand, Nicolas; Baltensperger, Urs; Prevot, Andre; El Haddad, Imad

    2014-05-01

    Long before the industrial evolution and the era of fossil fuels, high concentrations of aerosol particles were alluded to in heavily populated areas, including ancient Rome and medieval London. Recent radiocarbon measurements (14C) conducted in modern megacities came as a surprise: carbonaceous aerosol (mainly organic aerosol, OA), a predominant fraction of particulate matter (PM), remains overwhelmingly non-fossil despite extensive fossil fuel combustion. Such particles are directly emitted (primary OA, POA) or formed in-situ in the atmosphere (secondary OA, SOA) via photochemical reactions of volatile organic compounds (VOCs). Urban levels of non-fossil OA greatly exceed the levels measured in pristine environments strongly impacted by biogenic emissions, suggesting a contribution from unidentified anthropogenic non-fossil sources to urban OA. Positive matrix factorization (PMF) techniques applied to ambient aerosol mass spectrometer (AMS, Aerodyne) data identify primary cooking emissions (COA) as one of the main sources of primary non-fossil OA in major cities like London (Allan et al., 2010), New York (Sun et al., 2011) and Beijing (Huang et al., 2010). Cooking processes can also emit VOCs that can act as SOA precursors, potentially explaining in part the high levels of oxygenated OA (OOA) identified by the AMS in urban areas. However, at present, the chemical nature of these VOCs and their secondary aerosol production potential (SAPP) remain virtually unknown. The approach adopted here involves laboratory quantification of PM and VOC emission factors from the main primary COA emitting processes and their SAPP. Primary emissions from deep-fat frying, vegetable boiling, vegetable frying and meat cooking for different oils, meats and vegetables were analysed under controlled conditions after ~100 times dilution. A high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS) and a high resolution proton transfer time-of-flight mass spectrometer (PTR

  18. Gas-Phase Oxidation Kinetics and Organic Aerosol Products of Ethanolamine

    NASA Astrophysics Data System (ADS)

    Borduas, N.; Abbatt, J.; Murphy, J. G.

    2012-12-01

    Ethanolamine is currently the solvent of choice in carbon capture and storage technology (CCS) which aims to reduce CO2 emissions to the atmosphere in coal powered pilot plants. CCS technology represents an unprecedented large scale application of ethanolamine and little is known of its fate if it was unintentionally released into the atmosphere. Relative kinetic experiments were conducted in a 1m3 smog chamber using online proton-transfer-reaction mass spectrometry. The kinetics of oxidation with hydroxyl radicals from light and dark sources converge to a value of (7.6 ± 1.1) x 10-11 cm3 molec-1 s-1. The reaction of ethanolamine with ozone was determined to be (1.05 ± 0.08) x 10-18 cm3 molec-1 s-1. We find that ethanolamine has a short lifetime in the atmosphere and readily deposits onto wall and particle surfaces, as observed by considerable formation of organonitrogen aerosol products. An investigation into the oxidation product formation using a combination of reagent ions with online chemical ionization mass spectrometry approaches lead to the detection of higher order products. The formation of these high molecular weight products is simultaneous with the oxidation of ethanolamine and implies substantial organic aerosol chemistry.

  19. Multiday production of condensing organic aerosol mass in urban and forest outflow

    DOE PAGESBeta

    Lee-Taylor, J.; Hodzic, A.; Madronich, S.; Aumont, B.; Camredon, M.; Valorso, R.

    2015-01-16

    Secondary organic aerosol (SOA) production in air masses containing either anthropogenic or biogenic (terpene-dominated) emissions is investigated using the explicit gas-phase chemical mechanism generator GECKO-A. Simulations show several-fold increases in SOA mass continuing for multiple days in the urban outflow, even as the initial air parcel is diluted into the regional atmosphere. The SOA mass increase in the forest outflow is more modest (~50%) and of shorter duration (1–2 days). The multiday production in the urban outflow stems from continuing oxidation of gas-phase precursors which persist in equilibrium with the particle phase, and can be attributed to multigenerational reaction productsmore » of both aromatics and alkanes, especially those with relatively low carbon numbers (C4–15). In particular we find large contributions from substituted maleic anhydrides and multi-substituted peroxide-bicyclic alkenes. The results show that the predicted production is a robust feature of our model even under changing atmospheric conditions and different vapor pressure schemes, and contradict the notion that SOA undergoes little mass production beyond a short initial formation period. The results imply that anthropogenic aerosol precursors could influence the chemical and radiative characteristics of the atmosphere over an extremely wide region, and that SOA measurements near precursor sources may routinely underestimate this influence.« less

  20. Quantifying VOC-Reaction Tracers, Ozone Production, and Continuing Aerosol Production Rates in Urban and Far-Downwind Atmospheres

    NASA Technical Reports Server (NTRS)

    Chatfield, Robert; Ren, X.; Brune, W.; Fried, A.; Schwab, J.

    2008-01-01

    We have found a surprisingly informative decomposition of the complex question of smoggy ozone production (basically, [HO2] in a more locally determined field of [NO]) in the process of linked investigations of modestly smoggy Eastern North America (by NASA aircraft, July 2004) and rather polluted Flushing, NYC (Queens College, July, 2001). In both rural and very polluted situations, we find that a simple contour graph parameterization of the local principal ozone production rate can be estimated using only the variables [NO] and j(sub rads) [HCHO]: Po(O3) = c (j(sub rads) [HCHO])(sup a) [HCHO](sup b). Here j(sub rads) is the photolysis of HCHO to radicals, presumably capturing many harder-UV photolytic processes and the principle ozone production is that due to HO2; mechanisms suggest that ozone production due to RO2 is closely correlated, often suggesting a limited range of different proportionality factors. The method immediately suggests a local interpretation for concepts of VOC limitation and NOx limitation. We believe that the product j(sub rads) [HCHO] guages the oxidation rate of observed VOC mixtures in a way that also provides [HO2] useful for the principle ozone production rate k [HO2] [NO], and indeed, all ozone chemical production. The success of the method suggests that dominant urban primary-HCHO sources may transition to secondary plume-HCHO sources in a convenient way. Are there other, simple, near-terminal oxidized VOC's which help guage ozone production and aerosol particle formation? Regarding particles, we report on, to the extent NASA Research resources allow, on appealing relationships between far-downwind (Atlantic PBL) HCHO and very fine aerosol (including sulfate. Since j(sub rads) [HCHO] provides a time-scale, we may understand distant-plume particle production in a more quantitative manner. Additionally we report on a statistical search in the nearer field for relationships between glyoxals (important near-terminal aromatic and isoprene

  1. Secondary organic aerosol (trans)formation through aqueous phase guaiacol photonitration: chemical characterization of the products

    NASA Astrophysics Data System (ADS)

    Grgić, Irena; Kitanovski, Zoran; Kroflič, Ana; Čusak, Alen

    2014-05-01

    One of the largest primary sources of organic aerosol in the atmosphere is biomass burning (BB) (Laskin et al. 2009); in Europe its contribution to annual mean of PM10 is between 3 and 14 % (Maenhaut et al. 2012). During the process of wood burning many different products are formed via thermal degradation of wood lignin. Hardwood burning produces mainly syringol (2,6-dimetoxyphenol) derivatives, while softwood burning exclusively guaiacol (2-methoxyphenol) and its derivatives. Taking into account physical properties of methoxyphenols only, their concentrations in atmospheric waters might be underestimated. So, their aqueous phase reactions can be an additional source of SOA, especially in regions under significant influence of wood combustion. An important class of compounds formed during physical and chemical aging of the primary BBA in the atmosphere is nitrocatechols, known as strong absorbers of UV and Vis light (Claeys et al. 2012). Very recently, methyl-nitrocatechols were proposed as suitable markers for highly oxidized secondary BBA (Iinuma et al. 2010, Kitanovski et al. 2012). In the present work, the formation of SOA through aqueous phase photooxidation and nitration of guaiacol was examined. The key objective was to chemically characterize the main low-volatility products and further to check their possible presence in the urban atmospheric aerosols. The aqueous phase reactions were performed in a thermostated reactor under simulated sunlight in the presence of H2O2 and nitrite. Guaiacol reaction products were first concentrated by solid-phase extraction (SPE) and then subjected to semi-preparative liquid chromatography.The main product compounds were fractionated and isolated as pure solids and their structure was further elucidated by using nuclear magnetic resonance spectroscopy (1H, 13C and 2D NMR) and direct infusion negative ion electro-spray ionization tandem mass spectrometry (( )ESI-MS/MS). The main photonitration products of guaiacol (4

  2. Production of low fat french-fries with single and multi-layer hydrocolloid coatings.

    PubMed

    Daraei Garmakhany, A; Mirzaei, H O; Maghsudlo, Y; Kashaninejad, M; Jafari, S M

    2014-07-01

    In this study the influence of coating with different hydrocolloids on the oil absorption and quality attributes of French fries was investigated. Our results revealed that hydrocolloid coatings reduced the moisture loss during frying, and hence, reduced the oil uptake of French fries. Among the studied gums as a single layer coating, combination of carboxy methyl cellulose and pectin (0.5 and 1% w/w) lead to the lowest oil uptake of French fries. In samples coated with two and three-layer hydrocolloids, the oil absorption reduced further and the moisture content of final products was higher than the blank samples. PMID:24966427

  3. Production of nano-ceramic coatings on titanium implants

    NASA Astrophysics Data System (ADS)

    Fomin, A. A.; Rodionov, I. V.; Fomina, M. A.; Petrova, N. V.

    2015-03-01

    Composite titania coatings modified with hydroxyapatite nanoparticles were obtained on intraosseous implants fabricated from commercially pure titanium and titanium alloy Ti-2.5Al-5Mo-5V. The present study aims to identify consistency changes of morphological characteristics and physico-mechanical properties of titanium items coatings obtained by oxidation during induction heat treatment and modification with colloidal hydroxyapatite nanoparticles. The influence of temperature between 600 and 1200 °C and duration of thermal modification from 1 to 300 s was studied. It was established that high hardness about 6.7±1.9 GPa for nanocrystalline TiO2 coatings and 19.2±0.6 GPa for nanoceramic "TiO2+HAp" coatings is reached at 1000 °C and 120 s.

  4. Spatiotemporal fusion of multiple-satellite aerosol optical depth (AOD) products using Bayesian maximum entropy method

    NASA Astrophysics Data System (ADS)

    Tang, Qingxin; Bo, Yanchen; Zhu, Yuxin

    2016-04-01

    Merging multisensor aerosol optical depth (AOD) products is an effective way to produce more spatiotemporally complete and accurate AOD products. A spatiotemporal statistical data fusion framework based on a Bayesian maximum entropy (BME) method was developed for merging satellite AOD products in East Asia. The advantages of the presented merging framework are that it not only utilizes the spatiotemporal autocorrelations but also explicitly incorporates the uncertainties of the AOD products being merged. The satellite AOD products used for merging are the Moderate Resolution Imaging Spectroradiometer (MODIS) Collection 5.1 Level-2 AOD products (MOD04_L2) and the Sea-viewing Wide Field-of-view Sensor (SeaWiFS) Deep Blue Level 2 AOD products (SWDB_L2). The results show that the average completeness of the merged AOD data is 95.2%,which is significantly superior to the completeness of MOD04_L2 (22.9%) and SWDB_L2 (20.2%). By comparing the merged AOD to the Aerosol Robotic Network AOD records, the results show that the correlation coefficient (0.75), root-mean-square error (0.29), and mean bias (0.068) of the merged AOD are close to those (the correlation coefficient (0.82), root-mean-square error (0.19), and mean bias (0.059)) of the MODIS AOD. In the regions where both MODIS and SeaWiFS have valid observations, the accuracy of the merged AOD is higher than those of MODIS and SeaWiFS AODs. Even in regions where both MODIS and SeaWiFS AODs are missing, the accuracy of the merged AOD is also close to the accuracy of the regions where both MODIS and SeaWiFS have valid observations.

  5. Aqueous secondary organic aerosol (SOA) production from the oxidation of phenols by triplet excited state organics

    NASA Astrophysics Data System (ADS)

    Smith, J.; Yu, L.; Zhang, Q.; Anastasio, C.

    2011-12-01

    Recent literature has shown that atmospheric condensed-phase chemistry can play a significant role in the evolution of organic aerosols, including the formation of secondary organic aerosol (SOA). SOA formation from the oxidation of volatile organic compounds (VOCs) in the aqueous phase has largely focused on oxidations involving the hydroxyl radical and other oxidants, such as photochemically created triplet excited states, have not been fully investigated. Phenolic compounds are one of the primary carbon emission classes from biomass and wood combustion and have significant water solubility. Once in the aqueous phase, phenolic compounds can react with the triplet excited states of non-phenolic aromatic carbonyls (NPCs), particle-bound organics that are also emitted in large quantities from wood combustion. The oxidation of phenolic species in the condensed phase by triplet excited states can result in the production of SOA. A main goal of this study was to investigate bulk solution reaction kinetics under atmospherically relevant conditions in order to ascertain how these reactions can impact aqueous-phase SOA production. In our experiments, we studied the reactions of five phenols (phenol, guaiacol, syringol, catechol, and resorcinol) with the triplet state of 3,4-dimethoxybenzaldehyde (34-DMB) during simulated solar radiation. We have characterized the impacts of pH, ionic strength and reactant concentrations on the reaction behavior of this system. In addition, we analyzed the SOA formed using high-resolution aerosol mass spectrometry, ion chromatography, and liquid chromatography-mass spectrometry to infer the reaction mechanisms. Our evidence suggests that under atmospherically relevant conditions, triplet excited states can be the dominant oxidant of phenolics and contribute significantly to the total SOA budget.

  6. Production and characterization of HA and SiHA coatings.

    PubMed

    Tang, Qian; Brooks, Roger; Rushton, Neil; Best, Serena

    2010-01-01

    Plasma sprayed hydroxyapatite (HA) coatings on metallic prostheses have been used clinically in dentistry and orthopedics since the mid 1980s. The coating properties are dependent on the spraying parameters. Since silicon-substituted hydroxyapatite (SiHA) has been shown to offer improved bioactivity over phase pure HA, SiHA coatings have the potential for enhanced performance in clinical application. In this study, phase pure HA and 0.8 wt% SiHA powders were synthesized with similar particle size distribution and morphology. The powders were plasma sprayed onto Ti-6Al-4V substrates at 37 kW and 40 kW plasma gun input power respectively. Four kinds of samples were prepared, HAC 37, HAC 40, SiHAC 37 and SiHAC 40. Materials characterization showed that the coatings were of relatively high phase purity. In vitro cell culture demonstrated that human osteoblast cells grew well on all samples, with the highest cell growth observed on SiHA coatings produced under the lower plasma gun input power. PMID:19672562

  7. Chemicals: UV-curable coating for aluminum can production

    SciTech Connect

    1999-09-29

    Fact sheet on curing aluminum can coatings written for the NICE3 Program. Coors Brewing Company has been using ultraviolet (UV) light curing technology on its aluminum beverage cans for 25 years. The company is now looking to share its cost-saving technology with other aluminum can producers. Traditional curing methods for creating external decorations on cans rely on convective-heat ovens to cure ink and over-varnish coatings. These thermal-curing methods require large amounts of energy and money, and can have unintended environmental impacts. Coors' technique uses coating materials that cure when exposed to UV light, thereby eliminating the expensive heat treatments used by conventional coating methods. Additionally, the UV-coating process creates much lower emissions and a smaller pollution waste stream than rival thermal processes because it requires much less solvent than thermal processes. This technology can be used not only in the aluminum can industry, but in the automotive, airline, wood, paper, and plastics industries, as well.

  8. Development of coated tubes RIA for serum T3 (tri-iodothyronine) for production scale.

    PubMed

    Karir, T; Samuel, G; Sivaprasad, N; Meera, V; Samuel, G; Meera, V; Pillai, M R A

    2005-01-01

    A coating procedure that could provide immobilization of antibodies, with increased binding capacity, that is cost effective, simple, robust, and appropriate for production scale application, is described. This coating approach of T3 antibodies to the polystyrene tubes has been systematically investigated to determine its utility for the development of coated tube Radioimmunoassay (RIA) for T3 in human serum. Further, the results obtained by the developed coating procedure are found to be comparable with those obtained by the "gold standard," the liquid phase RIA for T3. The coating procedure is completed in three major steps, each step involving an overnight incubation. The normal rabbit gamma-globulins are physically adsorbed onto the polystyrene tubes and incubated. After washing, a second antibody (goat anti-rabbit antiserum) is added and incubated. To this antigen specific antibody is added (T3 antibody produced in rabbit) and further incubated. Finally, the non-specific sites on the tubes are saturated by the blocking solution. The concentration of normal rabbit globulin, titers of second antibody and T3 antibody, and time required for coating are optimized to arrive at a suitable coating protocol. The coated tubes were evaluated for precision, reproducibility, and stability. Various parameters such as total reaction volume, incubation time and temperature, total number and volume of washings, concentration of 8-anilino-1-naphthalene sulfonic acid (ANS), and quantity of tracer per tube are optimized to arrive at a suitable standard curve. The optimized assay is validated for the quality control parameters such as intra- and inter-assay variations, recovery, and parallelism. The developed coated tubes assay had an assay range of 0.3-4.8 ng/mL with a sensitivity of 0.3 ng/mL at 90% B/B0. Batch to batch variation in coating was < 10%. The coated tubes were stable up to 1 year, which is adequate for production scale. PMID:15754806

  9. The optical, physical and chemical properties of the products of glyoxal uptake on ammonium sulfate seed aerosols

    NASA Astrophysics Data System (ADS)

    Trainic, M.; Abo Riziq, A.; Lavi, A.; Flores, J. M.; Rudich, Y.

    2011-09-01

    The heterogeneous reaction between gas phase glyoxal and ammonium sulfate (AS) aerosols, a proxy for inorganic atmospheric aerosol, was studied in terms of the dependence of the optical, physical and chemical properties of the product aerosols on initial particle size and ambient relative humidity (RH). Our experiments imitate an atmospheric scenario of a dry particle hydration at ambient RH conditions in the presence of glyoxal gas followed by efflorescence due to decrease of the ambient RH. The reactions were studied under different RH conditions, starting from dry conditions (~20% RH) and up to 90% RH, covering conditions prevalent in many atmospheric environments, and followed by consequent drying of the reacted particles before their analysis by the aerosol mass spectrometer (AMS), cavity ring down (CRD) and scanning mobility particle sizer (SMPS) systems. At λ = 355 nm, the reacted aerosols demonstrate a substantial growth in optical extinction cross section, as well as in mobility diameter under a broad range of RH values (35-90%). The ratio of the product aerosol to seed aerosol geometric cross section reached up to ~3.5, and the optical extinction cross-section up to ~250. The reactions show a trend of increasing physical and optical growth with decreasing seed aerosol size, from 100 nm to 300 nm, as well as with decreasing RH values from 90% to ~40%. Optically inactive aerosols, at the limit of the Mie range (100 nm diameter) become optically active as they grow due to the reaction. AMS analyses of the reaction of 300 nm AS at RH values of 50%, 75% and 90% show that the main products of the reaction are glyoxal oligomers, formed by acetal formation in the presence of AS. In addition, imidazole formation, which is a minor channel, is observed for all reactions, yielding a product which absorbs at λ = 290 nm, with possible implications on the radiative properties of the product aerosols. The ratio of absorbing substances (C-N compounds, including

  10. Global Long-Term SeaWiFS Deep Blue Aerosol Products available at NASA GES DISC

    NASA Astrophysics Data System (ADS)

    Shen, S.; Sayer, A. M.; Bettenhausen, C.; Wei, J. C.; Ostrenga, D.; Vollmer, B.; Hsu, N. C.

    2012-12-01

    Long-term climate data records of aerosols are needed in order to study regional air quality and the uncertainty of aerosol radiative forcing with numerical models. Recently, global long-term (over 13 years from 1997 to 2010) SeaWiFS Deep Blue (SWDB) aerosol products have become available. The SWDB aerosol dataset has been produced by the "Consistent Long-Term Aerosol Data Records over Land and Ocean from SeaWIFS" project led by Dr. N. Christina Hsu as part of the Making Earth Science data records for Use in Research for Earth Science (MEaSUREs) program. The latest Deep Blue algorithm retrieves aerosol properties not only over bright desert surfaces, but also vegetated surfaces, oceans, and inland water bodies. Comparisons with AERONET observations have shown that the data are suitable for quantitative scientific use. The resolution of the Level 2 pixels is 13.5x13.5 km2 at the center of the swath. The Level 3 daily and monthly data are composed by using best quality level 2 pixels at resolution of both 0.5x0.5 and 1.0x1.0 degrees. This presentation, focusing over the south Asia region, will show sample higher resolution Level 2 images of dust events and the Level 3 monthly climatology at large scale. The data are compared with the widely-used MODIS (Deep Blue and Dark Target) aerosol dataset. The SWDB aerosol data are available from NASA Goddard Earth Sciences Data and Information Services Center (GES DISC) through a number of data services, such as FTP; the data search system, Mirador; OPeNDAP; and online subsetting services. The global daily and monthly Level 3 products are also available in the innovative online visualization and analysis system, Giovanni. More information about SWBD aerosol products can be found from the project portal: http://disc.gsfc.nasa.gov/dust. Seasonal climatology of SeaWiFS Deep Blue Aerosol Optical Depth at 550nm for the period from 1997.09 to 2010.12.

  11. Production of CaCO3/hyperbranched polyglycidol hybrid films using spray-coating technique.

    PubMed

    Malinova, Kalina; Gunesch, Manfred; Montero Pancera, Sabrina; Wengeler, Robert; Rieger, Bernhard; Volkmer, Dirk

    2012-05-15

    Biomineralizing organisms employ macromolecules and cellular processing strategies in order to produce highly complex composite materials such as nacre. Bionic approaches translating this knowledge into viable technical production schemes for a large-scale production of biomimetic hybrid materials have met with limited success so far. Investigations presented here thus focus on the production of CaCO(3)/polymer hybrid coatings that can be applied to huge surface areas via reactive spray-coating. Technical requirements for simplicity and cost efficiency include a straightforward one-pot synthesis of low molecular weight hyperbranched polyglycidols (polyethers of 2,3-epoxy-1-propanol) as a simple mimic of biological macromolecules. Polymers functionalized with phosphate monoester, sulfate or carboxylate groups provide a means of controlling CaCO(3) particle density and morphology in the final coatings. We employ reactive spray-coating techniques to generate CaCO(3)/hybrid coatings among which vaterite composites can be prepared in the presence of sulfate-containing hyperbranched polyglycidol. These coatings show high stability and remained unchanged for periods longer than 9 months. By employing carboxylate-based hyperbranched polyglycidol, it is possible to deposit vaterite-calcite composites, whereas phosphate-ester-based hyperbranched polyglycidol leads to calcite composites. Nanoindentation was used to study mechanical properties, showing that coatings thus obtained are slightly harder than pure calcite. PMID:22386308

  12. A Comparison of Parameterizations of Secondary Organic Aerosol Production: Global Budget and Spatiotemporal Variability

    NASA Astrophysics Data System (ADS)

    Liu, J.; Chen, Z.; Horowitz, L. W.; Carlton, A. M. G.; Fan, S.; Cheng, Y.; Ervens, B.; Fu, T. M.; He, C.; Tao, S.

    2014-12-01

    Secondary organic aerosols (SOA) have a profound influence on air quality and climate, but large uncertainties exist in modeling SOA on the global scale. In this study, five SOA parameterization schemes, including a two-product model (TPM), volatility basis-set (VBS) and three cloud SOA schemes (Ervens et al. (2008, 2014), Fu et al. (2008) , and He et al. (2013)), are implemented into the global chemical transport model (MOZART-4). For each scheme, model simulations are conducted with identical boundary and initial conditions. The VBS scheme produces the highest global annual SOA production (close to 35 Tg·y-1), followed by three cloud schemes (26-30 Tg·y-1) and TPM (23 Tg·y-1). Though sharing a similar partitioning theory to the TPM scheme, the VBS approach simulates the chemical aging of multiple generations of VOCs oxidation products, resulting in a much larger SOA source, particularly from aromatic species, over Europe, the Middle East and Eastern America. The formation of SOA in VBS, which represents the net partitioning of semi-volatile organic compounds from vapor to condensed phase, is highly sensitivity to the aging and wet removal processes of vapor-phase organic compounds. The production of SOA from cloud processes (SOAcld) is constrained by the coincidence of liquid cloud water and water-soluble organic compounds. Therefore, all cloud schemes resolve a fairly similar spatial pattern over the tropical and the mid-latitude continents. The spatiotemporal diversity among SOA parameterizations is largely driven by differences in precursor inputs. Therefore, a deeper understanding of the evolution, wet removal, and phase partitioning of semi-volatile organic compounds, particularly above remote land and oceanic areas, is critical to better constrain the global-scale distribution and related climate forcing of secondary organic aerosols.

  13. In situ aerosol optics in Reno, NV, USA during and after the summer 2008 California wildfires and the influence of absorbing and non-absorbing organic coatings on spectral light absorption

    NASA Astrophysics Data System (ADS)

    Gyawali, M.; Arnott, W. P.; Lewis, K.; Moosmüller, H.

    2009-10-01

    Hundreds of wildfires in Northern California were sparked by lightning during the summer of 2008, resulting in downwind smoke for the months of June and July. Comparisons are reported for aerosol optics measurements in Reno, Nevada made during the very smoky month of July and the relatively clean month of August. Photoacoustic instruments equipped with integrating nephelometers were used to measure aerosol light scattering and absorption coefficients at wavelengths of 405 nm and 870 nm, revealing a strong variation of aerosol light absorption with wavelength. Insight on fuels burned is gleaned from comparison of Ångström exponents of absorption (AEA) versus single scattering albedo (SSA) of the ambient measurements with laboratory biomass smoke measurements for many fuels. Measurements during the month of August, which were largely unaffected by fire smoke, exhibit surprisingly low AEA for aerosol light absorption when the SSA is highest, again likely as a consequence of the underappreciated wavelength dependence of aerosol light absorption by particles coated with non-absorbing organic and inorganic matter. Coated sphere calculations were used to show that AEA as large as 1.6 are possible for wood smoke even with non-absorbing organic coatings on black carbon cores, suggesting care be exercised when diagnosing AEA.

  14. Spatial and Temporal Characteristics of Aerosols from Collection 6 Aqua and Terra MODIS e-Deep Blue Products

    NASA Astrophysics Data System (ADS)

    Bettenhausen, C.; Hsu, N. Y. C.; Sayer, A. M.; Lee, J.; Carletta, N.

    2015-12-01

    Aerosols continue to attract a significant amount of attention from researchers worldwide due to their extensive effects on Earth's climate, ecology, public health, and even energy production. In order to truly understand these effects, a long, stable, and well-calibrated data record is required. Since 2000 and 2002, the Moderate Resolution Imaging Spectroradiometer (MODIS) instruments aboard the Terra and Aqua satellites together with the e-Deep Blue aerosol retrieval algorithm have been providing such a data record. After a multi-year development effort, the production of both Aqua and Terra MODIS Collection 6 (C6) atmosphere products successfully completed earlier this year and the data was released to the public shortly thereafter. The C6 Deep Blue products (now enhanced Deep Blue or e-Deep Blue) have been significantly improved over the previous Collection 5.1 version. In this poster we provide an overview of the latest C6 e-Deep Blue products and the improvements implemented since the previous collection including coverage over dark surfaces and updates to the Terra calibration. Validation results utilizing Aerosol Robotic Network (AERONET) data are also summarized. We then use the C6 e-Deep Blue products from both Aqua and Terra to explore the spatial characteristics in addition to the seasonal and inter-annual variability of aerosols on both regional and global scales. We also use this as an opportunity to compare these results and investigate any differences found between the two instruments.

  15. Light-absorbing aldol condensation products in acidic aerosols: Spectra, kinetics, and contribution to the absorption index

    NASA Astrophysics Data System (ADS)

    Nozière, Barbara; Esteve, William

    The radiative properties of aerosols that are transparent to light in the near-UV and visible, such as sulfate aerosols, can be dramatically modified when mixed with absorbing material such as soot. In a previous work we had shown that the aldol condensation of carbonyl compounds produces light-absorbing compounds in sulfuric acid solutions. In this work we report the spectroscopic and kinetic parameters necessary to estimate the effects of these reactions on the absorption index of sulfuric acid aerosols in the atmosphere. The absorption spectra obtained from the reactions of six different carbonyl compounds (acetaldehyde, acetone, propanal, butanal, 2-butanone, and trifluoroacetone) and their mixtures were compared over 190-1100 nm. The results indicated that most carbonyl compounds should be able to undergo aldol condensation. The products are oligomers absorbing light in the 300-500 nm region where few other compounds absorb, making them important for the radiative properties of aerosols. Kinetic experiments in 96-75 wt% H 2SO 4 solutions and between 273 and 314 K gave an activation energy for the rate constant of formation of the aldol products of acetaldehyde of -(70±15) kJ mol -1 in 96 wt% solution and showed that the effect of acid concentration was exponential. A complete expression for this rate constant is proposed where the absolute value in 96 wt% H 2SO 4 and at 298 K is scaled to the Henry's law coefficient for acetaldehyde and the absorption cross-section for the aldol products assumed in this work. The absorption index of stratospheric sulfuric acid aerosols after a 2-year residence time was estimated to 2×10 -4, optically equivalent to a content of 0.5% of soot and potentially significant for the radiative forcing of these aerosols and for satellite observations in channels where the aldol products absorb.

  16. Kinetics, Mechanism, and Secondary Organic Aerosol Yield of Aqueous Phase Photo-oxidation of α-Pinene Oxidation Products.

    PubMed

    Aljawhary, Dana; Zhao, Ran; Lee, Alex K Y; Wang, Chen; Abbatt, Jonathan P D

    2016-03-10

    Formation of secondary organic aerosol (SOA) involves atmospheric oxidation of volatile organic compounds (VOCs), the majority of which are emitted from biogenic sources. Oxidation can occur not only in the gas-phase but also in atmospheric aqueous phases such as cloudwater and aerosol liquid water. This study explores for the first time the aqueous-phase OH oxidation chemistry of oxidation products of α-pinene, a major biogenic VOC species emitted to the atmosphere. The kinetics, reaction mechanisms, and formation of SOA compounds in the aqueous phase of two model compounds, cis-pinonic acid (PIN) and tricarballylic acid (TCA), were investigated in the laboratory; TCA was used as a surrogate for 3-methyl-1,2,3-butanetricarboxylic acid (MBTCA), a known α-pinene oxidation product. Aerosol time-of-flight chemical ionization mass spectrometry (Aerosol-ToF-CIMS) was used to follow the kinetics and reaction mechanisms at the molecular level. Room-temperature second-order rate constants of PIN and TCA were determined to be 3.3 (±0.5) × 10(9) and 3.1 (±0.2) × 10(8) M(-1) s(-1), respectively, from which were estimated their condensed-phase atmospheric lifetimes. Aerosol-ToF-CIMS detected a large number of products leading to detailed reaction mechanisms for PIN and MBTCA. By monitoring the particle size distribution after drying, the amount of SOA material remaining in the particle phase was determined. An aqueous SOA yield of 40 to 60% was determined for PIN OH oxidation. Although recent laboratory studies have focused primarily on aqueous-phase processing of isoprene-related compounds, we demonstrate that aqueous formation of SOA materials also occurs from monoterpene oxidation products, thus representing an additional source of biogenically driven aerosol formation. PMID:26299576

  17. Lymphoid Cell-Glioma Cell Interaction Enhances Cell Coat Production by Human Gliomas: Novel Suppressor Mechanism

    NASA Astrophysics Data System (ADS)

    Dick, Steven J.; Macchi, Beatrice; Papazoglou, Savvas; Oldfield, Edward H.; Kornblith, Paul L.; Smith, Barry H.; Gately, Maurice K.

    1983-05-01

    Certain human glioma lines produce mucopolysaccharide coats that impair the generation of cytolytic lymphocytes in response to these lines in vitro. Coat production is substantially enhanced by the interaction of glioma cells with a macromolecular factor released by human peripheral blood mononuclear cells in culture. This interaction thus constitutes an unusual mechanism by which inflammatory cells may nonspecifically suppress the cellular immune response to at least one class of solid tumors in humans.

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

    EPA Science Inventory

    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...

  19. Progressive Powder Coating: New Infrared Curing Oven at Metal Finishing Plant Increases Production by 50%

    SciTech Connect

    2003-05-01

    Progressive Powder Coating in Mentor, Ohio, is a metal finishing plant that uses a convection oven in its manufacturing process. In an effort to save energy and improve production, the company installed an infrared oven in between the powder coating booth and the convection oven on its production line. This installation allowed the plant to increase its conveyor line speed and increase production by 50 percent. In addition, the plant reduced its natural gas consumption, yielding annual energy savings of approximately $54,000. With a total project cost of $136,000, the simple payback is 2.5 years.

  20. Progressive Powder Coating: New Infrared Curing Oven at Metal Finishing Plant Increases Production by 50%

    SciTech Connect

    Not Available

    2003-05-01

    Progressive Powder Coating in Mentor, Ohio, is a metal finishing plant that uses a convection oven in its manufacturing process. In an effort to save energy and improve production, the company installed an infrared oven in between the powder coating booth and the convection oven on its production line. This installation allowed the plant to increase its conveyor line speed and increase production by 50 percent. In addition, the plant reduced its natural gas consumption, yielding annual energy savings of approximately$54,000. With a total project cost of$136,000, the simple payback is 2.5 years.

  1. 76 FR 60530 - Notice Pursuant to the National Cooperative Research and Production Act of 1993-Plastic Aerosol...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-09-29

    ... Antitrust Division Notice Pursuant to the National Cooperative Research and Production Act of 1993--Plastic...''), Plastic Aerosol Research Group, L.L.C. (``PARG'') has filed written notifications simultaneously with the... are: Aerofil Technology Inc, Sullivan, MO; Aptar Beauty & Home, Cary, IL; Berry Plastics...

  2. Gastro-resistant characteristics of GRAS-grade enteric coatings for pharmaceutical and nutraceutical products.

    PubMed

    Czarnocka, Justyna K; Alhnan, Mohamed A

    2015-01-01

    The use of naturally derived excipients to develop enteric coatings offers significant advantages over conventional synthetic polymers. Unlike synthetic polymers, they are biodegradable, relatively abundant, have no daily intake limits or restrictions on use for dietary and nutraceutical products. However, little information is available on their dissolution properties under different gastrointestinal conditions and in comparison to each other. This work investigated the gastric resistance properties of commercially available GRAS-based coating technologies. Three coating systems were evaluated: ethyl cellulose+carboxymethyl cellulose (EC-CMC), ethyl cellulose+sodium alginate (EC-Alg) and shellac+sodium alginate (Sh-Alg) combinations. The minimum coating levels were optimized to meet USP pharmacopoeial criteria for delayed release formulations (<10% release after 2h in pH 1.2 followed by >80% release after 45 min of pH change). Theophylline 150 mg tablets were coated with 6.5%, 7%, and 2.75% coating levels of formulations EC-CMC, EC-Alg and Sh-Alg, respectively. In vitro dissolution test revealed a fast release in pH 6.8 for ethyl cellulose based coatings: t80% value of 65 and 45 min for EC-CMC and EC-Alg respectively, while a prolonged drug release from Sh-Alg coating was observed in both pH 6.8 and 7.4 phosphate buffers. However, when more biologically relevant bicarbonate buffer was used, all coatings showed slower drug release. Disintegration test, carried out in both simulated gastric and intestinal fluid, confirmed good mechanical resistance of EC-CMC and EC-Alg coating, and revealed poor durability of the thinner Sh-Alg. Under elevated gastric pH conditions (pH 2, 3 and 4), EC-CMC and EC-Alg coatings were broken after 70, 30, 55 min and after 30, 15, 15 min, respectively, while Sh-Alg coated tablets demonstrated gastric resistance at all pH values. In conclusion, none of the GRAS-grade coatings fully complied with the different biological demands of delayed

  3. 40 CFR Table 1 to Subpart E of... - Product-Weighted Reactivity Limits by Coating Category

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 6 2012-07-01 2012-07-01 false Product-Weighted Reactivity Limits by Coating Category 1 Table 1 to Subpart E of Part 59 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NATIONAL VOLATILE ORGANIC COMPOUND EMISSION STANDARDS FOR CONSUMER AND COMMERCIAL PRODUCTS...

  4. 40 CFR Table 1 to Subpart E of... - Product-Weighted Reactivity Limits by Coating Category

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 6 2013-07-01 2013-07-01 false Product-Weighted Reactivity Limits by Coating Category 1 Table 1 to Subpart E of Part 59 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NATIONAL VOLATILE ORGANIC COMPOUND EMISSION STANDARDS FOR CONSUMER AND COMMERCIAL PRODUCTS...

  5. 40 CFR Table 1 to Subpart E of... - Product-Weighted Reactivity Limits by Coating Category

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 5 2010-07-01 2010-07-01 false Product-Weighted Reactivity Limits by Coating Category 1 Table 1 to Subpart E of Part 59 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NATIONAL VOLATILE ORGANIC COMPOUND EMISSION STANDARDS FOR CONSUMER AND COMMERCIAL PRODUCTS...

  6. Secondary organic material formed by methylglyoxal in aqueous aerosol mimics - Part 1: Surface tension depression and light-absorbing products

    NASA Astrophysics Data System (ADS)

    Schwier, A. N.; Shapiro, E. L.; Sareen, N.; McNeill, V. F.

    2009-07-01

    We show that methylglyoxal forms light-absorbing secondary organic material in aqueous ammonium sulfate and ammonium nitrate solutions mimicking tropospheric aerosol particles. The light-absorbing products form on the order of minutes, and solution composition continues to change over several days. The results suggest an aldol condensation pathway involving the participation of the ammonium ion. Aqueous solutions of methylglyoxal, with and without inorganic salts, exhibit surface tension depression. Methylglyoxal uptake could potentially change the optical properties, climate effects, and heterogeneous chemistry of the seed aerosol over its lifetime.

  7. Dimers and organosulfates derived from biogenic oxidation products in aerosols during the Biosphere Effects on Aerosols and Photochemistry Experiment (BEARPEX) in California 2007 and 2009 (Invited)

    NASA Astrophysics Data System (ADS)

    Glasius, M.; Worton, D. R.; Kristensen, K.; Nguyen, Q.; Surratt, J.; Enggrob, K. L.; Bouvier-Brown, N. C.; Farmer, D.; Docherty, K. S.; Platt, S.; Bilde, M.; Nøjgaard, J. K.; Seinfeld, J.; Jimenez, J. L.; Goldstein, A.

    2010-12-01

    Oxidation products of biogenic volatile organic compounds, such as monoterpenes and isoprene, contribute to biogenic secondary organic aerosol (BSOA). The organosulfate derivatives of these compounds are formed through heterogeneous reactions involving sulphur compounds, with a considerable contribution from anthropogenic sources. Organosulfate derivatives of biogenic oxidation products thus belong to a new group of anthropogenic enhanced biogenic SOA (ABSOA). The Biosphere Effects on Aerosols and Photochemistry Experiment (BEARPEX) during summers of 2007 and 2009 provided an excellent platform at Blodgett Forest, California (a ponderosa pine plantation) for studying ABSOA. Typically, polluted air masses were transported upslope from the California Central Valley during day, while night conditions were influenced by downslope transport of air masses, low local atmospheric mixing and formation of a shallow boundary layer. We collected particle samples (PM2.5) as one nighttime and two daytime samples per day. After extraction of filters in polar organic solvents (i.e. acetonitrile or methanol), organic aerosol constituents were analyzed by HPLC coupled through an electrospray inlet to a quadrupole time-of-flight mass spectrometer (qTOF-MS). Organosulfates and nitrooxy organosulfates derived from oxidation products of α-pinene, β-pinene, limonene and isoprene were identified based on their molecular mass and MS fragmentation patterns. Measurements by High Resolution Time of Flight Aerosol Mass Spectrometry (HR-ToF-AMS) show high mass loadings of nitrate in the night and morning samples with highest levels of the nitrooxy organosulfates with MW 295 and MW 297. This may indicate that elevated levels of nitrate and nitrooxy organosulfates are formed in the same polluted air mass, probably through nitrate radical reactions. Terpenylic acid, diterpenylic acid acetate, and methylbutane tricarboxylic acid were found at concentrations comparable to pinic acid. A dimer of

  8. Global and regional validation of the Collection 6 MODIS dark target aerosol products, and comparison to Collection 5

    NASA Astrophysics Data System (ADS)

    Munchak, L. A.; Levy, R. C.; Mattoo, S.

    2014-12-01

    The MODIS Collection 6 (C6) dark targets aerosol algorithms include several updates, including multiple wind speed look up tables over ocean and improved sensor calibration. We analyze the entirety of the MODIS-Aqua aerosol record against AERONET to characterize uncertainty in the products, and relate the new collection to the well-characterized Collection 5 (C5) products to understand specific improvements. Over land, ~70% of high quality AOD retrievals at 0.55 μm are within the C5 expected error bounds, which is comparable to C5; however, a slight overestimation of AOD at low optical depths and a slight underestimation at high optical depths that was observed in C5 has been eliminated in C6. The highest agreement with AERONET occurs in the Eastern U.S. and Europe. Regions with large surface reflectance, such as the Western U.S., or higher aerosol loading, including much of Africa and South America, remain a challenge. Over ocean, the inclusion of wind speed in the surface characterization has removed a wind speed dependant bias, and globally, ~63% of high quality AOD retrievals at 0.55 μm are within the C5 expected error bounds. The dust outflow regions off the coast of Africa show the poorest agreement with AERONET. The aerosol products validate acceptably for science, though users should be aware of some regional biases we present in this work.

  9. The Statistical Evolution of Multiple Generations of Oxidation Products in the Photochemical Aging of Chemically Reduced Organic Aerosol

    SciTech Connect

    Wilson, Kevin R.; Smith, Jared D.; Kessler, Sean; Kroll, Jesse H.

    2011-10-03

    The heterogeneous reaction of hydroxyl radicals (OH) with squalane and bis(2-ethylhexyl) sebacate (BES) particles are used as model systems to examine how distributions of reactionproducts evolve during the oxidation of chemically reduced organic aerosol. A kinetic model of multigenerational chemistry, which is compared to previously measured (squalane) and new(BES) experimental data, reveals that it is the statistical mixtures of different generations of oxidation products that control the average particle mass and elemental composition during thereaction. The model suggests that more highly oxidized reaction products, although initially formed with low probability, play a large role in the production of gas phase reaction products.In general, these results highlight the importance of considering atmospheric oxidation as a statistical process, further suggesting that the underlying distribution of molecules could playimportant roles in aerosol formation as well as in the evolution of key physicochemical properties such as volatility and hygroscopicity.

  10. Rethinking the global secondary organic aerosol (SOA) budget: stronger production, faster removal, shorter lifetime

    NASA Astrophysics Data System (ADS)

    Hodzic, Alma; Kasibhatla, Prasad S.; Jo, Duseong S.; Cappa, Christopher D.; Jimenez, Jose L.; Madronich, Sasha; Park, Rokjin J.

    2016-06-01

    Recent laboratory studies suggest that secondary organic aerosol (SOA) formation rates are higher than assumed in current models. There is also evidence that SOA removal by dry and wet deposition occurs more efficiently than some current models suggest and that photolysis and heterogeneous oxidation may be important (but currently ignored) SOA sinks. Here, we have updated the global GEOS-Chem model to include this new information on formation (i.e., wall-corrected yields and emissions of semi-volatile and intermediate volatility organic compounds) and on removal processes (photolysis and heterogeneous oxidation). We compare simulated SOA from various model configurations against ground, aircraft and satellite measurements to assess the extent to which these improved representations of SOA formation and removal processes are consistent with observed characteristics of the SOA distribution. The updated model presents a more dynamic picture of the life cycle of atmospheric SOA, with production rates 3.9 times higher and sinks a factor of 3.6 more efficient than in the base model. In particular, the updated model predicts larger SOA concentrations in the boundary layer and lower concentrations in the upper troposphere, leading to better agreement with surface and aircraft measurements of organic aerosol compared to the base model. Our analysis thus suggests that the long-standing discrepancy in model predictions of the vertical SOA distribution can now be resolved, at least in part, by a stronger source and stronger sinks leading to a shorter lifetime. The predicted global SOA burden in the updated model is 0.88 Tg and the corresponding direct radiative effect at top of the atmosphere is -0.33 W m-2, which is comparable to recent model estimates constrained by observations. The updated model predicts a population-weighed global mean surface SOA concentration that is a factor of 2 higher than in the base model, suggesting the need for a reanalysis of the contribution of

  11. Rethinking the global secondary organic aerosol (SOA) budget: stronger production, faster removal, shorter lifetime

    NASA Astrophysics Data System (ADS)

    Hodzic, A.; Kasibhatla, P. S.; Jo, D. S.; Cappa, C.; Jimenez, J. L.; Madronich, S.; Park, R. J.

    2015-11-01

    Recent laboratory studies suggest that secondary organic aerosol (SOA) formation rates are higher than assumed in current models. There is also evidence that SOA removal by dry and wet deposition occurs more efficiently than some current models suggest, and that photolysis and heterogeneous oxidation may be important (but currently ignored) SOA sinks. Here, we have updated the global GEOS-Chem model to include this new information on formation (i.e. wall-corrected yields and emissions of semi-volatile and intermediate volatility organic compounds) and on removal processes (photolysis and heterogeneous oxidation). We compare simulated SOA from various model configurations against ground, aircraft and satellite measurements to assess the extent to which these improved representations of SOA formation and removal processes are consistent with observed characteristics of the SOA distribution. The updated model presents a more dynamic picture of the lifecycle of atmospheric SOA, with production rates 4 times higher and sinks a factor of 3.7 more efficient than in the base model. In particular, the updated model predicts larger SOA concentrations in the boundary layer and lower concentrations in the upper troposphere, leading to better agreement with surface and aircraft measurements of organic aerosol compared to the base model. Our analysis thus suggests that the long-standing discrepancy in model predictions of the vertical SOA distribution can now be resolved, at least in part, by a stronger source and stronger sinks leading to a shorter lifetime. The predicted global SOA burden in the updated model is 0.95 Tg and the corresponding direct radiative forcing at top of the atmosphere is -0.35 W m-2, which is comparable to recent model estimates constrained by observations. The updated model predicts a population-weighed global mean surface SOA concentration that is a factor of 2 higher than in the base model, suggesting the need for a reanalysis of the contribution of

  12. Secondary organic aerosol from ozone-initiated reactions with terpene-rich household products

    SciTech Connect

    Coleman, Beverly; Coleman, Beverly K.; Lunden, Melissa M.; Destaillats, Hugo; Nazaroff, William W.

    2008-01-01

    We analyzed secondary organic aerosol (SOA) data from a series of small-chamber experiments in which terpene-rich vapors from household products were combined with ozone under conditions analogous to product use indoors. Reagents were introduced into a continuously ventilated 198 L chamber at steady rates. Consistently, at the time of ozone introduction, nucleation occurred exhibiting behavior similar to atmospheric events. The initial nucleation burst and growth was followed by a period in which approximately stable particle levels were established reflecting a balance between new particle formation, condensational growth, and removal by ventilation. Airborne particles were measured with a scanning mobility particle sizer (SMPS, 10 to 400 nm) in every experiment and with an optical particle counter (OPC, 0.1 to 2.0 ?m) in a subset. Parameters for a three-mode lognormal fit to the size distribution at steady state were determined for each experiment. Increasing the supply ozone level increased the steady-state mass concentration and yield of SOA from each product tested. Decreasing the air-exchange rate increased the yield. The steady-state fine-particle mass concentration (PM1.1) ranged from 10 to> 300 mu g m-3 and yields ranged from 5percent to 37percent. Steady-state nucleation rates and SOA mass formation rates were on the order of 10 cm-3 s-1 and 10 mu g m-3 min-1, respectively.

  13. Production and characterization of large-area sputtered selective solar absorber coatings

    NASA Astrophysics Data System (ADS)

    Graf, Wolfgang; Koehl, Michael; Wittwer, Volker

    1992-11-01

    Most of the commercially available selective solar absorber coatings are produced by electroplating. Often the reproducibility or the durability of their optical properties is not very satisfying. Good reproducibility can be achieved by sputtering, the technique for the production of low-(epsilon) coatings for windows. The suitability of this kind of deposition technique for flat-plate solar absorber coatings based on the principle of ceramic/metal composites was investigated for different material combinations, and prototype collectors were manufactured. The optical characterization of the coatings is based on spectral measurements of the near-normal/hemispherical and the angle-dependent reflectance in the wavelength-range 0.38 micrometers - 17 micrometers . The durability assessment was carried out by temperature tests in ovens and climatic chambers.

  14. Science verification of operational aerosol and cloud products for TROPOMI on Sentinel-5 precursor

    NASA Astrophysics Data System (ADS)

    Lelli, Luca; Gimeno-Garcia, Sebastian; Sanders, Abram; Sneep, Maarten; Rozanov, Vladimir V.; Kokhanvosky, Alexander A.; Loyola, Diego; Burrows, John P.

    2016-04-01

    With the approaching launch of the Sentinel-5 precursor (S-5P) satellite, scheduled by mid 2016, one preparatory task of the L2 working group (composed by the Institute of Environmental Physics IUP Bremen, the Royal Netherlands Meteorological Institute KNMI De Bilt, and the German Aerospace Center DLR Oberpfaffenhofen) has been the assessment of biases among aerosol and cloud products, that are going to be inferred by the respective algorithms from measurements of the platform's payload TROPOspheric Monitoring Instrument (TROPOMI). The instrument will measure terrestrial radiance with varying moderate spectral resolutions from the ultraviolet throughout the shortwave infrared. Specifically, all the operational and verification algorithms involved in this comparison exploit the sensitivity of molecular oxygen absorption (the A-band, 755-775 nm, with a resolution of 0.54 nm) to changes in optical and geometrical parameters of tropospheric scattering layers. Therefore, aerosol layer height (ALH) and thickness (AOT), cloud top height (CTH), thickness (COT) and albedo (CA) are the targeted properties. First, the verification of these properties has been accomplished upon synchronisation of the respective forward radiative transfer models for a variety of atmospheric scenarios. Then, biases against independent techniques have been evaluated with real measurements of selected GOME-2 orbits. Global seasonal bias assessment has been carried out for CTH, CA and COT, whereas the verification of ALH and AOT is based on the analysis of the ash plume emitted by the icelandic volcanic eruption Eyjafjallajökull in May 2010 and selected dust scenes off the Saharan west coast sensed by SCIAMACHY in year 2009.

  15. The use of MODIS data and aerosol products for air quality prediction

    NASA Astrophysics Data System (ADS)

    Hutchison, Keith D.; Smith, Solar; Faruqui, Shazia

    2004-09-01

    The Center for Space Research (CSR) is exploring new approaches to integrate data collected by the MODerate resolution Imaging Spectroradiometer (MODIS) sensor, flown on NASA's Earth Observing System (EOS) satellites, into a real-time prediction methodology to support operational air quality forecasts issued by the Monitoring Operations Division (MOD) of the Texas Commission on Environmental Quality (TCEQ). Air pollution is a widespread problem in the United States, with over 130 million individuals exposed to levels of air pollution that exceed one or more health-based standards. Texas air quality is under assault by a variety of anthropogenic sources associated with a rapidly growing population along with increases in emissions from the diesel engines that drive international trade between the US and Central America. The challenges of meeting air quality standards established by the Environmental Protection Agency are further impacted by the transport of pollution into Texas that originates from outside its borders and are cumulative with those generated by local sources. In an earlier study, CSR demonstrated the value of MODIS imagery and aerosol products for monitoring ozone-laden pollution that originated in the central US before migrating into Texas and causing TCEQ to issue a health alert for 150 counties. Now, data from this same event are re-analyzed in an attempt to predict air quality from MODIS aerosol optical thickness (AOT) observations. The results demonstrate a method to forecast air quality from remotely sensed satellite observations when the transient pollution can be isolated from local sources. These pollution sources can be separated using TCEQ's network of ground-based Continuous Air quality Monitoring (CAM) stations.

  16. Production of Inhalable Submicrometer Aerosols from Conventional Mesh Nebulizers for Improved Respiratory Drug Delivery

    PubMed Central

    Longest, P. Worth; Spence, Benjamin M.; Holbrook, Landon T.; Mossi, Karla M.; Son, Yoen-Ju; Hindle, Michael

    2012-01-01

    Submicrometer and nanoparticle aerosols may significantly improve the delivery efficiency, dissolution characteristics, and bioavailability of inhaled pharmaceuticals. The objective of this study was to explore the formation of submicrometer and nanometer aerosols from mesh nebulizers suitable for respiratory drug delivery using experiments and computational fluid dynamics (CFD) modeling. Mesh nebulizers were coupled with add-on devices to promote aerosol drying and the formation of submicrometer particles, as well as to control the inhaled aerosol temperature and relative humidity. Cascade impaction experiments were used to determine the initial mass median aerodynamic diameters of 0.1% albuterol aerosols produced by the AeroNeb commercial (4.69 μm) and lab (3.90 μm) nebulizers and to validate the CFD model in terms of droplet evaporation. Through an appropriate selection of flow rates, nebulizers, and model drug concentrations, submicrometer and nanometer aerosols could be formed with the three devices considered. Based on CFD simulations, a wire heated design was shown to overheat the airstream producing unsafe conditions for inhalation if the aerosol was not uniformly distributed in the tube cross-section or if the nebulizer stopped producing droplets. In comparison, a counter-flow heated design provided sufficient thermal energy to produce submicrometer particles, but also automatically limited the maximum aerosol outlet temperature based on the physics of heat transfer. With the counter-flow design, submicrometer aerosols were produced at flow rates of 5, 15, and 30 LPM, which may be suitable for various forms of oral and nasal aerosol delivery. Thermodynamic conditions of the aerosol stream exiting the counter-flow design were found be in a range of 21-45 °C with relative humidity greater than 40% in some cases, which was considered safe for direct inhalation and advantageous for condensational growth delivery. PMID:22707794

  17. Effect of heavy haze and aerosol pollution on rice and wheat productions in China

    NASA Astrophysics Data System (ADS)

    Tie, Xuexi; Huang, Ru-Jin; Dai, Wenting; Cao, Junji; Long, Xin; Su, Xiaoli; Zhao, Shuyu; Wang, Qiyuan; Li, Guohui

    2016-07-01

    In China, regional haze pollution is a serious environmental problem. The impact on ecosystem, however, is not clearly understood. This study investigates the effect of regional haze pollution on the yields of rice and wheat in China. The spatial and temporal distributions of aerosol optical depth (AOD) show high particulate pollution in the North China Plain region, Yangtze River Delta region, the central eastern China, and the Si Chuan Basin, coexisted largely with crop growth in time and space. The solar irradiance reaching these regions is estimated to reduce by up to 28–49%, calculated using the AOD distributions and tropospheric ultraviolet-visible (TUV) model. Reduction of solar irradiance in these regions can depress optimal yields of about 45% of rice and 75% of wheat growth in China, leading to 2% reduction in total rice production and 8% reduction in total wheat production in China. However, there are large uncertainties of the estimate related to the diffuse solar radiation. For high diffuse radiation case, the estimate reductions of rice and wheat decrease to 1% and 4.5%, respectively. A further detailed study is needed to clearly understand this effect to meet the growing food demand in the nation in the coming decades.

  18. Effect of heavy haze and aerosol pollution on rice and wheat productions in China.

    PubMed

    Tie, Xuexi; Huang, Ru-Jin; Dai, Wenting; Cao, Junji; Long, Xin; Su, Xiaoli; Zhao, Shuyu; Wang, Qiyuan; Li, Guohui

    2016-01-01

    In China, regional haze pollution is a serious environmental problem. The impact on ecosystem, however, is not clearly understood. This study investigates the effect of regional haze pollution on the yields of rice and wheat in China. The spatial and temporal distributions of aerosol optical depth (AOD) show high particulate pollution in the North China Plain region, Yangtze River Delta region, the central eastern China, and the Si Chuan Basin, coexisted largely with crop growth in time and space. The solar irradiance reaching these regions is estimated to reduce by up to 28-49%, calculated using the AOD distributions and tropospheric ultraviolet-visible (TUV) model. Reduction of solar irradiance in these regions can depress optimal yields of about 45% of rice and 75% of wheat growth in China, leading to 2% reduction in total rice production and 8% reduction in total wheat production in China. However, there are large uncertainties of the estimate related to the diffuse solar radiation. For high diffuse radiation case, the estimate reductions of rice and wheat decrease to 1% and 4.5%, respectively. A further detailed study is needed to clearly understand this effect to meet the growing food demand in the nation in the coming decades. PMID:27388031

  19. Effect of heavy haze and aerosol pollution on rice and wheat productions in China

    PubMed Central

    Tie, Xuexi; Huang, Ru-Jin; Dai, Wenting; Cao, Junji; Long, Xin; Su, Xiaoli; Zhao, Shuyu; Wang, Qiyuan; Li, Guohui

    2016-01-01

    In China, regional haze pollution is a serious environmental problem. The impact on ecosystem, however, is not clearly understood. This study investigates the effect of regional haze pollution on the yields of rice and wheat in China. The spatial and temporal distributions of aerosol optical depth (AOD) show high particulate pollution in the North China Plain region, Yangtze River Delta region, the central eastern China, and the Si Chuan Basin, coexisted largely with crop growth in time and space. The solar irradiance reaching these regions is estimated to reduce by up to 28–49%, calculated using the AOD distributions and tropospheric ultraviolet-visible (TUV) model. Reduction of solar irradiance in these regions can depress optimal yields of about 45% of rice and 75% of wheat growth in China, leading to 2% reduction in total rice production and 8% reduction in total wheat production in China. However, there are large uncertainties of the estimate related to the diffuse solar radiation. For high diffuse radiation case, the estimate reductions of rice and wheat decrease to 1% and 4.5%, respectively. A further detailed study is needed to clearly understand this effect to meet the growing food demand in the nation in the coming decades. PMID:27388031

  20. APPLICATION OF POLLUTION PREVENTION TECHNIQUES TO REDUCE INDOOR AIR EMISSIONS FROM AEROSOL CONSUMER PRODUCTS (PROJECT SUMMARY)

    EPA Science Inventory

    report gives results of research, undertaken to develop tools and meth-odologies to measure aerosol chemical and particle dispersion through space. Georgia Tech Research Institute re-searchers built an Aerosol Mass Spec-tral Interface (AMSI), which is interfaced with a mass spect...

  1. Gas-phase products and secondary organic aerosol formation from the ozonolysis and photooxidation of myrcene

    NASA Astrophysics Data System (ADS)

    Böge, Olaf; Mutzel, Anke; Iinuma, Yoshiteru; Yli-Pirilä, Pasi; Kahnt, Ariane; Joutsensaari, Jorma; Herrmann, Hartmut

    2013-04-01

    Terrestrial vegetation releases a great variety of volatile organic compounds (VOC) into the atmosphere. Monoterpenes, like myrcene, contribute significantly to this global biogenic VOC emission. In the atmosphere, monoterpenes rapidly undergo oxidation reactions by OH radicals (mainly during the daytime), NO3 radicals (mainly during the nighttime) and O3 to form multifunctional oxidation products. The products of these reactions are likely to be of low volatility and hence might lead to secondary organic aerosol (SOA) formation. In the present study, we report results from a series of chamber experiments performed in the LEAK chamber at TROPOS in which the gas-phase products and SOA yields obtained from myrcene O3 reactions with and without an OH radical scavenger as well as from the myrcene OH radical reaction in the presence of NOx have been measured. During the experiments the consumption of myrcene as well as the formation of gas-phase products was monitored using a proton transfer reaction mass spectrometer (PTR-MS). Ozone concentration was measured by an O3 monitor and the mixing ratios of nitrogen oxides were measured by a NOx monitor. Particle size distributions between 3-900 nm were monitored every 11 min using a differential mobility particle sizer (DMPS) system. In addition to the products observed by means of the PTR-MS by their m/z values, an identification of carbonylic compounds by their DNPH derivatives was performed. Beside low molecular mass products the formation of 4-vinyl-4-pentenal with a yield of 55 % in myrcene ozonolysis has been observed. The further oxidation of this major first generation product lead to the formation of two dicarbonylic products with m/z 113 and to SOA formation. The influence of the continuing oxidation of 4-vinyl-4-pentenal on SOA formation will be discussed in detail. The emergence of the gas-phase product hydroxyacetone as direct result of the myrcene ozone reaction will be mooted, because hydroxyacetone seems to

  2. Study on particulate matter air pollution in Beijing with MODIS aerosol level 2 products

    NASA Astrophysics Data System (ADS)

    Mao, Jietai; Li, Chengcai; Lau, Alexis K.

    2004-09-01

    In the run-up to the 2008 Olympic Games in Beijing, Chinese government officials at both the central and municipal levels are keenly aware that they must transform Beijing into a world-class city. According to the Beijing Municipal Environmental Protection Bureau (BJEPB) to improve its air quality some actions are adopting, including taking steps to increase the forested area surrounding the city preventing dust storms, reducing the automotive vehicles, moving polluting factories now inside the fourth ring road ringing the inner city to locations outside of the fourth ring road, and switching the fuel of public buses and taxis from diesel to natural gas, etc. Will they eliminate most serious environmental problems in Beijing? MODIS aerosol products are helping us to answer this kind of questions. A long-term validation has been finished by sun-photometer observations, and the results proved the relative error of MODIS level 2 products was slightly larger than the estimation of Chu et al. (2002) from the results in most AERONET sites. However, the comparison between the products and moisture-corrected air pollution index (API) data, which were daily released to public by EPB, showed a high correlation coefficient. An air pollution episode in 2003 was investigated by the usage of satellite products. Our conclusion for the air pollution control strategy in Beijing is that only reducing the pollution sources from inner city can't fully solve the pollution problems in Beijing and the regional transports from the nearby southern provinces are contributing a lot to the pollution situation in Beijing.

  3. An improved whitecap timescale for sea spray aerosol production flux modeling using the discrete whitecap method

    NASA Astrophysics Data System (ADS)

    Callaghan, Adrian H.

    2013-09-01

    The discrete whitecap method (DWM) to model the sea spray aerosol (SSA) production flux explicitly requires a whitecap timescale, which up to now has only considered a whitecap decay timescale, τdecay. A reevaluation of the DWM suggests that the whitecap timescale should account for the total whitecap lifetime (τwcap), which consists of both the formation timescale (τform) and the decay timescale (timescale definitions are given in the text). Here values of τform for 552 oceanic whitecaps measured at the Martha's Vineyard Coastal Observatory on the east coast of the USA are presented, and added to the corresponding values of τdecay to form 552 whitecap timescales. For the majority of whitecaps, τform makes up about 20-25% of τwcap, but this can be as large as 70% depending on the value of τdecay. Furthermore, an area-weighted mean whitecap timescale for use in the DWM (τDWM) is defined that encompasses the variable nature of individual whitecap lifetimes within a given time period, and is calculated to be 5.3 s for this entire data set. This value is combined with previously published whitecap coverage parameterizations and estimates of SSA particle production per whitecap area to form a size-resolved SSA production flux parameterization (dF(r80)/dlog10r80). This parameterization yields integrated sea-salt mass fluxes that are largely within the range of uncertainty of recent measurements over the size range 0.029 µm < r80 < 0.580 µm. Physical factors controlling whitecap lifetime such as bubble plume lifetime and surfactant stabilization are discussed in the context of SSA production from whitecaps.

  4. Highly efficient photocatalytic TiO2 coatings deposited by open air atmospheric pressure plasma jet with aerosolized TTIP precursor

    NASA Astrophysics Data System (ADS)

    Fakhouri, H.; Ben Salem, D.; Carton, O.; Pulpytel, J.; Arefi-Khonsari, F.

    2014-07-01

    A simple method to deposit photocatalytic TiO2 coatings, at a high rate (20-40 µm s-1), and with a high porosity, is reported in this paper. This method, which allows the treatment of membranes (with an 800 nm pore size), is based on the introduction of a liquid precursor sprayed into an open-air atmospheric pressure plasma jet (APPJ). The photocatalytic activity of the TiO2 thin films prepared by APPJ have been compared with our best N-doped TiO2 thin films, deposited by reactive radio frequency (RF) magnetron sputtering, previously reported in the literature. The morphology, chemical composition, photoelectrochemical, and photocatalytic properties of the coatings have been studied in this paper. Significant control of the porosity and crystallinity was achieved by varying the deposition parameters and the annealing temperature. Under optimized conditions, the TiO2 coatings deposited by APPJ are characterized by a higher photocatalytic activity as compared to the optimized thin films deposited by RF sputtering. This difference can be explained by the higher specific surface of the APPJ coatings. Finally, the most interesting characteristic of this APPJ-liquid spray process is its capacity to treat membranes without blocking the pores, and to produce photocatalytic membranes which can efficiently combine filtration and photocatalysis for water treatment.

  5. High-time resolved measurements of biogenic and anthropogenic secondary organic aerosol precursors and products in urban air

    NASA Astrophysics Data System (ADS)

    Flores, Rosa M.; Doskey, Paul V.

    2016-04-01

    Volatile organic compounds (VOCs), which are present in the atmosphere entirely in the gas phase are directly emitted by biogenic (~1089 Tg yr-1) and anthropogenic sources (~185 Tg yr-1). However, the sources and molecular speciation of intermediate VOCs (IVOCs), which are for the most part also present almost entirely in the gas phase, are not well characterized. The VOCs and IVOCs participate in reactions that form ozone and semivolatile OC (SVOC) that partition into the aerosol phase. Formation and evolution of secondary organic aerosol (SOA) are part of a complex dynamic process that depends on the molecular speciation and concentration of VOCs, IVOCs, primary organic aerosol (POA), and the level of oxidants (NO3, OH, O3). The current lack of understanding of OA properties and their impact on radiative forcing, ecosystems, and human health is partly due to limitations of models to predict SOA production on local, regional, and global scales. More accurate forecasting of SOA production requires high-temporal resolution measurement and molecular characterization of SOA precursors and products. For the subject study, the IVOCs and aerosol-phase organic matter were collected using the high-volume sampling technique and were analyzed by multidimensional gas chromatography with time-of-flight mass spectrometry (GCxGC-ToFMS). The IVOCs included terpenes, terpenoids, n-alkanes, branched alkanes, isoprenoids, alkylbenzenes, cycloalkylbenzenes, PAH, alkyl PAH, and an unresolved complex mixture (UCM). Diurnal variations of OA species containing multiple oxygenated functionalities and selected SOA tracers of isorprene, α-pinene, toluene, cyclohexene, and n-dodecane oxidation were also quantified. The data for SOA precursor and oxidation products presented here will be useful for evaluating the ability of molecular-specific SOA models to forecast SOA production in and downwind of urban areas.

  6. A protocol for the production of gliadin-cyanoacrylate nanoparticles for hydrophilic coating

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This article presents a protocol for the production of protein-based nanoparticles that change the hydrophobic surface to hydrophilic by a simple spray coating. These nanoparticles are produced by the polymerization reaction of alkyl cyanoacrylate on the surface of cereal protein (gliadin) molecules...

  7. COPAR-FD. Release of Metallic Fission Products from Coated Nuclear Fuel Particles

    SciTech Connect

    Tzung, F.; Richards, M.

    1992-09-01

    COPAR-FD is used to calculate the release of metallic fission products from coated nuclear fuel particles, using a finite-difference solution of the governing partial differential equation. COPAR-FD interfaces with the TRAMP and TRAFIC codes for calculating transport in and release from graphite fuel blocks.

  8. Heterogeneous oxidation of saturated organic aerosols by hydroxyl radicals: uptake kinetics, condensed-phase products, and particle size change

    NASA Astrophysics Data System (ADS)

    George, I. J.; Vlasenko, A.; Slowik, J. G.; Broekhuizen, K.; Abbatt, J. P. D.

    2007-08-01

    The kinetics and reaction mechanism for the heterogeneous oxidation of saturated organic aerosols by gas-phase OH radicals were investigated under NOx-free conditions. The reaction of 150 nm diameter Bis(2-ethylhexyl) sebacate (BES) particles with OH was studied as a proxy for chemical aging of atmospheric aerosols containing saturated organic matter. An aerosol reactor flow tube combined with an Aerodyne time-of-flight aerosol mass spectrometer (ToF-AMS) and scanning mobility particle sizer (SMPS) was used to study this system. Hydroxyl radicals were produced by 254 nm photolysis of O3 in the presence of water vapour. The kinetics of the heterogeneous oxidation of the BES particles was studied by monitoring the loss of a mass fragment of BES with the ToF-AMS as a function of OH exposure. We measured an initial OH uptake coefficient of γ0=1.3 (±0.4), confirming that this reaction is highly efficient. The density of BES particles increased by up to 20% of the original BES particle density at the highest OH exposure studied, consistent with the particle becoming more oxidized. Electrospray ionization mass spectrometry analysis showed that the major particle-phase reaction products are multifunctional carbonyls and alcohols with higher molecular weights than the starting material. Volatilization of oxidation products accounted for a maximum of 17% decrease of the particle volume at the highest OH exposure studied. Tropospheric organic aerosols will become more oxidized from heterogeneous photochemical oxidation, which may affect not only their physical and chemical properties, but also their hygroscopicity and cloud nucleation activity.

  9. Comparison Between NPP-VIIRS Aerosol Data Products and the MODIS AQUA Deep Blue Collection 6 Dataset Over Land

    NASA Technical Reports Server (NTRS)

    Sayer, Andrew M.; Hsu, N. C.; Bettenhausen, C.; Lee, J.; Kondragunta, S.

    2013-01-01

    Aerosols are small particles suspended in the atmosphere and have a variety of natural and man-made sources. Knowledge of aerosol optical depth (AOD), which is a measure of the amount of aerosol in the atmosphere, and its change over time, is important for multiple reasons. These include climate change, air quality (pollution) monitoring, monitoring hazards such as dust storms and volcanic ash, monitoring smoke from biomass burning, determining potential energy yields from solar plants, determining visibility at sea, estimating fertilization of oceans and rainforests by transported mineral dust, understanding changes in weather brought upon by the interaction of aerosols and clouds, and more. The Suomi-NPP satellite was launched late in 2011. The Visible Infrared Imaging Radiometer Suite (VIIRS) aboard Suomi-NPP is being used, among other things, to determine AOD. This study compares the VIIRS dataset to ground-based measurements of AOD, along with a state-of-the-art satellite AOD dataset (the new version of the Moderate Resolution Imaging Spectrometer Deep Blue algorithm) to assess its reliability. The Suomi-NPP satellite was launched late in 2011, carrying several instruments designed to continue the biogeophysical data records of current and previous satellite sensors. The Visible Infrared Imaging Radiometer Suite (VIIRS) aboard Suomi-NPP is being used, among other things, to determine aerosol optical depth (AOD), and related activities since launch have been focused towards validating and understanding this new dataset through comparisons with other satellite and ground-based products. The operational VIIRS AOD product is compared over land with AOD derived from Moderate Resolution Imaging Spectrometer (MODIS) observations using the Deep Blue (DB) algorithm from the forthcoming Collection 6 of MODIS data

  10. Satellite assessment of sea spray aerosol productivity: Southern Ocean case study

    NASA Astrophysics Data System (ADS)

    Witek, Marcin L.; Diner, David J.; Garay, Michael J.

    2016-01-01

    Despite many years of observations by multiple sensors, there is still substantial ambiguity regarding aerosol optical depths (AOD) over remote oceans, in particular, over the pristine Southern Ocean. Passive satellite retrievals (e.g., Multiangle Imaging Spectroradiometer (MISR) and Moderate Resolution Imaging Spectroradiometer (MODIS)) and global aerosol transport models show a distinct AOD maximum around the 60°S latitude band. Sun photometer measurements performed by the Maritime Aerosol Network (MAN), on the other hand, indicate no increased AODs over the Southern Ocean. In this study elevated Southern Ocean AODs are examined from the modeling perspective. The primary aerosol component over the Southern Ocean is sea spray aerosol (SSA). Multiple simulations of SSA concentrations and optical depths are carried out using a single modeling framework, the Navy Aerosol Analysis and Prediction System (NAAPS) model. Several SSA emission functions are examined, including recently proposed formulations with sea surface temperature corrections. The differences between NAAPS simulations are primarily due to different SSA emission formulations. The results are compared against satellite-derived AODs from the MISR and MODIS instruments. MISR and MODIS AOD retrievals are further filtered to eliminate retrievals potentially affected by cloud contamination and cloud adjacency effects. The results indicate a very large impact of SSA emission parameterization on the simulated AODs. For some scenarios, the Southern Ocean AOD maximum almost completely disappears. Further MISR and MODIS AOD quality screening substantially improves model/satellite agreement. Based on these comparisons, an optimal SSA emission function for global aerosol transport models is recommended.

  11. A Spatio-Temporal Approach for Global Validation and Analysis of MODIS Aerosol Products

    NASA Technical Reports Server (NTRS)

    Ichoku, Charles; Chu, D. Allen; Mattoo, Shana; Kaufman, Yoram J.; Remer, Lorraine A.; Tanre, Didier; Slutsker, Ilya; Holben, Brent N.; Lau, William K. M. (Technical Monitor)

    2001-01-01

    With the launch of the MODIS sensor on the Terra spacecraft, new data sets of the global distribution and properties of aerosol are being retrieved, and need to be validated and analyzed. A system has been put in place to generate spatial statistics (mean, standard deviation, direction and rate of spatial variation, and spatial correlation coefficient) of the MODIS aerosol parameters over more than 100 validation sites spread around the globe. Corresponding statistics are also computed from temporal subsets of AERONET-derived aerosol data. The means and standard deviations of identical parameters from MOMS and AERONET are compared. Although, their means compare favorably, their standard deviations reveal some influence of surface effects on the MODIS aerosol retrievals over land, especially at low aerosol loading. The direction and rate of spatial variation from MODIS are used to study the spatial distribution of aerosols at various locations either individually or comparatively. This paper introduces the methodology for generating and analyzing the data sets used by the two MODIS aerosol validation papers in this issue.

  12. Aerosol Radiative Forcing Estimates from South Asian Clay Brick Production Based on Direct Emission Measurements

    NASA Astrophysics Data System (ADS)

    Weyant, C.; Athalye, V.; Ragavan, S.; Rajarathnam, U.; Kr, B.; Lalchandani, D.; Maithel, S.; Malhotra, G.; Bhanware, P.; Thoa, V.; Phuong, N.; Baum, E.; Bond, T. C.

    2012-12-01

    About 150-200 billion clay bricks are produced in India every year. Most of these bricks are fired in small-scale traditional kilns that burn coal or biomass without pollution controls. Reddy and Venkataraman (2001) estimated that 8% of fossil fuel related PM2.5 emissions and 23% of black carbon emissions in India are released from brick production. Few direct emissions measurements have been done in this industry and black carbon emissions, in particular, have not been previously measured. In this study, 9 kilns representing five common brick kiln technologies were tested for aerosol properties and gaseous pollutant emissions, including optical scattering and absorption and thermal-optical OC/EC. Simple relationships are then used to estimate the radiative-forcing impact. Kiln design and fuel quality greatly affect the overall emission profiles and relative climate warming. Batch production kilns, such as the Downdraft kiln, produce the most PM2.5 (0.97 gPM2.5/fired brick) with an OC/EC fraction of 0.3. Vertical Shaft Brick kilns using internally mixed fuels produce the least PM (0.09 gPM2.5/kg fired brick) with the least EC (OC/EC = 16.5), but these kilns are expensive to implement and their use throughout Southern Asia is minimal. The most popular kiln in India, the Bull's Trench kiln, had fewer emissions per brick than the Downdraft kiln, but an even higher EC fraction (OC/EC = 0.05). The Zig-zag kiln is similar in structure to the Bull's Trench kiln, but the emission factors are significantly lower: 50% reduction for CO, 17% for PM2.5 and 60% for black carbon. This difference in emissions suggests that converting traditional Bull's Trench kilns into less polluting Zig-zag kilns would result in reduced atmospheric warming from brick production.

  13. The Remote Sensing of Mineral Aerosols and Their Impact on Phytoplankton Productivity using Sea WiFS

    NASA Technical Reports Server (NTRS)

    Stegmann, Petra M.

    1998-01-01

    The main objective of this proposal was to use SeaWiFs data to study the relationship between aerosols found in aeollan dust and photosynthesis of phytoplankton in open ocean surface waters. This project was a collaborative effort between myself and Dr. Neil Tindale at Texas A&M University and followed on our earlier funded proposal which had been designed as a proof-of-concept study to determine if ocean color sensors such as the Coastal Zone Color Scanner (CZCS) could be used to detect and map large-scale mineral aerosol plumes. Despite the large spatial and temporal gaps inherent in the CZCS data coverage, our results from this initial study indicated that an ocean color sensor could indeed be used to detect aerosols. These encouraging results led us to propose in this proposal the use of SeaWiFS data to study mineral aerosol transport and its impact on phytoplankton production. This proposal orignally intended to make use of SeaWiFS images, but as the launch delay of SeaWiFS dragged on, we had to make do with other satellite data sets. Thus, the focus of this proposal became the CSCS image archive instead. I detail my results and accomplishments with this data set.

  14. Preliminary results for salt aerosol production intended for marine cloud brightening, using effervescent spray atomization.

    PubMed

    Cooper, Gary; Foster, Jack; Galbraith, Lee; Jain, Sudhanshu; Neukermans, Armand; Ormond, Bob

    2014-12-28

    The large-scale production of vast numbers of suitable salt nuclei and their upward launch is one of the main technological barriers to the experimental testing of marine cloud brightening (MCB). Very promising, though not definitive, results have been obtained using an adapted version of effervescent spray atomization. The process is simple, robust and inexpensive. This form of effervescent spraying uses only pressurized water and air sprayed from small nozzles to obtain very fine distributions. While it is far from optimized, and may not be the best method if full deployment is ever desired, we believe that even in its present form the process would lend itself well to preliminary field test investigations of MCB. Measurements obtained using standard aerosol instrumentation show approximately lognormal distributions of salt nuclei with median diameters of approximately 65 nm and geometric standard deviations slightly less than 2. However, these measurements are not in agreement with those based on scanning electron microscopy imaging of collected particles, an observation that has not yet been explained. Assuming the above distribution, 10(15) particles per second could be made with 21 kW of spray power, using approximately 200 nozzles. It is envisioned that existing snow making equipment can be adapted to launch the nuclei 60-100 m into the air, requiring approximately 20 kW of additional power. PMID:25404673

  15. Preliminary results for salt aerosol production intended for marine cloud brightening, using effervescent spray atomization

    PubMed Central

    Cooper, Gary; Foster, Jack; Galbraith, Lee; Jain, Sudhanshu; Neukermans, Armand; Ormond, Bob

    2014-01-01

    The large-scale production of vast numbers of suitable salt nuclei and their upward launch is one of the main technological barriers to the experimental testing of marine cloud brightening (MCB). Very promising, though not definitive, results have been obtained using an adapted version of effervescent spray atomization. The process is simple, robust and inexpensive. This form of effervescent spraying uses only pressurized water and air sprayed from small nozzles to obtain very fine distributions. While it is far from optimized, and may not be the best method if full deployment is ever desired, we believe that even in its present form the process would lend itself well to preliminary field test investigations of MCB. Measurements obtained using standard aerosol instrumentation show approximately lognormal distributions of salt nuclei with median diameters of approximately 65 nm and geometric standard deviations slightly less than 2. However, these measurements are not in agreement with those based on scanning electron microscopy imaging of collected particles, an observation that has not yet been explained. Assuming the above distribution, 1015 particles per second could be made with 21 kW of spray power, using approximately 200 nozzles. It is envisioned that existing snow making equipment can be adapted to launch the nuclei 60–100 m into the air, requiring approximately 20 kW of additional power. PMID:25404673

  16. Global dust sources detection using MODIS Deep Blue Collection 6 aerosol products

    NASA Astrophysics Data System (ADS)

    Pérez García-Pando, C.; Ginoux, P. A.

    2015-12-01

    Our understanding of the global dust cycle is limited by a dearth of information about dust sources, especially small-scale features which could account for a large fraction of global emissions. Remote sensing sensors are the most useful tool to locate dust sources. These sensors include microwaves, visible channels, and lidar. On the global scale, major dust source regions have been identified using polar orbiting satellite instruments. The MODIS Deep Blue algorithm has been particularly useful to detect small-scale sources such as floodplains, alluvial fans, rivers, and wadis , as well as to identify anthropogenic sources from agriculture. The recent release of Collection 6 MODIS aerosol products allows to extend dust source detection to the entire land surfaces, which is quite useful to identify mid to high latitude dust sources and detect not only dust from agriculture but fugitive dust from transport and industrial activities. This presentation will overview the advantages and drawbacks of using MODIS Deep Blue for dust detection, compare to other instruments (polar orbiting and geostationary). The results of Collection 6 with a new dust screening will be compared against AERONET. Applications to long range transport of anthropogenic dust will be presented.

  17. Aerosol and product yields from NO{sub 3} radical-initiated oxidation o/f selected monoterpenes

    SciTech Connect

    Hallquist, M.; Ljungstroem, E.; Waengberg, I.; Barnes, I.; Becker, K.H.

    1999-02-15

    Atmospheric transformation of monoterpenes gives products that may cause environmental consequences. In this work the NO{sub 3} radical-initiated oxidation of the monoterpenes {alpha}-pinene, {beta}-pinene, {Delta}{sup 3}-carene, and limonene has been investigated. All experiments were conducted in EUPHORE, the EUropean PHOto REactor facility in Valencia, Spain. The aerosol and product yields were measured in experiments with a conversion of the terpenes in the interval from 7 to 400 ppb. The lower end of the concentrations used are close to those measured in ambient pine forest air. Products were measured using long path in situ FTIR. Aerosol yields were obtained using a DMA-CPC system. The aerosol mass yields measured at low concentrations were <1, 10, 15, and 17% for {alpha}-pinene, {beta}-pinene, {Delta}{sup 3}-carene, and limonene, respectively. The total molar alkylnitrate yields were calculated to be 19, 61, 66, and 48%, and molar carbonyl compound yields were estimated to be 71, 14, 29, and 69% for {alpha}-pinene, {beta}-pinene, {Delta}{sup 3}-carene, and limonene, respectively. The aerosol yields were strongly dependent on the amounts of terpene reacted, whereas the nitrate and carbonyl yields do not depend on the amount of terpene converted. The principal carbonyl compound from {alpha}pinene oxidation was pinonaldehyde. In the case of limonene, endolim was tentatively identified and appears to be a major product. The reactions with {beta}-pinene and {Delta}{sup 3}-carene yielded 1--2% of nopinone and 2--3% caronaldehyde, respectively. The results show that it is not possible to use generalized descriptions of terpene chemistry, e.g., in mathematical models.

  18. The generation of aerosols by accidents which may occur during plant-scale production of micro-organisms.

    PubMed Central

    Ashcroft, J.; Pomeroy, N. P.

    1983-01-01

    Experiments have been performed to simulate accidents which may occur during large-scale production of micro-organisms. Four types of accident, which were considered to be the most likely to result in the greatest hazard to health, were simulated using a bacterial model. The accidents were all concerned with faults occurring in the operation of the microbial fermenter. Gross contamination of surfaces occurred in all experiments, but only three types of accident produced a measurable aerosol. PMID:6350448

  19. Chemical composition of individual aerosol particles in workplace air during production of manganese alloys.

    PubMed

    Gunst, S; Weinbruch, S; Wentzel, M; Ortner, H M; Skogstad, A; Hetland, S; Thomassen, Y

    2000-02-01

    Aerosol particle samples were collected at ELKEM ASA ferromanganese (FeMn) and silicomanganese (SiMn) smelters at Porsgrunn, Norway, during different production steps: raw material mixing, welding of protective steel casings, tapping of FeMn and slag, crane operation moving the ladles with molten metal, operation of the Metal Oxygen Refinement (MOR) reactor and casting of SiMn. Aerosol fractions were assessed for the analysis of the bulk elemental composition as well as for individual particle analysis. The bulk elemental composition was determined by inductively coupled plasma atomic emission spectrometry. For individual particle analysis, an electron microprobe was used in combination with wavelength-dispersive techniques. Most particles show a complex composition and cannot be attributed to a single phase. Therefore, the particles were divided into six groups according to their chemical composition: Group I, particles containing mainly metallic Fe and/or Mn; Group II, slag particles containing mainly Fe and/or Mn oxides; Group III, slag particles consisting predominantly of oxidized flux components such as Si, Al, Mg, Ca, Na and K; Group IV, particles consisting mainly of carbon; Group V, mixtures of particles from Groups II, III and IV; Group VI, mixtures of particles from Groups II and III. In raw material mixing, particles originating from the Mn ores were mostly found. In the welding of steel casings, most particles were assigned to Group II, Mn and Fe oxides. During the tapping of slag and metal, mostly slag particles from Group III were found (oxides of the flux components). During movement of the ladles, most particles came from Group II. At the MOR reactor, most of the particles belonged to the slag phase consisting of the flux components (Group III). The particles collected during the casting of SiMn were mainly attributed to the slag phase (Groups III and V). Due to the compositional complexity of the particles, toxicological investigations on the

  20. The effect of organic aerosol material on aerosol reactivity towards ozone

    NASA Astrophysics Data System (ADS)

    Batenburg, Anneke; Gaston, Cassandra; Thornton, Joel; Virtanen, Annele

    2015-04-01

    After aerosol particles are formed or emitted into the atmosphere, heterogeneous reactions with gaseous oxidants cause them to 'age'. Aging can change aerosol properties, such as the hygroscopicity, which is an important parameter in how the particles scatter radiation and form clouds. Conversely, heterogeneous reactions on aerosol particles play a significant role in the cycles of various atmospheric trace gases. Organic compounds, a large part of the total global aerosol matter, can exist in liquid or amorphous (semi)solid physical phases. Different groups have shown that reactions with ozone (O3) can be limited by bulk diffusion in organic aerosol, particularly in viscous, (semi)solid materials, and that organic coatings alter the surface interactions between gas and aerosol particles. We aim to better understand and quantify how the viscosity and phase of organic aerosol matter affect gas-particle interactions. We have chosen the reaction of O3 with particles composed of a potassium iodide (KI) core and a variable organic coating as a model system. The reaction is studied in an aerosol flow reactor that consists of a laminar flow tube and a movable, axial injector for the injection of O3. The aerosol-containing air is inserted at the tube's top. The interaction length (and therefore time), between the particles and the O3 can be varied by moving the injector. Alternatively, the production of aerosol particles can be modulated. The remaining O3 concentration is monitored from the bottom of the tube and particle concentrations are measured simultaneously, which allows us to calculate the reactive uptake coefficient γ. We performed exploratory experiments with internally mixed KI and polyethylene glycol (PEG) particles at the University of Washington (UW) in a setup with a residence time around 50 s. Aerosol particles were generated in an atomizer from solutions with varying concentrations of KI and PEG and inserted into the flow tube after they were diluted and

  1. Printing versus coating - What will be the future production technology for printed electronics?

    SciTech Connect

    Glawe, Andrea; Eggerath, Daniel; Schäfer, Frank

    2015-02-17

    The market of Large Area Organic Printed Electronics is developing rapidly to increase efficiency and quality as well as to lower costs further. Applications for OPV, OLED, RFID and compact Printed Electronic systems are increasing. In order to make the final products more affordable, but at the same time highly accurate, Roll to Roll (R2R) production on flexible transparent polymer substrates is the way forward. There are numerous printing and coating technologies suitable depending on the design, the product application and the chemical process technology. Mainly the product design (size, pattern, repeatability) defines the application technology.

  2. Printing versus coating - What will be the future production technology for printed electronics?

    NASA Astrophysics Data System (ADS)

    Glawe, Andrea; Eggerath, Daniel; Schäfer, Frank

    2015-02-01

    The market of Large Area Organic Printed Electronics is developing rapidly to increase efficiency and quality as well as to lower costs further. Applications for OPV, OLED, RFID and compact Printed Electronic systems are increasing. In order to make the final products more affordable, but at the same time highly accurate, Roll to Roll (R2R) production on flexible transparent polymer substrates is the way forward. There are numerous printing and coating technologies suitable depending on the design, the product application and the chemical process technology. Mainly the product design (size, pattern, repeatability) defines the application technology.

  3. Study of a CCP RF Dusty Plasma for the Production of Titan's Aerosols Analogues

    SciTech Connect

    Alcouffe, G.; Cernogora, G.; Ouni, F.; Correia, J. J.; Cavarroc, M.; Boufendi, L.; Szopa, C.

    2008-09-07

    The CCP-RF discharge PAMPRE experiment produces analogues of Titan's aerosols. Here are presented the plasma characteristics as a function of gas mixtures and dust formation. Electronic density, optical emission spectroscopy, and self-bias voltage measurements are presented.

  4. Thermal shock removal of defective glass-enamel coating from cast-iron products

    NASA Astrophysics Data System (ADS)

    Aleutdinov, A. D.; Ghyngazov, S. A.; Mylnikova, T. S.; Luchnikov, P. A.

    2015-04-01

    A setup for light beam exposure has been developed. The setup was used to consider the technology of thermal shock destruction of the coating by pulsed-periodic exposure to powerful focused light from the xenon arc lamp DKsShRB-10000. It is shown that this type of exposure can effectively remove the glass-enamel coating from iron products. The optimal mode of setup operation to efficiently remove the defective glass-enamel coating is found: the diameter of the focused light beams is 2.5-3.5 cm; the lamp arc pulse current is 350-450 A; pulse duration is (0.5-1) s and pulse repetition frequency is (0.15-0.5) s-1.

  5. Operational Retrieval of aerosol optical depth over Indian subcontinent and Indian Ocean using INSAT-3D/Imager product validation

    NASA Astrophysics Data System (ADS)

    Mishra, M. K.; Rastogi, G.; Chauhan, P.

    2014-11-01

    Aerosol optical depth (AOD) over Indian subcontinent and Indian Ocean region is derived operationally for the first time from the geostationary earth orbit (GEO) satellite INSAT-3D Imager data at 0.65 μm wavelength. Single visible channel algorithm based on clear sky composites gives larger retrieval error in AOD than other multiple channel algorithms due to errors in estimating surface reflectance and atmospheric property. However, since MIR channel signal is insensitive to the presence of most aerosols, therefore in present study, AOD retrieval algorithm employs both visible (centred at 0.65 μm) and mid-infrared (MIR) band (centred at 3.9 μm) measurements, and allows us to monitor transport of aerosols at higher temporal resolution. Comparisons made between INSAT-3D derived AOD (τI) and MODIS derived AOD (τM) co-located in space (at 1° resolution) and time during January, February and March (JFM) 2014 encompasses 1165, 1052 and 900 pixels, respectively. Good agreement found between τI and τM during JFM 2014 with linear correlation coefficients (R) of 0.87, 0.81 and 0.76, respectively. The extensive validation made during JFM 2014 encompasses 215 co-located AOD in space and time derived by INSAT 3D (τI) and 10 sun-photometers (τA) that includes 9 AERONET (Aerosol Robotic Network) and 1 handheld sun-photometer site. INSAT-3D derived AOD i.e. τI, is found within the retrieval errors of τI = ±0.07 ±0.15τA with linear correlation coefficient (R) of 0.90 and root mean square error equal (RMSE) to 0.06. Present work shows that INSAT-3D aerosol products can be used quantitatively in many applications with caution for possible residual clouds, snow/ice, and water contamination.

  6. Integrated Cloud-Aerosol-Radiation Product using CERES, MODIS, CALIPSO and CloudSat Data

    NASA Technical Reports Server (NTRS)

    Sun-Mack, Sunny; Minnis, Patrick; Chen, Yan; Gibson, Sharon; Yi, Yuhong; Trepte, Qing; Wielicki, Bruce; Kato, Seiji; Winker, Dave

    2007-01-01

    This paper documents the development of the first integrated data set of global vertical profiles of clouds, aerosols, and radiation using the combined NASA A-Train data from the Aqua Clouds and Earth's Radiant Energy System (CERES) and Moderate Resolution Imaging Spectroradiometer (MODIS), Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO), and CloudSat. As part of this effort, cloud data from the CALIPSO lidar and the CloudSat radar are merged with the integrated column cloud properties from the CERES-MODIS analyses. The active and passive datasets are compared to determine commonalities and differences in order to facilitate the development of a 3- dimensional cloud and aerosol dataset that will then be integrated into the CERES broadband radiance footprint. Preliminary results from the comparisons for April 2007 reveal that the CERES-MODIS global cloud amounts are, on average, 0.14 less and 0.15 greater than those from CALIPSO and CloudSat, respectively. These new data will provide unprecedented ability to test and improve global cloud and aerosol models, to investigate aerosol direct and indirect radiative forcing, and to validate the accuracy of global aerosol, cloud, and radiation data sets especially in polar regions and for multi-layered cloud conditions.

  7. Impact of Stronger Production and Loss Rates of Secondary Organic Aerosols on their Global Distribution and Budget

    NASA Astrophysics Data System (ADS)

    Hodzic, A.; Kasibhatla, P. S.; Cappa, C. D.; Madronich, S.; Jo, D. S.; Park, R.; Jimenez, J. L.

    2015-12-01

    Organic aerosols are observed to be the major constituents of submicron particles worldwide, and yet their atmospheric lifecycle including formation, ageing, and removal processes is poorly understood. Recent laboratory and ambient measurements suggest that both production yields and removal rates of chemically produced secondary organic aerosols (SOA) are much stronger and more diverse than currently assumed in chemistry-climate models (which typically consider wet deposition as the major loss process). In this study, we re-assess the global SOA distribution and budget with newly proposed SOA production and loss processes derived from these recent measurements, as well as from theoretical calculations. We evaluate and discuss the relative importance of removal pathways for organic vapors and particles (e.g. dry and wet deposition, photo-dissociation, evaporation, and heterogeneous surface reactions), and their effect on the SOA vertical distribution and budget using the GEOS-Chem global chemistry-transport model. We compare simulated SOA from various model configurations against ground, aircraft and satellite measurements to assess the extent to which these new developments in our understanding of SOA formation and removal processes are consistent with observed characteristics of the SOA distribution. Our results show strong changes in predicted vertical profiles of organic aerosols with higher SOA concentrations in the boundary layer and lower concentrations in the upper troposphere, which appear to be in a better agreement with aircraft measurements.

  8. AMS+ALS: Kinetic and Product Studies of the Heterogeneous Oxidation of Organic Aerosol at the Advanced Light Source

    NASA Astrophysics Data System (ADS)

    Kroll, J. H.; Wilson, K. R.; Kessler, S. H.; Browne, E. C.; Nah, T.; Smith, J.; Worsnop, D. R.

    2014-12-01

    The atmospheric oxidation of condensed-phase organic species can have a major influence on the composition, properties, and impacts of organic aerosol (OA); however the rates and products of such "aging" reactions are poorly constrained. Here we describe a series of laboratory experiments aimed at better understanding one class of aging reactions, the heterogeneous oxidation of OA by gas-phase oxidants. Central to these experiments is the availability of vacuum ultraviolet (VUV) light at the Chemical Dynamics Beamline of the Advanced Light Source at LBNL, which enables the implementation of VUV photoionization aerosol mass spectrometry. This technique allows for the real-time, speciated measurement of OA composition, yielding molecular information that is highly complementary to ensemble data from electron-impact ionization. OA composition is measured with both ionization schemes as a function of oxidant exposure within a flow reactor, providing detailed information on the kinetics and products of heterogeneous oxidation over multiple generations of oxidation. Specific topics investigated include the branching between functionalization and fragmentation of OA components, the formation of secondary organic aerosol from photolytically-generated radical species, and the heterogeneous aging of soot-associated organic species.

  9. Comparison of ground based indices (API and AQI) with satellite based aerosol products.

    PubMed

    Zheng, Sheng; Cao, Chun-Xiang; Singh, Ramesh P

    2014-08-01

    Air quality in mega cities is one of the major concerns due to serious health issues and its indirect impact to the climate. Among mega cities, Beijing city is considered as one of the densely populated cities with extremely poor air quality. The meteorological parameters (wind, surface temperature, air temperature and relative humidity) control the dynamics and dispersion of air pollution. China National Environmental Monitoring Centre (CNEMC) started air pollution index (API) as of 2000 to evaluate air quality, but over the years, it was felt that the air quality is not well represented by API. Recently, the Ministry of Environmental Protection (MEP) of the People's Republic of China (PRC) started using a new index "air quality index (AQI)" from January 2013. We have compared API and AQI with three different MODIS (MODIS - Moderate Resolution Imaging SpectroRadiometer, onboard the Terra/Aqua satellites) AOD (aerosol optical depth) products for ten months, January-October, 2013. The correlation between AQI and Aqua Deep Blue AOD was found to be reasonably good as compared with API, mainly due to inclusion of PM2.5 in the calculation of AQI. In addition, for every month, the correlation coefficient between AQI and Aqua Deep Blue AOD was found to be relatively higher in the month of February to May. According to the monthly average distribution of precipitation, temperature, and PM10, the air quality in the months of June-September was better as compared to those in the months of February-May. AQI and Aqua Deep Blue AOD show highly polluted days associated with dust event, representing true air quality of Beijing. PMID:24412562

  10. Validation of radiolabeling of drug formulations for aerosol deposition assessment of orally inhaled products.

    PubMed

    Devadason, Sunalene G; Chan, Hak-Kim; Haeussermann, Sabine; Kietzig, Claudius; Kuehl, Philip J; Newman, Stephen; Sommerer, Knut; Taylor, Glyn

    2012-12-01

    Radiolabeling of inhaler formulations for imaging studies is an indirect method of determining lung deposition and regional distribution of drug in human subjects. Hence, ensuring that the radiotracer and drug exhibit similar aerodynamic characteristics when aerosolized, and that addition of the radiotracer has not significantly altered the characteristics of the formulation, are critical steps in the development of a radiolabeling method. The validation phase should occur during development of the radiolabeling method, prior to commencement of in vivo studies. The validation process involves characterization of the aerodynamic particle size distribution (APSD) of drug in the reference formulation, and of both drug and radiotracer in the radiolabeled formulation, using multistage cascade impaction. We propose the adoption of acceptance criteria similar to those recommended by the EMA and ISAM/IPAC-RS for determination of therapeutic equivalence of orally inhaled products: (a) if only total lung deposition is being quantified, the fine particle fraction ratio of both radiolabeled drug and radiotracer to that of the reference drug should fall between 0.85 and 1.18, and (b) if regional lung deposition (e.g., outer and inner lung regions) is to be quantified, the ratio of both radiolabeled drug and radiotracer to reference drug on each impactor stage or group of stages should fall between 0.85 and 1.18. If impactor stages are grouped together, at least four separate groups should be provided. In addition, while conducting in vivo studies, measurement of the APSD of the inhaler used on each study day is recommended to check its suitability for use in man. PMID:23215848

  11. Chemical characterization of the main secondary organic aerosol (SOA) products formed through aqueous-phase photonitration of guaiacol

    NASA Astrophysics Data System (ADS)

    Kitanovski, Z.; Čusak, A.; Grgić, I.; Claeys, M.

    2014-04-01

    Guaiacol (2-methoxyphenol) and its derivatives can be emitted into the atmosphere by thermal degradation (i.e. burning) of wood lignins. Due to its volatility, guaiacol is predominantly distributed in the atmospheric gaseous phase. Recent studies have shown the importance of aqueous-phase reactions in addition to the dominant gas-phase and heterogeneous reactions of guaiacol, in the formation of secondary organic aerosol (SOA) in the atmosphere. The main objectives of the present study were to chemically characterize the low-volatility SOA products of the aqueous-phase photonitration of guaiacol and examine their possible presence in urban atmospheric aerosols. The aqueous-phase reactions were carried out under simulated sunlight and in the presence of H2O2 and nitrite. The formed guaiacol reaction products were concentrated by using solid-phase extraction (SPE) and then purified by means of semi-preparative high-performance liquid chromatography (HPLC). The fractionated individual compounds were isolated as pure solids and further analyzed with liquid-state 1H, 13C and 2D nuclear magnetic resonance (NMR) spectroscopy and direct infusion negative ion electrospray ionization tandem mass spectrometry ((-)ESI-MS/MS). The NMR and product ion (MS2) spectra were used for unambiguous product structure elucidation. The main products of guaiacol photonitration are 4-nitroguaiacol (4NG), 6-nitroguaiacol (6NG), and 4,6-dinitroguaiacol (4,6DNG). Using the isolated compounds as standards, 4NG and 4,6DNG were unambiguously identified in winter PM10 aerosols from the city of Ljubljana (Slovenia) by means of HPLC/(-)ESI-MS/MS. Owing to the strong absorption of UV and visible light, 4,6DNG could be an important constituent of atmospheric "brown" carbon, especially in regions affected by biomass burning.

  12. Neutron Production from In-situ Heavy Ice Coated Targets at Vulcan

    NASA Astrophysics Data System (ADS)

    Morrison, John; Krygier, A. G.; Kar, S.; Ahmed, H.; Alejo, A.; Clarke, R.; Fuchs, J.; Green, A.; Jung, D.; Kleinschmidt, A.; Najmudin, Z.; Nakamura, H.; Norreys, P.; Notley, M.; Oliver, M.; Roth, M.; Vassura, L.; Zepf, M.; Borghesi, M.; Freeman, R. R.

    2015-05-01

    Laser based neutron production experiments have been performed utilizing ultra-high intensity laser accelerated ions impinging upon a secondary target. The neutron yield from such experiments may be improved if the accelerated ions were primarily deuterons taking advantage of the d-d cross section. Recent experiments have demonstrated that selective deuteron acceleration from in-situ heavy ice coating of targets can produce ion spectra where deuterons comprise > 99 % of the measured ions. Results will be presented from integrated neutron production experiments from heavy ice targets coated in-situ recently performed on the Vulcan laser at Rutherford Appleton Laboratory. We are grateful for the Staff at RAL and acknowledge funding from the US DoE. AFOSR, European Social Fund, and the Czech Republic.

  13. A High-Spatial-Resolution, Localized MODIS Aerosol Optical Depth Product for Use in Air Quality Exposure Assessment During Large Wildfire Smoke Events

    NASA Astrophysics Data System (ADS)

    McCarthy, M. C.; Raffuse, S. M.; DeWinter, J. L.; Craig, K. J.; Jumbam, L. K.; Fruin, S.; Lurmann, F.

    2011-12-01

    Aerosol optical depth (AOD) has potential use for determining the intra-urban variability of airborne particulate matter exposure during wildfire events; however, the standard Moderate Resolution Imaging Spectroradiometer (MODIS) AOD products have limitations for this application. Specifically, the 10x10 km resolution is too coarse for intra-urban population exposure assessments, the assumed aerosol optical properties are not representative of biomass burning aerosol, and the cloud masking algorithm misinterprets heavy smoke as clouds. We developed a localized MODIS AOD product at 1.5 and 2.5 km resolutions and tested the performance in northern California during the 2008 wildfires. The localized product's algorithm uses local biomass burning aerosol optical properties, local surface reflectance data, and a relaxed cloud filter. During the 2008 season, persistent heavy smoke was produced over northern California and the San Joaquin Valley for over two months. As California is both highly populated and covered with a relatively dense network of ground-based aerosol monitoring stations, this event provided an excellent opportunity to develop the AOD product and test its ability to predict aerosol concentrations on the ground to assess population exposure. We will present our methodology and discuss its potential for air quality and public health applications.

  14. Validation of MODIS aerosol product with in-situ AERONET data (a study case in Hermosillo, Sonora, Mexico)

    NASA Astrophysics Data System (ADS)

    Valdes, M.; Leyva-Contreras, A.; Bonifaz, R.; Llamas, R.

    2009-12-01

    The aerosol optical thickness (AOT) is known as blocking particles which avoid the transmission of solar radiation coming from the Sun, and is defined as the integral of the coefficient of extinction over a vertical column of the Atmosphere. This coefficient of extinction is also defined as the limited fraction of the irradiance over the trajectory at a specific wavelength. The MODIS (Moderate Resolution Imaging Spectroradiometer) sensor provides aerosol data products all over the planet. However this data requires constant evaluation and validation using in-situ data such as the provided by the network of photometers managed by AERONET (Aerosol Robotic Network). In this work, the procedure of validation of the MODIS AOT data using AERONET data in the wavelengths of 660 and 675 nm is presented. It is expected that using validate remote sensing data which provides spatial and temporal information about the AOT will help to a better understanding of the behavior of the complex atmospheric conditions which characterize the NW of Mexico and SW of the US such as the Mexican monsoon.

  15. A Critical Examination of Spatial Biases Between MODIS and MISR Aerosol Products - Application for Potential AERONET Deployment

    NASA Technical Reports Server (NTRS)

    Shi, Y.; Zhang, J.; Reid, J. S.; Hyer, E. J.; Eck, T. F.; Holben, B. N.; Kahn, R. A.

    2011-01-01

    AErosol RObotic NETwork (AERONET) data are the primary benchmark for evaluating satellite-retrieved aerosol properties. However, despite its extensive coverage, the representativeness of the AERONET data is rarely discussed. Indeed, many studies have shown that satellite retrieval biases have a significant degree of spatial correlation that may be problematic for higher-level processes or inverse-emissions-modeling studies. To consider these issues and evaluate relative performance in regions of few surface observations, cross-comparisons between the Aerosol Optical Depth (AOD) products of operational MODIS Collection 5.1 Dark Target (DT) and operational MODIS Collection 5.1 Deep Blue (DB) with MISR version 22 were conducted. Through such comparisons, we can observe coherent spatial features of the AOD bias while side-stepping the full analysis required for determining when or where either retrieval is more correct. We identify regions where MODIS to MISR AOD ratios were found to be above 1.4 and below 0.7. Regions where lower boundary condition uncertainty is likely to be a dominant factor include portions of Western North America, the Andes mountains, Saharan Africa, the Arabian Peninsula, and Central Asia. Similarly, microphysical biases may be an issue in South America, and specific parts of Southern Africa, India Asia, East Asia, and Indonesia. These results help identify high-priority locations for possible future deployments of both in situ and ground based remote sensing measurements. The Supplement includes a km1 file.

  16. Global Long-Term SeaWiFS Deep Blue Aerosol Products available at NASA GES DISC

    NASA Technical Reports Server (NTRS)

    Shen, Suhung; Sayer, A. M.; Bettenhausen, Corey; Wei, Jennifer C.; Ostrenga, Dana M.; Vollmer, Bruce E.; Hsu, Nai-Yung; Kempler, Steven J.

    2012-01-01

    Long-term climate data records about aerosols are needed in order to improve understanding of air quality, radiative forcing, and for many other applications. The Sea-viewing Wide Field-of-view Sensor (SeaWiFS) provides a global well-calibrated 13- year (1997-2010) record of top-of-atmosphere radiance, suitable for use in retrieval of atmospheric aerosol optical depth (AOD). Recently, global aerosol products derived from SeaWiFS with Deep Blue algorithm (SWDB) have become available for the entire mission, as part of the NASA Making Earth Science data records for Use in Research for Earth Science (MEaSUREs) program. The latest Deep Blue algorithm retrieves aerosol properties not only over bright desert surfaces, but also vegetated surfaces, oceans, and inland water bodies. Comparisons with AERONET observations have shown that the data are suitable for quantitative scientific use [1],[2]. The resolution of Level 2 pixels is 13.5x13.5 km2 at the center of the swath. Level 3 daily and monthly data are composed by using best quality level 2 pixels at resolution of both 0.5ox0.5o and 1.0ox1.0o. Focusing on the southwest Asia region, this presentation shows seasonal variations of AOD, and the result of comparisons of 5-years (2003- 2007) of AOD from SWDB (Version 3) and MODIS Aqua (Version 5.1) for Dark Target (MYD-DT) and Deep Blue (MYD-DB) algorithms.

  17. Emissions of biogenic volatile organic compounds and subsequent photochemical production of secondary organic aerosol in mesocosm studies of temperate and tropical plant species

    NASA Astrophysics Data System (ADS)

    Wyche, K. P.; Ryan, A. C.; Hewitt, C. N.; Alfarra, M. R.; McFiggans, G.; Carr, T.; Monks, P. S.; Smallbone, K. L.; Capes, G.; Hamilton, J. F.; Pugh, T. A. M.; MacKenzie, A. R.

    2014-12-01

    Silver birch (Betula pendula) and three Southeast Asian tropical plant species (Ficus cyathistipula, Ficus benjamina and Caryota millis) from the pantropical fig and palm genera were grown in a purpose-built and environment-controlled whole-tree chamber. The volatile organic compounds emitted from these trees were characterised and fed into a linked photochemical reaction chamber where they underwent photo-oxidation under a range of controlled conditions (relative humidity or RH ~65-89%, volatile organic compound-to-NOx or VOC / NOx ~3-9 and NOx ~2 ppbV). Both the gas phase and the aerosol phase of the reaction chamber were monitored in detail using a comprehensive suite of on-line and off-line chemical and physical measurement techniques. Silver birch was found to be a high monoterpene and sesquiterpene but low isoprene emitter, and its emissions were observed to produce measurable amounts of secondary organic aerosol (SOA) via both nucleation and condensation onto pre-existing seed aerosol (YSOA 26-39%). In contrast, all three tropical species were found to be high isoprene emitters with trace emissions of monoterpenes and sesquiterpenes. In tropical plant experiments without seed aerosol there was no measurable SOA nucleation, but aerosol mass was shown to increase when seed aerosol was present. Although principally isoprene emitting, the aerosol mass produced from tropical fig was mostly consistent (i.e. in 78 out of 120 aerosol mass calculations using plausible parameter sets of various precursor specific yields) with condensation of photo-oxidation products of the minor volatile organic compounds (VOCs) co-emitted; no significant aerosol yield from condensation of isoprene oxidation products was required in the interpretations of the experimental results. This finding is in line with previous reports of organic aerosol loadings consistent with production from minor biogenic VOCs co-emitted with isoprene in principally isoprene-emitting landscapes in Southeast

  18. APPLICATION OF POLLUTION PREVENTION TECHNIQUES TO REDUCE INDOOR AIR EMISSONS FROM AEROSOL CONSUMER PRODUCTS

    EPA Science Inventory

    The report gives results of a research project to develop tools and methodologies to measure aerosol chemical and particle dispersion through space. These tools can be used to devise pollution prevention strategies that could reduce occupant chemical exposures and guide manufactu...

  19. Probing aerosol formation by comprehensive measurements of gas phase oxidation products

    NASA Astrophysics Data System (ADS)

    Ehn, Mikael; Kleist, Einhard; Junninen, Heikki; Sipilä, Mikko; Petäjä, Tuukka; Pullinen, Iida; Springer, Monika; Andres, Stefanie; Rissanen, Matti; Kontkanen, Jenni; Schobesberger, Siegfried; Rubach, Florian; Tillman, Ralf; Lee, Ben H.; Lopez-Hilfiker, Felipe; Kerminen, Veli-Matti; Kulmala, Markku; Worsnop, Douglas R.; Thornton, Joel; Wildt, Jürgen; Mentel, Thomas F.

    2013-05-01

    A comprehensive suite of chemical ionization mass spectrometers (CIMS) were deployed for chamber studies of monoterpene oxidation. The CIMS instruments were able to detect several different groups of compounds ranging from volatile to practically non-volatile. The compound groups showed very different behavior and correlations with aerosol number and mass. Results suggest that major gas phase contributors are not considered in current models.

  20. Influence of aerosol estimation on coastal water products retrieved from HICO images

    NASA Astrophysics Data System (ADS)

    Patterson, Karen W.; Lamela, Gia

    2011-06-01

    The Hyperspectral Imager for the Coastal Ocean (HICO) is a hyperspectral sensor which was launched to the International Space Station in September 2009. The Naval Research Laboratory (NRL) has been developing the Coastal Water Signatures Toolkit (CWST) to estimate water depth, bottom type and water column constituents such as chlorophyll, suspended sediments and chromophoric dissolved organic matter from hyperspectral imagery. The CWST uses a look-up table approach, comparing remote sensing reflectance spectra observed in an image to a database of modeled spectra for pre-determined water column constituents, depth and bottom type. In order to successfully use this approach, the remote sensing reflectances must be accurate which implies accurately correcting for the atmospheric contribution to the HICO top of the atmosphere radiances. One tool the NRL is using to atmospherically correct HICO imagery is Correction of Coastal Ocean Atmospheres (COCOA), which is based on Tafkaa 6S. One of the user input parameters to COCOA is aerosol optical depth or aerosol visibility, which can vary rapidly over short distances in coastal waters. Changes to the aerosol thickness results in changes to the magnitude of the remote sensing reflectances. As such, the CWST retrievals for water constituents, depth and bottom type can be expected to vary in like fashion. This work is an illustration of the variability in CWST retrievals due to inaccurate aerosol thickness estimation during atmospheric correction of HICO images.

  1. Aerosol typing - key information from aerosol studies

    NASA Astrophysics Data System (ADS)

    Mona, Lucia; Kahn, Ralph; Papagiannopoulos, Nikolaos; Holzer-Popp, Thomas; Pappalardo, Gelsomina

    2016-04-01

    Aerosol typing is a key source of aerosol information from ground-based and satellite-borne instruments. Depending on the specific measurement technique, aerosol typing can be used as input for retrievals or represents an output for other applications. Typically aerosol retrievals require some a priori or external aerosol type information. The accuracy of the derived aerosol products strongly depends on the reliability of these assumptions. Different sensors can make use of different aerosol type inputs. A critical review and harmonization of these procedures could significantly reduce related uncertainties. On the other hand, satellite measurements in recent years are providing valuable information about the global distribution of aerosol types, showing for example the main source regions and typical transport paths. Climatological studies of aerosol load at global and regional scales often rely on inferred aerosol type. There is still a high degree of inhomogeneity among satellite aerosol typing schemes, which makes the use different sensor datasets in a consistent way difficult. Knowledge of the 4d aerosol type distribution at these scales is essential for understanding the impact of different aerosol sources on climate, precipitation and air quality. All this information is needed for planning upcoming aerosol emissions policies. The exchange of expertise and the communication among satellite and ground-based measurement communities is fundamental for improving long-term dataset consistency, and for reducing aerosol type distribution uncertainties. Aerosol typing has been recognized as one of its high-priority activities of the AEROSAT (International Satellite Aerosol Science Network, http://aero-sat.org/) initiative. In the AEROSAT framework, a first critical review of aerosol typing procedures has been carried out. The review underlines the high heterogeneity in many aspects: approach, nomenclature, assumed number of components and parameters used for the

  2. Monitoring Airborne Dust from Source to Sink Using the e-Deep Blue Aerosol Products from VIIRS, MODIS, and Seawifs

    NASA Astrophysics Data System (ADS)

    Carletta, N.; Hsu, N. Y. C.; Bettenhausen, C.; Sayer, A. M.; Lee, J.

    2014-12-01

    Mineral dust sources are typically located in very bright, arid desert regions across the globe. In the past, aerosol retrieval algorithms were unable to properly handle these bright surfaces which lead to large, persistent data gaps. In order to eliminate these gaps, the Deep Blue algorithm was developed and first entered into the MODIS operational stream in Collection 5.1. Since then, the Deep Blue algorithm has evolved to retrieve not only over bright surfaces, but also vegetated surfaces. This updated algorithm has been named the enhanced Deep Blue (e-Deep Blue) algorithm and has been successfully applied to reflectances from the Sea-viewing, Wide Field-of-view Sensor (SeaWiFS, 1997-2010), Moderate Resolution Imaging Spectroradiometer (MODIS, 2000/2002-present), and now the Visible Infrared Imaging Radiometer Suite (VIIRS, 2012-present) aboard the Suomi-NPP platform. This algorithm has been partnered with a new over-ocean algorithm for our SeaWiFS and VIIRS datasets. Due to the broad swath of VIIRS, daily global coverage is achieved at higher spatial resolution compared to MODIS and SeaWiFS. Thus, the evolution of dust can be tracked from source to sink, across both land and ocean using these satellite products. We introduce the basics of the e-Deep Blue algorithm along with our preliminary VIIRS e-Deep Blue products, including aerosol optical thickness at 550nm and Ǻngström exponent. Validation with AErosol RObotic NETwork (AERONET) data are also presented along with the intercomparisons between VIIRS Deep Blue and other satellite products.

  3. Using MAIAC Aerosol Products to Estimate PM10 Concentrations in the Southeastern U.S

    NASA Astrophysics Data System (ADS)

    Jinnagara Puttaswamy, S.; Hu, X.; Lyapustin, A.; Wang, Y.; Liu, Y.

    2012-12-01

    Acute and chronic exposure to particulate matter has been linked to various adverse health effects. High PM levels including inhalable particles (PM10) and fine particles (PM2.5) are commonly found in large urban centers in the developing world. Unlike PM2.5 whose routine ground monitoring is very sparse, PM10 is regularly measured in many large cities in developing countries. In this analysis, we evaluate the potential for satellite aerosol remote sensing product to estimate PM10 levels. We chose AOD values in 2003 retrieved by the Multiangle Implementation of Atmospheric Correction (MAIAC) algorithm based on MODIS measurements, which has a high spatial resolution of 1 km. Our study area is a 600 km x 600 km region centered in Atlanta, GA. Linear mixed effect (LME) models were developed with MAIAC AOD as the primary predictor variable, meteorology, PM10 emission locations and land use variables as secondary predictor variables. Daily PM10 concentrations measured at ~70 EPA air quality monitoring stations were used as the dependent variable. Model day of year was used as the grouping factor for the random effect of MAIAC AOD. We aggregated AOD and other covariates on 1 km, 3km, 5km and 10km resolution grids and similar LME models were developed for each spatial resolution to compare their abilities to capture the spatial patterns of PM10 mass concentrations at various scales. Our models show that MAIAC AOD, temperature, wind speed and PM 10 emissions source locations are statistically significant predictors of PM 10 at all the spatial scales. Model fitting R2 ranges from 0.35 in winter to 0.56 in the summer. Model performances show a slight decline as the grid resolution decreases. Although the performances of PM10 exposure models are not as good as those of PM2.5 models reported in the literature, these models can still provide spatially resolved PM10 levels at urban scale, which would enable preliminary PM10-related public health research in developing countries.

  4. Polyelectrolyte-versus membrane-coated electrodes for energy production by capmix salinity exchange methods

    NASA Astrophysics Data System (ADS)

    Fernández, M. M.; Wagterveld, R. M.; Ahualli, S.; Liu, F.; Delgado, A. V.; Hamelers, H. V. M.

    2016-01-01

    In this paper we analyze the energy and power achievable by means of a recently proposed salinity gradient technique for energy production. The method, denominated soft electrode or SE, is based on the potential difference that can be generated between two porous electrodes coated with cationic and anionic polyelectrolytes. It is related to the Capacitive Donnan Potential (CDP) technique, where the electrical potential variations are mostly related to the Donnan potential, of ion-selective membranes in the case of CDP, and of the polyelectrolyte coating in SE. It is found that although SE is comparable to CDP in terms of energy production, it presents slower rates of voltage change, and lower achieved power. The separate analysis of the response of positively and negatively coated electrodes shows that the latter produces most of the voltage rise and also of the response delay. These results, together with electrokinetic techniques, give an idea on how the two types of polyelectrolytes adsorb on the carbon surface and affect differently the diffusion layer. It is possible to suggest that the SE technique is a promising one, and it may overcome the drawbacks associated to the use of membranes in CDP.

  5. Impact of Zr metal and coking reactions on the fission product aerosol release during MCCI (Molten Core Concrete Interactions)

    SciTech Connect

    Lee, M.; Davis, R.E.; Khatib-Rahbar, M.

    1987-01-01

    During a core meltdown accident in a light water reactor, molten core materials (corium) could leave the reactor vessel and interact with concrete. In this paper, the impact of the zirconium content of the corium pool and the coking reaction on the release of fission products during Molten Core Concrete Interactions (MCCI) are quantified using CORCON/MOD2 and VANESA computer codes. Detailed calculations show that the total aerosol generation is proportional to the zirconium content of the corium pool. Among the twelve fission product groups treated by the VANESA code, CsI, CsO/sub 2/ and Nb/sub 2/O/sub 5/ are completely released over the course of the core/concrete interaction, while an insignificant quantity of Mo, Ru and ZrO/sub 2/ are predicted to be released. The release of BaO, SrO and CeO/sub 2/ increase with increased Zr content, while the releases of Te and La/sub 2/O/sub 3/ are relatively unaffected by the Zr content of the corium pool. The impact of the coking reaction on the radiological releases is estimated to be significant; while the impact of the coking reaction on the aerosol production is insignificant.

  6. Application of a production line phosphorescence sensor coating system on a jet engine for surface temperature detection

    NASA Astrophysics Data System (ADS)

    Sollazzo, P. Y.; Feist, J. P.; Berthier, S.; Charnley, B.; Wells, J.; Heyes, A. L.

    2013-09-01

    Thermal Barrier Coatings (TBC) are used to reduce the working temperature of the high pressure turbine blade metal surface and hence permit engines to operate at higher temperatures/ efficiencies. A sensor TBC is an adaptation of existing TBCs to enhance their functionality, such that they become sensors and allow measurement of component temperatures. The sensing capability is introduced by embedding optically active materials into the TBC and by illuminating these coatings with excitation light phosphorescence can be observed. The phosphorescence carries temperature and structural information about the coating. This paper describes the first ever implementation of a sensor coating system on a full-scale jet engine. The system consists of three main components: industrially manufactured coatings, advanced remote detection optics with large stand-off distances and tailored control and readout software. The majority of coatings were based on yttrium stabilized zirconia doped with Dy and Eu, although other coatings were manufactured, too. Coatings were produced on a production line using atmospheric plasma spraying. An advanced optical system was designed, manufactured and operated permitting scanning of coated components using a wide acceptance angle. Successful measurements were taken from the nozzle guide vanes at the inlet to the turbine section and are reported in the paper.

  7. Seed coating with arbuscular mycorrhizal fungi as an ecotechnologicalapproach for sustainable agricultural production of common wheat (Triticum aestivum L.).

    PubMed

    Oliveira, Rui S; Rocha, Inês; Ma, Ying; Vosátka, Miroslav; Freitas, Helena

    2016-01-01

    The exploitation of arbuscular mycorrhizal (AM) fungi has become of great interest in agriculture due to their potential roles in reducing the need for agrochemicals, while improving plant growth and nutrition. Nevertheless, the application of AM fungi by dispersing inocula in granular form to open agricultural fields is not feasible because nontargeted spreading of inocula over large surface areas results in high cost per plant. Seed coating has the potential to significantly reduce the amount of inoculum needed, resulting in cost reduction and increased efficiency. The aim of this study was to assess whether seed coating with AM fungal inoculum is a feasible delivery system for production of common wheat (Triticum aestivum L.). Wheat seeds were coated with inoculum of Rhizophagus irregularis BEG140 and grown under different fertilization conditions: (1) none, (2) partial, or (3) complete. Data indicated that mycorrhizal inoculation via seed coating significantly increased the dry weight of shoot and seed spikes of wheat associated with reduced fertilization. Assessment of nutritional status of wheat showed that plants inoculated with R. irregularis via seed coating displayed enhanced stem concentrations of potassium (K), sulfur (S), and zinc (Zn). There were no significant differences in root colonization between plants conventionally inoculated with R. irregularis in soil and those inoculated via seed coating. Seed coating with AM fungi may be as effective as conventional soil inoculation and may contribute to reduce the utilization of chemical fertilizers. The application of AM via seed coating is proposed as an ecotechnological approach for sustainable agricultural wheat production. PMID:27077274

  8. Emissions of biogenic volatile organic compounds and subsequent photochemical production of secondary organic aerosol in mesocosm studies of temperate and tropical plant species

    NASA Astrophysics Data System (ADS)

    Wyche, K. P.; Ryan, A. C.; Hewitt, C. N.; Alfarra, M. R.; McFiggans, G.; Carr, T.; Monks, P. S.; Smallbone, K. L.; Capes, G.; Hamilton, J. F.; Pugh, T. A. M.; MacKenzie, A. R.

    2014-06-01

    Silver birch (Betula pendula) and three Southeast Asian tropical plant species (Ficus cyathistipula, Ficus benjamina and Caryota millis) from the pantropical fig and palm genera were grown in a purpose-built and environment-controlled whole-tree chamber. The volatile organic compounds emitted from these trees were characterised and fed into a linked photochemical reaction chamber where they underwent photooxidation under a range of controlled conditions (RH ∼65-89%, VOC/NOx ∼3-9 and NOx ∼2 ppbV). Both the gas phase and the aerosol phase of the reaction chamber were monitored in detail using a comprehensive suite of on-line and off-line, chemical and physical measurement techniques. Silver birch was found to be a high monoterpene and sesquiterpene, but low isoprene emitter, and its emissions were observed to produce measureable amounts of SOA via both nucleation and condensation onto pre-existing seed aerosol (YSOA 26-39%). In contrast, all three tropical species were found to be high isoprene emitters with trace emissions of monoterpenes and sesquiterpenes. In tropical plant experiments without seed aerosol there was no measurable SOA nucleation, but aerosol mass was shown to increase when seed aerosol was present. Although principally isoprene emitting, the aerosol mass produced from tropical fig was mostly consistent (i.e., in 78 out of 120 aerosol mass calculations using plausible parameter sets of various precursor specific yields) with condensation of photooxidation products of the minor VOCs co-emitted; no significant aerosol yield from condensation of isoprene oxidation products was required in the interpretations of the experimental results. This finding is in line with previous reports of organic aerosol loadings consistent with production from minor biogenic VOCs co-emitted with isoprene in principally-isoprene emitting landscapes in Southeast Asia. Moreover, in general the amount of aerosol mass produced from the emissions of the principally

  9. Aldol Condensation Products and Polyacetals in Organic Films Formed from Reactions of Propanal in Sulfuric Acid at Upper Troposphere/Lower Stratosphere (UT/LS) Aerosol Acidities

    NASA Astrophysics Data System (ADS)

    Bui, J. V. H.; Perez-Montano, S.; Li, E. S. W.; Nelson, T. E.; Ha, K. T.; Leong, L.; Iraci, L. T.; Van Wyngarden, A. L.

    2015-12-01

    Aerosols in the upper troposphere and lower stratosphere (UT/LS) consist mostly of concentrated sulfuric acid (40-80 wt. %) which is highly reflective towards UV and visible radiation. However, airborne measurements have shown that these particles may also contain a significant amount of organic material. Experiments combining organics (propanal, glyoxal and/or methylglyoxal) with sulfuric acid at concentrations typical of UT/LS aerosols produced highly colored surface films (and solutions) that have the potential to impact chemical, optical and/or cloud-forming properties of aerosols. In order to assess the potential for such films to impact aerosol chemistry or climate properties, experiments were performed to identify the chemical processes responsible for film formation. Surface films were analyzed via Attenuated Total Reflectance-FTIR and Nuclear Magnetic Resonance spectroscopies and are shown to consist primarily of aldol condensation products and cyclic and linear polyacetals, the latter of which are likely responsible for separation from the aqueous phase.

  10. Reaction of oleic acid particles with NO3 radicals: Products, mechanism, and implications for radical-initiated organic aerosol oxidation.

    PubMed

    Docherty, Kenneth S; Ziemann, Paul J

    2006-03-16

    The heterogeneous reaction of liquid oleic acid aerosol particles with NO3 radicals in the presence of NO2, N2O5, and O2 was investigated in an environmental chamber using a combination of on-line and off-line mass spectrometric techniques. The results indicate that the major reaction products, which are all carboxylic acids, consist of hydroxy nitrates, carbonyl nitrates, dinitrates, hydroxydinitrates, and possibly more highly nitrated products. The key intermediate in the reaction is the nitrooxyalkylperoxy radical, which is formed by the addition of NO3 to the carbon-carbon double bond and subsequent addition of O2. The nitrooxyalkylperoxy radicals undergo self-reactions to form hydroxy nitrates and carbonyl nitrates, and may also react with NO2 to form nitrooxy peroxynitrates. The latter compounds are unstable and decompose to carbonyl nitrates and dinitrates. It is noteworthy that in this reaction nitrooxyalkoxy radicals appear not to be formed, as indicated by the absence of the expected products of decomposition or isomerization of these species. This is different from gas-phase alkene-NO3 reactions, in which a large fraction of the products are formed through these pathways. The results may indicate that, for liquid organic aerosol particles in low NOx environments, the major products of the radical-initiated oxidation (including by OH radicals) of unsaturated and saturated organic compounds will be substituted forms of the parent compound rather than smaller decomposition products. These compounds will remain in the particle and can potentially enhance particle hygroscopicity and the ability of particles to act as cloud condensation nuclei. PMID:16526637

  11. Production Mechanisms, Number Concentration, Size Distribution. Chemical Composition, and Optical Properties of Sea Spray Aerosols

    NASA Technical Reports Server (NTRS)

    Meskhidze, Nicholas; Petters, Markus; Tsigaridis, Kostas; Bates. Tim; O'Dowd, Colin; Reid, Jeff; Lewis, Ernie R.; Gantt, Brett; Anguelova, Magdalena D.; Bhave, Prakash V.; Bird, James; Callaghan, Adrian H.; Ceburnis, Darius; Chang, Rachel; Clark, Antony; deLeeuw, Gerrit; Deane, Grant; DeMott, Paul J.; Elliot, Scott; Facchini, Maria Cristina; Fairall, Chris W.; Hawkins, Lelia; Hu, Yongxiang; Smirnov, Alexander

    2013-01-01

    Over forty scientists from six countries convened in Raleigh, NC on June 4-6 2012 to review the status and prospects of sea spray aerosol research. Participants were researchers from the oceanography and atmospheric science communities, including academia, private industry, and government agencies. The recommendations from the working groups are summarized in a science prioritization matrix that is meant to prioritize the research agenda and identify areas of investigation by the magnitude of their impact on proposed science questions. Str

  12. Reactive uptake of ozone by proxies for organic aerosols: Surface-bound and gas-phase products

    NASA Astrophysics Data System (ADS)

    Thomas, Elan R.; Frost, Gregory J.; Rudich, Yinon

    2001-02-01

    Gas-phase and surface-bound products were determined for the reaction of ozone with self assembled monolayers of alkanes and terminal alkenes serving as proxies for atmospheric organic aerosols. The organic surfaces were characterized using infrared (IR) spectroscopy (direct absorption and attenuated total reflection) as well as contact angle measurements with water before and after the reaction with ozone. The contact angle of the organic surfaces was reduced by ˜20° owing to the reaction. Following the reaction, IR absorption due to the presence of carbonyls and carboxylic acids was observed on the surface. Gas-phase products were determined using infrared spectroscopy immediately above the reaction surface. Under dry conditions, gas-phase formaldehyde yields of 0.5±0.1 for organic monolayers of allyltrichlorosilane (C3=) and octenyltrichlorosilane (C8=) terminal alkenes were observed, in good agreement with the yields observed for gas phase ozonolysis of terminal alkenes. Surfaces of n-octane (C8) as well as processed alkene surfaces were nonreactive toward ozone. The reaction mechanism of ozone with the surface alkenes is discussed. Finally, the possible implications for the chemistry of organic aerosols are discussed and studied using a box model and realistic atmospheric scenarios.

  13. Synthesis and Analysis of Putative Terpene Oxidation Products and the Secondary Organic Aerosol Particles that Form from Them

    NASA Astrophysics Data System (ADS)

    Ebben, C. J.; Strick, B. F.; Upshur, M.; Shrestha, M.; Velarde, L.; Lu, Z.; Wang, H.; Xiao, D.; Batista, V. S.; Martin, S. T.; Thomson, R. J.; Geiger, F. M.

    2013-12-01

    The terpenes isoprene and α-pinene are abundant volatile organic compounds (VOCs) that are emitted by trees and oxidized in the atmosphere. However, the chemical processes involved in the formation of secondary organic aerosol (SOA) particles from VOCs are not well understood. In this work, we use a combined synthetic, analytical, and theoretical approach to gain a molecular level understanding of the chemistry involved in the formation of SOA particles from VOC precursors. To this end, we have synthesized putative products of isoprene and α-pinene oxidation and the oligomers that form from them. Specifically, we have focused on the epoxide and 2-methyltetraols that form from isoprene oxidation by hydroxyl radicals, as well as products of α-pinene ozonolysis. In our analysis, we utilize a spectroscopic technique called sum frequency generation (SFG). SFG is a coherent, surface-specific, vibrational spectroscopy that uses infrared and visible laser light fields, overlapped spatially and temporally at a surface, to probe vibrational transitions within molecules. Our use of this technique allows us to assess the chemical identity of aerosol-forming components at their surfaces, where interactions with the gas phase occur. The spectral responses from these compounds are compared to those of synthetic isoprene- and α-pinene-derived aerosol particles, as well as natural aerosol particles collected in tropical and boreal forests to begin to predict the constituents that may be present at the surfaces of these particles. In addition, isotope editing is utilized to gain a better understanding of α-pinene. The rigidity of this molecule makes it difficult to understand spectroscopically. The combination of synthesis with deuterium labeling, theory, and broadband and high-resolution SFG spectroscopy in the C-H and C-D stretching regions allow us to determine the orientation of this important molecule on a surface, which could have implications for its reactivity in the

  14. Relationships linking primary production, sea ice melting, and biogenic aerosol in the Arctic

    NASA Astrophysics Data System (ADS)

    Becagli, S.; Lazzara, L.; Marchese, C.; Dayan, U.; Ascanius, S. E.; Cacciani, M.; Caiazzo, L.; Di Biagio, C.; Di Iorio, T.; di Sarra, A.; Eriksen, P.; Fani, F.; Giardi, F.; Meloni, D.; Muscari, G.; Pace, G.; Severi, M.; Traversi, R.; Udisti, R.

    2016-07-01

    This study examines the relationships linking methanesulfonic acid (MSA, arising from the atmospheric oxidation of the biogenic dimethylsulfide, DMS) in atmospheric aerosol, satellite-derived chlorophyll a (Chl-a), and oceanic primary production (PP), also as a function of sea ice melting (SIM) and extension of the ice free area in the marginal ice zone (IF-MIZ) in the Arctic. MSA was determined in PM10 samples collected over the period 2010-2012 at two Arctic sites, Ny Ålesund (78.9°N, 11.9°E), Svalbard islands, and Thule Air Base (76.5°N, 68.8°W), Greenland. PP is calculated by means of a bio-optical, physiologically based, semi-analytical model in the potential source areas located in the surrounding oceanic regions (Barents and Greenland Seas for Ny Ålesund, and Baffin Bay for Thule). Chl-a peaks in May in the Barents sea and in the Baffin Bay, and has maxima in June in the Greenland sea; PP follows the same seasonal pattern of Chl-a, although the differences in absolute values of PP in the three seas during the blooms are less marked than for Chl-a. MSA shows a better correlation with PP than with Chl-a, besides, the source intensity (expressed by PP) is able to explain more than 30% of the MSA variability at the two sites; the other factors explaining the MSA variability are taxonomic differences in the phytoplanktonic assemblages, and transport processes from the DMS source areas to the sampling sites. The taxonomic differences are also evident from the slopes of the correlation plots between MSA and PP: similar slopes (in the range 34.2-36.2 ng m-3of MSA/(gC m-2 d-1)) are found for the correlation between MSA at Ny Ålesund and PP in Barents Sea, and between MSA at Thule and PP in the Baffin Bay; conversely, the slope of the correlation between MSA at Ny Ålesund and PP in the Greenland Sea in summer is smaller (16.7 ng m-3of MSA/(gC m-2 d-1)). This is due to the fact that DMS emission from the Barents Sea and Baffin Bay is mainly related to the MIZ

  15. Aerosol-chamber study of the α-pinene/O 3 reaction: influence of particle acidity on aerosol yields and products

    NASA Astrophysics Data System (ADS)

    Iinuma, Yoshiteru; Böge, Olaf; Gnauk, Thomas; Herrmann, Hartmut

    α-Pinene ozonolysis was carried out in the presence of ammonium sulfate or sulfuric acid seed particles in a 9 m 3 Teflon chamber at the mixing ratios of 100 ppbv for α-pinene and about 70 ppbv for ozone. The evolution of size distribution was measured by means of a differential mobility particle sizer (DMPS). The resulting secondary organic aerosol (SOA) was sampled by a denuder/quartz fiber filter combination for the determination of the total organic carbon concentration (TOC) in the particle phase, using a thermographic method and by a denuder/PTFE filter combination for the analysis of individual chemical species in the particle phase using capillary electrophoresis-electrospray ionization-mass spectrometry (CE-ESI-MS). cis-Pinic acid ( m/ z 185) and another species tentatively identified at m/ z 171 and 199 were the major particle phase species for both seed particles although the product yields were different, indicating the influence of seed particle acidity. A thermographic method for the determination of TOC showed an increase of particle phase organics by 40% for the experiments with higher acidity. CE-ESI-MS analysis showed a large increase in the concentration of compounds with Mw>300 from the experiments with sulfuric acid seed particles. These results suggest that the seed particle acidity enhances the yield of SOA and plays an important role in the formation of larger molecules in the particle phase. Our results from direct particle phase chemical analysis suggest for the first time that condensation of smaller organics takes place by polymerization or aldol condensation following the formation of aldehydes, such as pinonaldehyde from the terpene ozonolysis.

  16. The validation and comparison of the GOCI aerosol optical thickness products: a case study of Tianjin 8.12

    NASA Astrophysics Data System (ADS)

    Yao, Lingling; Zhang, Xiaoyu; Yu, Hui; Jiang, Binbin

    2016-01-01

    COMSGOCI (Geostationary Ocean Color Imager) is the first geostationary ocean color satellite in the world launched by South Korea in June 2010, which includes eight bands from the visible to the infrared band. GOCI aerosol optical thickness (AOT) at 555nm was retrieved by atmospheric radiative transfer model based on two-stream approximation algorithm. Due to GOCI without near infrared band and has a high solar elevation angle, solar zenith angle must be recalibrated to solve the earth system albedo, and the surface reflectance solved by quack atmospheric correction and recalculated backward scatter coefficient. Evaluation of GOCIAOT with AERONET measurements showed that the average error becomes 0.107 from the original 0.393, that means GOCI aerosol optical thickness can be more accurately with the advanced two-stream approximation. Taking the eastern China in 3 and 4 December 2013 for example, comparing the GOCIAOT at 555nm, MODISAOT retrievals at 550nm, NPPAOT at 550nm and AERONET data products indicated that: take the AERONET data as reference, the error of three kinds of satellite data can be ordered as following: MODISAOT< GOCIAOT< NPPAOT and the GOCI-MODIS shows a bias of 0.02917 with the GOCI-NPP. GOCIAOT is 0.05714 generally bigger than that of MODISAOT. NPP-GOCI deviation is 0.10253. The deficiency of MODIS is its low spatial resolution and the high concentration of AOT will be mistaken for a cloud area. However, GOCI can well reflect the concentration and distribution of aerosols. Therefore, GOGI can provide real-time dynamic monitoring on China Eastern atmospheric environment and the accurate time event information of haze for each process can be obtained. Finally, applied GOCI to the "8.12 Tianjin bombings" and to monitor the migration and dispersion of pollutant.

  17. An Accuracy Assessment of the CALIOP/CALIPSO Version 2/Version 3 Daytime Aerosol Extinction Product Based on a Detailed Multi-Sensor, Multi-Platform Case Study

    NASA Technical Reports Server (NTRS)

    Kacenelenbogen, M.; Vaughan, M. A.; Redemann, J.; Hoff, R. M.; Rogers, R. R.; Ferrare, R. A.; Russell, P. B.; Hostetler, C. A.; Hair, J. W.; Holben, B. N.

    2011-01-01

    The Cloud Aerosol LIdar with Orthogonal Polarization (CALIOP), on board the CALIPSO platform, has measured profiles of total attenuated backscatter coefficient (level 1 products) since June 2006. CALIOP s level 2 products, such as the aerosol backscatter and extinction coefficient profiles, are retrieved using a complex succession of automated algorithms. The goal of this study is to help identify potential shortcomings in the CALIOP version 2 level 2 aerosol extinction product and to illustrate some of the motivation for the changes that have been introduced in the next version of CALIOP data (version 3, released in June 2010). To help illustrate the potential factors contributing to the uncertainty of the CALIOP aerosol extinction retrieval, we focus on a one-day, multi-instrument, multiplatform comparison study during the CALIPSO and Twilight Zone (CATZ) validation campaign on 4 August 2007. On that day, we observe a consistency in the Aerosol Optical Depth (AOD) values recorded by four different instruments (i.e. spaceborne MODerate Imaging Spectroradiometer, MODIS: 0.67 and POLarization and Directionality of Earth s Reflectances, POLDER: 0.58, airborne High Spectral Resolution Lidar, HSRL: 0.52 and ground-based AErosol RObotic NETwork, AERONET: 0.48 to 0.73) while CALIOP AOD is a factor of two lower (0.32 at 532 nm). This case study illustrates the following potential sources of uncertainty in the CALIOP AOD: (i) CALIOP s low signal-to-noise ratio (SNR) leading to the misclassification and/or lack of aerosol layer identification, especially close to the Earth s surface; (ii) the cloud contamination of CALIOP version 2 aerosol backscatter and extinction profiles; (iii) potentially erroneous assumptions of the aerosol extinction-to-backscatter ratio (Sa) used in CALIOP s extinction retrievals; and (iv) calibration coefficient biases in the CALIOP daytime attenuated backscatter coefficient profiles. The use of version 3 CALIOP extinction retrieval for our case

  18. NASA GES DISC Level 2 Aerosol Analysis and Visualization Services

    NASA Technical Reports Server (NTRS)

    Wei, Jennifer; Petrenko, Maksym; Ichoku, Charles; Yang, Wenli; Johnson, James; Zhao, Peisheng; Kempler, Steve

    2015-01-01

    Overview of NASA GES DISC Level 2 aerosol analysis and visualization services: DQViz (Data Quality Visualization)MAPSS (Multi-sensor Aerosol Products Sampling System), and MAPSS_Explorer (Multi-sensor Aerosol Products Sampling System Explorer).

  19. Production and characterization of Ni and Cu composite coatings by electrodeposition reinforced with carbon nanotubes or graphite nanoplatelets

    NASA Astrophysics Data System (ADS)

    Karim, M. R. Abdul; Pavese, M.; Ambrosio, E. P.; Ugues, D.; Lombardi, M.; Biamino, S.; Badini, C.; Fino, P.

    2013-06-01

    Electrodeposition is well-known as a versatile and economical processing technique to produce metal coatings on conductive substrates. Recently, it has been gaining increasing interest also for the production of tailored composite coatings, containing for instance floropolymers or silicon carbide. A more novel approach concerns the use of carbon nanotubes or even graphene, in the form of graphite nano-platelets. The production of Ni- and Cu-based nanocomposites containing carbon nanoreinforcements was carried out by using standard electrodeposition conditions, but with a particular attention to the dispersion of the nanotubes. The obtained coatings were strong and well adherent to the steel substrate, and presented rather well dispersed carbon nanotubes or graphite nanoplatelets, even if some agglomerates could be present in samples obtained from highly concentrated suspensions. In the case of nickel-based composite coatings, the size of nickel grains was reduced, and pin-on-disc tests demonstrated a significant increase in the life of the coating. In the case of copper-based composite coatings, thermal diffusivity measurements demonstrated that the carbon nanomaterial does not reduce the conductivity of the pure copper coating.

  20. Unattended Monitoring of HEU Production in Gaseous Centrifuge Enrichment Plants using Automated Aerosol Collection and Laser-based Enrichment Assay

    SciTech Connect

    Anheier, Norman C.; Bushaw, Bruce A.

    2010-08-11

    Nuclear power is enjoying rapid growth as government energy policies and public demand shift toward low carbon energy production. Pivotal to the global nuclear power renaissance is the development and deployment of robust safeguards instrumentation that allows the limited resources of the IAEA to keep pace with the expansion of the nuclear fuel cycle. Undeclared production of highly enriched uranium (HEU) remains a primary proliferation concern for modern gaseous centrifuge enrichment plants (GCEPs), due to their massive separative work unit (SWU) processing power and comparably short cascade equilibrium timescale. The Pacific Northwest National Laboratory is developing an unattended safeguards instrument, combining continuous aerosol particulate collection with uranium isotope assay, to provide timely detection of HEU production within a GCEP. This approach is based on laser vaporization of aerosol particulates, followed by laser spectroscopy to characterize the uranium enrichment level. Our prior investigation demonstrated single-shot detection sensitivity approaching the femtogram range and relative isotope ratio uncertainty better than 10% using gadolinium as a surrogate for uranium. In this paper we present measurement results on standard samples containing traces of depleted, natural, and low enriched uranium, as well as measurements on aerodynamic size uranium particles mixed in background materials (e.g., dust, minerals, soils). Improvements and optimizations in the detection electronics, signal timing, calibration, and laser alignment have lead to significant improvements in detection sensitivity and enrichment accuracy, contributing to an overall reduction in the false alarm probability. The sample substrate media was also found to play a significant role in facilitating laser-induced vaporization and the production of energetic plasma conditions, resulting in ablation optimization and further improvements in the isotope abundance sensitivity.

  1. Preservation of H2 production activity in nanoporous latex coatings of Rhodopseudomonas palustris CGA009 during dry storage at ambient temperatures

    PubMed Central

    Piskorska, M; Soule, T; Gosse, J L; Milliken, C; Flickinger, M C; Smith, G W; Yeager, C M

    2013-01-01

    Summary To assess the applicability of latex cell coatings as an ‘off-the-shelf’ biocatalyst, the effect of osmoprotectants, temperature, humidity and O2 on preservation of H2 production in Rhodopseudomonas palustris coatings was evaluated. Immediately following latex coating coalescence (24 h) and for up to 2 weeks of dry storage, rehydrated coatings containing different osmoprotectants displayed similar rates of H2 production. Beyond 2 weeks of storage, sorbitol-treated coatings lost all H2 production activity, whereas considerable H2 production was still detected in sucrose- and trehalose-stabilized coatings. The relative humidity level at which the coatings were stored had a significant impact on the recovery and subsequent rates of H2 production. After 4 weeks storage under air at 60% humidity, coatings produced only trace amounts of H2 (0–0.1% headspace accumulation), whereas those stored at < 5% humidity retained 27–53% of their H2 production activity after 8 weeks of storage. When stored in argon at < 5% humidity and room temperature, R. palustris coatings retained full H2 production activity for 3 months, implicating oxidative damage as a key factor limiting coating storage. Overall, the results demonstrate that biocatalytic latex coatings are an attractive cell immobilization platform for preservation of bioactivity in the dry state. PMID:23331993

  2. PRESERVATION OF H2 PRODUCTION ACTIVITY IN NANOPOROUS LATEX COATINGS OF RHODOPSEUDOMONAS PALUSTRIS CGA009 DURING DRY STORAGE AT AMBIENT TEMPERATURES

    SciTech Connect

    Milliken, C.; Piskorska, M.; Soule, T.; Gosse, J.; Flickinger, M.; Smith, G.; Yeager, C.

    2012-08-27

    To assess the applicability of latex cell coatings as an "off-the-shelf' biocatalyst, the effect of osmoprotectants, temperature, humidity and O{sub 2} on preservation of H{sub 2} production in Rhodopseudomonas palustris coatings was evaluated. Immediately following latex coating coalescence (24 h) and for up to 2 weeks of dry storage, rehydrated coatings containing different osmoprotectants displayed similar rates of H{sub 2} production. Beyond 2 weeks of storage, sorbitol- treated coatings lost all H{sub 2} production activity, whereas considerable H{sub 2} production was still detected in sucrose- and trehalose-stabilized coatings. The relative humidity level at which the coatings were stored had a significant impact on the recovery and subsequent rates of H{sub 2} production. After 4 weeks storage under air at 60% humidity, coatings produced only trace amounts of H{sub 2} (0-0.1% headspace accumulation), whereas those stored at <5% humidity retained 27-53% of their H{sub 2} production activity after 8 weeks of storage. When stored in argon at <5% humidity and room temperature, R. palustris coatings retained full H{sub 2} production activity for 3 months, implicating oxidative damage as a key factor limiting coating storage. Overall, the results demonstrate that biocatalytic latex coatings are an attractive cell immobilization platform for preservation of bioactivity in the dry state.

  3. Aerosol Monitoring during Carbon Nanofiber Production: Mobile Direct-Reading Sampling

    PubMed Central

    Evans, Douglas E.; Ku, Bon Ki; Birch, M. Eileen; Dunn, Kevin H.

    2010-01-01

    Detailed investigations were conducted at a facility that manufactures and processes carbon nanofibers (CNFs). Presented research summarizes the direct-reading monitoring aspects of the study. A mobile aerosol sampling platform, equipped with an aerosol instrument array, was used to characterize emissions at different locations within the facility. Particle number, respirable mass, active surface area, and photoelectric response were monitored with a condensation particle counter (CPC), a photometer, a diffusion charger, and a photoelectric aerosol sensor, respectively. CO and CO2 were additionally monitored. Combined simultaneous monitoring of these metrics can be utilized to determine source and relative contribution of airborne particles (CNFs and others) within a workplace. Elevated particle number concentrations, up to 1.15 × 106 cm−3, were found within the facility but were not due to CNFs. Ultrafine particle emissions, released during thermal treatment of CNFs, were primarily responsible. In contrast, transient increases in respirable particle mass concentration, with a maximum of 1.1 mg m−3, were due to CNF release through uncontrolled transfer and bagging. Of the applied metrics, our findings suggest that particle mass was probably the most useful and practical metric for monitoring CNF emissions in this facility. Through chemical means, CNFs may be selectively distinguished from other workplace contaminants (Birch et al., in preparation), and for direct-reading monitoring applications, the photometer was found to provide a reasonable estimate of respirable CNF mass concentration. Particle size distribution measurements were conducted with an electrical low-pressure impactor and a fast particle size spectrometer. Results suggest that the dominant CNF mode by particle number lies between 200 and 250 nm for both aerodynamic and mobility equivalent diameters. Significant emissions of CO were also evident in this facility. Exposure control recommendations

  4. Production of sulfate aerosols in the plume of a coal-fired power plant under normal and reduced precipitator operation

    SciTech Connect

    Meagher, J.F.; Bailey, E.M.; Stockburger, L. III

    1981-12-01

    A series of field experiments were conducted at TVA's Cumberland Steam Plant to examine the effect of primary aerosol on sulfate aerosol production. Plume measurements were made using an instrumented helicopter and flue gas analyses were performed on each of the two stacks. The plume particle loading was increased during four of the experiments through a reduction in the electrostatic precipitator (ESP) capacity. The average rate of oxidation of SO/sub 2/ to SO/sub 4//sup 2 -/ in the plume was found to be 0.014 +- 0.015 h/sup -1/. The average rate measured for daytime and normal ESP operation was 0.019 +- 0.015 h/sup -1/. The average nighttime rate was also 0.019 +- 0.021 h/sup -1/. The average rate measured during periods of reduced ESP operation was 0.007 +- 0.01 h/sup -1/. The relatively high night-time rates were measured just after sunset and may result from delayed reactions of free radical precursors which were produced during the day-light hours. The difference between extrapolated intercepts from aircraft measurements and flue gas sampling indicates that a region of rapid SO/sub 2/ oxidation must exist for the first few minutes after the flue gas is emitted from the stacks.

  5. Antimicrobial Edible Films and Coatings for Meat and Meat Products Preservation

    PubMed Central

    Sánchez-Ortega, Irais; García-Almendárez, Blanca E.; Santos-López, Eva María; Amaro-Reyes, Aldo; Barboza-Corona, J. Eleazar; Regalado, Carlos

    2014-01-01

    Animal origin foods are widely distributed and consumed around the world due to their high nutrients availability but may also provide a suitable environment for growth of pathogenic and spoilage microorganisms. Nowadays consumers demand high quality food with an extended shelf life without chemical additives. Edible films and coatings (EFC) added with natural antimicrobials are a promising preservation technology for raw and processed meats because they provide good barrier against spoilage and pathogenic microorganisms. This review gathers updated research reported over the last ten years related to antimicrobial EFC applied to meat and meat products. In addition, the films gas barrier properties contribute to extended shelf life because physicochemical changes, such as color, texture, and moisture, may be significantly minimized. The effectiveness showed by different types of antimicrobial EFC depends on meat source, polymer used, film barrier properties, target microorganism, antimicrobial substance properties, and storage conditions. The perspective of this technology includes tailoring of coating procedures to meet industry requirements and shelf life increase of meat and meat products to ensure quality and safety without changes in sensory characteristics. PMID:25050387

  6. Antimicrobial edible films and coatings for meat and meat products preservation.

    PubMed

    Sánchez-Ortega, Irais; García-Almendárez, Blanca E; Santos-López, Eva María; Amaro-Reyes, Aldo; Barboza-Corona, J Eleazar; Regalado, Carlos

    2014-01-01

    Animal origin foods are widely distributed and consumed around the world due to their high nutrients availability but may also provide a suitable environment for growth of pathogenic and spoilage microorganisms. Nowadays consumers demand high quality food with an extended shelf life without chemical additives. Edible films and coatings (EFC) added with natural antimicrobials are a promising preservation technology for raw and processed meats because they provide good barrier against spoilage and pathogenic microorganisms. This review gathers updated research reported over the last ten years related to antimicrobial EFC applied to meat and meat products. In addition, the films gas barrier properties contribute to extended shelf life because physicochemical changes, such as color, texture, and moisture, may be significantly minimized. The effectiveness showed by different types of antimicrobial EFC depends on meat source, polymer used, film barrier properties, target microorganism, antimicrobial substance properties, and storage conditions. The perspective of this technology includes tailoring of coating procedures to meet industry requirements and shelf life increase of meat and meat products to ensure quality and safety without changes in sensory characteristics. PMID:25050387

  7. 40 CFR Table 1 to Subpart E of... - Product-Weighted Reactivity Limits by Coating Category

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... PCP 1.20 Ground Traffic/Marking GTM 1.20 Art Fixatives or Sealants AFS 1.80 Auto body primers ABP 1.55... Sprays FSP 1.70 Glass Coatings GCP 1.40 High Temperature Coatings HTC 1.85 Hobby/Model/Craft Coatings, Enamel HME 1.45 Hobby/Model/Craft Coatings, Lacquer HML 2.70 Hobby/Model/Craft Coatings, Clear...

  8. Production and Study of Titan's Aerosols Analogues with A RF Low Pressure Plasma Discharge

    NASA Astrophysics Data System (ADS)

    Szopa, C.; Cernogora, G.; Correia, J. J.; Boufendi, L.; Jolly, A.

    2005-10-01

    The atmosphere of Titan, the biggest satellite of Saturn, contains aerosols produced by the organic chemistry induced by the photochemistry of N2 and CH4, the major gaseous atmospheric compounds. In spite of their importance for the properties of the Titan's atmosphere, and for organic chemistry, only few direct information are available about them because of the limitations of the observational techniques, and their processes of formation and growth are not understood. In order to bring answers to these questions, we developed a new type of laboratory simulation to produce analogues of Titan's aerosols (known as tholins) with a low pressure Radio Frequency plasma discharge. The main originality of this experiment (named PAMPRE) comes from its ability to produce particles in volume, as they are maintained in levitation by electrostatic forces compensating gravity, whereas the other experiments produce tholins on the reactors walls or a substrate. We initiated our investigations by a study of the properties of the produced particles as a function of the plasma operating conditions (i.e. amount of CH4 in N2, injected RF power, pressure, and gas flow). We here present the results of this study.

  9. Production of pristine, sulfur-coated and silicon-alloyed germanium nanoparticles via laser pyrolysis.

    PubMed

    Kim, Seongbeom; Yi Park, Song; Jeong, Jaeki; Kim, Gi-Hwan; Rohani, Parham; Suk Kim, Dong; Swihart, Mark T; Young Kim, Jin

    2015-07-31

    Here we demonstrate production of three types of germanium containing nanoparticles (NPs) by laser pyrolysis of GeH4 and characterize their sizes, structures and composition. Pristine Ge NPs were fabricated with 50 standard cubic centimeter per minute (sccm) of GeH4 and 25 sccm of SF6 as a photosensitizer gas, while sulfur-coated Ge NPs were produced with 25 sccm of GeH4 and 50 sccm of SF6. The laser pyrolysis of SiH4/GeH4 mixtures produced Si1-xGex alloy NPs. Effects of key process parameters including laser intensity and gas flow rates on NP properties have been investigated. The ability of the laser pyrolysis technique to flexibly produce a variety of germanium-containing NPs, as illustrated in this study shows promise for commercial-scale production of new nanomaterials as high purity dry powders. PMID:26152899

  10. Production of pristine, sulfur-coated and silicon-alloyed germanium nanoparticles via laser pyrolysis

    NASA Astrophysics Data System (ADS)

    Kim, Seongbeom; Park, Song Yi; Jeong, Jaeki; Kim, Gi-Hwan; Rohani, Parham; Kim, Dong Suk; Swihart, Mark T.; Kim, Jin Young

    2015-07-01

    Here we demonstrate production of three types of germanium containing nanoparticles (NPs) by laser pyrolysis of GeH4 and characterize their sizes, structures and composition. Pristine Ge NPs were fabricated with 50 standard cubic centimeter per minute (sccm) of GeH4 and 25 sccm of SF6 as a photosensitizer gas, while sulfur-coated Ge NPs were produced with 25 sccm of GeH4 and 50 sccm of SF6. The laser pyrolysis of SiH4/GeH4 mixtures produced Si1-xGex alloy NPs. Effects of key process parameters including laser intensity and gas flow rates on NP properties have been investigated. The ability of the laser pyrolysis technique to flexibly produce a variety of germanium-containing NPs, as illustrated in this study shows promise for commercial-scale production of new nanomaterials as high purity dry powders.

  11. Organosulfates and oxidation products from biogenic hydrocarbons in fine aerosols from a forest in North West Europe during spring

    NASA Astrophysics Data System (ADS)

    Kristensen, Kasper; Glasius, Marianne

    2011-09-01

    Organosulfates of monoterpenes and isoprene, as well as their oxidation products have been identified in biogenic secondary organic aerosols (BSOA) from both laboratory and field studies. Organosulfates provide an interesting coupling between air pollution and formation of low-volatility BSOA. HPLC quadrupole time-of-flight mass spectrometry was used to study polar acidic monoterpene and isoprene oxidation products including pinic acid, pinonic and terpenylic acid along with organosulfates and nitrooxy organosulfates in aerosols from ambient air. The method was first validated by analysis of spiked quartz filters, which showed acceptable recoveries >74% for pinic acid, pinonic acid, camphor sulphonic acid and adipic acid. Acetonitrile was identified as a better solvent than methanol for extraction and analysis of pinonic acid and adipic acid, due to improved analytical sensitivity and prevention of methyl ester formation during sample extraction. PM 1 (i.e, aerosols with an aerodynamic diameter ≤1 μm) were collected during spring 2008 in a forest in Denmark with mixed deciduous and coniferous trees. Average concentrations of the most abundant compounds were: pinic acid: 1.5 ng m -3, pinonic acid: 3.0 ng m -3, terpenylic acid: 0.8 ng m -3 and 3-methyl-1,2,3-butanetricarboxylic acid: 3.0 ng m -3. Organosulfates and nitrooxy organosulfates were identified in a majority of the daily samples and the highest levels were observed during a warm period in late spring. As a first approach, due to the lack of authentic standards, organosulfates and nitrooxy organosulfates were tentatively quantified based on the analytical response of camphor sulphonic acid. Generally the concentrations of organosulfates and nitrooxy organosulfates were lower than first generation oxidation products. The maximum concentration of a total of 10 organosulfates and nitrooxy organosulfates were found to be about three times lower than pinonic acid with a maximum concentration of 8 ng m -3. A

  12. Application of the CALIOP Layer Product to Evaluate the Vertical Distribution of Aerosols Estimated by Global Models: AeroCom Phase I Results

    SciTech Connect

    Koffi, Brigitte; Schultz, Michael; Breon, Francois-Marie; Griesfeller, Jan; Winker, D.; Balkanski, Y.; Bauer, Susanne E.; Berntsen, T.; Chin, Mian; Collins, William D.; Dentener, Frank; Diehl, Thomas; Easter, Richard C.; Ghan, Steven J.; Ginoux, P.; Gong, S.; Horowitz, L.; Iversen, T.; Kirkevag, A.; Koch, Dorothy; Krol, Maarten; Myhre, G.; Stier, P.; Takemura, T.

    2012-05-19

    The CALIOP (Cloud-Aerosol Lidar with Orthogonal Polarization) layer product is used for a multimodel evaluation of the vertical distribution of aerosols. Annual and seasonal aerosol extinction profiles are analyzed over 13 sub-continental regions representative of industrial, dust, and biomass burning pollution, from CALIOP 2007-2009 observations and from AeroCom (Aerosol Comparisons between Observations and Models) 2000 simulations. An extinction mean height diagnostic (Z{sub a}) is defined to quantitatively assess the models performance. It is calculated over the 0-6 km and 0-10 km altitude ranges by weighting the altitude of each 100 m altitude layer by its aerosol extinction coefficient. The mean extinction profiles derived from CALIOP layer products provide consistent regional and seasonal specificities and a low inter-annual variability. While the outputs from most models are significantly correlated with the observed Z{sub a} climatologies, some do better than others, and 2 of the 12 models perform particularly well in all seasons. Over industrial and maritime regions, most models show higher Z{sub a} than observed by CALIOP, whereas over the African and Chinese dust source regions, Z{sub a} is underestimated during Northern Hemisphere Spring and Summer. The positive model bias in Z{sub a} is mainly due to an overestimate of the extinction above 6 km. Potential CALIOP and model limitations, and methodological factors that might contribute to the differences are discussed.

  13. Application of the CALIOP Layer Product to Evaluate the Vertical Distribution of Aerosols Estimated by Global Models: AeroCom Phase I Results

    NASA Technical Reports Server (NTRS)

    Koffi, Brigitte; Schulz, Michael; Breon, Francois-Marie; Griesfeller, Jan; Winker, David; Balkanski, Yves; Bauer, Susanne; Berntsen, Terje; Chin, Mian; Collins, William D.; Dentener, Frank; Diehl, Thomas; Easter, Richard; Ghan, Steven; Gimoux, Paul; Gong, Sunling; Horowitz, Larry W.; Iversen, Trond; Kirkevag, Alf; Koch, Dorothy; Krol, Maarten; Myhre, Gunnar; Stier, Philip; Takemura, Toshihiko

    2012-01-01

    The CALIOP (Cloud-Aerosol Lidar with Orthogonal Polarization) layer product is used for a multimodel evaluation of the vertical distribution of aerosols. Annual and seasonal aerosol extinction profiles are analyzed over 13 sub-continental regions representative of industrial, dust, and biomass burning pollution, from CALIOP 2007-2009 observations and from AeroCom (Aerosol Comparisons between Observations and Models) 2000 simulations. An extinction mean height diagnostic (Z-alpha) is defined to quantitatively assess the models' performance. It is calculated over the 0-6 km and 0-10 km altitude ranges by weighting the altitude of each 100 m altitude layer by its aerosol extinction coefficient. The mean extinction profiles derived from CALIOP layer products provide consistent regional and seasonal specificities and a low inter-annual variability. While the outputs from most models are significantly correlated with the observed Z-alpha climatologies, some do better than others, and 2 of the 12 models perform particularly well in all seasons. Over industrial and maritime regions, most models show higher Z-alpha than observed by CALIOP, whereas over the African and Chinese dust source regions, Z-alpha is underestimated during Northern Hemisphere Spring and Summer. The positive model bias in Z-alpha is mainly due to an overestimate of the extinction above 6 km. Potential CALIOP and model limitations, and methodological factors that might contribute to the differences are discussed.

  14. In vitro aerosol characterization of Staccato(®) Loxapine.

    PubMed

    Dinh, Khe; Myers, Dan J; Glazer, Marc; Shmidt, Tamara; Devereaux, Caitlin; Simis, Kathleen; Noymer, Peter D; He, Min; Choosakul, Corinna; Chen, Qiang; Cassella, James V

    2011-01-17

    Medicinal aerosol products (metered dose and dry powder inhalers) require characterization testing over a wide range of use and pre-operating stress scenarios in order to ensure robust product performance and support submissions for regulatory approval. Aerosol characterization experiments on Staccato(®) Loxapine for inhalation (Staccato Loxapine) product (emitted dose, particle size, and purity) were assessed at different operating settings (flow rates, ambient temperature and humidity, altitude, and orientation) and at nominal test conditions following exposure to various stresses on the device (mechanical shock, vibration, drop, thermal cycling, and light exposure). Emitted dose values were approximately 90% of the coated dose at every condition, meeting target specifications in each case. Aerosol purity was consistently >99.5% for every test setting, with no reportable impurities according to ICH standards (>0.1%). Particle size averaged 2μm (MMAD) and was independent of the different test conditions with the exception of different airflow rates. Particle size decreased slightly with airflow, which may assist in maintaining constant deep lung deposition. The combination of high emitted dose efficiency and a particle size range ideally suited for lung deposition, along with the consistency of these key aerosol attributes, suggests that the Staccato system has distinct advantages over more traditional aerosol systems. PMID:20971174

  15. Introduction to MODIS Collection 6 'Deep Blue' aerosol products and strategy for cirrus-signal correction in AOD retrievals using 1.38 μm reflectance data

    NASA Astrophysics Data System (ADS)

    Lee, J.; Hsu, N. C.; Sayer, A. M.; Bettenhausen, C.

    2012-12-01

    This study shows the characteristics of the Moderate Resolution Imaging Spectroradiometer (MODIS) Collection 6 Deep Blue aerosol products (hereafter, C006 DB products) and a strategy for correcting cirrus-signal in the aerosol optical depth (AOD) retrievals. The C006 DB products have several changes over the C005, including extended coverage, surface reflectance model, aerosol microphysical model, and cloud screening, etc. One of the new features is the inclusion of pixel-level uncertainty estimates on the retrieved AOD. These uncertainty estimates have been determined based on a validation against Aerosol Robotic Network (AERONET) direct-Sun AOD measurements, and are parameterized as a function of AOD, viewing geometry, and retrieval quality flag. This will provide users with a simple way to assess the uncertainty on Deep Blue AOD data for their particular application of interest. Preliminary results show strong agreement with AERONET, suggesting that the Deep Blue algorithm performs as well as other state-of-the-art satellite AOD datasets. In addition, a strategy for cirrus-signal correction in the retrieved AOD is presented. The cirrus reflectance at each wavelength to be used in the aerosol retrieval algorithms is determined by the relationships between reflectances at 1.38 μm and the aerosol bands and subtracted from the original TOA reflectance values assuming linear relationship for the optically thin case (ρ1.38 < 0.05). Since the 1.38 μm band is located in the strong water vapor absorption band, thus representing cirrus signal only, the slope between the 1.38 μm reflectance values and minimum reflectance values at each aerosol band for the corresponding values at 1.38 μm can be used to convert the 1.38 μm reflectance to the cirrus reflectance at each wavelength. Then, the cirrus-signal-corrected AOD can be retrieved by using the corrected reflectance data as input data into the aerosol retrieval algorithms. The retrieval results show that the AOD

  16. Plasma Sprayed Coatings of High-Purity Ceramics for Semiconductor and Flat-Panel-Display Production Equipment

    NASA Astrophysics Data System (ADS)

    Kitamura, Junya; Ibe, Hiroyuki; Yuasa, Fumi; Mizuno, Hiroaki

    2008-12-01

    High-purity oxide ceramic powders of alumina (Al2O3) and yttria (Y2O3) have been developed to apply to semiconductor and flat-panel-display (FPD) production equipment. The ceramic coatings on the inside chamber wall of the equipment are required to have high erosion resistance against CFx plasma in dry etching process for microfabrications of the devices. It is found that the yttria coating formed from agglomerated-and-sintered powder consisting of large primary particles has smoother eroded surface with high erosion resistance. Considering the particle deposition on the devices, this coating will be effective in decreasing generation of large-sized particles, which easily deposit on the devices. Electric insulating properties of the coatings are also investigated to apply to electrostatic chuck. Electric breakdown voltage of yttria coatings is comparable to that of alumina coatings. Smaller powder is effective for improving the electric properties, and the influence of coating purity is lower than that of the powder size.

  17. Volcanic Aerosol Evolution: Model vs. In Situ Sampling

    NASA Astrophysics Data System (ADS)

    Pfeffer, M. A.; Rietmeijer, F. J.; Brearley, A. J.; Fischer, T. P.

    2002-12-01

    Volcanoes are the most significant non-anthropogenic source of tropospheric aerosols. Aerosol samples were collected at different distances from 92°C fumarolic source at Poás Volcano. Aerosols were captured on TEM grids coated by a thin C-film using a specially designed collector. In the sampling, grids were exposed to the plume for 30-second intervals then sealed and frozen to prevent reaction before ATEM analysis to determine aerosol size and chemistry. Gas composition was established using gas chromatography, wet chemistry techniques, AAS and Ion Chromatography on samples collected directly from a fumarolic vent. SO2 flux was measured remotely by COSPEC. A Gaussian plume dispersion model was used to model concentrations of the gases at different distances down-wind. Calculated mixing ratios of air and the initial gas species were used as input to the thermo-chemical model GASWORKS (Symonds and Reed, Am. Jour. Sci., 1993). Modeled products were compared with measured aerosol compositions. Aerosols predicted to precipitate out of the plume one meter above the fumarole are [CaSO4, Fe2.3SO4, H2SO4, MgF2. Na2SO4, silica, water]. Where the plume leaves the confines of the crater, 380 meters distant, the predicted aerosols are the same, excepting FeF3 replacing Fe2.3SO4. Collected aerosols show considerable compositional differences between the sampling locations and are more complex than those predicted. Aerosols from the fumarole consist of [Fe +/- Si,S,Cl], [S +/- O] and [Si +/- O]. Aerosols collected on the crater rim consist of the same plus [O,Na,Mg,Ca], [O,Si,Cl +/- Fe], [Fe,O,F] and [S,O +/- Mg,Ca]. The comparison between results obtained by the equilibrium gas model and the actual aerosol compositions shows that an assumption of chemical and thermal equilibrium evolution is invalid. The complex aerosols collected contrast the simple formulae predicted. These findings show that complex, non-equilibrium chemical reactions take place immediately upon volcanic

  18. Mass Spectral Observations of Submicron Aerosol Particles and Production of Secondary Organic Aerosol at an Anthropogenically Influenced Site during the Wet Season of GoAmazon2014

    NASA Astrophysics Data System (ADS)

    de Sá, S. S.; Palm, B. B.; Campuzano Jost, P.; Day, D. A.; Hu, W.; Newburn, M. K.; Ferreira De Brito, J.; Artaxo, P.; Shilling, J. E.; Souza, R. A. F. D.; Manzi, A. O.; Alexander, M. L.; Jimenez, J. L.; Martin, S. T.

    2014-12-01

    As part of GoAmazon2014, a high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS) was deployed to characterize the composition, size, and spectral markers present in submicron atmospheric aerosol particles at a site downwind of Manaus, Brazil, in the central Amazon basin. The focus was on the influence of biogenic-anthropogenic interactions on the measured aerosol particles, especially as related to the formation of secondary organic aerosol (SOA). Through a combination of meteorology, emissions, and chemistry, the research site was affected by biogenic emissions from the tropical rainforest that were periodically mixed with urban outflow from the Manaus metropolitan area. Results from the first intensive operation period, from 1 February to 31 March 2014, show that for the wet season the PM1 mass concentration had typical values on order of 1 to 2 μg/m3. The organic species were dominant, followed by sulfate. The mass-diameter distribution of the particle population had a prevailing mode between 300 and 400 nm (vacuum aerodynamic diameter, dva), and at times a smaller mode at finer size was also present. Highly oxidized organic material was frequently observed, characterized by a dominant peak at m/z 44. There was a diel trend in the elemental oxygen-to-carbon (O:C) ratio peaking in the afternoon. The analysis of the results aims at delineating the anthropogenic impact on the measurements. Multivariate statistical analysis by positive-matrix factorization (PMF) is applied to the time series of organic particle mass spectra. The factors and their loadings provide information on the relative and time-varying contributions of different sources and processes affecting the organic component of the aerosol particle phase. Relationships between AMS results and measurements from co-located instruments that provide information on anthropogenic and biogenic gas and particle tracers are investigated, toward the goal of improving the understanding of

  19. Ballistic projectile metallurgical issues and fundamentals: Aerosol production in rod penetration erosion and erosion phenomena associated with railgun development

    NASA Astrophysics Data System (ADS)

    Machado, Brenda I.

    The issue is derived from ballistic erosion as it relates to nanoparticle production and respiration of these particles as a health concern ballistic erosion and ballistic erosion as it relates to railgun performance. A common thread between these two issues is dynamic recrystallization (DRX). DRX has been demonstrated to be the dominant mechanism for solid-state flow associated with ballistic projectile/target penetration and interaction, friction-stir welding phenomena, and other high-strain rate deformation phenomena. Aerosol particulates collected on filters from ballistic penetration and erosion events for W-Ni-Co and W-Ni-Fe kinetic energy rod projectiles penetrating steel target plates were observed to be highly cytotoxic after 48 h exposure to human epithelial A549 lung cells. The aerosol consisted of micron-size Fe particulates and nanoparticulate aggregates consisting of W, Ni or W, Co and some Fe, characterized by SEM and TEM, and using energy-dispersive (X-ray) spectrometry by (EDS) for elemental analysis and mapping. Cytotoxic assays of micron and nano-size, manufactured metal particulates of W, Ni, Fe, and Co demonstrated that only the nanoparticulate elements demonstrated measurable cytotoxicity. Aluminum projectile (or armature) tribomaterial deposition onto copper conducting rails in an experimental solid-armature railgun system was observed, by optical, SEM and TEM. The extreme deformation at the aluminum/copper interface creates a solid-state flow regime by dynamic recrystallization which also leads to the erosion-product deposition. Melting of the low-temperature aluminum deposit also contributes to the rail damage and degradation of electromagnetic behavior. The creation of nano-grains by dynamic recrystallization allows for mixing at the aluminum/copper interface, and there is no evidence for traditional alloying.

  20. Effect of MODIS Terra radiometric calibration improvements on Collection 6 Deep Blue aerosol products: Validation and Terra/Aqua consistency

    NASA Astrophysics Data System (ADS)

    Sayer, A. M.; Hsu, N. C.; Bettenhausen, C.; Jeong, M.-J.; Meister, G.

    2015-12-01

    The Deep Blue (DB) algorithm's primary data product is midvisible aerosol optical depth (AOD). DB applied to Moderate Resolution Imaging Spectroradiometer (MODIS) measurements provides a data record since early 2000 for MODIS Terra and mid-2002 for MODIS Aqua. In the previous data version (Collection 5, C5), DB production from Terra was halted in 2007 due to sensor degradation; the new Collection 6 (C6) has both improved science algorithms and sensor radiometric calibration. This includes additional calibration corrections developed by the Ocean Biology Processing Group to address MODIS Terra's gain, polarization sensitivity, and detector response versus scan angle, meaning DB can now be applied to the whole Terra record. Through validation with Aerosol Robotic Network (AERONET) data, it is shown that the C6 DB Terra AOD quality is stable throughout the mission to date. Compared to the C5 calibration, in recent years the RMS error compared to AERONET is smaller by ˜0.04 over bright (e.g., desert) and ˜0.01-0.02 over darker (e.g., vegetated) land surfaces, and the fraction of points in agreement with AERONET within expected retrieval uncertainty higher by ˜10% and ˜5%, respectively. Comparisons to the Aqua C6 time series reveal a high level of correspondence between the two MODIS DB data records, with a small positive (Terra-Aqua) average AOD offset <0.01. The analysis demonstrates both the efficacy of the new radiometric calibration efforts and that the C6 MODIS Terra DB AOD data remain stable (to better than 0.01 AOD) throughout the mission to date, suitable for quantitative scientific analyses.

  1. Effect of MODIS Terra Radiometric Calibration Improvements on Collection 6 Deep Blue Aerosol Products: Validation and Terra/Aqua Consistency

    NASA Technical Reports Server (NTRS)

    Sayer, A. M.; Hsu, N. C.; Bettenhausen, C.; Jeong, M.-J.; Meister, G.

    2015-01-01

    The Deep Blue (DB) algorithm's primary data product is midvisible aerosol optical depth (AOD). DB applied to Moderate Resolution Imaging Spectroradiometer (MODIS) measurements provides a data record since early 2000 for MODIS Terra and mid-2002 for MODIS Aqua. In the previous data version (Collection 5, C5), DB production from Terra was halted in 2007 due to sensor degradation; the new Collection 6 (C6) has both improved science algorithms and sensor radiometric calibration. This includes additional calibration corrections developed by the Ocean Biology Processing Group to address MODIS Terra's gain, polarization sensitivity, and detector response versus scan angle, meaning DB can now be applied to the whole Terra record. Through validation with Aerosol Robotic Network (AERONET) data, it is shown that the C6 DB Terra AOD quality is stable throughout the mission to date. Compared to the C5 calibration, in recent years the RMS error compared to AERONET is smaller by approximately 0.04 over bright (e.g., desert) and approximately 0.01-0.02 over darker (e.g., vegetated) land surfaces, and the fraction of points in agreement with AERONET within expected retrieval uncertainty higher by approximately 10% and approximately 5%, respectively. Comparisons to the Aqua C6 time series reveal a high level of correspondence between the two MODIS DB data records, with a small positive (Terra-Aqua) average AOD offset <0.01. The analysis demonstrates both the efficacy of the new radiometric calibration efforts and that the C6 MODIS Terra DB AOD data remain stable (to better than 0.01 AOD) throughout the mission to date, suitable for quantitative scientific analyses.

  2. Positron emission tomography (PET) for assessing aerosol deposition of orally inhaled drug products.

    PubMed

    Dolovich, Myrna B; Bailey, Dale L

    2012-12-01

    The topical distribution of inhaled therapies in the lung can be viewed using radionuclides and imaging. Positron emission tomography (PET) is a three-dimensional functional imaging technique providing quantitatively accurate localization of the quantity and distribution of an inhaled or injected PET radiotracer in the lung. A series of transaxial slices through the lungs are obtained, comparable to an X-ray computed tomography (CT) scan. Subsequent reformatting allows coronal and sagittal images of the distribution of radioactivity to be viewed. This article describes procedures for administering [(18)F]-fluorodeoxyglucose aerosol to human subjects for the purpose of determining dose and distribution following inhalation from an aerosol drug delivery device (ADDD). The advantages of using direct-labeled PET drugs in the ADDD are discussed with reference to the literature. The methods for designing the inhalation system, determining proper radiation shielding, calibration, and validation of administered radioactivity, scanner setup, and data handling procedures are described. Obtaining an X-ray CT or radionuclide transmission scan to provide accurate geometry of the lung and also correct for tissue attenuation of the PET radiotracer is discussed. Protocols for producing accurate images, including factors that need to be incorporated into the data calibration, are described, as well as a proposed standard method for partitioning the lung into regions of interest. Alternate methods are described for more detailed assessments. Radiation dosimetry/risk calculations for the procedures are appended, as well as a sample data collection form and spreadsheet for calculations. This article should provide guidance for those interested in using PET to determine quantity and distribution of inhaled therapeutics. PMID:23215847

  3. A Protocol for the Production of Gliadin-cyanoacrylate Nanoparticles for Hydrophilic Coating.

    PubMed

    Kim, Sanghoon

    2016-01-01

    This article presents a protocol for the production of protein-based nanoparticles that changes the hydrophobic surface to hydrophilic by a simple spray coating. These nanoparticles are produced by the polymerization reaction of alkyl cyanoacrylate on the surface of cereal protein (gliadin) molecules. Alkyl cyanoacrylate is a monomer that instantly polymerizes at RT when it is applied to the surface of materials. Its polymerization reaction is initiated by the trace amounts of weakly basic or nucleophilic species on the surface, including moisture. Once polymerized, the polymerized alkyl cyanoacrylates show a strong affinity with the object materials because nitrile groups are in the backbone of poly (alkyl cyanoacrylate). Proteins also work as initiator for this polymerization because they contain amine groups that can initiate the polymerization of cyanoacrylate. If aggregated protein is used as an initiator, protein aggregate is surrounded by the hydrophobic poly(alkyl cyanoacrylate) chains after the polymerization reaction of alkyl cyanoacrylate. By controlling the experimental condition, particles in the nanometer range are produced. The produced nanoparticles readily adsorb to the surface of most materials including glass, metals, plastics, wood, leather, and fabrics. When the surface of a material is sprayed with the produced nanoparticle suspension and rinsed with water, the micellar structure of nanoparticle changes its conformation, and the hydrophilic proteins are exposed to the air. As a result, the nanoparticle-coated surface changes to hydrophilic. PMID:27500790

  4. Design of Gas-phase Synthesis of Core-Shell Particles by Computational Fluid - Aerosol Dynamics.

    PubMed

    Buesser, B; Pratsinis, S E

    2011-11-01

    Core-shell particles preserve the bulk properties (e.g. magnetic, optical) of the core while its surface is modified by a shell material. Continuous aerosol coating of core TiO2 nanoparticles with nanothin silicon dioxide shells by jet injection of hexamethyldisiloxane precursor vapor downstream of titania particle formation is elucidated by combining computational fluid and aerosol dynamics. The effect of inlet coating vapor concentration and mixing intensity on product shell thickness distribution is presented. Rapid mixing of the core aerosol with the shell precursor vapor facilitates efficient synthesis of hermetically coated core-shell nanoparticles. The predicted extent of hermetic coating shells is compared to the measured photocatalytic oxidation of isopropanol by such particles as hermetic SiO2 shells prevent the photocatalytic activity of titania. Finally the performance of a simpler, plug-flow coating model is assessed by comparisons to the present detailed CFD model in terms of coating efficiency and silica average shell thickness and texture. PMID:23729817

  5. The Use Of An IBM PC For Maximizing Production In Coating Laboratories

    NASA Astrophysics Data System (ADS)

    Songer, Larry H.

    1986-10-01

    A small desk top computer, when properly programmed, can be used in the design of optical coatings, analysis of new designs, for instructions to coating machine operators, cost estimations, and to help in the computation of machine tooling.

  6. Influences of vertical transport and scavenging on aerosol particle surface area and radon decay product concentrations at the Jungfraujoch (3454 m above sea level)

    NASA Astrophysics Data System (ADS)

    Lugauer, M.; Baltensperger, U.; Furger, M.; GäGgeler, H. W.; Jost, D. T.; Nyeki, S.; Schwikowski, M.

    2000-08-01

    Concentrations of the aerosol particle surface area (SA) and aerosol-attached radon decay products 214Pb and 212Pb have been measured by means of an aerosol and a radon epiphaniometer at the Jungfraujoch research station (JFJ; 3454 m above sea level, Switzerland). These parameters exhibit a pronounced seasonal cycle with minimum values in winter and maximum values in summer. In summer, pronounced diurnal variations with a maximum at 1800 LST are often present. Highest concentrations and most pronounced diurnal variations occur during anticyclonic weather conditions in summer. Thermally driven vertical transport over alpine topography is responsible for this observation. During this synoptic condition, concentrations vary greatly with the 500 hPa wind direction, exhibiting low concentrations for NW-N winds and high concentrations for weak or S-SW winds. Lead-214 and SA are highly correlated during anticyclonic conditions, indicating transport equivalence of the gaseous 214Pb precursor, 222Rn, and of aerosol particles. When cyclonic lifting is the dominant vertical transport, wet scavenging of aerosol particles can explain the weak correlation of 214Pb and SA. This conclusion is corroborated by the 214Pb/SA ratio, being twice as high during cyclonic than during anticyclonic conditions. Lead-212 is a tracer for the influence of surface contact on a local scale due to its short lifetime of 15.35 hours. The analysis of this parameter suggests that high-alpine surfaces play an important role in thermally driven transport to the JFJ.

  7. 40 CFR Table 1 to Subpart E of... - Product-Weighted Reactivity Limits by Coating Category

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ....40 Primers PCP 1.20 Ground Traffic/Marking GTM 1.20 Art Fixatives or Sealants AFS 1.80 Auto Body.../Craft Coatings, Enamel HME 1.45 Hobby/Model/Craft Coatings, Lacquer HML 2.70 Hobby/Model/Craft Coatings, Clear or Metallic HMC 1.60 Marine Spar Varnishes MSV 0.90 Photograph Coatings PHC 1.00 Pleasure...

  8. Understanding polysaccharide production and properties using seed coat mutants: future perspectives for the exploitation of natural variants

    PubMed Central

    North, Helen M.; Berger, Adeline; Saez-Aguayo, Susana; Ralet, Marie-Christine

    2014-01-01

    Background The epidermal cells of the seed coat of certain species accumulate polysaccharides during seed development for cell wall reinforcement or release on imbibition to form mucilage. Seed-coat epidermal cells show natural variation in their structure and mucilage production, which could explain the diverse ecophysiological roles proposed for the latter. Arabidopsis mucilage mutants have proved to be an important tool for the identification of genes involved in the production of seed-coat polysaccharides. Scope This review documents genes that have been characterized as playing a role in the differentiation of the epidermal cells of the arabidopsis seed coat, the natural variability in polysaccharide features of these cells and the physiological roles attributed to seed mucilage. Conclusions Seed-coat epidermal cells are an excellent model for the study of polysaccharide metabolism and properties. Intra- and interspecies natural variation in the differentiation of these epidermal cells is an under-exploited resource for such studies and promises to play an important part in improving our knowledge of polysaccharide production and ecophysiological function. PMID:24607722

  9. Improvement of Production Rate of YBCO Coated Conductors Fabricated by TFA-MOD Method

    NASA Astrophysics Data System (ADS)

    Nakaoka, K.; Yoshizumi, M.; Usui, Y.; Izumi, T.; Shiohara, Y.

    The metal-organic deposition (MOD) method using trifluoroacetate (TFA) salts is considered to be an effective method for inexpensively fabricating YBa2Cu3O7-y (YBCO) coated conductors with high critical current density property. The long-length TFA-MOD YBCO coated conductors have been fabricated by multi-turn reel-to-reel system. Increasing the thickness per single coating in the multi-turn reel-to-reel system is a cost-effective technique for fabrication of the precursor films in the calcination process since it reduces the number of coatings and shortens the processing time. In this work, we have developed a new starting solution consisting of non-fluorine salts of yttrium propionate and copper 2-ethylhexanoate with focusing on increasing the thickness per single coating for a high-rate fabrication of the YBCO coated conductors by the TFA-MOD method. The critical thickness per single coating of the precursor film fabricated from the new starting solution was improved to 0.44 μm/coat. Furthermore, the addition of diacetoneacrylamide in the new starting solution increased the critical thickness per single coating to 0.79 μm/coat. High critical current of 791 A/cm-width with high critical current density of 2.7 MA/cm2 was obtained using the new starting solution with diacetoneacrylamide at the thickness per single coating of 0.49 μm/coat.

  10. A kinetic study of the interaction between atomic oxygen and aerosols

    NASA Technical Reports Server (NTRS)

    Akers, F. I.; Wightman, J. P.

    1976-01-01

    This study was concerned with the effects of NH4Cl and (NH4)2SO4 aerosols on the kinetics of disappearance of atomic oxygen. Atomic oxygen was generated by a 2.45-GHz microwave discharge and the kinetics of disappearance measured in a fast flow system using NO2 titration. Values of the recombination coefficient for heterogeneous wall recombination were determined for clean, H2SO4-coated, and (NH4)2SO4-coated Pyrex to be 0.000050, 0.000020, and 0.000019, respectively. A rapid exothermic chemical reaction was found to occur between atomic oxygen and an NH4Cl wall coating; the products were NH3, NO, H2O, and HCl. The NH4Cl aerosol was generated by gas phase reaction of NH3 with HCl. The aerosol particles were approximately spherical and nearly monodisperse with a mean diameter of 1.6 plus or minus 0.2 micron. The rate constant for the disappearance of atomic oxygen in the presence of NH4Cl aerosol was measured. No significant decrease was observed in the rate of disappearance of atomic oxygen in the presence of an (NH4)2SO4 aerosol at a concentration of 285 mg per cu m.

  11. Mixing state of aerosols over the Indo-Gangetic Plain: Radiative forcing and heating rate

    NASA Astrophysics Data System (ADS)

    Srivastava, R.; Ramachandran, S.

    2012-12-01

    Aerosols are a major atmospheric variable which perturb the Earth-atmosphere radiation balance by absorbing and scattering the solar and terrestrial radiation. Aerosols are produced by natural and anthropogenic processes. The presence of different types of aerosol over a location and aerosols transported from long-range can give rise to different mixing states because of aging and interaction among the different aerosol species. Knowledge of the mixing state of aerosols is important for an accurate assessment of aerosols in climate forcing, as assumptions regarding the mixing state of aerosol and its effect on optical properties can give rise to uncertainties in modeling their direct and indirect effects [1]. Seasonal variations in mixing states of aerosols over an urban (Kanpur) and a rural location (Gandhi College) in the Indo-Gangetic Plain (IGP) are determined using the measured and modeled aerosol optical properties, and the impact of aerosol mixing state on aerosol radiative forcing are investigated. IGP is one of the most populated and polluted river basins in the world, rich in fertile lands and agricultural production. Kanpur is an urban, industrial and densely populated city, and has several large/small scale industries and vehicles, while Gandhi College in IGP is a rural village, located southeast of Kanpur. Aerosol optical properties obtained from Aerosol Robotic Network sun/sky radiometers [2] over these two environmentally distinct locations in Indo-Gangetic Plain are used in the study, along with aerosol vertical profiles obtained from CALIPSO (Cloud- Aerosol Lidar and Infrared Pathfinder Satellite Observations) lidar observations. Probable mixing state of aerosols is determined utilizing the aerosol optical properties viz., aerosol optical depth, single scattering albedo and asymmetry parameter. The coated-sphere Mie calculation requires the refractive index of core and shell species, and the radius of core and shell particles. Core to shell radius

  12. Aerosol Stable Peptide-Coated Liposome Nanoparticles: A Proof-of-Concept Study with Opioid Fentanyl in Enhancing Analgesic Effects and Reducing Plasma Drug Exposure

    PubMed Central

    HOEKMAN, JOHN D; SRIVASTAVA, PRAMOD; HO, RODNEY J Y

    2014-01-01

    Previous we reported a novel pressurized olfactory drug (POD) delivery device that deposit aerosolized drug preferentially to upper nasal cavity. This POD device provided sustained CNS levels of soluble morphine analgesic effects. However, analgesic onset of less soluble fentanyl was more rapid but brief, likely due to hydrophobic fentanyl redistribution readily back to blood. To determine whether fentanyl incorporated into an aerosol stable liposome that binds to nasal epithelial cells will enhance CNS drug exposure and analgesic effects and reduce plasma exposure, we constructed RGD liposomes anchored with acylated integrin binding peptides (palmitoyl-GRGDS). The RGD liposomes, which assume gel-phase membrane structure at 25°C were stable under the stress of aerosolization as only 2.2 ± 0.5 % calcein leakage detected. The RGD mediated integrin binding of liposome is also verified to be unaffected by aerosolization. Rats treated with fentanyl in RGD-liposome and POD device exhibited greater analgesic effect, compared to the free drug counterpart (AUCeffect = 1387.l vs. 760.1 %MPE*min); while ~20% reduced plasma drug exposure was noted (AUC0-120 = 208.2 vs 284.8 ng*min/ml). Collectively, fentanyl incorporated in RGD-liposomes are physically and biologically stable under aerosolization, enhanced the overall analgesic effects and reduced plasma drug exposure for the first 2 hours. PMID:24909764

  13. Glyoxal uptake on ammonium sulphate seed aerosol: reaction products and reversibility of uptake under dark and irradiated conditions

    NASA Astrophysics Data System (ADS)

    Galloway, M. M.; Chhabra, P. S.; Chan, A. W. H.; Surratt, J. D.; Flagan, R. C.; Seinfeld, J. H.; Keutsch, F. N.

    2008-12-01

    Chamber studies of glyoxal uptake onto neutral ammonium sulphate aerosol were performed under dark and irradiated conditions to gain further insight into processes controlling glyoxal uptake onto ambient aerosol. Organic fragments from glyoxal dimers and trimers were observed within the aerosol under dark and irradiated conditions; glyoxal oligomer formation and overall organic growth were found to be reversible under dark conditions. Analysis of high-resolution time-of-flight aerosol mass spectra provides evidence for irreversible formation of carbon-nitrogen (C-N) compounds in the aerosol. These compounds are likely to be imidazoles formed by reaction of glyoxal with the ammonium sulphate seed. To the authors' knowledge, this is the first time C-N compounds resulting from condensed phase reactions with ammonium sulphate seed have been detected in aerosol. Organosulphates were not detected under dark conditions. However, active oxidative photochemistry, similar to that found in cloud processing, was found to occur within aerosol during irradiated experiments. Organosulphates, carboxylic acids, and organic esters were identified within the aerosol. Our study suggests that both C-N compound formation and photochemical processes should be considered in models of secondary organic aerosol formation via glyoxal.

  14. Kinetics and Products of Heterogeneous Oxidation of Oleic acid, Linoleic acid and Linolenic acid in Aerosol Particles by Hydroxyl radicals

    NASA Astrophysics Data System (ADS)

    Nah, T.; Leone, S. R.; Wilson, K. R.

    2010-12-01

    A significant mass fraction of atmospheric aerosols is composed of a variety of oxidized organic compounds with varying functional groups that may affect the rate at which they chemically age. Here we study the heterogeneous reaction of OH radicals with different sub-micron, alkenoic acid particles: Oleic acid (OA), Linoleic acid (LA), and Linolenic acid (LNA), in the presence of H2O2 and O2. This research explores how OH addition reactions initiate chain reactions that rapidly transform the chemical composition of an organic particle. Particles are chemically aged in a photochemical flow tube reactor where they are exposed to OH radicals (~ 1011 molecule cm-3 s) that are produced by the photolysis of H2O2 at 254 nm. The aerosols are then sized and their composition analyzed via Atmospheric Pressure Chemical Ionization (APCI). Detailed kinetic measurements show that the reactive uptake coefficient is larger than 1, indicating the presence of secondary chemistry occurring in the condensed phase. Reactive uptake coefficient is found to scale linearly with the number of double bonds present in the molecule. In addition, the reactive uptake coefficient is found to depend sensitively upon the concentrations of O2 in the photochemical flow tube reactor, indicating that O2 plays a role in secondary chemistry. In the absence of O2 the reactive uptake coefficient increases to ~ 8, 5 and 3 for LNA, LA, and OA, respectively. The reactive uptake coefficient approaches values of 6, 4 and 2 for LNA, LA, and OA respectively when 18% of the total nitrogen flow is replaced with O2. Mechanistic pathways and products will also be presented herein.

  15. Optimization Control of the Color-Coating Production Process for Model Uncertainty.

    PubMed

    He, Dakuo; Wang, Zhengsong; Yang, Le; Mao, Zhizhong

    2016-01-01

    Optimized control of the color-coating production process (CCPP) aims at reducing production costs and improving economic efficiency while meeting quality requirements. However, because optimization control of the CCPP is hampered by model uncertainty, a strategy that considers model uncertainty is proposed. Previous work has introduced a mechanistic model of CCPP based on process analysis to simulate the actual production process and generate process data. The partial least squares method is then applied to develop predictive models of film thickness and economic efficiency. To manage the model uncertainty, the robust optimization approach is introduced to improve the feasibility of the optimized solution. Iterative learning control is then utilized to further refine the model uncertainty. The constrained film thickness is transformed into one of the tracked targets to overcome the drawback that traditional iterative learning control cannot address constraints. The goal setting of economic efficiency is updated continuously according to the film thickness setting until this reaches its desired value. Finally, fuzzy parameter adjustment is adopted to ensure that the economic efficiency and film thickness converge rapidly to their optimized values under the constraint conditions. The effectiveness of the proposed optimization control strategy is validated by simulation results. PMID:27247563

  16. Optimization Control of the Color-Coating Production Process for Model Uncertainty

    PubMed Central

    He, Dakuo; Wang, Zhengsong; Yang, Le; Mao, Zhizhong

    2016-01-01

    Optimized control of the color-coating production process (CCPP) aims at reducing production costs and improving economic efficiency while meeting quality requirements. However, because optimization control of the CCPP is hampered by model uncertainty, a strategy that considers model uncertainty is proposed. Previous work has introduced a mechanistic model of CCPP based on process analysis to simulate the actual production process and generate process data. The partial least squares method is then applied to develop predictive models of film thickness and economic efficiency. To manage the model uncertainty, the robust optimization approach is introduced to improve the feasibility of the optimized solution. Iterative learning control is then utilized to further refine the model uncertainty. The constrained film thickness is transformed into one of the tracked targets to overcome the drawback that traditional iterative learning control cannot address constraints. The goal setting of economic efficiency is updated continuously according to the film thickness setting until this reaches its desired value. Finally, fuzzy parameter adjustment is adopted to ensure that the economic efficiency and film thickness converge rapidly to their optimized values under the constraint conditions. The effectiveness of the proposed optimization control strategy is validated by simulation results. PMID:27247563

  17. Direct Aerosol Forcing Uncertainty

    DOE Data Explorer

    Mccomiskey, Allison

    2008-01-15

    Understanding sources of uncertainty in aerosol direct radiative forcing (DRF), the difference in a given radiative flux component with and without aerosol, is essential to quantifying changes in Earth's radiation budget. We examine the uncertainty in DRF due to measurement uncertainty in the quantities on which it depends: aerosol optical depth, single scattering albedo, asymmetry parameter, solar geometry, and surface albedo. Direct radiative forcing at the top of the atmosphere and at the surface as well as sensitivities, the changes in DRF in response to unit changes in individual aerosol or surface properties, are calculated at three locations representing distinct aerosol types and radiative environments. The uncertainty in DRF associated with a given property is computed as the product of the sensitivity and typical measurement uncertainty in the respective aerosol or surface property. Sensitivity and uncertainty values permit estimation of total uncertainty in calculated DRF and identification of properties that most limit accuracy in estimating forcing. Total uncertainties in modeled local diurnally averaged forcing range from 0.2 to 1.3 W m-2 (42 to 20%) depending on location (from tropical to polar sites), solar zenith angle, surface reflectance, aerosol type, and aerosol optical depth. The largest contributor to total uncertainty in DRF is usually single scattering albedo; however decreasing measurement uncertainties for any property would increase accuracy in DRF. Comparison of two radiative transfer models suggests the contribution of modeling error is small compared to the total uncertainty although comparable to uncertainty arising from some individual properties.

  18. Gas-phase products and secondary aerosol yields from the photooxidation of 16 different terpenes

    NASA Astrophysics Data System (ADS)

    Lee, Anita; Goldstein, Allen H.; Kroll, Jesse H.; Ng, Nga L.; Varutbangkul, Varuntida; Flagan, Richard C.; Seinfeld, John H.

    2006-09-01

    The photooxidation of isoprene, eight monoterpenes, three oxygenated monoterpenes, and four sesquiterpenes were conducted individually at the Caltech Indoor Chamber Facility under atmospherically relevant HC:NOx ratios to monitor the time evolution and yields of SOA and gas-phase oxidation products using PTR-MS. Several oxidation products were calibrated in the PTR-MS, including formaldehyde, acetaldehyde, formic acid, acetone, acetic acid, nopinone, methacrolein + methyl vinyl ketone; other oxidation products were inferred from known fragmentation patterns, such as pinonaldehyde; and other products were identified according to their mass to charge (m/z) ratio. Numerous unidentified products were formed, and the evolution of first- and second-generation products was clearly observed. SOA yields from the different terpenes ranged from 1 to 68%, and the total gas- plus particle-phase products accounted for ˜50-100% of the reacted carbon. The carbon mass balance was poorest for the sesquiterpenes, suggesting that the observed products were underestimated or that additional products were formed but not detected by PTR-MS. Several second-generation products from isoprene photooxidation, including m/z 113, and ions corresponding to glycolaldehyde, hydroxyacetone, methylglyoxal, and hydroxycarbonyls, were detected. The detailed time series and relative yields of identified and unidentified products aid in elucidating reaction pathways and structures for the unidentified products. Many of the unidentified products from these experiments were also observed within and above the canopy of a Ponderosa pine plantation, confirming that many products of terpene oxidation can be detected in ambient air using PTR-MS, and are indicative of concurrent SOA formation.

  19. AEROSOL INDUSTRY SUCCESS IN REDUCING CFC PROPELLANT USAGE

    EPA Science Inventory

    Part I of this report discusses the U.S. aerosol industry's experience in converting from chlorofluorocarbon (CFC) propellants to alternative aerosol formulations. Detailed examples of non-CFC formulations are provided for 28 categories of aerosol products. ydrocarbon propellants...

  20. Culturability of Bacillus spores on aerosol collection filters exposed to airborne combustion products of Al, Mg, and B·Ti.

    PubMed

    Adhikari, Atin; Yermakov, Michael; Indugula, Reshmi; Reponen, Tiina; Driks, Adam; Grinshpun, Sergey A

    2016-05-01

    Destruction of bioweapon facilities due to explosion or fire could aerosolize highly pathogenic microorganisms. The post-event air quality assessment is conducted through air sampling. A bioaerosol sample (often collected on a filter for further culture-based analysis) also contains combustion products, which may influence the microbial culturability and, thus, impact the outcome. We have examined the interaction between spores deposited on collection filters using two simulants of Bacillus anthracis [B. thuringiensis (Bt) and B. atrophaeus (referred to as BG)] and incoming combustion products of Al as well as Mg and B·Ti (common ingredient of metalized explosives). Spores extracted from Teflon, polycarbonate, mixed cellulose ester (MCE), and gelatin filters (most common filter media for bioaerosol sampling), which were exposed to combustion products during a short-term sampling, were analyzed by cultivation. Surprisingly, we observed that aluminum combustion products enhanced the culturability of Bt (but not BG) spores on Teflon filters increasing the culturable count by more than an order of magnitude. Testing polycarbonate and MCE filter materials also revealed a moderate increase of culturability although gelatin did not. No effect was observed with either of the two species interacting on either filter media with products originated by combustion of Mg and B·Ti. Sample contamination, spore agglomeration, effect of a filter material on the spore survival, changes in the spore wall ultrastructure and germination, as well as other factors were explored to interpret the findings. The study raises a question about the reliability of certain filter materials for collecting airborne bio-threat agents in combustion environments. PMID:26914458

  1. Preparation and characterization of PTFE coating in new polymer quartz piezoelectric crystal sensor for testing liquor products

    NASA Astrophysics Data System (ADS)

    Gu, Yu; Li, Qiang

    2015-07-01

    A new method was developed based on the electron beam vacuum dispersion (EBVD) technology to prepare the PTFE polymer coating of the new polymer quartz piezoelectric crystal sensor for testing liquor products. The new method was applied in the new EBVD equipment which we designed. A real-time system monitoring the polymer coating’s thickness was designed for the new EBVD equipment according to the quartz crystal microbalance (QCM) principle, playing an important role in preparing stable and uniform PTFE polymer coatings of the same thickness. 30 pieces of PTFE polymer coatings on the surface of the quartz crystal basis were prepared with the PTFE polymer ultrafine powder (purity ≥ 99.99%) as the starting material. We obtained 30 pieces of new PTFE polymer sensors. By using scanning electron microscopy (SEM), the structure of the PTFE polymer coating’s column clusters was studied. One sample from the 30 pieces of new PTFE polymer sensors was analysed by SEM in four scales, i.e., 400×, 1000×, 10000×, and 25000×. It was shown that under the condition of high bias voltage and low bias current, uniformly PTFE polymer coating could be achieved, which indicates that the new EBVD equipment is suitable for mass production of stable and uniform polymer coating. Project supported by the National High Technology Research and Development Program of China (Grant No. 2013AA030901).

  2. ESTIMATION OF THE RATE OF VOC EMISSIONS FROM SOLVENT-BASED INDOOR COATING MATERIALS BASED ON PRODUCT FORMULATION

    EPA Science Inventory

    Two computational methods are proposed for estimation of the emission rate of volatile organic compounds (VOCs) from solvent-based indoor coating materials based on the knowledge of product formulation. The first method utilizes two previously developed mass transfer models with ...

  3. Personal computer guide for selecting alternative coatings for metal parts and products painting. Report for July 1995--January 1996

    SciTech Connect

    Cornstubble, D.R.; Baskir, K.N.; Kosusko, M.

    1996-01-01

    The paper describes the principles of the Coating Alternatives Guide (CAGE) program and the development of its Beta version for metal parts and products painting. The paper discusses the background of CAGE, the content and function of the CAGE program, the current needs of the program, and the long term goals of CAGE development.

  4. Aerosol gels

    NASA Technical Reports Server (NTRS)

    Sorensen, Christopher M. (Inventor); Chakrabarti, Amitabha (Inventor); Dhaubhadel, Rajan (Inventor); Gerving, Corey (Inventor)

    2010-01-01

    An improved process for the production of ultralow density, high specific surface area gel products is provided which comprises providing, in an enclosed chamber, a mixture made up of small particles of material suspended in gas; the particles are then caused to aggregate in the chamber to form ramified fractal aggregate gels. The particles should have a radius (a) of up to about 50 nm and the aerosol should have a volume fraction (f.sub.v) of at least 10.sup.-4. In preferred practice, the mixture is created by a spark-induced explosion of a precursor material (e.g., a hydrocarbon) and oxygen within the chamber. New compositions of matter are disclosed having densities below 3.0 mg/cc.

  5. Organic aerosols

    SciTech Connect

    Penner, J.E.

    1994-01-01

    Organic aerosols scatter solar radiation. They may also either enhance or decrease concentrations of cloud condensation nuclei. This paper summarizes observed concentrations of aerosols in remote continental and marine locations and provides estimates for the sources of organic aerosol matter. The anthropogenic sources of organic aerosols may be as large as the anthropogenic sources of sulfate aerosols, implying a similar magnitude of direct forcing of climate. The source estimates are highly uncertain and subject to revision in the future. A slow secondary source of organic aerosols of unknown origin may contribute to the observed oceanic concentrations. The role of organic aerosols acting as cloud condensation nuclei (CCN) is described and it is concluded that they may either enhance or decrease the ability of anthropogenic sulfate aerosols to act as CCN.

  6. Production, growth and properties of ultrafine atmospheric aerosol particles in an urban environment

    NASA Astrophysics Data System (ADS)

    Salma, I.; Borsós, T.; Weidinger, T.; Aalto, P.; Hussein, T.; Dal Maso, M.; Kulmala, M.

    2010-06-01

    Number concentrations of atmospheric aerosol particles were measured by a flow-switching type differential mobility particle sizer in an electrical mobility diameter range of 6-1000 nm in 30 channels near central Budapest with a time resolution of 10 min continuously from 3 November 2008 to 2 November 2009. Daily median number concentrations of particles varied from 3.8×103 to 29×103 cm-3 with a yearly median of 11.8×103 cm-3. Contribution of ultrafine particles to the total particle number ranged from 58 to 92% with a mean ratio and standard deviation of (79±6)%. Daily average number concentrations in various size fractions and contribution of ultrafine particles to the total particle number showed no seasonal dependency. Monthly mean number size distributions were similar to each other. Overall mean for the number median mobility diameter of the Aitken and accumulation modes were 26 and 93 nm, respectively, which are substantially smaller than for rural or background environments. The Aitken and accumulation modes contributed similarly to the total particle number concentrations at the actual measurement location. Median diameters of the Aitken and accumulation modes were shifted to larger values before nucleation started and over the growth process, which can be related to the presence of aged aerosol under the conditions that favour nucleation and growth. Particle concentrations were usually increased substantially after nucleations. Overall mean and standard deviation of the nucleation mode number concentrations were (10.4±2.8)×103 cm-3. Mean ratio and standard deviation of the nucleation mode number concentration to the total particle number concentration that was averaged for two hours just before the formation was detected was 2.3±1.1. Nucleation unambiguously occurred on 83 days, which represent 27% of all relevant days. Its frequency showed a remarkable seasonal variation with a minimum of 7.3% in winter and a maximum of 44% in spring. Formation

  7. Experimental determination of the partitioning coefficient and volatility of important BVOC oxidation products using the Aerosol Collection Module (ACM) coupled to a PTR-ToF-MS

    NASA Astrophysics Data System (ADS)

    Gkatzelis, G.; Hohaus, T.; Tillmann, R.; Schmitt, S. H.; Yu, Z.; Schlag, P.; Wegener, R.; Kaminski, M.; Kiendler-Scharr, A.

    2015-12-01

    Atmospheric aerosol can alter the Earth's radiative budget and global climate but can also affect human health. A dominant contributor to the submicrometer particulate matter (PM) is organic aerosol (OA). OA can be either directly emitted through e.g. combustion processes (primary OA) or formed through the oxidation of organic gases (secondary organic aerosol, SOA). A detailed understanding of SOA formation is of importance as it constitutes a major contribution to the total OA. The partitioning between the gas and particle phase as well as the volatility of individual components of SOA is yet poorly understood adding uncertainties and thus complicating climate modelling. In this work, a new experimental methodology was used for compound-specific analysis of organic aerosol. The Aerosol Collection Module (ACM) is a newly developed instrument that deploys an aerodynamic lens to separate the gas and particle phase of an aerosol. The particle phase is directed to a cooled sampling surface. After collection particles are thermally desorbed and transferred to a detector for further analysis. In the present work, the ACM was coupled to a Proton Transfer Reaction-Time of Flight-Mass Spectrometer (PTR-ToF-MS) to detect and quantify organic compounds partitioning between the gas and particle phase. This experimental approach was used in a set of experiments at the atmosphere simulation chamber SAPHIR to investigate SOA formation. Ozone oxidation with subsequent photochemical aging of β-pinene, limonene and real plant emissions from Pinus sylvestris (Scots pine) were studied. Simultaneous measurement of the gas and particle phase using the ACM-PTR-ToF-MS allows to report partitioning coefficients of important BVOC oxidation products. Additionally, volatility trends and changes of the SOA with photochemical aging are investigated and compared for all systems studied.

  8. Stability of Monodisperse Phospholipid-Coated Microbubbles Formed by Flow-Focusing at High Production Rates.

    PubMed

    Segers, Tim; de Rond, Leonie; de Jong, Nico; Borden, Mark; Versluis, Michel

    2016-04-26

    Monodisperse microbubble ultrasound contrast agents may dramatically increase the sensitivity and efficiency in ultrasound imaging and therapy. They can be produced directly in a microfluidic flow-focusing device, but questions remain as to the interfacial chemistry, such as the formation and development of the phospholipid monolayer coating over time. Here, we demonstrate the synthesis of monodisperse bubbles with radii of 2-10 μm at production rates ranging from 10(4) to 10(6) bubbles/s. All bubbles were found to dissolve to a stable final radius 2.55 times smaller than their initial radius, independent of the nozzle size and shear rate, indicating that the monolayer self-assembles prior to leaving the nozzle. The corresponding decrease in surface area by a factor 6.6 reveals that lipid molecules are adsorbed to the gas-liquid interface in the disordered expanded state, and they become mechanically compressed by Laplace pressure-driven bubble dissolution to a more ordered condensed state with near zero surface tension. Acoustic characterization of the stabilized microbubbles revealed that their shell stiffness gradually increased from 0.8 to 2.5 N/m with increasing number of insonations through the selective loss of the more soluble lipopolymer molecules. This work therefore demonstrates high-throughput production of clinically relevant monodisperse contrast microbubbles with excellent control over phospholipid monolayer elasticity and microbubble resonance. PMID:27006083

  9. Seasonal monitoring and estimation of regional aerosol distribution over Po valley, northern Italy, using a high-resolution MAIAC product

    NASA Astrophysics Data System (ADS)

    Arvani, Barbara; Pierce, R. Bradley; Lyapustin, Alexei I.; Wang, Yujie; Ghermandi, Grazia; Teggi, Sergio

    2016-09-01

    In this work, the new 1 km-resolved Multi-Angle Implementation of Atmospheric Correction (MAIAC) algorithm is employed to characterize seasonal PM10 - AOD correlations over northern Italy. The accuracy of the new dataset is assessed compared to the widely used Moderate Resolution Imaging Spectroradiometer (MODIS) Collection 5.1 Aerosol Optical Depth (AOD) data, retrieved at 0.55 μm with spatial resolution of 10 km (MYD04_L2). We focused on evaluating the ability of these two products to characterize both temporal and spatial distributions of aerosols within urban and suburban areas. Ground PM10 measurements were obtained from 73 of the Italian Regional Agency for Environmental Protection (ARPA) monitoring stations, spread across northern Italy, during a three-year period from 2010 to 2012. The Po Valley area (northern Italy) was chosen as the study domain because of its severe urban air pollution, resulting from it having the highest population and industrial manufacturing density in the country, being located in a valley where two surrounding mountain chains favor the stagnation of pollutants. We found that the global correlations between the bin-averaged PM10 and AOD are R2 = 0.83 and R2 = 0.44 for MYD04_L2 and for MAIAC, respectively, suggesting a greater sensitivity of the high-resolution product to small-scale deviations. However, the introduction of Relative Humidity (RH) and Planetary Boundary Layer (PBL) depth corrections allowed for a significant improvement to the bin-averaged PM - AOD correlation, which led to a similar performance: R2 = 0.96 for MODIS and R2 = 0.95 for MAIAC. Furthermore, the introduction of the PBL information in the corrected AOD values was found to be crucial in order to capture the clear seasonal cycle shown by measured PM10 values. The study allowed us to define four seasonal linear correlations that estimate PM10 concentrations satisfactorily from the remotely sensed MAIAC AOD retrieval. Overall, the results show that

  10. Induction heat treatment and technique of bioceramic coatings production on medical titanium alloys

    NASA Astrophysics Data System (ADS)

    Fomin, Aleksandr A.; Rodionov, Igor V.; Fomina, Marina A.; Poshivalova, Elena Y.; Krasnikov, Aleksandr V.; Petrova, Natalia N.; Zakharevich, Andrey M.; Skaptsov, Alexander A.; Gribov, Andrey N.; Atkin, Vsevolod S.

    2015-03-01

    Prospective composite bioceramic titania coatings were obtained on intraosseous implants fabricated from medical titanium alloy VT16 (Ti-2.5Al-5Mo-5V). Consistency changes of morphological characteristics, physico-mechanical properties and biocompatibility of experimental titanium implant coatings obtained by oxidation during induction heat treatment are defined. Technological recommendations for obtaining bioceramic coatings with extremely high strength on titanium items surface are given.

  11. Ceramic fiber insulation impregnated with an infra-red retardant coating and method for production thereof

    NASA Technical Reports Server (NTRS)

    Zinn, Alfred A. (Inventor); Tarkanian, Ryan Jeffrey (Inventor)

    2007-01-01

    The invented insulation is a ceramic fiber insulation wherein the ceramic fibers are treated with a coating which contains transition metal oxides. The invented process for coating the insulation is a process of applying the transition metal oxide coating to the fibers of the insulation after the fibers have been formed into a tile or other porous body. The coating of transition metal oxide lowers the transmittance of radiation through the insulation thereby lowering the temperature of the backface of the insulation and better protecting the structure that underlies the insulation.

  12. History of the development and industrial production of low thermal emissivity coatings for high heat insulating glass units.

    PubMed

    Gläser, Hans J

    2008-05-01

    Low-emissivity (low-E) coatings play a dominate role in high heat insulating multiple glass units with which an essential part of heat energy can be saved in buildings. With such coatings as the main part, and to a lesser part with low thermal conductive filling gases of the units' interspaces, their heat transmittance can be reduced from 6.0 W/m(2)? K for a single glazing--still glazed to a high degree--to 0.4 W/m(2) K for a triple insulating glass unit. This astonishing development is regarded as one of the most important innovations of the flat glass industry in the past century. The roots of low-E coatings in the 1960s, their startup for production in the 1970s, and, most important, further development steps accompanied by, and partly also codesigned actively by the author, are depicted. PMID:18449246

  13. Comparative In Vitro Toxicity Profile of Electronic and Tobacco Cigarettes, Smokeless Tobacco and Nicotine Replacement Therapy Products: E-Liquids, Extracts and Collected Aerosols

    PubMed Central

    Misra, Manoj; Leverette, Robert D.; Cooper, Bethany T.; Bennett, Melanee B.; Brown, Steven E.

    2014-01-01

    The use of electronic cigarettes (e-cigs) continues to increase worldwide in parallel with accumulating information on their potential toxicity and safety. In this study, an in vitro battery of established assays was used to examine the cytotoxicity, mutagenicity, genotoxicity and inflammatory responses of certain commercial e-cigs and compared to tobacco burning cigarettes, smokeless tobacco (SLT) products and a nicotine replacement therapy (NRT) product. The toxicity evaluation was performed on e-liquids and pad-collected aerosols of e-cigs, pad-collected smoke condensates of tobacco cigarettes and extracts of SLT and NRT products. In all assays, exposures with e-cig liquids and collected aerosols, at the doses tested, showed no significant activity when compared to tobacco burning cigarettes. Results for the e-cigs, with and without nicotine in two evaluated flavor variants, were very similar in all assays, indicating that the presence of nicotine and flavors, at the levels tested, did not induce any cytotoxic, genotoxic or inflammatory effects. The present findings indicate that neither the e-cig liquids and collected aerosols, nor the extracts of the SLT and NRT products produce any meaningful toxic effects in four widely-applied in vitro test systems, in which the conventional cigarette smoke preparations, at comparable exposures, are markedly cytotoxic and genotoxic. PMID:25361047

  14. OH- Initiated Heterogeneous Oxidation of Saturated Organic Aerosols in the Presence of SO2: Uptake Kinetics and Product Identification.

    NASA Astrophysics Data System (ADS)

    Richards-Henderson, N. K.; Ward, M.; Goldstein, A. H.; Wilson, K. R.

    2014-12-01

    Gas-phase oxidation mechanisms for organic gases are often used as a starting point to understand heterogeneous oxidation. The reaction of a simple alkane hydrocarbon by OH proceeds through hydrogen abstraction and under ambient conditions leads to peroxy radical (RO2) formation. RO2 can further react to form: (1) smaller molecular weight products (i.e. fragmentation) via alkoxy radical formation and dissociation and/or (2) higher molecular weight products with oxygenated functional groups (i.e. functionalization). The ability to perturb these two pathways (functionalization vs. fragmentation) is critical for understanding the detailed reaction mechanism that control atmospheric aging chemistry of particles. At high temperatures the presence of sulfur dioxide (SO2) during organic-OH gas-phase oxidation enhances the fragmentation pathway leading to increased alkoxy formation. It is unknown if a comparative affect occurs at room temperature during a heterogeneous reaction. We used the heterogeneous reaction of OH radicals with sub-micron squalane particles in the presence and absence of SO2 as a model system to explore changes in individual mechanistic pathways. Detailed kinetic measurements were made in a flow tube reactor using a vacuum ultraviolet (VUV) photoionization aerosol mass spectrometer and oxidation products are identified from samples collected on quartz filters using thermal desorption two-dimensional chromatographic separation and ionization by either VUV (10.5 eV) or electron impact (70 eV), with detection by high resolution time of flight mass spectrometry (GCxGC-VUV/EI-HRTOFMS). In the presence of SO2 the yields of alcohols were enhanced compared to without SO2, suggesting that the alkoxy formation pathway was dominant. The results from this work will provide an experimentally-confirmed kinetic framework that could be used to model atmospheric aging mechanisms.

  15. MISR Level 2 Aerosol and Land Versioning

    Atmospheric Science Data Center

    2013-04-01

    ... Current F12_0022 (aerosol), F07_0022 (land) 12/01/2007 Data Product Specification Rev Q ... AEROSOL: Revised Dark Water algorithm to use a common subregion location across all channels. Revised ...

  16. Study of MPLNET-Derived Aerosol Climatology over Kanpur, India, and Validation of CALIPSO Level 2 Version 3 Backscatter and Extinction Products

    NASA Technical Reports Server (NTRS)

    Misra, Amit; Tripathi, S. N.; Kaul, D. S.; Welton, Ellsworth J.

    2012-01-01

    The level 2 aerosol backscatter and extinction profiles from the NASA Micropulse Lidar Network (MPLNET) at Kanpur, India, have been studied from May 2009 to September 2010. Monthly averaged extinction profiles from MPLNET shows high extinction values near the surface during October March. Higher extinction values at altitudes of 24 km are observed from April to June, a period marked by frequent dust episodes. Version 3 level 2 Cloud Aerosol Lidar with Orthogonal Polarization (CALIOP) aerosol profile products have been compared with corresponding data from MPLNET over Kanpur for the above-mentioned period. Out of the available backscatter profiles, the16 profiles used in this study have time differences less than 3 h and distances less than 130 km. Among these profiles, four cases show good comparison above 400 m with R2 greater than 0.7. Comparison with AERONET data shows that the aerosol type is properly identified by the CALIOP algorithm. Cloud contamination is a possible source of error in the remaining cases of poor comparison. Another source of error is the improper backscatter-to-extinction ratio, which further affects the accuracy of extinction coefficient retrieval.

  17. Production, growth and properties of ultrafine atmospheric aerosol particles in an urban environment

    NASA Astrophysics Data System (ADS)

    Salma, I.; Borsós, T.; Weidinger, T.; Aalto, P.; Hussein, T.; Dal Maso, M.; Kulmala, M.

    2011-02-01

    Number concentrations of atmospheric aerosol particles were measured by a flow-switching type differential mobility particle sizer in an electrical mobility diameter range of 6-1000 nm in 30 channels near central Budapest with a time resolution of 10 min continuously from 3 November 2008 to 2 November 2009. Daily median number concentrations of particles varied from 3.8 × 103 to 29 ×103 cm-3 with a yearly median of 11.8 × 103 cm-3. Contribution of ultrafine particles to the total particle number ranged from 58 to 92% with a mean ratio and standard deviation of (79 ± 6)%. Typical diurnal variation of the particle number concentration was related to the major emission patterns in cities, new particle formation, sinks of particles and meteorology. Shapes of the monthly mean number size distributions were similar to each other. Overall mean for the number median mobility diameter of the Aitken and accumulation modes were 26 and 93 nm, respectively, which are substantially smaller than for rural or background environments. The Aitken and accumulation modes contributed similarly to the total particle number concentrations at the actual measurement location. New particle formation and growth unambiguously occurred on 83 days, which represent 27% of all relevant days. Hence, new particle formation and growth are not rare phenomena in Budapest. Their frequency showed an apparent seasonal variation with a minimum of 7.3% in winter and a maximum of 44% in spring. New particle formation events were linked to increased gas-phase H2SO4 concentrations. In the studied area, new particle formation is mainly affected by condensation sink and solar radiation. The formation process seems to be not sensitive to SO2, which was present in a yearly median concentration of 6.7 μg m-3. This suggests that the precursor gas was always available in excess. Formation rate of particles with a diameter of 6 nm varied between 1.65 and 12.5 cm-3 s-1 with a mean and standard deviation of (4.2

  18. Observational Constraints on Glyoxal Production from Isoprene Oxidation and Its Contribution to Organic Aerosol Over the Southeast United States

    NASA Astrophysics Data System (ADS)

    Li, J.; Mao, J.; Min, K. E.; Washenfelder, R. A.; Brown, S. S.; Kaiser, J.; Keutsch, F. N.; Wolfe, G. M.; Hanisco, T. F.; Pollack, I. B.; Ryerson, T. B.; Graus, M.; Gilman, J.; Lerner, B. M.; Warneke, C.; De Gouw, J. A.; Middlebrook, A. M.; Henderson, B. H.; Paulot, F.; Horowitz, L. W.; Liao, J.; Welti, A.

    2015-12-01

    We use observations from the NOAA Southeast Nexus (SENEX) aircraft campaign, evaluated with a nudged global chemistry-climate model, to better understand the sources and sinks of glyoxal over the Southeast United States. We find that the model with an isoprene oxidation mechanism that does not account for δ-hydroxyl peroxy radicals (δ-ISOPO2), can better reproduce the observed vertical profiles of glyoxal and HCHO, as well as their correlation (RGF) in the continental boundary layer. The suppression of δ-ISOPO2 is consistent with recent theoretical and laboratory studies, reflecting different fates of δ-ISOPO2 under chamber conditions (NO > 100 ppbv) vs. ambient conditions (NO ~ 0.1 ppbv). By including a reactive uptake of glyoxal in the model (γglyx=2.9×10-3), we find that this improves modeled glyoxal in the surface layer but leads to an underestimate of glyoxal above the surface. We estimate an upper limit (1.0 μg/m3) for SOA contributed by glyoxal uptake by aerosols and clouds in the boundary layer of this region. Our work highlights several uncertainties in current chemical mechanisms on glyoxal production from isoprene oxidation under high and low NOx conditions, which may lead to large biases in the estimates of its contribution to SOA formation. Further investigation on these pathways is warranted to quantify the sources and sinks of glyoxal in regional and global scales.

  19. Evaluation of Lactobacillus rhamnosus GG and Lactobacillus acidophilus NCFM encapsulated using a novel impinging aerosol method in fruit food products.

    PubMed

    Sohail, Asma; Turner, Mark S; Prabawati, Elisabeth Kartika; Coombes, Allan G A; Bhandari, Bhesh

    2012-07-01

    This study investigated the effect of microencapsulation on the survival of Lactobacillus rhamnosus GG and Lactobacillus acidophilus NCFM and their acidification in orange juice at 25°C for nine days and at 4°C over thirty five days of storage. Alginate micro beads (10-40 μm) containing the probiotics were produced by a novel dual aerosol method of alginate and CaCl(2) cross linking solution. Unencapsulated L. rhamnosus GG was found to have excellent survivability in orange juice at both temperatures. However unencapsulated L. acidophilus NCFM showed significant reduction in viability. Encapsulation of these two bacteria did not significantly enhance survivability but did reduce acidification at 25°C and 4°C. In agreement with this, encapsulation of L. rhamnosus GG also reduced acidification in pear and peach fruit-based foods at 25°C, however at 4°C difference in pH was insignificant between free and encapsulated cells. In conclusion, L. rhamnosus GG showed excellent survival in orange juice and microencapsulation has potential in reducing acidification and possible negative sensory effects of probiotics in orange juice and other fruit-based products. PMID:22633536

  20. Fe-Zn Alloy Coating on Galvannealed (GA) Steel Sheet to Improve Product Qualities

    NASA Astrophysics Data System (ADS)

    Pradhan, Debabrata; Guin, Akshya Kumar; Raju, Pankaj; Manna, Manindra; Dutta, Monojit; Venugopalan, T.

    2014-09-01

    Galvannealed steel sheets (GA) have become the mainstream steel sheet for automobile applications because of their superior corrosion resistance, paintability, and weldability. To impart specific properties, different coatings on GA steel sheet were reported to improve properties further. In this context, we have developed an electroplating process (flash coating) for bright and adherent Fe-Zn alloy coating on GA steel sheet to enhance performances such as weldability, frictional behavior, phosphatability, and defect coverage. A comparative study with bare GA steel sheet was carried out for better elastration. The electroplating time was reduced below 10 s for practical applicability in an industrial coating line by modulating the bath composition. Electroplating was performed at current density of 200-500 A/m2 which yielded with higher cathode current efficiency of 85-95%. The performance results show that Fe-10 wt.% Zn-coated GA steel sheet (coating time 7 s) has better spot weldability, lower dynamic coefficient of friction (0.06-0.07 in lubrication), and better corrosion resistance compared to bare GA steel sheet. Uniform phosphate coating with globular crystal size of 2-5 µm was obtained on Fe-Zn flash-coated GA steel sheet. Hopeite was the main phosphate compound (77.9 wt.%) identified along with spencerite (13.6 wt.%) and phosphophyllite (8.5 wt.%).

  1. Method of producing a carbon coated ceramic membrane and associated product

    DOEpatents

    Liu, P.K.T.; Gallaher, G.R.; Wu, J.C.S.

    1993-11-16

    A method is described for producing a carbon coated ceramic membrane including passing a selected hydrocarbon vapor through a ceramic membrane and controlling ceramic membrane exposure temperature and ceramic membrane exposure time. The method produces a carbon coated ceramic membrane of reduced pore size and modified surface properties having increased chemical, thermal and hydrothermal stability over an uncoated ceramic membrane. 12 figures.

  2. Method of producing a carbon coated ceramic membrane and associated product

    DOEpatents

    Liu, Paul K. T.; Gallaher, George R.; Wu, Jeffrey C. S.

    1993-01-01

    A method of producing a carbon coated ceramic membrane including passing a selected hydrocarbon vapor through a ceramic membrane and controlling ceramic membrane exposure temperature and ceramic membrane exposure time. The method produces a carbon coated ceramic membrane of reduced pore size and modified surface properties having increased chemical, thermal and hydrothermal stability over an uncoated ceramic membrane.

  3. High-Resolution Mass Spectrometry and Molecular Characterization of Aqueous Photochemistry Products of Common Types of Secondary Organic Aerosols

    SciTech Connect

    Romonosky, Dian E.; Laskin, Alexander; Laskin, Julia; Nizkorodov, Sergey

    2015-03-19

    A significant fraction of atmospheric organic compounds is predominantly found in condensed phases, such as aerosol particles and cloud droplets. Many of these compounds are photolabile and can degrade through direct photolysis or indirect photooxidation processes on time scales that are comparable to the typical lifetimes of aqueous droplets (hours) and particles (days). This paper presents a systematic investigation of the molecular level composition and the extent of aqueous photochemical processing in different types of secondary organic aerosol (SOA) from biogenic and anthropogenic precursors including α-pinene, β-pinene, β-myrcene, d- limonene, α-humulene, 1,3,5-trimethylbenzene, and guaiacol, oxidized by ozone (to simulate a remote atmosphere) or by OH in the presence of NOx (to simulate an urban atmosphere). Chamber- and flow tube-generated SOA samples were collected, extracted in a methanol/water solution, and photolyzed for 1 h under identical irradiation conditions. In these experiments, the irradiation was equivalent to about 3-8 h of exposure to the sun in its zenith. The molecular level composition of the dissolved SOA was probed before and after photolysis with direct-infusion electrospray ionization high-resolution mass spectrometry (ESI-HR-MS). The mass spectra of unphotolyzed SOA generated by ozone oxidation of monoterpenes showed qualitatively similar features, and contained largely overlapping subsets of identified compounds. The mass spectra of OH/NOx generated SOA had more unique visual appearance, and indicated a lower extent of products overlap. Furthermore, the fraction of nitrogen containing species (organonitrates and nitroaromatics) was highly sensitive to the SOA precursor. These observations suggest that attribution of high-resolution mass spectra in field SOA samples to specific SOA precursors should be more straightforward under OH/NOx oxidation conditions compared to the ozone driven oxidation. Comparison of the SOA constituents

  4. Biogenic oxidized organic functional groups in aerosol particles from a mountain forest site and their similarities to laboratory chamber products

    NASA Astrophysics Data System (ADS)

    Schwartz, R. E.; Russell, L. M.; Sjostedt, S. J.; Vlasenko, A.; Slowik, J. G.; Abbatt, J. P. D.; MacDonald, A. M.; Li, S. M.; Liggio, J.; Toom-Sauntry, D.; Leaitch, W. R.

    2010-06-01

    Submicron particles collected at Whistler, British Columbia, at 1020 m a.s.l. during May and June 2008 on Teflon filters were analyzed by Fourier transform infrared (FTIR) and X-ray fluorescence (XRF) techniques for organic functional groups (OFG) and elemental composition. Organic mass (OM) concentrations ranged from less than 0.5 to 3.1 μg m-3, with a project mean and standard deviation of 1.3±1.0 μg m-3 and 0.21±0.16 μg m-3 for OM and sulfate, respectively. On average, organic hydroxyl, alkane, and carboxylic acid groups represented 34%, 33%, and 23% of OM, respectively. Ketone, amine and organosulfate groups constituted 6%, 5%, and <1% of the average organic aerosol composition, respectively. Measurements of volatile organic compounds (VOC), including isoprene and monoterpenes from biogenic VOC (BVOC) emissions and their oxidation products (methyl-vinylketone / methacrolein, MVK/MACR), were made using co-located proton transfer reaction mass spectrometry (PTR-MS). We present chemically-specific evidence of OFG associated with BVOC emissions. Positive matrix factorization (PMF) analysis attributed 65% of the campaign OM to biogenic sources, based on the correlations of one factor to monoterpenes and MVK/MACR. The remaining fraction was attributed to anthropogenic sources based on a correlation to sulfate. The functional group composition of the biogenic factor (consisting of 32% alkane, 25% carboxylic acid, 21% organic hydroxyl, 16% ketone, and 6% amine groups) was similar to that of secondary organic aerosol (SOA) reported from the oxidation of BVOCs in laboratory chamber studies, providing evidence that the magnitude and chemical composition of biogenic SOA simulated in the laboratory is similar to that found in actual atmospheric conditions. The biogenic factor OM is also correlated to dust elements, indicating that dust may act as a non-acidic SOA sink. This role is supported by the organic functional group composition and morphology of single particles

  5. Biogenic oxidized organic functional groups in aerosol particles from a mountain forest site and their similarities to laboratory chamber products

    NASA Astrophysics Data System (ADS)

    Schwartz, R. E.; Russell, L. M.; Sjosted, S. J.; Vlasenko, A.; Slowik, J. G.; Abbatt, J. P. D.; MacDonald, A. M.; Li, S. M.; Liggio, J.; Toom-Sauntry, D.; Leaitch, W. R.

    2010-02-01

    Submicron particles collected at Whistler, British Columbia, at 1020 masl during May and June 2008 on Teflon filters were analyzed by Fourier transform infrared (FTIR) and X-ray fluorescence (XRF) techniques for organic functional groups (OFG) and elemental composition. Organic mass (OM) ranged from less than 0.5 to 3.1μg m-3, with a project mean and standard deviation of 1.3±1.0 μg m-3 and 0.21±0.16 μg m-3 for OM and sulfate, respectively. On average, organic hydroxyl, alkane, and carboxylic acid groups represented 34%, 33%, and 23% of OM, respectively. Ketone, amine and organosulfate groups constituted 6%, 5%, and <1% of the average organic aerosol composition, respectively. Measurements of volatile organic compounds (VOC), including isoprene and monoterpenes from biogenic VOC (BVOC) emissions and their oxidation products (methyl-vinylketone/methacrolein, MVK/MACR), were made using co-located proton transfer reaction mass spectrometry (PTR-MS). We present chemically-specific evidence of OFG associated with BVOC emissions. Positive matrix factorization (PMF) analysis attributed 65% of the campaign OM to biogenic sources, based on the correlations of one factor to monoterpenes and MVK/MACR. The remaining fraction was attributed to anthropogenic sources based on a correlation to sulfate. The functional group composition of the biogenic factor (consisting of 32% alkane, 25% carboxylic acid, 2% organic hydroxyl, 16% ketone, and 6% amine groups) was similar to that of secondary organic aerosol (SOA) reported from the oxidation of BVOCs in laboratory chamber studies, providing evidence that the magnitude and chemical composition of biogenic SOA simulated in the laboratory is similar to that found in actual atmospheric conditions. The biogenic factor OM is also correlated to dust elements, indicating that dust may act as a non-acidic SOA sink. This role is supported by the organic functional group composition and morphology of single particles, which were analyzed

  6. Improvement of black nickel coatings. [product development for use in solar collectors

    NASA Technical Reports Server (NTRS)

    Peterson, R. E.; Lin, J. H.

    1976-01-01

    Selectively absorbing black nickel coatings are among the most optically efficient low cost coatings for use on flat plate solar collectors. However, a current Ni-Zn-S-O coating in use is quite susceptible to a humid environment, degrading badly in less than ten days at 38 C (100 F) at 95 percent relative humidity. Therefore, a black nickel formula was developed which can withstand such exposures with no loss of optical efficiency, solar absorption of 0.92 and an infrared emittance (at 100 C) of 1.00 were still present after 14 days of humidity exposure. This compares to a solar absorptance of only 0.72 for the previous formula after a similar time period. The electroplating bath and conditions were changed to obtain the more stable coating configuration. The effect of bath composition, temperature, pH, and plating current density and time on the coating composition, spectral optical properties and durability were investigated systematically.

  7. Crystalline coats or hollow crystals as tools for product design in pharmaceutical industry

    NASA Astrophysics Data System (ADS)

    Ulrich, J.; Schuster, A.; Stelzer, T.

    2013-01-01

    The coating of pharmaceutical compounds is a field of high interest. As most of the coating materials form an amorphous layer around the material, the studies on crystalline coatings are rare. In this work the progress in this domain should be summarized and innovative results concerning crystalline hollow needles as coating material are presented. Since the first reports on needles formed via a solvent-mediated phase transition from solvates to hydrates, the field could be widened to hydrate-to-anhydrate and anhydrate-to-hydrate transformations. Novel investigations on hollow theophylline monohydrate and carbamazepine dihydrate needles are presented. It is shown that the inclusion of substances into the hollow needle crystals is feasible by simple means, which enable an application in industry as coating for sensitive materials.

  8. DEVELOPMENT OF AN INNOVATIVE SPRAY DISPENSER TO REDUCE INDOOR AIR EMISSIONS FROM AEROSOL CONSUMER PRODUCTS

    EPA Science Inventory

    The report presents the operating principles and performance of a new type of spray nozzle. This nozzle, termed a "ligament-controlled effervescent atomizer," was developed to allow consumer product manufacturers to replace volatile organic compound (VOC) solvents with water, and...

  9. Porous carbon-coated graphite electrodes for energy production from salinity gradient using reverse electrodialysis

    NASA Astrophysics Data System (ADS)

    Lee, Su-Yoon; Jeong, Ye-Jin; Chae, So-Ryong; Yeon, Kyeong-Ho; Lee, Yunkyu; Kim, Chan-Soo; Jeong, Nam-Jo; Park, Jin-Soo

    2016-04-01

    Performance of graphite foil electrodes coated by porous carbon black (i.e., Vulcan) was investigated in comparison with metal electrodes for reverse electrodialysis (RED) application. The electrode slurry that was used for fabrication of the porous carbon-coated graphite foil is composed of 7.2 wt% of carbon black (Vulcan X-72), 0.8 wt% of a polymer binder (polyvinylidene fluoride, PVdF), and 92.0 wt% of a mixing solvent (dimethylacetamide, DMAc). Cyclic voltammograms of both the porous carbon (i.e., Vulcan)-coated graphite foil electrode and the graphite foil electrode without Vulcan showed good reversibility in the hexacyanoferrate(III) (i.e., Fe(CN)63-) and hexacyanoferrate(II) (i.e., Fe(CN)64-) redox couple and 1 M Na2SO4 at room temperature. However, anodic and cathodic current of the Vulcan-coated graphite foil electrode was much higher than those of the graphite foil electrode. Using a bench-scale RED stack, the current-voltage polarization curve of the Vulcan-coated graphite electrode was compared to that of metal electrodes such as iridium (Ir) and platinum (Pt). From the results, it was confirmed that resistance of four different electrodes increased with the following order: the Vulcan-coated graphite foilcoated titanium (Ti) meshcoated Ti platecoated graphite foil showed 5-10% higher power density than the metal mesh electrodes. From the polarization curve of the Vulcan-coated graphite foil electrode, it was found that total resistance decreased as thickness and geometric surface area of the electrode increased.

  10. Production of volatiles in fresh-cut apple: effect of applying alginate coatings containing linoleic acid or isoleucine.

    PubMed

    Maya-Meraz, Irma O; Espino-Díaz, Miguel; Molina-Corral, Francisco J; González-Aguilar, Gustavo A; Jacobo-Cuellar, Juan L; Sepulveda, David R; Olivas, Guadalupe I

    2014-11-01

    One of the main quality parameters in apples is aroma, its main precursors are fatty acids (FA) and amino acids (AA). In this study, alginate edible coatings were used as carriers of linoleic acid or isoleucine to serve as precursors for the production of aroma in cut apples. Apple wedges were immersed in a CaCl2 solution and coated with one of the following formulations: alginate solution (Alg-Ca), Alg-Ca-low-level linoleic acid (0.61 g/Lt), (LFA), Alg-Ca-high-level linoleic acid (2.44 g/L; HFA), Alg-Ca-low-level isoleucine (0.61 g/L; LAA), and Alg-Ca-high-level isoleucine (2.44 g/L; HAA). Apple wedges were stored at 3 °C and 85% relative humidity for 21 d and key volatiles were studied during storage. Addition of precursors, mainly isoleucine, showed to increase the production of some key volatiles on coated fresh-cut apples during storage. The concentration of 2-methyl-1-butanol was 4 times higher from day 12 to day 21 in HAA, while 2-methyl butyl acetate increased from day 12 to day 21 in HAA. After 21 d, HAA-apples presented a 40-fold value of 2-methyl-butyl acetate, compared to Alg-Ca cut apples. Values of hexanal increased during cut apple storage when the coating carried linoleic acid, mainly on HFA, from 3 to 12 d. The ability of apples to metabolize AA and FA depends on the concentration of precursors, but also depends on key enzymes, previous apple storage, among others. Further studies should be done to better clarify the behavior of fresh-cut apples as living tissue to metabolize precursors contained in edible coatings for the production of volatiles. PMID:25296624

  11. Design of Gas-phase Synthesis of Core-Shell Particles by Computational Fluid – Aerosol Dynamics

    PubMed Central

    Buesser, B.; Pratsinis, S.E.

    2013-01-01

    Core-shell particles preserve the bulk properties (e.g. magnetic, optical) of the core while its surface is modified by a shell material. Continuous aerosol coating of core TiO2 nanoparticles with nanothin silicon dioxide shells by jet injection of hexamethyldisiloxane precursor vapor downstream of titania particle formation is elucidated by combining computational fluid and aerosol dynamics. The effect of inlet coating vapor concentration and mixing intensity on product shell thickness distribution is presented. Rapid mixing of the core aerosol with the shell precursor vapor facilitates efficient synthesis of hermetically coated core-shell nanoparticles. The predicted extent of hermetic coating shells is compared to the measured photocatalytic oxidation of isopropanol by such particles as hermetic SiO2 shells prevent the photocatalytic activity of titania. Finally the performance of a simpler, plug-flow coating model is assessed by comparisons to the present detailed CFD model in terms of coating efficiency and silica average shell thickness and texture. PMID:23729817

  12. Laboratory Experiments and Instrument Intercomparison Studies of Carbonaceous Aerosol Particles

    SciTech Connect

    Davidovits, Paul

    2015-10-20

    Aerosols containing black carbon (and some specific types of organic particulate matter) directly absorb incoming light, heating the atmosphere. In addition, all aerosol particles backscatter solar light, leading to a net-cooling effect. Indirect effects involve hydrophilic aerosols, which serve as cloud condensation nuclei (CCN) that affect cloud cover and cloud stability, impacting both atmospheric radiation balance and precipitation patterns. At night, all clouds produce local warming, but overall clouds exert a net-cooling effect on the Earth. The effect of aerosol radiative forcing on climate may be as large as that of the greenhouse gases, but predominantly opposite in sign and much more uncertain. The uncertainties in the representation of aerosol interactions in climate models makes it problematic to use model projections to guide energy policy. The objective of our program is to reduce the uncertainties in the aerosol radiative forcing in the two areas highlighted in the ASR Science and Program Plan. That is, (1) addressing the direct effect by correlating particle chemistry and morphology with particle optical properties (i.e. absorption, scattering, extinction), and (2) addressing the indirect effect by correlating particle hygroscopicity and CCN activity with particle size, chemistry, and morphology. In this connection we are systematically studying particle formation, oxidation, and the effects of particle coating. The work is specifically focused on carbonaceous particles where the uncertainties in the climate relevant properties are the highest. The ongoing work consists of laboratory experiments and related instrument inter-comparison studies both coordinated with field and modeling studies, with the aim of providing reliable data to represent aerosol processes in climate models. The work is performed in the aerosol laboratory at Boston College. At the center of our laboratory setup are two main sources for the production of aerosol particles: (a

  13. Primary gas- and particle-phase emissions and secondary organic aerosol production from gasoline and diesel off-road engines.

    PubMed

    Gordon, Timothy D; Tkacik, Daniel S; Presto, Albert A; Zhang, Mang; Jathar, Shantanu H; Nguyen, Ngoc T; Massetti, John; Truong, Tin; Cicero-Fernandez, Pablo; Maddox, Christine; Rieger, Paul; Chattopadhyay, Sulekha; Maldonado, Hector; Maricq, M Matti; Robinson, Allen L

    2013-12-17

    Dilution and smog chamber experiments were performed to characterize the primary emissions and secondary organic aerosol (SOA) formation from gasoline and diesel small off-road engines (SOREs). These engines are high emitters of primary gas- and particle-phase pollutants relative to their fuel consumption. Two- and 4-stroke gasoline SOREs emit much more (up to 3 orders of magnitude more) nonmethane organic gases (NMOGs), primary PM and organic carbon than newer on-road gasoline vehicles (per kg of fuel burned). The primary emissions from a diesel transportation refrigeration unit were similar to those of older, uncontrolled diesel engines used in on-road vehicles (e.g., premodel year 2007 heavy-duty diesel trucks). Two-strokes emitted the largest fractional (and absolute) amount of SOA precursors compared to diesel and 4-stroke gasoline SOREs; however, 35-80% of the NMOG emissions from the engines could not be speciated using traditional gas chromatography or high-performance liquid chromatography. After 3 h of photo-oxidation in a smog chamber, dilute emissions from both 2- and 4-stroke gasoline SOREs produced large amounts of semivolatile SOA. The effective SOA yield (defined as the ratio of SOA mass to estimated mass of reacted precursors) was 2-4% for 2- and 4-stroke SOREs, which is comparable to yields from dilute exhaust from older passenger cars and unburned gasoline. This suggests that much of the SOA production was due to unburned fuel and/or lubrication oil. The total PM contribution of different mobile source categories to the ambient PM burden was calculated by combining primary emission, SOA production and fuel consumption data. Relative to their fuel consumption, SOREs are disproportionately high total PM sources; however, the vastly greater fuel consumption of on-road vehicles renders them (on-road vehicles) the dominant mobile source of ambient PM in the Los Angeles area. PMID:24261886

  14. AERUS-GEO: a MSG/SEVIRI satellite-based aerosol product allowing to capture dust events for the last 10 years over Europe and Africa

    NASA Astrophysics Data System (ADS)

    Carrer, Dominique; Roujean, Jean-Louis; Ceamanos, Xavier; Six, Bruno; Moparthy, Suman

    2016-04-01

    The aerosol signal derived from visible and near-infrared remote sensing observations can now be isolated thanks to a method allowing a proper separation of the atmosphere and surface components. This product is called AERUS-Geo (Aerosol and surface albEdo Retrieval Using a directional Splitting method - application to Geo data) and covers Europe, Africa, and the Eastern part of South America. It fully exploits the directional and temporal dimensions of the MSG/SEVIRI satellite signal through the use of a semi-empirical kernel-driven BRDF (Bidirectional Reflectance Distribution Function) model mimicking the radiative anisotropy for the surface/atmosphere coupled system. The AOD values estimated at 0.63 μm and 1.64 μm serve to calculate an Ångström coefficient that is further used to classify the aerosol layer into a continental, maritime, or a desert type. The AERUS-GEO product compares favourably with measurements of several AERONET stations, MODIS-derived (Moderate Resolution Imaging Spectro-radiometer), and MISR-derived (Multi-angle Imaging Spectro-Radiometer) products within a 20% of accuracy. The method proves to be competitive, not only in tracking anthropogenic aerosol emissions in the troposphere but also in estimating dust events. In addition, the higher frequency of AOD products with AERUS-GEO provides the means to quantify the aerosol radiative forcing in a more accurate manner than using low-orbit satellite data. The AERUS-GEO algorithm was implemented by the ICARE Data Center (http://www.icare.univ-lille1.fr), which operationally disseminates in near real time (NRT) a daily AOD product at 0.63 μm over the MSG (Meteosat Second Generation) disk since 2014. In addition to an NRT AOD product, also a long term reprocessing of satellite derived AOD still based on MSG/SEVIRI observations has been implemented. This allows to perform a thorough monitoring of the dust events over Europe and Africa for the last 10 years (2005 to 2015) for the benefit of a

  15. Phase partitioning and volatility of secondary organic aerosol components formed from α-pinene ozonolysis and OH oxidation: the importance of accretion products and other low volatility compounds

    NASA Astrophysics Data System (ADS)

    Lopez-Hilfiker, F. D.; Mohr, C.; Ehn, M.; Rubach, F.; Kleist, E.; Wildt, J.; Mentel, Th. F.; Carrasquillo, A.; Daumit, K.; Hunter, J.; Kroll, J. H.; Worsnop, D.; Thornton, J. A.

    2015-02-01

    We measured a large suite of gas and particle phase multi-functional organic compounds with a Filter Inlet for Gases and AEROsols (FIGAERO) coupled to a high-resolution time-of-flight chemical ionization mass spectrometer (HR-ToF-CIMS) developed at the University of Washington. The instrument was deployed on environmental simulation chambers to study monoterpene oxidation as a secondary organic aerosol (SOA) source. We focus here on results from experiments utilizing an ionization method most selective towards acids (acetate negative ion proton transfer), but our conclusions are based on more general physical and chemical properties of the SOA. Hundreds of compounds were observed in both gas and particle phases, the latter being detected upon temperature programmed thermal desorption of collected particles. Particulate organic compounds detected by the FIGAERO HR-ToF-CIMS are highly correlated with, and explain at least 25-50% of, the organic aerosol mass measured by an Aerodyne Aerosol Mass Spectrometer (AMS). Reproducible multi-modal structures in the thermograms for individual compounds of a given elemental composition reveal a significant SOA mass contribution from large molecular weight organics and/or oligomers (i.e. multi-phase accretion reaction products). Approximately 50% of the HR-ToF-CIMS particle phase mass is associated with compounds having effective vapor pressures 4 or more orders of magnitude lower than commonly measured monoterpene oxidation products. The relative importance of these accretion-type and other extremely low volatility products appears to vary with photochemical conditions. We present a desorption temperature based framework for apportionment of thermogram signals into volatility bins. The volatility-based apportionment greatly improves agreement between measured and modeled gas-particle partitioning for select major and minor components of the SOA, consistent with thermal decomposition during desorption causing the conversion of

  16. Phase partitioning and volatility of secondary organic aerosol components formed from α-pinene ozonolysis and OH oxidation: the importance of accretion products and other low volatility compounds

    NASA Astrophysics Data System (ADS)

    Lopez-Hilfiker, F. D.; Mohr, C.; Ehn, M.; Rubach, F.; Kleist, E.; Wildt, J.; Mentel, Th. F.; Carrasquillo, A. J.; Daumit, K. E.; Hunter, J. F.; Kroll, J. H.; Worsnop, D. R.; Thornton, J. A.

    2015-07-01

    We measured a large suite of gas- and particle-phase multi-functional organic compounds with a Filter Inlet for Gases and AEROsols (FIGAERO) coupled to a high-resolution time-of-flight chemical ionization mass spectrometer (HR-ToF-CIMS) developed at the University of Washington. The instrument was deployed on environmental simulation chambers to study monoterpene oxidation as a secondary organic aerosol (SOA) source. We focus here on results from experiments utilizing an ionization method most selective towards acids (acetate negative ion proton transfer), but our conclusions are based on more general physical and chemical properties of the SOA. Hundreds of compounds were observed in both gas and particle phases, the latter being detected by temperature-programmed thermal desorption of collected particles. Particulate organic compounds detected by the FIGAERO-HR-ToF-CIMS are highly correlated with, and explain at least 25-50 % of, the organic aerosol mass measured by an Aerodyne aerosol mass spectrometer (AMS). Reproducible multi-modal structures in the thermograms for individual compounds of a given elemental composition reveal a significant SOA mass contribution from high molecular weight organics and/or oligomers (i.e., multi-phase accretion reaction products). Approximately 50 % of the HR-ToF-CIMS particle-phase mass is associated with compounds having effective vapor pressures 4 or more orders of magnitude lower than commonly measured monoterpene oxidation products. The relative importance of these accretion-type and other extremely low volatility products appears to vary with photochemical conditions. We present a desorption-temperature-based framework for apportionment of thermogram signals into volatility bins. The volatility-based apportionment greatly improves agreement between measured and modeled gas-particle partitioning for select major and minor components of the SOA, consistent with thermal decomposition during desorption causing the conversion of

  17. Phase partitioning and volatility of secondary organic aerosol components formed from α-pinene ozonolysis and OH oxidation: the importance of accretion products and other low volatility compounds

    DOE PAGESBeta

    Lopez-Hilfiker, F. D.; Mohr, C.; Ehn, M.; Rubach, F.; Kleist, E.; Wildt, J.; Mentel, Th. F.; Carrasquillo, A. J.; Daumit, K. E.; Hunter, J. F.; et al

    2015-07-16

    We measured a large suite of gas- and particle-phase multi-functional organic compounds with a Filter Inlet for Gases and AEROsols (FIGAERO) coupled to a high-resolution time-of-flight chemical ionization mass spectrometer (HR-ToF-CIMS) developed at the University of Washington. The instrument was deployed on environmental simulation chambers to study monoterpene oxidation as a secondary organic aerosol (SOA) source. We focus here on results from experiments utilizing an ionization method most selective towards acids (acetate negative ion proton transfer), but our conclusions are based on more general physical and chemical properties of the SOA. Hundreds of compounds were observed in both gas andmore » particle phases, the latter being detected by temperature-programmed thermal desorption of collected particles. Particulate organic compounds detected by the FIGAERO–HR-ToF-CIMS are highly correlated with, and explain at least 25–50 % of, the organic aerosol mass measured by an Aerodyne aerosol mass spectrometer (AMS). Reproducible multi-modal structures in the thermograms for individual compounds of a given elemental composition reveal a significant SOA mass contribution from high molecular weight organics and/or oligomers (i.e., multi-phase accretion reaction products). Approximately 50 % of the HR-ToF-CIMS particle-phase mass is associated with compounds having effective vapor pressures 4 or more orders of magnitude lower than commonly measured monoterpene oxidation products. The relative importance of these accretion-type and other extremely low volatility products appears to vary with photochemical conditions. We present a desorption-temperature-based framework for apportionment of thermogram signals into volatility bins. The volatility-based apportionment greatly improves agreement between measured and modeled gas-particle partitioning for select major and minor components of the SOA, consistent with thermal decomposition during desorption causing the

  18. Phase partitioning and volatility of secondary organic aerosol components formed from α-pinene ozonolysis and OH oxidation: the importance of accretion products and other low volatility compounds

    DOE PAGESBeta

    Lopez-Hilfiker, F. D.; Mohr, C.; Ehn, M.; Rubach, F.; Kleist, E.; Wildt, J.; Mentel, Th. F.; Carrasquillo, A.; Daumit, K.; Hunter, J.; et al

    2015-02-18

    We measured a large suite of gas and particle phase multi-functional organic compounds with a Filter Inlet for Gases and AEROsols (FIGAERO) coupled to a high-resolution time-of-flight chemical ionization mass spectrometer (HR-ToF-CIMS) developed at the University of Washington. The instrument was deployed on environmental simulation chambers to study monoterpene oxidation as a secondary organic aerosol (SOA) source. We focus here on results from experiments utilizing an ionization method most selective towards acids (acetate negative ion proton transfer), but our conclusions are based on more general physical and chemical properties of the SOA. Hundreds of compounds were observed in both gasmore » and particle phases, the latter being detected upon temperature programmed thermal desorption of collected particles. Particulate organic compounds detected by the FIGAERO HR-ToF-CIMS are highly correlated with, and explain at least 25–50% of, the organic aerosol mass measured by an Aerodyne Aerosol Mass Spectrometer (AMS). Reproducible multi-modal structures in the thermograms for individual compounds of a given elemental composition reveal a significant SOA mass contribution from large molecular weight organics and/or oligomers (i.e. multi-phase accretion reaction products). Approximately 50% of the HR-ToF-CIMS particle phase mass is associated with compounds having effective vapor pressures 4 or more orders of magnitude lower than commonly measured monoterpene oxidation products. The relative importance of these accretion-type and other extremely low volatility products appears to vary with photochemical conditions. We present a desorption temperature based framework for apportionment of thermogram signals into volatility bins. The volatility-based apportionment greatly improves agreement between measured and modeled gas–particle partitioning for select major and minor components of the SOA, consistent with thermal decomposition during desorption causing the

  19. Chemical characteristics of organic aerosol in Bab-Ezzouar (Algiers). Contribution of bituminous product manufacture.

    PubMed

    Yassaa, N; Meklati, B Y; Cecinato, A; Marino, F

    2001-10-01

    The organic compositions of atmospheric particulate matter from Bab-Ezzouar (Algiers) have been investigated to assess the air pollution levels suspected to be caused by asphalt product and yeast manufactures. After a medium-volume air sampling, soxhlet extraction, alumina elution and HPLC separation, the extracts were analysed by high-resolution gas chromatography (HRGC) and gas chromatography coupled to mass spectrometry (GC-MS). The composition of n-alkane and polycyclic aromatic hydrocarbons (PAH) fractions reflected the petrogenic origin from the emission of asphalt materials production in addition to vascular plant wax emissions. In contrast, microbial activities seemed to play the main role for the presence of n-alkanoic acids at Bab-Ezzouar. The sole nitrated polycyclic aromatic hydrocarbons (NPAH) observed, i.e., 2-nitrofluoranthene (2NFA), was very likely to arise from gas-phase photochemical reaction of parent PAH in the atmosphere. The total aerial levels ranged from 75 to 206 ng m(-3) for n-alkanes, from 153 to 345 ng m(-3) for n-alkanoic acids and from 44 to 100 ng m(-3) for PAH and NPAH. Although the samples were collected during the hot season, the levels of these pollutants seemed to be important and of environmental concern, especially for PAH species. PMID:11592421

  20. Natural products and altered derivatives as tracers for biomass combustion in aerosols

    SciTech Connect

    Simoneit, B.R.T.; Radzi bin Abas, M.; Cass, G.R.

    1995-12-01

    Biomass combustion is an important primary source of carbonaceous particles in the global atmosphere. Various molecular markers have been proposed for this process but additional specific tracers are needed. The injection of natural product organic compounds into smoke occurs primarily by direct volatilization/steam stripping and by pyrolysis. Although the composition of organic matter in smoke particles is highly variable, the molecular structures of the tracers are generally source specific. Homologous compounds and biomarkers present in smoke are derived directly from plant wax, gum and resin by volatilization and secondarily from pyrolysis of biopolymers (e.g., lignin, cutin, suberin), wax, gum and resin. The component complexity is illustrated with examples from controlled bums of temperate and tropical biomass fuels. Conifer smoke contains characteristic tracers from diterpenoids as well as phenolics and other oxygenated species. These are recognizable in urban airsheds. The major organic components of smoke from tropical biomass are straight-chain, aliphatic and oxygenated compounds and triterpenoids. Several compounds are potential key indicators for combustion of such biomass. The precursor to product approach of organic geochemistry can be applied successfully to provide molecular tracers for studying smoke plume chemistry and dispersion.

  1. Apparatus for hydrogen and carbon production via carbon aerosol-catalyzed dissociation of hydrocarbons

    NASA Technical Reports Server (NTRS)

    Muradov, Nazim Z. (Inventor); Smith, Franklyn (Inventor); Tabatabaie-Raissi, Ali (Inventor)

    2012-01-01

    A novel process and apparatus is disclosed for sustainable, continuous production of hydrogen and carbon by catalytic dissociation or decomposition of hydrocarbons at elevated temperatures using in-situ generated carbon particles. Carbon particles are produced by decomposition of carbonaceous materials in response to an energy input. The energy input can be provided by at least one of a non-oxidative and oxidative means. The non-oxidative means of the energy input includes a high temperature source, or different types of plasma, such as, thermal, non-thermal, microwave, corona discharge, glow discharge, dielectric barrier discharge, or radiation sources, such as, electron beam, gamma, ultraviolet (UV). The oxidative means of the energy input includes oxygen, air, ozone, nitrous oxide (NO.sub.2) and other oxidizing agents. The method, apparatus and process of the present invention is applicable to any gaseous or liquid hydrocarbon fuel and it produces no or significantly less CO.sub.2 emissions compared to conventional processes.

  2. Evaluating Sources of Chemical Pathways of Aerosol Production on the Southern Ute Indian Reservation and Navajo Nation using Isotopic and Geochemical Analysis

    NASA Astrophysics Data System (ADS)

    King, M. Z.; Michalski, G. M.

    2012-12-01

    Increase emissions of nitrogen oxides (NOx) as a result of the development of oil, gas and coal resources in the Four Corners region of the United States have caused concern for area American Indian tribes that levels of ozone, acid rain, and aerosols or particulate matter (PM) may increase on reservation lands. NOx in the atmosphere plays an important role in the formation of these pollutants and high levels are indicators of poor air quality and exposure to them has been linked to a host of human health effects and environmental problems facing today's society. Nitrogen oxides are eventually oxidized in the atmosphere to form nitric acid and particulate nitrate which falls to earth's surface by way of dry or wet deposition. In the end, it is the removal of NOx from the atmosphere by chemical conversion to nitrate that halts this production of oxidants, acid, and aerosols. Despite the importance of understanding atmospheric nitrate production there remains major deficiencies in estimating the significant key reactions that transform atmospheric NOx. This project will examine the chemical composition (Cl-, NO3-, SO42-) and stable isotope composition (N15, O17, O18, Δ17O) of aerosols (PM2.5-PM10) collected on the Southern Ute Indian Reservation and Navajo Nation to provide insight into the sources of NOx and the oxidation pathways that convert NOx into nitrate on these reservation lands.

  3. Alkali resistant optical coatings for alkali lasers and methods of production thereof

    DOEpatents

    Soules, Thomas F; Beach, Raymond J; Mitchell, Scott C

    2014-11-18

    In one embodiment, a multilayer dielectric coating for use in an alkali laser includes two or more alternating layers of high and low refractive index materials, wherein an innermost layer includes a thicker, >500 nm, and dense, >97% of theoretical, layer of at least one of: alumina, zirconia, and hafnia for protecting subsequent layers of the two or more alternating layers of high and low index dielectric materials from alkali attack. In another embodiment, a method for forming an alkali resistant coating includes forming a first oxide material above a substrate and forming a second oxide material above the first oxide material to form a multilayer dielectric coating, wherein the second oxide material is on a side of the multilayer dielectric coating for contacting an alkali.

  4. CALIPSO Observations of Aerosol Properties Near Clouds

    NASA Technical Reports Server (NTRS)

    Marshak, Alexander; Varnai, Tamas; Yang, Weidong

    2010-01-01

    Clouds are surrounded by a transition zone of rapidly changing aerosol properties. Characterizing this zone is important for better understanding aerosol-cloud interactions and aerosol radiative effects as well as for improving satellite measurements of aerosol properties. We present a statistical analysis of a global dataset of CALIPSO (Cloud-Aerosol Lidar and infrared Pathfinder Satellite Observation) Lidar observations over oceans. The results show that the transition zone extends as far as 15 km away from clouds and it is ubiquitous over all oceans. The use of only high confidence level cloud-aerosol discrimination (CAD) data confirms the findings. However, the results underline the need for caution to avoid biases in studies of satellite aerosol products, aerosol-cloud interactions, and aerosol direct radiative effects.

  5. Polymer coating for immobilizing soluble ions in a phosphate ceramic product

    DOEpatents

    Singh, Dileep; Wagh, Arun S.; Patel, Kartikey D.

    2000-01-01

    A polymer coating is applied to the surface of a phosphate ceramic composite to effectively immobilize soluble salt anions encapsulated within the phosphate ceramic composite. The polymer coating is made from ceramic materials, including at least one inorganic metal compound, that wet and adhere to the surface structure of the phosphate ceramic composite, thereby isolating the soluble salt anions from the environment and ensuring long-term integrity of the phosphate ceramic composite.

  6. Polymer Coating for Immobilizing Soluble Ions in a Phosphate Ceramic Product

    SciTech Connect

    Singh, Dileep; Wagh, Arun S.; Patel, Kartikey D.

    1999-05-05

    A polymer coating is applied to the surface of a phosphate ceramic composite to effectively immobilize soluble salt anions encapsulated within the phosphate ceramic composite. The polymer coating is made from ceramic materials, including at least one inorganic metal compound, that wet and adhere to the surface structure of the phosphate ceramic composite, thereby isolating the soluble salt anions from the environment and ensuring long-term integrity of the phosphate ceramic composite.

  7. Application of an active alginate coating to control the growth of Listeria monocytogenes on poached and deli turkey products.

    PubMed

    Juck, Greg; Neetoo, Hudaa; Chen, Haiqiang

    2010-09-01

    The relatively high prevalence of Listeria monocytogenes in ready-to-eat (RTE) turkey products is of great concern. The overall objective of this study was to develop antimicrobial edible coating formulations to effectively control the growth of this pathogen. The antimicrobials studied were nisin (500IU/g), Novagard CB 1 (0.25%), Guardian NR100 (500ppm), sodium lactate (SL, 2.4%), sodium diacetate (SD, 0.25%), and potassium sorbate (PS, 0.3%). These were incorporated alone or in binary combinations into five edible coatings: alginate, kappa-carrageenan, pectin, xanthan gum, and starch. The coatings were applied onto the surface of home-style poached and processed deli turkey discs inoculated with ~3log CFU/g of L. monocytogenes. The turkey samples were then stored at 22 degrees C for 7days. For poached and processed deli turkey, the coatings were found to be equally effective, with pectin being slightly less effective than the others. The most effective poached turkey treatments seemed to be SL (2.4%)/SD (0.25%) and Nisin (500IU/g)/SL (2.4%), which yielded final populations of 3.0 and 4.9log CFU/g respectively compared to the control which was 7.9log CFU/g. For processed deli turkey, the most effective antimicrobial treatments seemed to be Nisin (500IU/g)/SD (0.25%) and Nisin (500IU/g)/SL (2.4%) with final populations of 1.5 and 1.7log CFU/g respectively compared to the control which was 6.5log CFU/g. In the second phase of the study, home-style poached and store-purchased roasted (deli) turkey inoculated with the pathogen at a level of ~3log CFU/g were coated with alginate incorporating selected antimicrobial combinations and stored for 8weeks at 4 degrees C. Alginate coatings supplemented with SL (2.4%)/PS (0.3%) delayed the growth of L. monocytogenes with final counts reaching 4.3log CFU/g (home-style poached turkey) and 6.5log CFU/g (roasted deli turkey) respectively while the counts in their untreated counterparts were significantly higher (P<0.05) reaching 9

  8. Fission Product Monitoring of TRISO Coated Fuel For The Advanced Gas Reactor -1 Experiment

    SciTech Connect

    Dawn M. Scates; John K Hartwell; John B. Walter

    2008-09-01

    The US Department of Energy has embarked on a series of tests of TRISO-coated particle reactor fuel intended for use in the Very High Temperature Reactor (VHTR) as part of the Advanced Gas Reactor (AGR) program. The AGR-1 TRISO fuel experiment, currently underway, is the first in a series of eight fuel tests planned for irradiation in the Advanced Test Reactor (ATR) located at the Idaho National Laboratory (INL). The AGR-1 experiment reached a peak compact averaged burn up of 9% FIMA with no known TRISO fuel particle failures in March 2008. The burnup goal for the majority of the fuel compacts is to have a compact averaged burnup greater than 18% FIMA and a minimum compact averaged burnup of 14% FIMA. At the INL the TRISO fuel in the AGR-1 experiment is closely monitored while it is being irradiated in the ATR. The effluent monitoring system used for the AGR-1 fuel is the Fission Product Monitoring System (FPMS). The FPMS is a valuable tool that provides near real-time data indicative of the AGR-1 test fuel performance and incorporates both high-purity germanium (HPGe) gamma-ray spectrometers and sodium iodide [NaI(Tl)] scintillation detector-based gross radiation monitors. To quantify the fuel performance, release-to-birth ratios (R/B’s) of radioactive fission gases are computed. The gamma-ray spectra acquired by the AGR-1 FPMS are analyzed and used to determine the released activities of specific fission gases, while a dedicated detector provides near-real time count rate information. Isotopic build up and depletion calculations provide the associated isotopic birth rates. This paper highlights the features of the FPMS, encompassing the equipment, methods and measures that enable the calculation of the release-to-birth ratios. Some preliminary results from the AGR-1 experiment are also presented.

  9. Fission Product Monitoring of TRISO Coated Fuel For The Advanced Gas Reactor -1 Experiment

    SciTech Connect

    Dawn M. Scates; John K. Hartwell; John b. Walter

    2010-10-01

    The US Department of Energy has embarked on a series of tests of TRISO-coated particle reactor fuel intended for use in the Very High Temperature Reactor (VHTR) as part of the Advanced Gas Reactor (AGR) program. The AGR-1 TRISO fuel experiment, currently underway, is the first in a series of eight fuel tests planned for irradiation in the Advanced Test Reactor (ATR) located at the Idaho National Laboratory (INL). The AGR-1 experiment reached a peak compact averaged burn up of 9% FIMA with no known TRISO fuel particle failures in March 2008. The burnup goal for the majority of the fuel compacts is to have a compact averaged burnup greater than 18% FIMA and a minimum compact averaged burnup of 14% FIMA. At the INL the TRISO fuel in the AGR-1 experiment is closely monitored while it is being irradiated in the ATR. The effluent monitoring system used for the AGR-1 fuel is the Fission Product Monitoring System (FPMS). The FPMS is a valuable tool that provides near real-time data indicative of the AGR-1 test fuel performance and incorporates both high-purity germanium (HPGe) gamma-ray spectrometers and sodium iodide [NaI(Tl)] scintillation detector-based gross radiation monitors. To quantify the fuel performance, release-to-birth ratios (R/B’s) of radioactive fission gases are computed. The gamma-ray spectra acquired by the AGR-1 FPMS are analyzed and used to determine the released activities of specific fission gases, while a dedicated detector provides near-real time count rate information. Isotopic build up and depletion calculations provide the associated isotopic birth rates. This paper highlights the features of the FPMS, encompassing the equipment, methods and measures that enable the calculation of the release-to-birth ratios. Some preliminary results from the AGR-1 experiment are also presented.

  10. Toward Understanding Amines and Their Degradation Products from Postcombustion CO2 Capture Processes with Aerosol Mass Spectrometry

    PubMed Central

    2015-01-01

    Amine-based postcombustion CO2 capture (PCCC) is a promising technique for reducing CO2 emissions from fossil fuel burning plants. A concern of the technique, however, is the emission of amines and their degradation byproducts. To assess the environmental risk of this technique, standardized stack sampling and analytical methods are needed. Here we report on the development of an integrated approach that centers on the application of a high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS) for characterizing amines and PCCC-relevant species. Molecular characterization is achieved via ion chromatography (IC) and electrospray ionization high-resolution mass spectrometry (ESI-MS). The method has been optimized, particularly, by decreasing the AMS vaporizer temperature, to gain quantitative information on the elemental composition and major nitrogen-containing species in laboratory-degraded amine solvents commonly tested for PCCC applications, including ethanolamine (MEA), methyldiethanolamine (MDEA), and piperazine (PIP). The AMS-derived nitrogen-to-carbon (N/C) ratios for the degraded solvent and product mixtures agree well with the results from a total organic carbon and total nitrogen (TOC/TN) analyzer. In addition, marker ions identified in the AMS spectra are used to estimate the mass contributions of individual species. Overall, our results indicate that this new approach is suitable for characterizing PCCC-related mixtures as well as organic nitrogen species in other sample types. As an online instrument, AMS can be used for both real-time characterization of emissions from operating PCCC plants and ambient particles in the vicinity of the facilities. PMID:24617831

  11. Toward understanding amines and their degradation products from postcombustion CO2 capture processes with aerosol mass spectrometry.

    PubMed

    Ge, Xinlei; Shaw, Stephanie L; Zhang, Qi

    2014-05-01

    Amine-based postcombustion CO2 capture (PCCC) is a promising technique for reducing CO2 emissions from fossil fuel burning plants. A concern of the technique, however, is the emission of amines and their degradation byproducts. To assess the environmental risk of this technique, standardized stack sampling and analytical methods are needed. Here we report on the development of an integrated approach that centers on the application of a high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS) for characterizing amines and PCCC-relevant species. Molecular characterization is achieved via ion chromatography (IC) and electrospray ionization high-resolution mass spectrometry (ESI-MS). The method has been optimized, particularly, by decreasing the AMS vaporizer temperature, to gain quantitative information on the elemental composition and major nitrogen-containing species in laboratory-degraded amine solvents commonly tested for PCCC applications, including ethanolamine (MEA), methyldiethanolamine (MDEA), and piperazine (PIP). The AMS-derived nitrogen-to-carbon (N/C) ratios for the degraded solvent and product mixtures agree well with the results from a total organic carbon and total nitrogen (TOC/TN) analyzer. In addition, marker ions identified in the AMS spectra are used to estimate the mass contributions of individual species. Overall, our results indicate that this new approach is suitable for characterizing PCCC-related mixtures as well as organic nitrogen species in other sample types. As an online instrument, AMS can be used for both real-time characterization of emissions from operating PCCC plants and ambient particles in the vicinity of the facilities. PMID:24617831

  12. CALIPSO Data Products Catalog

    Atmospheric Science Data Center

    2013-11-12

    ... aerosol, and stratospheric subtypes The cloud layer fraction was added to the aerosol profile data products. The aerosol layer fraction and surface winds were added to the cloud profile data product. ...

  13. Protective Coatings

    NASA Technical Reports Server (NTRS)

    1996-01-01

    Ameron International Protective Coatings Group developed a special coating for NASA that would withstand the high temperatures generated by the Space Shuttle rocket engines. The coating remains intact for at least 10 minutes, and insulates the launch pad so that it does not exceed 150 degrees and buckle. The NASA formulation was from Ameron's Engineered Siloxane (PSX) chemistry, which employs an inorganic silicon-oxygen structure which the company states is stronger and more reliable than organic polymers. Some of Ameron's PSX product line is based on the NASA technology, used for everything from industrial equipment to bridges.

  14. Development of Long Coated Conductors with High In-field Ic Performance by PLD Method at High Production Rate

    NASA Astrophysics Data System (ADS)

    Ibi, Akira; Yoshida, Tomo; Izumi, Teruo; Shiohara, Yuh; Yokoe, Daisaku; Kato, Takeharu; Hirayama, Tsukasa

    We fabricated short samples and a 93 m long coated conductor (C. C.) of EuBa2Cu3O7-δ (EuBCO) with BaHfO3 (BHO) by the IBAD and the PLD methods, which exhibited the high in-field minimum Ic value, (Ic(min)), performance of 141.2 (77 K in 3 T) and 411.3 (65 K in 3 T) A/cm-w for a short sample, and 133.9 (77 K in 3 T) A/cm-w for 93 m long C. C. with 3.6 μm in thickness, respectively. Moreover, this long EuBCO with BHO coated conductor also showed high uniform longitudinal Ic distributions and n-value in magnetic fields. However, the deposition rate for obtaining the high in-field Ic performance was comparatively slow down to 10 μm/h. To realize the low production cost for EuBCO with BHO coated conductors, improvement of the deposition rate of the EuBCO with BHO layer with high Ic is required. To solve this problem, we optimized growth conditions including deposition conditions. One of the objectives of this work was changing the layer growth mode from the vapor-solid (VS) mode to the vapor-liquid-solid (VLS) one to fabricate EuBCO with BHO layers for achievement of high production rate and maintaining the high in-field Ic and Jc performance of the films deposited at slow deposition rates. As a result, we fabricated EuBCO with BHO coated conductors at a high deposition rate of about 40 μm/h and production rate of about 10 m/h, which revealed the Ic(min) value of 48.7 A/cm-w at 77 K in 3 T for 1.35 μm in thickness.

  15. Production of Nanocrystalline Ni-20Cr Coatings for High-Temperature Applications

    NASA Astrophysics Data System (ADS)

    Kumar, Manoj; Singh, Harpreet; Singh, Narinder

    2014-04-01

    Presynthesized nanocrystalline Ni-20Cr powder was deposited on SA 516 and T91 boiler steels by a high-velocity oxy-fuel spraying process. Ni-20Cr powder was synthesized by the ball milling approach. The high-temperature oxidation behavior of bare and coated samples was then studied under cyclic isothermal conditions at 900 °C for 50 cycles. The kinetics of oxidation was established using weight change measurements for the bare and coated boiler steels. Uncoated and coated samples of T91 steel were exposed to the superheated zone of a power plant boiler at 750 °C under cyclic conditions for 15 cycles. Each cycle consisted of 100 h of heating followed by 1 h of cooling. Attempts were made to study the kinetics of erosion-corrosion using weight change and thickness loss data for the samples. Different characterization techniques were used to study the oxidized and eroded-corroded samples, including x-ray diffraction, scanning electron microscopy/energy-dispersive spectroscopy, and x-ray mapping analyses. The Ni-20Cr alloy powder coating was found to offer excellent oxidation resistance to the base steels and was successful in reducing the weight gain of SA 516 steel by 98.5 % and that of T91 steel by 65 %. The coating was observed to reduce the erosion-corrosion rate of T91 steel by 86 % in terms of thickness loss. This indicates that the investigated nanostructured coating can be a better choice over conventional coating for erosion-corrosion control of boiler tubes.

  16. Expert judgment and occupational hygiene: application to aerosol speciation in the nickel primary production industry.

    PubMed

    Ramachandran, Gurumurthy; Banerjee, Sudipto; Vincent, James H

    2003-08-01

    In many situations characterized by sparse data, occupational hygienists have used subjective judgments that are claimed to be derived from their experience and knowledge. While this practice is widespread, there has been no systematic study of 'expert judgment' or the 'art' of occupational hygiene. Indeed, there is a need to address the question of whether there is such a thing as 'expert opinion' in occupational hygiene that is broadly shared by practicing professionals. This research, employing 11 experts who estimate an exposure parameter (the percentages of four nickel species) in 12 workplaces in a nickel primary production industry, provides a large dataset from which useful inferences can be drawn about the quality of expert judgments and the variability among the experts. A well-designed questionnaire that provided succinct information about the processes and baseline data served to calibrate the experts. The Bayesian framework has been used in this work to develop posterior means and standard deviations of the percentages of the four nickel species in the 12 workplaces of interest in the company. These estimates of the nickel speciation are at least as precise as--and most of the time more precise than--those provided by the sparse measurement data. There was a very high degree of agreement among the experts. A majority of the experts agreed among themselves 92% of the time, while almost two-thirds agreed 73% of the time. This, coupled with the fact that the experts came from varied backgrounds, seems to suggest that there is indeed some broad body of specialized knowledge that the experts are drawing on to reach similar judgments. It also seems that one type of expert is not necessarily any better than any other kind, and expertise does not necessarily require intimate familiarity with the workplace. In this example, the expert judgment exercise has indeed enhanced the quality of our knowledge of the exposure 'fingerprints' for the nickel industry

  17. Understanding the anthropogenic influence on formation of biogenic secondary organic aerosols via analysis of organosulfates and related oxidation products

    NASA Astrophysics Data System (ADS)

    Nguyen, Q. T.; Christensen, M. K.; Cozzi, F.; Zare, A.; Hansen, A. M. K.; Kristensen, K.; Tulinius, T. E.; Madsen, H. H.; Christensen, J. H.; Brandt, J.; Massling, A.; Nøjgaard, J. K.; Glasius, M.

    2014-01-01

    Anthropogenic emissions of sulfur dioxide (SO2) and nitrogen oxides (NOx) may affect concentration levels and composition of biogenic secondary organic aerosols (BSOA) through photochemical reactions with biogenic organic precursors to form organosulfates and nitrooxy organosulfates. We investigated this influence in a field study from 19 May-22 June 2011 at two sampling sites in Denmark. Within the study, we identified a substantial number of organic acids, organosulfates and nitrooxy organosulfates in the ambient urban curbside and semi-rural background air. A high degree of correlation in concentrations was found among a group of specific organic acids, organosulfates and nitrooxy organosulfates, which may originate from various precursors, suggesting a common mechanism or factor affecting their concentration levels at the sites. It was proposed that the formation of those species most likely occurred on a larger spatial scale with the compounds being long-range transported to the sites on the days with highest concentrations. The origin of the long-range transported aerosols was investigated using the Hybrid Single Particle Lagrangian Integrated Trajectory (HYSPLIT) model in addition to modeled emissions of related precursors including isoprene and monoterpenes using the global Model of Emissions of Gases and Aerosols from Nature (MEGAN) and SO2 emissions using the European Monitoring and Evaluation Program (EMEP) database. The local impacts were also studied by examining the correlation between selected species which showed significantly enhanced concentrations at the urban curbside site and the local concentrations of various gases including SO2, ozone (O3), carbon monoxide (CO), NOx, aerosol acidity and other meteorological conditions. This investigation showed that an inter-play of the local parameters such as the aerosol acidity, NOx, relative humidity (RH), temperature and global radiation seemed to influence the concentration level of those species, via

  18. Dry particle coating of polymer particles for tailor-made product properties

    SciTech Connect

    Blümel, C. Schmidt, J. Dielesen, A. Sachs, M. Winzer, B. Peukert, W. Wirth, K.-E.

    2014-05-15

    Disperse polymer powders with tailor-made particle properties are of increasing interest in industrial applications such as Selective Laser Beam Melting processes (SLM). This study focuses on dry particle coating processes to improve the conductivity of the insulating polymer powder in order to assemble conductive devices. Therefore PP particles were coated with Carbon Black nanoparticles in a dry particle coating process. This process was investigated in dependence of process time and mass fraction of Carbon Black. The conductivity of the functionalized powders was measured by impedance spectroscopy. It was found that there is a dependence of process time, respectively coating ratio and conductivity. The powder shows higher conductivities with increasing number of guest particles per host particle surface area, i.e. there is a correlation between surface functionalization density and conductivity. The assembled composite particles open new possibilities for processing distinct polymers such as PP in SLM process. The fundamentals of the dry particle coating process of PP host particles with Carbon Black guest particles as well as the influence on the electrical conductivity will be discussed.

  19. Dry particle coating of polymer particles for tailor-made product properties

    NASA Astrophysics Data System (ADS)

    Blümel, C.; Schmidt, J.; Dielesen, A.; Sachs, M.; Winzer, B.; Peukert, W.; Wirth, K.-E.

    2014-05-01

    Disperse polymer powders with tailor-made particle properties are of increasing interest in industrial applications such as Selective Laser Beam Melting processes (SLM). This study focuses on dry particle coating processes to improve the conductivity of the insulating polymer powder in order to assemble conductive devices. Therefore PP particles were coated with Carbon Black nanoparticles in a dry particle coating process. This process was investigated in dependence of process time and mass fraction of Carbon Black. The conductivity of the functionalized powders was measured by impedance spectroscopy. It was found that there is a dependence of process time, respectively coating ratio and conductivity. The powder shows higher conductivities with increasing number of guest particles per host particle surface area, i.e. there is a correlation between surface functionalization density and conductivity. The assembled composite particles open new possibilities for processing distinct polymers such as PP in SLM process. The fundamentals of the dry particle coating process of PP host particles with Carbon Black guest particles as well as the influence on the electrical conductivity will be discussed.

  20. Preparation of cross-linked lipase-coated micro-crystals for biodiesel production from waste cooking oil.

    PubMed

    Yan, Jinyong; Yan, Yunjun; Liu, Sanxiong; Hu, Jiang; Wang, Guilong

    2011-04-01

    A dual modification procedure composed of cross-linking and protein coating with K(2)SO(4) was employed to modify Geotrichum sp. lipase for catalyzing biodiesel production from waste cooking oil. Compared to single modification of protein coating with K(2)SO(4), the dual modification of cross-linking and lipase coating improved catalytic properties in terms of thermostable stability, organic solvent tolerance, pH stability and operational stability in biodiesel production process, although biodiesel yield and initial reaction rate for CLPCMCs were not improved. After five successive batch reactions, CLPCMCs could still maintain 80% of relative biodiesel yield. CLPCMCs retained 64% of relative biodiesel yield after incubation in a pH range of 4-6 for 4 h, and 85% of relative biodiesel yield after incubation in a range of 45-50 °C for 4 h. CLPCMCs still maintained 83% of relative biodiesel yield after both treated in polar organic solvent and non-polar organic solvent for 4 h. PMID:21277775

  1. Known Unknowns Explained: Hono Daytime Production from the Anion-Catalyzed Uptake of NO2 on Secondary Organic Aerosol

    NASA Astrophysics Data System (ADS)

    Colussi, A. J.

    2012-12-01

    Recent evidence strongly suggests that the decay of NO2 in urban air and the related production of HONO at daytime involve unidentified multiphase reactions. Here we address these issues and analyze the results of field campaigns from the perspective of our laboratory studies on interfacial NO2 chemistry. We note that the similar (~ 4 hr) NO2 decay lifetimes inferred from satellite sightings over megacities ranging from 2° N to 40° N at all seasons are incompatible with the conventional view that NO2 is removed (as HNO3) by gas-phase OH-radicals whose concentrations depend on solar irradiance. This insight also applies to the daytime source of HONO, a non-photochemical process that reaches its maximal strength at noon. Herein, we present new laboratory experiments and quantum mechanical calculations confirming that the reactive uptake of gaseous NO2 on aqueous interfaces is generally catalyzed by anions, and show that the preceding observations can be accounted for by the disproportionation of NO2 (via 2 NO2 + H2O = H+ + NO3- + HONO) on secondary organic aerosol particles containing carboxylate ion loadings that peak at noon, as reported elsewhere.IGURE 1 - Left axis: The frequencies of O(1D) atom production from the solar photolysis of ozone, J(O1D), at zero elevation under an ozone column of 300 Dobson units at noon on (from left to right) Feb. 1st, May 1st, Aug. 1st and Nov. 1st over: (1) Singapore 1.3° N, (2) Pearl River Delta 22.5° N, (3) Riyadh 24.6° N, (4) Isfahan 32.6° N, (5) Los Angeles 34° N, (6) Tokyo 35.6° N, (7) Four Corners 36.7° N, (8) Madrid 40.4° N and (9) Moscow 55.8° N. Right axis (note the logarithmic scale): red dashes correspond to the ratios J(O1D)mid-summer/J(O1D)mid-winter (herein midsummer is Aug. 1st, midwinter is Feb. 1st).

  2. Diamond Coatings

    NASA Technical Reports Server (NTRS)

    1990-01-01

    Advances in materials technology have demonstrated that it is possible to get the advantages of diamond in a number of applications without the cost penalty, by coating and chemically bonding an inexpensive substrate with a thin film of diamond-like carbon (DLC). Diamond films offer tremendous technical and economic potential in such advances as chemically inert protective coatings; machine tools and parts capable of resisting wear 10 times longer; ball bearings and metal cutting tools; a broad variety of optical instruments and systems; and consumer products. Among the American companies engaged in DLC commercialization is Diamonex, Inc., a diamond coating spinoff of Air Products and Chemicals, Inc. Along with its own proprietary technology for both polycrystalline diamond and DLC coatings, Diamonex is using, under an exclusive license, NASA technology for depositing DLC on a substrate. Diamonex is developing, and offering commercially, under the trade name Diamond Aegis, a line of polycrystalline diamond-coated products that can be custom tailored for optical, electronic and engineering applications. Diamonex's initial focus is on optical products and the first commercial product is expected in late 1990. Other target applications include electronic heat sink substrates, x-ray lithography masks, metal cutting tools and bearings.

  3. Atmospheric reactivity of hydroxyl radicals with guaiacol (2-methoxyphenol), a biomass burning emitted compound: Secondary organic aerosol formation and gas-phase oxidation products

    NASA Astrophysics Data System (ADS)

    Lauraguais, Amélie; Coeur-Tourneur, Cécile; Cassez, Andy; Deboudt, Karine; Fourmentin, Marc; Choël, Marie

    2014-04-01

    Methoxyphenols are low molecular weight semi-volatile polar aromatic compounds produced from the pyrolysis of wood lignin. The reaction of guaiacol (2-methoxyphenol) with hydroxyl radicals has been studied in the LPCA simulation chamber at (294 ± 2) K, atmospheric pressure, low relative humidity (RH < 1%) and under high-NOx conditions using CH3ONO as OH source. The aerosol production was monitored using a SMPS (Scanning Mobility Particle Sizer); the SOA yields were in the range from 0.003 to 0.87 and the organic aerosol formation can be expressed by a one-product gas/particle partitioning absorption model. Transmission (TEM) and Scanning (SEM) Electron Microscopy observations were performed to characterize the physical state of SOA produced from the OH reaction with guaiacol; they display both liquid and solid particles (in an amorphous state). GC-FID (Gas Chromatography - Flame Ionization Detection) and GC-MS (Gas Chromatography - Mass Spectrometry) analysis show the formation of nitroguaiacol isomers as main oxidation products in the gas- and aerosol-phases. In the gas-phase, the formation yields were (10 ± 2) % for 4-nitroguaiacol (1-hydroxy-2-methoxy-4-nitrobenzene; 4-NG) and (6 ± 2) % for 3- or 6-nitroguaiacol (1-hydroxy-2-methoxy-3-nitrobenzene or 1-hydroxy-2-methoxy-6-nitrobenzene; 3/6-NG; the standards are not commercially available so both isomers cannot be distinguished) whereas in SOA their yield were much lower (≤0.1%). To our knowledge, this work represents the first identification of nitroguaiacols as gaseous oxidation products of the OH reaction with guaiacol. As the reactivity of nitroguaiacols with atmospheric oxidants is probably low, we suggest using them as biomass burning emission gas tracers. The atmospheric implications of the guaiacol + OH reaction are also discussed.

  4. Small global effect on terrestrial net primary production due to increased fossil fuel aerosol emissions from East Asia during the last decade.

    NASA Astrophysics Data System (ADS)

    O'Sullivan, Michael; Rap, Alex; Reddington, Carly; Spracklen, Dominick; Buermann, Wolfgang

    2016-04-01

    The global terrestrial carbon sink has increased since the start of this century at a time of rapidly growing carbon dioxide emissions from fossil fuel burning. Here we test the hypothesis that increases in atmospheric aerosols from fossil fuel burning have increased the diffuse fraction of incoming solar radiation and the efficiency of photosynthesis leading to increased plant carbon uptake. Using a combination of atmospheric and biospheric models, we find that changes in diffuse light associated with fossil fuel aerosol emission accounts for only 2.8% of the increase in global net primary production (1.221 PgC/yr) over the study period 1998 to 2007. This relatively small global signal is however a result of large regional compensations. Over East Asia, the strong increase in fossil fuel emissions contributed nearly 70% of the increased plant carbon uptake (21 TgC/yr), whereas the declining fossil fuel aerosol emissions in Europe and North America contributed negatively (-16% and -54%, respectively) to increased plant carbon uptake. At global scale, we also find the CO2 fertilization effect on photosynthesis to be the dominant driver of increased plant carbon uptake, in line with previous studies. These results suggest that further research into alternative mechanisms by which fossil fuel emissions could increase carbon uptake, such as nitrogen deposition and carbon-nitrogen interactions, is required to better understand a potential link between the recent changes in fossil fuel emissions and terrestrial carbon uptake.

  5. Production and performance of multilayer-coated conical x-ray mirrors

    NASA Astrophysics Data System (ADS)

    Ulmer, Melville P.; Altkorn, Robert; Graham, Michael E.; Madan, Anita; Chu, Yong S.

    2003-12-01

    A method of fabricating replica figured x-ray optics with integral multilayer coatings is presented. With the intact electroforming multilayer process (IEMP) technique, we sputter multilayers onto a reusable superpolished mandrel, electroform nickel over the multilayers, and remove the multilayer-coated nickel shell intact from the mandrel. This approach offers advantages over more traditional, original, and segmented-replica fabrication techniques, including low cost; compatibility with a wide range of mirror designs, diameters, and focal lengths; simple integration with multilayer sputtering processes; and the ability to produce complete shells of revolution. The fabrication of W/Si multilayer-coated 10-cm-diameter conical x-ray mirrors is described, as are reflectivity measurements at 10 and 30 keV. The measured reflectivity of the IEMP multilayers at the 10-keV primary Bragg peak was 17%. Measurements of multiple points on the cone showed multilayer uniformity to within a few percent around the mirror.

  6. Photoactivated chlorophyllin-based gelatin films and coatings to prevent microbial contamination of food products.

    PubMed

    López-Carballo, G; Hernández-Muñoz, P; Gavara, R; Ocio, M J

    2008-08-15

    The aim of this work was to develop antimicrobial photosensitizer-containing edible films and coatings based on gelatin as the polymer matrix, incorporating sodium magnesium chlorophyllin (E-140) and sodium copper chlorophyllin (E-141). Chlorophyllins were incorporated into the gelatin film-forming solution and the inhibiting effect of the cast films was tested against Staphylococcus aureus and Listeria monocytogenes. The results demonstrated that water soluble sodium magnesium chlorophyllin and water soluble sodium copper chlorophyllin reduced the growth of S. aureus and L. monocytogenes by 5 log and 4 log respectively. Subsequently, the activity of self-standing films and coatings containing E-140 was assessed on cooked frankfurters inoculated with S. aureus and L. monocytogenes. These tests showed that it was possible to reduce microorganism growth in cooked frankfurters inoculated with S. aureus and L. monocytogenes by covering them with sodium magnesium chlorophyllin-gelatin films and coatings. PMID:18555550

  7. Contribution of methane to aerosol carbon mass

    NASA Astrophysics Data System (ADS)

    Bianchi, F.; Barmet, P.; Stirnweis, L.; El Haddad, I.; Platt, S. M.; Saurer, M.; Lötscher, C.; Siegwolf, R.; Bigi, A.; Hoyle, C. R.; DeCarlo, P. F.; Slowik, J. G.; Prévôt, A. S. H.; Baltensperger, U.; Dommen, J.

    2016-09-01

    Small volatile organic compounds (VOC) such as methane (CH4) have long been considered non-relevant to aerosol formation due to the high volatility of their oxidation products. However, even low aerosol yields from CH4, the most abundant VOC in the atmosphere, would contribute significantly to the total particulate carbon budget. In this study, organic aerosol (OA) mass yields from CH4 oxidation were evaluated at the Paul Scherrer Institute (PSI) smog chamber in the presence of inorganic and organic seed aerosols. Using labeled 13C methane, we could detect its oxidation products in the aerosol phase, with yields up to 0.09

  8. New Products for a Better Characterisation of Smoke Plume and Gas/Aerosol Dispersion from Boreal Eurasian Forest Fires: The ALANIS Smoke Plume Project

    NASA Astrophysics Data System (ADS)

    Krol, M.; Peters, W.; Muller, J.-P.; Yershov, V.; San-Miguel, J.; Palumbo, I.; Sedano, F.; Strobl, P.; Clerbaux, C.; George, M.; Helbert, J.; Guillaume, B.

    2011-01-01

    The ALANIS (Atmosphere-LANd Integrated Study) Smoke Plume project is an on-going study funded by the ESA’s Support to Science Element (STSE) dedicated to the monitoring of the fire aerosol and trace gases dispersion over Eurasia from multi-mission EO- based data, in link with the scientific issues of land- atmosphere processes in the iLEAPS community. The injection and dispersion of the smoke plumes are performed with the TM5 model from several new products (burnt areas and forest fire emissions amounts, smoke plumes injection heights) derived from the MERIS and AATSR products and from the validated IASI CO products. A first study focused on the Russian wildfire events of the summer of 2010 has shown the potential of the European missions to assess the forest fire emissions and the aerosols/gases injection and transport over Eurasia. The release of the integrated model, including the new products still under development, is planned for the summer of 2011.

  9. Solutions Network Formulation Report. Integration of OMI and TES Aerosol Products into the EPA Regional Planning Organizations' FASTNET Aerosol Tracking and Analysis Tool

    NASA Technical Reports Server (NTRS)

    Knowlton, Kelly; Andrews, Jane C.

    2006-01-01

    Every year, more than 280 million visitors tour our Nation s most treasured parks and wilderness areas. Unfortunately, many visitors are unable to see the spectacular vistas they expect because of white or brown haze in the air. Most of this haze is not natural; it is air pollution, carried by the wind often hundreds of miles from its origin. Some of the pollutants have been linked to serious health problems, such as asthma and other lung disorders, and even premature death. In addition, nitrates and sulfates contribute to acid rain formation, which contaminates rivers and lakes and erodes buildings and historical monuments. The U.S. Environmental Protection Agency RPOs (Regional Planning Organizations) have been tasked with monitoring and determining the nature and origin of haze in Class I scenic areas, and finding ways to reduce haze in order to improve visibility in these areas. The RPOs have developed an Internet-based air quality DST (Decision Support Tool) called FASTNET (Fast Aerosol Sensing Tools for Natural Event Tracking). While FASTNET incorporates a few satellite datasets, most of the data utilized by this DST comes from ground-based instrument networks. The problem is that in many areas the sensors are sparsely located, with long distances between them, causing difficulties in tracking haze over the United States, determining its source, and analyzing its content. Satellite data could help to fill in the data gaps and to supplement and verify ground-recorded air quality data. Although satellite data are now being used for air quality research applications, such data are not routinely used for environmental decision support, in part because of limited resources, difficulties with interdisciplinary data interpretation, and the need for advanced inter-agency partnerships. As a result, the validation and verification of satellite data for air quality operational system applications has been limited This candidate solution evaluates the usefulness of OMI

  10. The Formation and Aerosol Uptake of Isoprene Nitrooxyhydroxyepoxide (INHE), a Newly Identified Product from the RO2 + HO2 Pathway of Isoprene NO3 Oxidation

    NASA Astrophysics Data System (ADS)

    Schwantes, R.; Teng, A.; Nguyen, T.; Coggon, M. M.; Zhang, X.; Schilling-Fahnestock, K.; Crounse, J.; St Clair, J. M.; Seinfeld, J.; Wennberg, P. O.

    2014-12-01

    Isoprene (C5H8) reacts with the nitrate radical (NO3) during the night to produce a peroxy nitrate radical (RO2). This RO2 can react with nitrogen oxides (i.e., NO, NO2, or NO3) and other RO2 radicals to form isoprene nitrates or with the hydroperoxyl radical (HO2) to form nitrooxyhydroperoxide (INP). Both model and field studies have found that in the ambient atmosphere much of the RO2 radical reacts with HO2. More specifically, during the 2013 SOAS field campaign, INP was one of the main species that increased at sunset suggesting the RO2 + HO2 pathway from NO3 oxidation is important in the southeastern US and similar areas. However, chamber studies so far have been run under conditions that optimize RO2 + NO3 reactions and/or RO2 + RO2 reactions. In this work, we present a new way to run NO3 oxidation chamber experiments that optimize for the RO2 + HO2 pathway creating a more atmospherically relevant product distribution. The gas phase formation of INP and subsequent oxidation products were monitored using a chemical ionization mass spectrometer (CIMS). Because isoprene nitrates formed from NO3 oxidation react slowly with ozone (O3) and NO3, many of these nitrates will remain in the atmosphere until the sun rises and hydroxyl radical (OH) begins to form. Results from these chamber experiments suggest that OH will react with INP to form nitrooxyhydroxyepoxide (INHE), a newly identified product from INP. We suspect INHE could be important for Secondary Organic Aerosol (SOA) production due to its similarity to isoprene epoxydiol (IEPOX), a product from isoprene OH oxidation that has been shown to be a significant SOA precursor. We studied the uptake of INHE onto various seed types, and found that as expected INHE rapidly partitions to highly acidic seed aerosol due to an acid catalyzed ring opening. A time-of-flight aerosol mass spectrometer (ToF-AMS) was used to understand the chemical composition of the aerosol produced from the various seed types.

  11. Identification and characterization of aging products in the glyoxal/ammonium sulfate system - implications for light-absorbing material in atmospheric aerosols

    NASA Astrophysics Data System (ADS)

    Kampf, C. J.; Jakob, R.; Hoffmann, T.

    2012-02-01

    In this study we report the identification of bicyclic imidazoles in aqueous aerosol mimics using HPLC-ESI-MS/MS. 2,2´-Biimidazole was identified to be a major contributor to the 280 nm absorbance band observed in mixtures of glyoxal and ammonium sulfate, despite the fact that its production rate is two orders of magnitude lower than the previously reported production rates of imidazole or imidazole-2-carboxaldehyde. The molar absorptivity of 2,2´-biimidazole was determined to be (36 690±998) M-1 cm-1. This demonstrates the necessity of molecular product identification at trace levels to enable a better understanding of relevant absorbing species. Additionally the formation of lower polarity products including formamides of imidazoles is proposed. The role of imidazoles and other light-absorbing species in the formation of SOA and optical properties of SOA is discussed and potentially interesting fields for future investigations are outlined.

  12. Identification and characterization of aging products in the glyoxal/ammonium sulfate system - implications for light-absorbing material in atmospheric aerosols

    NASA Astrophysics Data System (ADS)

    Kampf, C. J.; Jakob, R.; Hoffmann, T.

    2012-07-01

    In this study we report the identification of bicyclic imidazoles in aqueous aerosol mimics using HPLC-ESI-MS/MS. 2,2'-Biimidazole was identified to be a major contributor to the 280 nm absorbance band observed in mixtures of glyoxal and ammonium sulfate, despite the fact that its production rate is two orders of magnitude lower than the previously reported production rates of imidazole or imidazole-2-carboxaldehyde. The molar absorptivity of 2,2'-biimidazole was determined to be (36 690 ± 998) M-1 cm-1. This demonstrates the necessity of molecular product identification at trace levels to enable a better understanding of relevant absorbing species. Additionally, the formation of lower polarity products including formamides of imidazoles is proposed. The role of imidazoles and other light-absorbing species in the formation of SOA and optical properties of SOA is discussed and potentially interesting fields for future investigations are outlined.

  13. Aglite Lidar: A Portable Elastic Lidar System for Investigating Aerosol and Wind Motions at or Around Agricultural Production Facilities

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Aglite Lidar is a portable scanning lidar that can be quickly deployed at agricultural and other air quality study sites. The purpose of Aglite is to map the concentration of PM10 and PM2.5 in aerosol plumes from agricultural and other sources. Aglite uses a high-repetition rate low-pulse energy...

  14. AGLITE Lidar: A Portable Elastic Lidar System for Investigating Aerosol and Wind Motions at or Around Agricultural Production Facilities

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The AGLITE Lidar is a portable scanning lidar that can be quickly deployed at agricultural and other air quality study sites. The purpose of AGLITE is to map the concentration of PM10 and PM2.5 in aerosol plumes from agricultural sources. AGLITE uses a high-repetition rate low-pulse-energy 3-wavelen...

  15. Quantification of isocyanates and amines in polyurethane foams and coated products by liquid chromatography–tandem mass spectrometry

    PubMed Central

    Mutsuga, Motoh; Yamaguchi, Miku; Kawamura, Yoko

    2014-01-01

    An analytical method for the identification and quantification of 10 different isocyanates and 11 different amines in polyurethane (PUR) foam and PUR-coated products was developed and optimized. Isocyanates were extracted and derivatized with di-n-butylamine, while amines were extracted with methanol. Quantification was subsequently performed by liquid chromatography–tandem mass spectrometry. Using this methodology, residual levels of isocyanates and amines in commercial PUR products were quantified. Although the recoveries of certain isocyanates and amines were low, the main compounds used as monomers in the production of PUR products, and their decomposition species, were clearly identified at quantifiable levels. 2,4-and 2,6-toluenediisocyanate were detected in most PUR foam samples and a pastry bag in the range of 0.02–0.92 mg/kg, with their decomposition compounds, 2,4-and 2,6-toluenediamine, detected in all PUR foam samples in the range of 9.5–59 mg/kg. PUR-coated gloves are manufactured using 4,4′-methylenebisphenyl diisocyanate as the main raw material, and a large amount of this compound, in addition to 4,4′-methylenedianiline and dicyclohexylmethane-4,4′-diamine were found in these samples. PMID:24804074

  16. Assimilation of Aerosol Optical Depths

    NASA Astrophysics Data System (ADS)

    Verver, Gé; Henzing, Bas

    Climate predictions are hampered by the large uncertainties involved in the estima- tion of the effects of atmospheric aerosol (IPCC,2001). These uncertainties are caused partly because sources and sinks as well as atmospheric processing of the different types of aerosol are not accurately known. Moreover, the climate impact (especially the indirect effect) of a certain distribution of aerosol is hard to quantify. There have been different approaches to reduce these uncertainties. In recent years intensive ob- servational campaigns such as ACE and INDOEX have been carried out, aiming to in- crease our knowledge of atmospheric processes that determine the fate of atmospheric aerosols and to quantify the radiation effects. With the new satellite instruments such as SCIAMACHY and OMI it will be possible in the near future to derive the ge- ographical distribution of the aerosol optical depths (AOD) and perhaps additional information on the occurrence of different aerosol types. The goal of the ARIA project (started in 2001) is to assimilate global satellite de- rived aerosol optical depth (AOD) in an off-line chemistry/transport model TM3. The TM3 model (Jeuken et al. 2001) describes sources, sinks, transformation and transport processes of different types of aerosol (mineral dust, carbon, sulfate, nitrate) that are relevant to radiative forcing. All meteorological input is provided by ECMWF. The assimilation procedure constrains the aerosol distribution produced by the model on the basis of aerosol optical depths observed by satellite. The product, i.e. an optimal estimation of global aerosol distribution, is then available for the calculation of radia- tive forcing. Error analyses may provide valuable information on deficiencies of the model. In the ARIA project it is tried to extract additional information on the type of aerosol present in the atmosphere by assimilating AOD at multiple wavelengths. First results of the ARIA project will be presented. The values

  17. 75 FR 24973 - Notice Pursuant to the National Cooperative Research and Production Act of 1993-Advanced Coatings...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-05-06

    ... Coatings for Infrastructure Joint Venture Agreement Notice is hereby given that, on March 10, 2010... seq. (``the Act''), Advanced Coatings for Infrastructure Joint Venture Agreement (``Advanced Coatings... EMTEC, The Edison Materials Technology Center, Dayton, OH. The general area of Advanced...

  18. Adjuvants to prolong the local anesthetic effects of coated microneedle products.

    PubMed

    Zhang, Ying; Siebenaler, Kris; Brown, Ken; Dohmeier, Daniel; Hansen, Kris

    2012-12-15

    The objective of this study was to identify an adjuvant for anesthetics coated on microneedles to provide rapid onset and prolonged analgesic action with minimal skin tissue reaction. Aqueous lidocaine or prilocaine formulations with or without clonidine or the related analogs, guanfacine and apraclonidine, were dip-coated onto polymeric microneedles. The amount of lidocaine or prilocaine coated onto the microneedles was assessed by high performance liquid chromatography (HPLC). Delivery efficiency and dermal pharmacokinetics associated with lidocaine or prilocaine delivered via the microneedles were characterized in vivo using domestic swine. Skin punch biopsies were collected and analyzed to determine the anesthetic concentrations in the skin using HPLC-mass spectrometry (LC-MS). Addition of clonidine to the formulations decreased the systemic absorption rate of the anesthetics from the patch application site without impacting the coating performance or the rapid onset of anesthesia. Formulations with 0.3 wt.% clonidine, identified as the optimal dose for lidocaine-delivery via microneedles, maintained the lidocaine skin concentration above the estimated therapeutic level (100 ng/mg) for 1 h without causing any skin irritation or color change. The other two clonidine analogs, guanfacine and apraclonidine, also led to delayed systemic absorption of lidocaine from the skin, indicating utility in providing prolonged analgesia. PMID:23022295

  19. FINISHING FABRICATED METAL PRODUCTS WITH POWDER COATING. Project Summary (EPA/600/SR-96/152)

    EPA Science Inventory

    This report provides a technical and economic evaluation of a polyester powder coating system applied to the exterior and interior surfaces of metal boxes fabricated for the telephone and cable industries. This evaluation summarized many of the requirements and benefits of a clea...

  20. High-resolution mass spectrometry and molecular characterization of aqueous photochemistry products of common types of secondary organic aerosols.

    PubMed

    Romonosky, Dian E; Laskin, Alexander; Laskin, Julia; Nizkorodov, Sergey A

    2015-03-19

    This work presents a systematic investigation of the molecular level composition and the extent of aqueous photochemical processing in different types of secondary organic aerosol (SOA) from biogenic and anthropogenic precursors including α-pinene, β-pinene, β-myrcene, d-limonene, α-humulene, 1,3,5-trimethylbenzene, and guaiacol, oxidized by ozone (to simulate a remote atmosphere) or by OH in the presence of NOx (to simulate an urban atmosphere). Chamber- and flow-tube-generated SOA samples were collected, extracted in a methanol/water solution, and photolyzed for 1 h under identical irradiation conditions. In these experiments, the irradiation was equivalent to about 3-8 h of exposure to the sun in its zenith. The molecular level composition of the dissolved SOA was probed before and after photolysis with direct-infusion electrospray ionization high-resolution mass spectrometry (ESI-HR-MS). The mass spectra of unphotolyzed SOA generated by ozone oxidation of monoterpenes showed qualitatively similar features and contained largely overlapping subsets of identified compounds. The mass spectra of OH/NOx-generated SOA had more unique visual appearance and indicated a lower extent of product overlap. Furthermore, the fraction of nitrogen-containing species (organonitrates and nitroaromatics) was highly sensitive to the SOA precursor. These observations suggest that attribution of high-resolution mass spectra in field SOA samples to specific SOA precursors should be more straightforward under OH/NOx oxidation conditions compared to the ozone-driven oxidation. Comparison of the SOA constituents before and after photolysis showed the tendency to reduce the average number of atoms in the SOA compounds without a significant effect on the overall O/C and H/C ratios. SOA prepared by OH/NOx photooxidation of 1,3,5-trimethylbenzene and guaiacol were more resilient to photolysis despite being the most light-absorbing. The composition of SOA prepared by ozonolysis of

  1. Fruit wastes fermentation for phenolic antioxidants production and their application in manufacture of edible coatings and films.

    PubMed

    Martinez-Avila, G C G; Aguilera, A F; Saucedo, S; Rojas, R; Rodriguez, R; Aguilar, C N

    2014-01-01

    Agro-industrial by-products are important sources of potent bioactive phenolic compounds. These compounds are of extreme relevance for food and pharmacological industries due to their great variety of biological activities. Fermentation represents an environmentally clean technology for production and extraction of these bioactive compounds, providing high quality and high activity extracts, which can be incorporated in foods using coatings/films wax-based in order to avoid alterations in their quality. In this document is presented an overview about importance and benefits of solid-state fermentation, pointing out this bioprocess as an alternative technology for use agro-industrial by-products as substrates to produce valuable secondary metabolites and their applications as food quality conservatives. PMID:24188304

  2. Determination of volatile glucosinolate degradation products in seed coat, stem and in vitro cultures of Moringa peregrina (Forssk.) Fiori.

    PubMed

    Dehshahri, S; Afsharypuor, S; Asghari, G; Mohagheghzadeh, A

    2012-01-01

    Moringaceae, a monogeneric family in Capparales (glucosinolate-containing species), includes 14 species. One of them is Moringa peregrina (Forssk.) Fiori., a small tree, which grows in south east of Iran. Volatile constituents of seed coat and stem of M. peregrina were determined by GC and GC/MS. Moreover, extracts of seed and different cultured cells were analyzed by TLC and GC. Three volatile isothiocyanates including isopropyl isothiocyanate (4.2%), sec-butyl isothiocyanate (< 0.1%) and isobutyl isothiocyanate (92.9%) were found in the volatile oil of the stem , while only two volatile isothiocyanates namely isopropyl isothiocyanate (7.0%) and isobutyl isothiocyanate (51.5%) were determined in the seed coat of the tree. For the first time, the callus and suspension cultures of M. peregrina were initiated and established successfully on Murashige and Skoog medium, containing plant growth hormones. Different precursors and elicitors were fed to the cultures to induce glucosinolates production. This is the first report of in vitro culture production of M. peregrina. There was no production of volatile isothiocyanates in M. peregrina callus and suspension cultures with different treatments. PMID:23181080

  3. Global Aerosols

    Atmospheric Science Data Center

    2013-04-19

    ... sizes and from multiple sources, including biomass burning, mineral dust, sea salt and regional industrial pollution. A color scale is ... desert source region. Deserts are the main sources of mineral dust, and MISR obtains aerosol optical depth at visible wavelengths ...

  4. Electron Microscopic Evaluation and Fission Product Identification of Irradiated TRISO Coated Particles from the AGR-1 Experiment: A Preliminary Review

    SciTech Connect

    IJ van Rooyen; DE Janney; BD Miller; PA DEmkowicz; J Riesterer

    2014-05-01

    Post-irradiation examination of coated particle fuel from the AGR-1 experiment is in progress at Idaho National Laboratory and Oak Ridge National Laboratory. In this paper a brief summary of results from characterization of microstructures in the coating layers of selected irradiated fuel particles with burnup of 11.3% and 19.3% FIMA will be given. The main objectives of the characterization were to study irradiation effects, fuel kernel porosity, layer debonding, layer degradation or corrosion, fission-product precipitation, grain sizes, and transport of fission products from the kernels across the TRISO layers. Characterization techniques such as scanning electron microscopy, transmission electron microscopy, energy dispersive spectroscopy, and wavelength dispersive spectroscopy were used. A new approach to microscopic quantification of fission-product precipitates is also briefly demonstrated. Microstructural characterization focused on fission-product precipitates in the SiC-IPyC interface, the SiC layer and the fuel-buffer interlayer. The results provide significant new insights into mechanisms of fission-product transport. Although Pd-rich precipitates were identified at the SiC-IPyC interlayer, no significant SiC-layer thinning was observed for the particles investigated. Characterization of these precipitates highlighted the difficulty of measuring low concentrations of Ag in precipitates with significantly higher concentrations of Pd and U. Different approaches to resolving this problem are discussed. An initial hypothesis is provided to explain fission-product precipitate compositions and locations. No SiC phase transformations were observed and no debonding of the SiC-IPyC interlayer as a result of irradiation was observed for the samples investigated. Lessons learned from the post-irradiation examination are described and future actions are recommended.

  5. Electron microscopic evaluation and fission product identification of irradiated TRISO coated particles from the AGR-1 experiment: A preliminary Study

    SciTech Connect

    I J van Rooyen; D E Janney; B D Miller; J L Riesterer; P A Demkowicz

    2012-10-01

    ABSTRACT Post-irradiation examination of coated particle fuel from the AGR-1 experiment is in progress at Idaho National Laboratory and Oak Ridge National Laboratory. In this presentation a brief summary of results from characterization of microstructures in the coating layers of selected irradiated fuel particles with burnup of 11.3% and 19.3% FIMA will be given. The main objective of the characterization were to study irradiation effects, fuel kernel porosity, layer debonding, layer degradation or corrosion, fission-product precipitation, grain sizes, and transport of fission products from the kernels across the TRISO layers. Characterization techniques such as scanning electron microscopy, transmission electron microscopy, energy dispersive spectroscopy, and wavelength dispersive spectroscopy were used. A new approach to microscopic quantification of fission-product precipitates is also briefly demonstrated. The characterization emphasized fission-product precipitates in the SiC-IPyC interface, SiC layer and the fuel-buffer interlayer, and provided significant new insights into mechanisms of fission-product transport. Although Pd-rich precipitates were identified at the SiC-IPyC interlayer, no significant SiC-layer thinning was observed for the particles investigated. Characterization of these precipitates highlighted the difficulty of measuring low concentration Ag in precipitates with significantly higher concentrations of contain Pd and U. Different approaches to resolving this problem are discussed. Possible microstructural differences between particles with high and low releases of Ag particles are also briefly discussed, and an initial hypothesis is provided to explain fission-product precipitate compositions and locations. No SiC phase transformations or debonding of the SiC-IPyC interlayer as a result of irradiation were observed. Lessons learned from the post-irradiation examination are described and future actions are recommended.

  6. Laser-assisted plasma coating at atmospheric pressure: production of yttria-stabilized zirconia thermal barriers

    NASA Astrophysics Data System (ADS)

    Ouyang, Zihao; Meng, Liang; Raman, Priya; Cho, Tae S.; Ruzic, D. N.

    2011-07-01

    A laser-assisted plasma-coating technique at atmospheric pressure (LAPCAP) has been investigated. The electron temperature, electron density and gas temperature of the atmospheric-pressure plasma have been measured using optical emission spectroscopy (OES). LAPCAP utilizes laser ablation of 3 mol% yttria-stabilized zirconia into an atmospheric helium/nitrogen plasma to deposit thermal barrier coatings on a nickel-based substrate. The deposited film shows columnar structures similar to films prepared by high-vacuum deposition methods, such as physical vapour deposition and conventional pulsed-laser deposition. However, the LAPCAP films have smaller columns and higher porosity, compared with the films deposited by other techniques. The morphology and characteristics of the films have been analysed by scanning electron microscope, focused ion beam and x-ray diffraction.

  7. The Effects of Long Term Cure on Offgassed Products of Coatings

    NASA Technical Reports Server (NTRS)

    Engle, Ginger; Whitfield, Steve

    1997-01-01

    The Environmental Chemistry and Compatability Team at The Marshall Space Flight Center conducts toxic offgassing analysis on materials and flight hardware for use in habitable environments aboard the Space Shuttle and the International Space Station. As part of Research and Development, the Toxic Offgassing Laboratory conducted a long term cure study on four polyurethane coatings which are slated for potential use on Space Station. This study demonstrates the effects of cure time and temperature on the total tox value (sum T) and the maximum usage weight for each coating. All analysis was conducted according to test procedures outlined specifically for Space Station environments. Therefore, the ratings and weight limits generated for these materials are most applicable to space environments. However, this test does give some indication of time frames for solvent removal and is therefore of interest to, the environmental community as a whole.

  8. Production development of organic nonflammable spacecraft potting, encapsulating and conformal coating compounds. Volume 4: Executive summary

    NASA Technical Reports Server (NTRS)

    Lieberman, S. L.

    1974-01-01

    The necessity of having nonflammable versions of potting and encapsulating compounds and conformal coatings for space vehicles is discussed. The formulation, EPOCAST 87517 A/B, was found to have the best balance of thermal, electrical, mechanical, physical, and chemical properties of those evaluated. The requirements which this formulation did not meet are listed, and other formulations which were evaluated are summarized. Recommendations for improving EPOCAST 87517 A/B are included.

  9. Biology of the Coarse Aerosol Mode: Insights Into Urban Aerosol Ecology

    NASA Astrophysics Data System (ADS)

    Dueker, E.; O'Mullan, G. D.; Montero, A.

    2015-12-01

    Microbial aerosols have been understudied, despite implications for climate studies, public health, and biogeochemical cycling. Because viable bacterial aerosols are often associated with coarse aerosol particles, our limited understanding of the coarse aerosol mode further impedes our ability to develop models of viable bacterial aerosol production, transport, and fate in the outdoor environment, particularly in crowded urban centers. To address this knowledge gap, we studied aerosol particle biology and size distributions in a broad range of urban and rural settings. Our previously published findings suggest a link between microbial viability and local production of coarse aerosols from waterways, waste treatment facilities, and terrestrial systems in urban and rural environments. Both in coastal Maine and in New York Harbor, coarse aerosols and viable bacterial aerosols increased with increasing wind speeds above 4 m s-1, a dynamic that was observed over time scales ranging from minutes to hours. At a New York City superfund-designated waterway regularly contaminated with raw sewage, aeration remediation efforts resulted in significant increases of coarse aerosols and bacterial aerosols above that waterway. Our current research indicates that bacterial communities in aerosols at this superfund site have a greater similarity to bacterial communities in the contaminated waterway with wind speeds above 4 m s-1. Size-fractionated sampling of viable microbial aerosols along the urban waterfront has also revealed significant shifts in bacterial aerosols, and specifically bacteria associated with coarse aerosols, when wind direction changes from onshore to offshore. This research highlights the key connections between bacterial aerosol viability and the coarse aerosol fraction, which is important in assessments of production, transport, and fate of bacterial contamination in the urban environment.

  10. Solar geoengineering using solid aerosol in the stratosphere

    NASA Astrophysics Data System (ADS)

    Weisenstein, D. K.; Keith, D. W.; Dykema, J. A.

    2015-10-01

    Solid aerosol particles have long been proposed as an alternative to sulfate aerosols for solar geoengineering. Any solid aerosol introduced into the stratosphere would be subject to coagulation with itself, producing fractal aggregates, and with the natural sulfate aerosol, producing liquid-coated solids. Solid aerosols that are coated with sulfate and/or have formed aggregates may have very different scattering properties and chemical behavior than uncoated non-aggregated monomers do. We use a two-dimensional (2-D) chemistry-transport-aerosol model to capture the dynamics of interacting solid and liquid aerosols in the stratosphere. As an example, we apply the model to the possible use of alumina and diamond particles for solar geoengineering. For 240 nm radius alumina particles, for example, an injection rate of 4 Tg yr-1 produces a global-average shortwave radiative forcing of -1.2 W m-2 and minimal self-coagulation of alumina although almost all alumina outside the tropics is coated with sulfate. For the same radiative forcing, these solid aerosols can produce less ozone loss, less stratospheric heating, and less forward scattering than sulfate aerosols do. Our results suggest that appropriately sized alumina, diamond or similar high-index particles may have less severe technology-specific risks than sulfate aerosols do. These results, particularly the ozone response, are subject to large uncertainties due to the limited data on the rate constants of reactions on the dry surfaces.

  11. Corrosion behaviors and effects of corrosion products of plasma electrolytic oxidation coated AZ31 magnesium alloy under the salt spray corrosion test

    NASA Astrophysics Data System (ADS)

    Wang, Yan; Huang, Zhiquan; Yan, Qin; Liu, Chen; Liu, Peng; Zhang, Yi; Guo, Changhong; Jiang, Guirong; Shen, Dejiu

    2016-08-01

    The effects of corrosion products on corrosion behaviors of AZ31 magnesium alloy with a plasma electrolytic oxidation (PEO) coating were investigated under the salt spray corrosion test (SSCT). The surface morphology, cross-sectional microstructure, chemical and phase compositions of the PEO coating were determined using scanning electron microscopy (SEM) equipped with energy dispersive X-ray spectroscopy (EDS) and X-ray diffraction analysis (XRD), respectively. Further, the corrosion process of the samples under the SSCT was examined in a non-aqueous electrolyte (methanol) using electrochemical impedance spectroscopy (EIS) coupled with equivalent circuit. The results show that the inner layer of the coating was destroyed firstly and the corrosion products have significant effects on the corrosion behaviors of the coating. The results above are discussed and an electrochemical corrosion model is proposed in the paper.

  12. Exposure based waiving: the application of the toxicological threshold of concern (TTC) to inhalation exposure for aerosol ingredients in consumer products.

    PubMed

    Carthew, P; Clapp, C; Gutsell, S

    2009-06-01

    The inhalation toxicology studies available in the public domain have been reviewed to establish a database for inhalation toxicology and derive thresholds of toxicological concern (TTC) for effects in the respiratory tract and systemically for Cramer class 1 and 3 chemicals. These TTCs can be used as the basis for developing an exposure based waiving (EBW) approach to evaluating the potential for adverse effects from exposure to ingredients in aerosol products, used by consumers. The measurement of consumer exposure in simulated product use is key to the application of an exposure based waiving approach to evaluating potential consumer risk. The detailed exposure evaluation for aerosol ingredients with defined use scenarios, in conjunction with an evaluation of the potential structure activity relationship for toxicity and the TTCs for inhalation exposure could be used to waive undertaking inhalation toxicology studies under REACH. Not all classes of chemicals are suitable for such an approach, but for chemicals with a predictable low potential toxicity, and very low levels of exposure, this approach, could reduce the amount of inhalation toxicology studies required for the implementation of the European REACH legislation. Such an approach is consistent with the concept of developing 'intelligent testing strategies' for REACH. PMID:19275927

  13. Emission and Photochemical Evolution of Low Vapor Pressure-Volatile Organic Compounds (LVP-VOCs): from Consumer Products to Secondary Organic Aerosol

    NASA Astrophysics Data System (ADS)

    Li, L.; Kacarab, M.; Chen, C. L.; Price, D.; Carter, W. P. L.; Cocker, D. R., III

    2015-12-01

    Missing emission sources contribute to potential problems in air quality modeling and human health. Low Vapor Pressure-Volatile Organic Compounds (LVP-VOCs) are widely used in consumer products and currently receive VOC exemptions based on their vapor pressure. However, 58.5 TPD LVP-VOC is estimated to emit in 2020 from consumer products in California based on government and industry inventory data. This work investigates the emission and photochemical evolution of major LVP-VOCs in consumer products to demonstrate LVP-VOC impacts on criteria air pollutants. LVP-VOC emission potential is investigated by offline gravimetric and online headspace tracking pure compounds and consumer product mixtures under ambient relevant conditions. Only 3 of the 14 pure LVP-VOCs were found to be atmospherically unavailable. All target LVP-VOCs are observed to evaporate from tested consumer product mixtures. We found improved thermodynamic parameters to predict LVP-VOC evaporation rate. LVP-VOCs photochemical evolution and their impact on ozone and secondary organic aerosol (SOA) formation are evaluated by integrating SAPRC-11 modeling with laboratory studies in a 90 m3 dual environmental chamber at UC Riverside/CE-CERT. Simultaneous photooxidation experiments, with and without the LVP-VOC, are conducted in the presence of reactive organic gas (ROG) surrogate representing urban chemical smog. Further, LVP-VOC photochemical evolution pathway is investigated under various atmospheric activity (LVP + H2O2, LVP+NO or LVP+H2O2+NO) in the environmental chamber. Gas phase and particle phase mass spectrometers (SIFT-MS, Selected Ion Flow Tube-Mass Spectrum and HR-ToF-MS, High Resolution Time-of-Flight Aerosol mass Spectrometer) are applied to monitor the evolution of LVP-VOCs in the controlled atmosphere. The potential of LVP-VOC oxidation into ELVOC is also illustrated. We finally interpret the health risk and environmental concern related to LVP-VOC emission and photoxidation.

  14. Evolution of Biomass Burning Aerosol Optical Properties in the Near Field

    NASA Astrophysics Data System (ADS)

    Sedlacek, A. J., III; Arnott, W. P.; Chand, D.; Fortner, E.; Freedman, A.; Kleinman, L. I.; Onasch, T. B.; Shilling, J. E.; Springston, S. R.

    2014-12-01

    Biomass burning (BB) events are known to produce chemically rich environments that can impact the evolution of primary aerosols and influence secondary aerosols production rates. With their increasing in frequency, BB events are expected to exert an ever-increasing impact on climate due to aerosol radiative forcing processes. One area that is still poorly understood is the evolution of these smoke aerosols in the near field. Recent literature suggests that BB aerosols undergo a rapid evolution near their source that is then followed by a slower aging phase. During the summer of 2013, the Department of Energy-sponsored an aircraft field campaign called the Biomass Burning Observation Project (BBOP) that specifically targeted the evolution of smoke aerosols in the near field (< 2 hours). Results examining the evolution of BB optical and microphysical properties will be presented. To probe these properties, the BBOP field campaign deployed a Single Particle Soot Photometer (SP2) to probe the mixing state of refractory black carbon (rBC) and a Soot Particle Aerosol Mass Spectrometer (SP-AMS) to investigate the composition of both non-refractory and rBC-containing particles. Aerosol optical properties were measured in situ using a 355 nm Photoacoustic spectrometer (PAS), a 532 nm photo thermal interferometer (PTI), a 630 nm cavity Attenuation Phase Shifted (CAPS) spectrometer, a 3-λ nephelometer, and a 3-λ PSAP. The BBOP study represented the maiden aircraft deployment for the SP-AMS, the 355 nm PAS and 532 nm PTI. Discussion will be on the near-field evolution of particle mixing state and morphology, chemical composition, and microphysical processes that determine aerosol size distributions and single scattering albedo (SSA) of light absorbing aerosols. In the cases studied, increases in the coating thickness of refractive black carbon (rBC) particles, organic aerosol/rBC ratio, scattering/CO ratio, and aerosol size distributions have been observed. Results will be

  15. CARBON COATED (CARBONOUS) CATALYST IN EBULLATED BED REACTOR FOR PRODUCTION OF OXYGENATED CHEMICALS FROM SYNGAS/CO2

    SciTech Connect

    Peizheng Zhou

    2001-10-26

    There are a number of exothermic chemical reactions which might benefit from the temperature control and freedom from catalyst fouling provided by the ebullated bed reactor technology. A particularly promising area is production of oxygenated chemicals, such as alcohols and ethers, from synthesis gas, which can be economically produced from coal or biomass. The ebullated bed operation requires that the small-diameter ({approx}1/32 inch) catalyst particles have enough mechanical strength to avoid loss by attrition. However, all of the State Of The Art (SOTA) catalysts and advanced catalysts for the purpose are low in mechanical strength. The patented carbon-coated catalyst technology developed in our laboratory converts catalyst particles with low mechanical strength to strong catalysts suitable for ebullated bed application. This R&D program is concerned with the modification on the mechanical strength of the SOTA and advanced catalysts so that the ebullated bed technology can be utilized to produce valuable oxygenated chemicals from syngas/CO{sub 2} efficiently and economically. The objective of this R&D program is to study the technical and economic feasibility of selective production of high-value oxygenated chemicals from synthesis gas and CO{sub 2} mixed feed in an ebullated bed reactor using carbon-coated catalyst particles.

  16. CARBON COATED (CARBONOUS) CATALYST IN EBULLATED BED REACTOR FOR PRODUCTION OF OXYGENATED CHEMICALS FROM SYNGAS/CO2

    SciTech Connect

    Peizheng Zhou

    2000-11-17

    There are a number of exothermic chemical reactions which might benefit from the temperature control and freedom from catalyst fouling provided by the ebullated bed reactor technology. A particularly promising area is production of oxygenated chemicals, such as alcohols and ethers, from synthesis gas, which can be economically produced from coal or biomass. The ebullated bed operation requires that the small-diameter ({approx} 1/32 inch) catalyst particles have enough mechanical strength to avoid loss by attrition. However, all of the State Of The Art (SOTA) catalysts and advanced catalysts for the purpose are low in mechanical strength. The patented carbon-coated catalyst technology developed in our laboratory converts catalyst particles with low mechanical strength to strong catalysts suitable for ebullated bed application. This R&D program is concerned with the modification on the mechanical strength of the SOTA and advanced catalysts so that the ebullated bed technology can be utilized to produce valuable oxygenated chemicals from syngas/CO{sub 2} efficiently and economically. The objective of this R&D program is to study the technical and economic feasibility of selective production of high-value oxygenated chemicals from synthesis gas and CO{sub 2} mixed feed in an ebullated bed reactor using carbon-coated catalyst particles.

  17. PIT Coating Requirements Analysis

    SciTech Connect

    MINTEER, D.J.

    2000-10-20

    This study identifies the applicable requirements for procurement and installation of a coating intended for tank farm valve and pump pit interior surfaces. These requirements are intended to be incorporated into project specification documents and design media. This study also evaluates previously recommended coatings and identifies requirement-compliant coating products.

  18. Extract of the seed coat of Tamarindus indica inhibits nitric oxide production by murine macrophages in vitro and in vivo.

    PubMed

    Komutarin, T; Azadi, S; Butterworth, L; Keil, D; Chitsomboon, B; Suttajit, M; Meade, B J

    2004-04-01

    The seed coat extract of Tamarindus indica, a polyphenolic flavonoid, has been shown to have antioxidant properties. The present studies investigated the inhibitory effect of the seed coat extract of T. indica on nitric oxide production in vitro using a murine macrophage-like cell line, RAW 264.7, and in vitro and in vivo using freshly isolated B6C3F1 mouse peritoneal macrophages. In vitro exposure of RAW 264.7 cells or peritoneal macrophages to 0.2-200 microg/mL of T. indica extract significantly attenuated (as much as 68%) nitric oxide production induced by lipopolysaccharide (LPS) and interferon gamma (IFN-gamma) in a concentration-dependent manner. In vivo administration of T. indica extract (100-500 mg/kg) to B6C3F1 mice dose-dependently suppressed TPA, LPS and/or IFN-gamma induced production of nitric oxide in isolated mouse peritoneal macrophages in the absence of any effect on body weight. Exposure to T. indica extract had no effect on cell viability as assessed by the MTT assay. In B6C3F1 mice, preliminary safety studies demonstrated a decrease in body weight at only the highest dose tested (1000 mg/kg) without alterations in hematology, serum chemistry or selected organ weights or effects on NK cell activity. A significant decrease in body weight was observed in BALB/c mice exposed to concentrations of extract of 250 mg/kg or higher. Oral exposure of BALB/c mice to T. indica extract did not modulate the development of T cell-mediated sensitization to DNFB or HCA as measured by the local lymph node assay, or dermal irritation to nonanoic acid or DNFB. These studies suggest that in mice, T. indica extract at concentrations up to 500 mg/kg may modulate nitric oxide production in the absence of overt acute toxicity. PMID:15019190

  19. Atmospheric oxidation of 1,3-butadiene: characterization of gas and aerosol reaction products and implications for PM2.5

    NASA Astrophysics Data System (ADS)

    Jaoui, M.; Lewandowski, M.; Docherty, K.; Offenberg, J. H.; Kleindienst, T. E.

    2014-12-01

    Secondary organic aerosol (SOA) was generated by irradiating 1,3-butadiene (13BD) in the presence of H2O2 or NOx. Experiments were conducted in a smog chamber operated in either flow or batch mode. A filter/denuder sampling system was used for simultaneously collecting gas- and particle-phase products. The chemical composition of the gas phase and SOA was analyzed using derivative-based methods (BSTFA, BSTFA + PFBHA, or DNPH) followed by gas chromatography-mass spectrometry (GC-MS) or high-performance liquid chromatography (HPLC) analysis of the derivative compounds. The analysis showed the occurrence of more than 60 oxygenated organic compounds in the gas and particle phases, of which 31 organic monomers were tentatively identified. The major identified products include glyceric acid, d-threitol, erythritol, d-threonic acid, meso-threonic acid, erythrose, malic acid, tartaric acid, and carbonyls including glycolaldehyde, glyoxal, acrolein, malonaldehyde, glyceraldehyde, and peroxyacryloyl nitrate (APAN). Some of these were detected in ambient PM2.5 samples, and could potentially serve as organic markers of 13BD. Furthermore, a series of oligoesters were detected and found to be produced through chemical reactions occurring in the aerosol phase between compounds bearing alcoholic groups and compounds bearing acidic groups. SOA was analyzed for organic mass to organic carbon (OM /OC) ratio, effective enthalpy of vaporization (Δ Hvapeff), and aerosol yield. The average OM /OC ratio and SOA density were 2.7 ± 0.09 and 1.2 ± 0.05, respectively. The average Δ Hvapeff was -26.08 ± 1.46 kJ mol-1, a value lower than that of isoprene SOA. The average laboratory SOA yield measured in this study at aerosol mass concentrations between 22.5 and 140.2 μg m-3 was 0.025 ± 0.011, a value consistent with the literature (0.021-0.178). While the focus of this study has been examination of the particle-phase measurements, the gas-phase photooxidation products have also been

  20. Studies of organic aerosol and aerosol-cloud interactions

    NASA Astrophysics Data System (ADS)

    Duong, Hanh To

    Atmospheric aerosols can influence society and the environment in many ways including altering the planet's energy budget, the hydrologic cycle, and public health. However, the Fourth Assessment Report of the Intergovernmental Panel on Climate Change indicates that the anthropogenic radiative forcing associated with aerosol effects on clouds has the highest uncertainty in the future climate predictions. This thesis focuses on the nature of the organic fraction of ambient particles and how particles interact with clouds using a combination of tools including aircraft and ground measurements, models, and satellite data. Fine aerosol particles typically contain between 20 - 90% organic matter by mass and a major component of this fraction includes water soluble organic carbon (WSOC). Consequently, water-soluble organic species can strongly influence aerosol water-uptake and optical properties. However, the chemical composition of this fraction is not well-understood. PILS-TOC was used to characterize WSOC in ambient aerosol in Los Angeles, California. The spatial distribution of WSOC was found to be influenced by (i) a wide range of aerosol sources within this urban metropolitan area, (ii) transport of pollutants by the characteristic daytime sea breeze trajectory, (iii) topography, and (iv) secondary production during transport. Meteorology is linked with the strength of many of these various processes. Many methods and instruments have been used to study aerosol-cloud interactions. Each observational platform is characterized by different temporal/spatial resolutions and operational principles, and thus there are disagreements between different studies for the magnitude of mathematical constructs used to represent the strength of aerosol-cloud interactions. This work points to the sensitivity of the magnitude of aerosol-cloud interactions to cloud lifetime and spatial resolution of measurements and model simulations. Failure to account for above-cloud aerosol layers

  1. AERONET: The Aerosol Robotic Network

    DOE Data Explorer

    The AERONET (AErosol RObotic NETwork) program is a federation of ground-based remote sensing aerosol networks established by NASA and LOA-PHOTONS (CNRS) and is greatly expanded by collaborators from national agencies, institutes, universities, individual scientists, and partners. The program provides a long-term, continuous and readily accessible public domain database of aerosol optical, mircrophysical and radiative properties for aerosol research and characterization, validation of satellite retrievals, and synergism with other databases. The network imposes standardization of instruments, calibration, processing and distribution. AERONET collaboration provides globally distributed observations of spectral aerosol optical Depth (AOD), inversion products, and precipitable water in diverse aerosol regimes. Aerosol optical depth data are computed for three data quality levels: Level 1.0 (unscreened), Level 1.5 (cloud-screened), and Level 2.0 (cloud screened and quality-assured). Inversions, precipitable water, and other AOD-dependent products are derived from these levels and may implement additional quality checks.[Copied from http://aeronet.gsfc.nasa.gov/new_web/system_descriptions.html

  2. Photocatalytic hydrogen production of Co(OH)2 nanoparticle-coated α-Fe2O3 nanorings

    NASA Astrophysics Data System (ADS)

    Wender, Heberton; Gonçalves, Renato V.; Dias, Carlos Sato B.; Zapata, Maximiliano J. M.; Zagonel, Luiz F.; Mendonça, Edielma C.; Teixeira, Sérgio R.; Garcia, Flávio

    2013-09-01

    The production of hydrogen from water using only a catalyst and solar energy is one of the most challenging and promising outlets for the generation of clean and renewable energy. Semiconductor photocatalysts for solar hydrogen production by water photolysis must employ stable, non-toxic, abundant and inexpensive visible-light absorbers capable of harvesting light photons with adequate potential to reduce water. Here, we show that α-Fe2O3 can meet these requirements by means of using hydrothermally prepared nanorings. These iron oxide nanoring photocatalysts proved capable of producing hydrogen efficiently without application of an external bias. In addition, Co(OH)2 nanoparticles were shown to be efficient co-catalysts on the nanoring surface by improving the efficiency of hydrogen generation. Both nanoparticle-coated and uncoated nanorings displayed superior photocatalytic activity for hydrogen evolution when compared with TiO2 nanoparticles, showing themselves to be promising materials for water-splitting using only solar light.The production of hydrogen from water using only a catalyst and solar energy is one of the most challenging and promising outlets for the generation of clean and renewable energy. Semiconductor photocatalysts for solar hydrogen production by water photolysis must employ stable, non-toxic, abundant and inexpensive visible-light absorbers capable of harvesting light photons with adequate potential to reduce water. Here, we show that α-Fe2O3 can meet these requirements by means of using hydrothermally prepared nanorings. These iron oxide nanoring photocatalysts proved capable of producing hydrogen efficiently without application of an external bias. In addition, Co(OH)2 nanoparticles were shown to be efficient co-catalysts on the nanoring surface by improving the efficiency of hydrogen generation. Both nanoparticle-coated and uncoated nanorings displayed superior photocatalytic activity for hydrogen evolution when compared with TiO2

  3. Tropospheric Aerosols

    NASA Astrophysics Data System (ADS)

    Buseck, P. R.; Schwartz, S. E.

    2003-12-01

    It is widely believed that "On a clear day you can see forever," as proclaimed in the 1965 Broadway musical of the same name. While an admittedly beautiful thought, we all know that this concept is only figurative. Aside from Earth's curvature and Rayleigh scattering by air molecules, aerosols - colloidal suspensions of solid or liquid particles in a gas - limit our vision. Even on the clearest day, there are billions of aerosol particles per cubic meter of air.Atmospheric aerosols are commonly referred to as smoke, dust, haze, and smog, terms that are loosely reflective of their origin and composition. Aerosol particles have arisen naturally for eons from sea spray, volcanic emissions, wind entrainment of mineral dust, wildfires, and gas-to-particle conversion of hydrocarbons from plants and dimethylsulfide from the oceans. However, over the industrial period, the natural background aerosol has been greatly augmented by anthropogenic contributions, i.e., those produced by human activities. One manifestation of this impact is reduced visibility (Figure 1). Thus, perhaps more than in other realms of geochemistry, when considering the composition of the troposphere one must consider the effects of these activities. The atmosphere has become a reservoir for vast quantities of anthropogenic emissions that exert important perturbations on it and on the planetary ecosystem in general. Consequently, much recent research focuses on the effects of human activities on the atmosphere and, through them, on the environment and Earth's climate. For these reasons consideration of the geochemistry of the atmosphere, and of atmospheric aerosols in particular, must include the effects of human activities. (201K)Figure 1. Impairment of visibility by aerosols. Photographs at Yosemite National Park, California, USA. (a) Low aerosol concentration (particulate matter of aerodynamic diameter less than 2.5 μm, PM2.5=0.3 μg m-3; particulate matter of aerodynamic diameter less than 10

  4. Solutions Network Formulation Report. Aerosol Polarimetry Sensor Measurements of Diffuse-to-Global Irradiance Ratio for Improved Forecasting of Plant Productivity and Health

    NASA Technical Reports Server (NTRS)

    Knowlton, Kelly; Andrews, Jane C.; Ryan, Robert E.

    2007-01-01

    Studies have shown that vegetation is directly sensitive to changes in the diffuse-to-global irradiance ratio and that increased percentage of diffuse irradiation can accelerate photosynthesis. Therefore, measurements of diffuse versus global irradiance could be useful for monitoring crop productivity and overall vegetative health as they relate to the total amount of particulates in the air that result from natural disasters or anthropogenic (manmade) causes. While the components of solar irradiance are measured by satellite and surface sensors and calculated with atmospheric models, disagreement exists between the results, creating a need for more accurate and comprehensive retrievals of atmospheric aerosol parameters. Two satellite sensors--APS and VIIRS--show promise for retrieving aerosol properties at an unprecedented level of accuracy. APS is expected to be launched in December 2008. The planned launch date for VIIRS onboard NPP is September 2009. Identified partners include the USDA s ARS, North Carolina State University, Purdue Climate Change Research Center, and the Cooperative Institute for Research in the Atmosphere at Colorado State University. Although at present no formal DSSs (decision support systems) require accurate values of diffuse-to-global irradiance, this parameter is sufficiently important that models are being developed that will incorporate these measurements. This candidate solution is aligned with the Agricultural Efficiency and Air Quality National Applications.

  5. Biological impact of cigarette smoke compared to an aerosol produced from a prototypic modified risk tobacco product on normal human bronchial epithelial cells.

    PubMed

    Kogel, U; Gonzalez Suarez, I; Xiang, Y; Dossin, E; Guy, P A; Mathis, C; Marescotti, D; Goedertier, D; Martin, F; Peitsch, M C; Hoeng, J

    2015-12-01

    Cigarette smoking causes serious and fatal diseases. The best way for smokers to avoid health risks is to quit smoking. Using modified risk tobacco products (MRTPs) may be an alternative to reduce the harm caused for those who are unwilling to quit smoking, but little is known about the toxic effects of MRTPs, nor were the molecular mechanisms of toxicity investigated in detail. The toxicity of an MRTP and the potential molecular mechanisms involved were investigated in high-content screening tests and whole genome transcriptomics analyses using human bronchial epithelial cells. The prototypic (p)MRTP that was tested had less impact than reference cigarette 3R4F on the cellular oxidative stress response and cell death pathways. Higher pMRTP aerosol extract concentrations had impact on pathways associated with the detoxification of xenobiotics and the reduction of oxidative damage. A pMRTP aerosol concentration up to 18 times higher than the 3R4F caused similar perturbation effects in biological networks and led to the perturbation of networks related to cell stress, and proliferation biology. These results may further facilitate the development of a systems toxicology-based impact assessment for use in future risk assessments in line with the 21st century toxicology paradigm, as shown here for an MRTP. PMID:26277032

  6. Use of a surrogate aerosol in a preliminary screening for the potential carcinogenicity of coal coated with No. 6 fuel oil.

    PubMed

    Dalbey, W E; Blackburn, G R; Roy, T A; Sasaki, J; Krueger, A J; Mackerer, C R

    1998-02-01

    Coal, which contains significant amounts of water, can be ground and dried to produce an efficient fuel for electric power plants; however, spontaneous combustion can occur in the dried coal. Liquid petroleum hydrocarbons inhibit this combustion, but not all petroleum streams are effective. No. 6 fuel oil, a readily available and inexpensive stream, provides an effective coating, but the carcinogenic potential of coal particles treated with No. 6 fuel oil, which contains polynuclear aromatic hydrocarbons (PNAs), was undefined. As part of the assessment process, a series of studies was conducted to compare this treated coal with similar particles (petroleum coke) that had been tested by chronic inhalation in monkeys and rats. The amounts of PNAs in petroleum coke and treated coal were compared in extraction studies; the treated coal had only two-thirds of the organics extractable with benzene compared with coke and only 7% as much of the 3-7 ring PNAs, the likely tumorigenic compounds. In addition, the analytical profile of 3-7 ring PNAs was of lower molecular weights in the coal treated with fuel oil. The mutagenicity of extracts from treated coal was much less than with petroleum coke and markedly less than that of No. 6 fuel oil itself. The percutaneous absorption of 3H-benzo(a)pyrene from both particles and from their benzene extracts, as measured in vitro, was approximately eight times greater with petroleum coke than with treated coal. Based on these preliminary results, there is no evidence suggesting that the treated coal would pose any greater carcinogenic risk than petroleum coke. PMID:9487662

  7. Protective Coatings

    NASA Technical Reports Server (NTRS)

    1980-01-01

    General Magnaplate Corporation's pharmaceutical machine is used in the industry for high speed pressing of pills and capsules. Machine is automatic system for molding glycerine suppositories. These machines are typical of many types of drug production and packaging equipment whose metal parts are treated with space spinoff coatings that promote general machine efficiency and contribute to compliance with stringent federal sanitation codes for pharmaceutical manufacture. Collectively known as "synergistic" coatings, these dry lubricants are bonded to a variety of metals to form an extremely hard slippery surface with long lasting self lubrication. The coatings offer multiple advantages; they cannot chip, peel or be rubbed off. They protect machine parts from corrosion and wear longer, lowering maintenance cost and reduce undesired heat caused by power-robbing friction.

  8. Spectra Aerosol Light Scattering and Absorption for Laboratory and Urban Aerosol

    NASA Astrophysics Data System (ADS)

    Gyawali, Madhu S.

    a shell-core model, we verified, for the first time, that AEA can be as high as 1.6 even for non-absorbing coating on BC, suggesting that the organic coating need not be intrinsically brown to observe effects commonly attributed to BrC absorption. Additionally, for laboratory generated incense burning aerosols, AEA varied as lambda -4.5for wavelengths ranging from 355 to 1047 nm. In contrast, the wood smoke aerosols during winter had a much weaker wavelength dependence (lambda-1.1), comparable to that of traffic emission aerosols. During these observations, the multispectral SSA decreased with the wavelength for traffic-related emissions, yet it increased for biomass and incense burning aerosol. The strong spectral dependence was due to the enhanced light absorption by BrC at UV and blue wavelengths. In all cases, results of this analysis suggested that inefficient smoldering combustion processes can emit predominantly BrC, in comparison to high-temperature and flaming burning processes. During the CARES field campaign, aerosols were dominated by biogenic emissions. Aerosol light absorption was modestly enhanced (lambda -1.6) at shorter wavelengths (355, 375, 405, and 532 nm) compared to 870 and 1047 nm, likely due to the spectral dependence of coating on BC. The secondary organic aerosol (SOA) mass concentration steadily increased in the latter half of the campaign, with strong 355 nm aerosol light scattering. Overall, results of this field campaign showed that the biogenic SOA was not BrC, i.e. it didn't have intrinsic characteristics near UV absorption. These results should be further tested and analyzed to assess the full implications of BrC aerosol light absorption.

  9. A 4-D climatology (1979-2009) of the monthly tropospheric aerosol optical depth distribution over the Mediterranean region from a comparative evaluation and blending of remote sensing and model products

    NASA Astrophysics Data System (ADS)

    Nabat, P.; Somot, S.; Mallet, M.; Chiapello, I.; Morcrette, J. J.; Solmon, F.; Szopa, S.; Dulac, F.; Collins, W.; Ghan, S.; Horowitz, L. W.; Lamarque, J. F.; Lee, Y. H.; Naik, V.; Nagashima, T.; Shindell, D.; Skeie, R.

    2013-05-01

    Since the 1980s several spaceborne sensors have been used to retrieve the aerosol optical depth (AOD) over the Mediterranean region. In parallel, AOD climatologies coming from different numerical model simulations are now also available, permitting to distinguish the contribution of several aerosol types to the total AOD. In this work, we perform a comparative analysis of this unique multi-year database in terms of total AOD and of its apportionment by the five main aerosol types (soil dust, sea-salt, sulfate, black and organic carbon). We use 9 different satellite-derived monthly AOD products: NOAA/AVHRR, SeaWiFS (2 products), TERRA/MISR, TERRA/MODIS, AQUA/MODIS, ENVISAT/MERIS, PARASOL/POLDER and MSG/SEVIRI, as well as 3 more historical datasets: NIMBUS7/CZCS, TOMS (onboard NIMBUS7 and Earth-Probe) and METEOSAT/MVIRI. Monthly model datasets include the aerosol climatology from Tegen et al. (1997), the climate-chemistry models LMDz-OR-INCA and RegCM-4, the multi-model mean coming from the ACCMIP exercise, and the reanalyses GEMS and MACC. Ground-based Level-2 AERONET AOD observations from 47 stations around the basin are used here to evaluate the model and satellite data. The sensor MODIS (on AQUA and TERRA) has the best average AOD scores over this region, showing a relevant spatio-temporal variability and highlighting high dust loads over Northern Africa and the sea (spring and summer), and sulfate aerosols over continental Europe (summer). The comparison also shows limitations of certain datasets (especially MERIS and SeaWiFS standard products). Models reproduce the main patterns of the AOD variability over the basin. The MACC reanalysis is the closest to AERONET data, but appears to underestimate dust over Northern Africa, where RegCM-4 is found closer to MODIS thanks to its interactive scheme for dust emissions. The vertical dimension is also investigated using the CALIOP instrument. This study confirms differences of vertical distribution between dust

  10. A 4-D Climatology (1979-2009) of the Monthly Tropospheric Aerosol Optical Depth Distribution over the Mediterranean Region from a Comparative Evaluation and Blending of Remote Sensing and Model Products

    NASA Technical Reports Server (NTRS)

    Nabat, P.; Somot, S.; Mallet, M.; Chiapello, I; Morcrette, J. J.; Solomon, F.; Szopa, S.; Dulac, F; Collins, W.; Ghan, S.; Horowitz, L. W.; Lamarque, J. F.; Lee, Y. H.; Naik, V.; Nagashima, T.; Shindell, D.; Skeie, R.

    2013-01-01

    Since the 1980s several spaceborne sensors have been used to retrieve the aerosol optical depth (AOD) over the Mediterranean region. In parallel, AOD climatologies coming from different numerical model simulations are now also available, permitting to distinguish the contribution of several aerosol types to the total AOD. In this work, we perform a comparative analysis of this unique multiyear database in terms of total AOD and of its apportionment by the five main aerosol types (soil dust, seasalt, sulfate, black and organic carbon). We use 9 different satellite-derived monthly AOD products: NOAA/AVHRR, SeaWiFS (2 products), TERRA/MISR, TERRA/MODIS, AQUA/MODIS, ENVISAT/MERIS, PARASOL/POLDER and MSG/SEVIRI, as well as 3 more historical datasets: NIMBUS7/CZCS, TOMS (onboard NIMBUS7 and Earth- Probe) and METEOSAT/MVIRI. Monthly model datasets include the aerosol climatology from Tegen et al. (1997), the climate-chemistry models LMDz-OR-INCA and RegCM-4, the multi-model mean coming from the ACCMIP exercise, and the reanalyses GEMS and MACC. Ground-based Level- 2 AERONET AOD observations from 47 stations around the basin are used here to evaluate the model and satellite data. The sensor MODIS (on AQUA and TERRA) has the best average AOD scores over this region, showing a relevant spatio-temporal variability and highlighting high dust loads over Northern Africa and the sea (spring and summer), and sulfate aerosols over continental Europe (summer). The comparison also shows limitations of certain datasets (especially MERIS and SeaWiFS standard products). Models reproduce the main patterns of the AOD variability over the basin. The MACC reanalysis is the closest to AERONET data, but appears to underestimate dust over Northern Africa, where RegCM-4 is found closer to MODIS thanks to its interactive scheme for dust emissions. The vertical dimension is also investigated using the CALIOP instrument. This study confirms differences of vertical distribution between dust

  11. Aerosol Quality Monitor (AQUAM)

    NASA Astrophysics Data System (ADS)

    Liang, X.; Ignatov, A.

    2011-12-01

    The Advanced Clear-Sky Processor for Oceans (ACSPO) developed at NESDIS generates three products from AVHRR, operationally: clear sky radiances in all bands, and sea surface temperature (SST) derived from clear-sky brightness temperatures (BT) in Ch3B (centered at 3.7 μm), Ch4 (11 μm) and Ch5 (12 μm), and aerosol optical depths (AOD) derived from clear-sky reflectances in Ch1 (0.63), Ch2 (0.83) and Ch3A (1.61 μm). An integral part of ACSPO is the fast Community Radiative Transfer Model (CRTM), which calculates first-guess clear-sky BTs using global NCEP forecast atmospheric and Reynolds SST fields. Simulated BTs are employed in ACSPO for improved cloud screening, physical (RTM-based) SST inversions, and to monitor and validate satellite BTs. The model minus observation biases are monitored online in near-real time using the Monitoring IR Clear-sky radiances over Oceans for SST (MICROS; http://www.star.nesdis.noaa.gov/sod/sst/micros/). A persistent positive M-O bias is observed in MICROS, partly attributed to missing aerosol in CRTM input, causing "M" to be warmer than "O". It is thus necessary to include aerosols in CRTM and quantify their effects on AVHRR BTs and SSTs. However, sensitivity of thermal bands to aerosol is only minimal, and use of solar reflectance bands is preferable to evaluate the accuracy of CRTM modeling, with global aerosol fields as input (from e.g. Goddard Chemistry Aerosol Radiation and Transport, GOCART, or Navy Aerosol Analysis and Prediction System, NAAPS). Once available, the corresponding M-O biases in solar reflectance bands will be added to MICROS. Also, adding CRTM simulated reflectances in ACSPO would greatly improve cloud detection, help validate CRTM in the solar reflectance bands, and assist aerosol retrievals. Running CRTM with global aerosol as input is very challenging, computationally. While CRTM is being optimized to handle such global scattering computations, a near-real time web-based Aerosol Quality Monitor (AQUAM

  12. Optical coatings for energy-efficient fenestration: principles, products and prospects

    NASA Astrophysics Data System (ADS)

    Granqvist, Claes G.

    2014-02-01

    Buildings use as much as 40% of the world's total primary energy. This huge energy consumption is mainly tied to poor designs and entrenched practices for buildings' envelopes. One major road toward more energy efficient buildings is to employ design principles that are in harmony with the radiation in our natural surroundings. Glass coatings with spectral selectivity can lead to windows and glass facades with good thermal insulation and capability to transmit mainly visible light or, alternatively, across the full solar spectrum. Chromogenic glazings, especially if based on electrochromism, can regulate the inflow of visible light and solar energy between widely separated limits and achieve further energy efficiency. The new fenestration technologies are able to improve indoor comfort.

  13. Long-Term Effects of Soldering By-Products on Nickel-Coated Copper Wire

    NASA Technical Reports Server (NTRS)

    Rolin, T. D.; Hodge, R. E.

    2008-01-01

    An analysis of thirty-year-old, down graded flight cables was conducted to determine the makeup of a green material on the surface of the shielded wire near soldered areas and to ascertain if the green material had corroded the nickel-coated copper wire. Two likely candidates were possible due to the handling and environments to which these cables were exposed. The flux used to solder the cables is known to contain abietic acid, a carboxylic acid found in many pine rosins used for the soldering process. The resulting material copper abietate is green in color and is formed during the application of heat during soldering operations. Copper (II) chloride, which is also green in color is known to contaminate flight parts and is corrosive. Data is presented that shows the material is copper abietate, not copper (II) chloride, and more importantly that the abietate does not aggressively attack nickel-plated copper wire.

  14. Molecular Dynamics Investigation of the Products of Alkoxysilane Condensation: Bulk Gels and Surface Coatings

    NASA Astrophysics Data System (ADS)

    Faller, Roland; Deetz, Joshua

    We characterize silica gels and organo-silicon surface coatings using reactive molecular dynamics simulations. To model the chemical reactions, we use a reactive force field (ReaxFF) which we have optimized in a novel parallelized semi-automatic way to model hydrolysis and condensation reactions. The morphologies of silica gels obtained from tetra- and tri-alkoxysilanes are determined by allowing the system to condense while simultaneously removing water and replacing it with precursor solution. It is found that the gels obtained from trialkoxysilanes are more loosely bonded, and that the chemistry of the headgroup is important to the gel morphology. We furthermore simulated the chemisorption of alkoxysilanes with organic headgroups to hydroxylated silica surfaces. We observe a competition between alkoxysilanes condensing with themselves or with the silica surface.

  15. Production of spherical apatite powders—the first step for optimized thermal-sprayed apatite coatings

    NASA Astrophysics Data System (ADS)

    Lugscheider, E.; Knepper, M.; Gross, K. A.

    1992-09-01

    Regardless of the thermal spraying system, a coating can only be as good as the quality of the input powders. Powder quality in turn is dependent on the manufacturing process and conditions. Thus, it is possible to alter characteristics such as morphology, porosity, phase composition, and the mechanical strength of the individual particles. This article looks at powder agglomerations using the spray drying technique. Two different spray drying configurations were used to produce spherical apatite powders. Apatite powders could be produced with variable densities. Rotary-atomized powders possessed internal porosity as well as open porosity. More applicable for thermal spraying are the nozzle-atomized powders, which are more dense. The particle size range produced is dependent on the many parameters in the spray drying process. Hydroxyapatite is more sensitive than fluorapatite to alterations in process conditions. The powders produced were clean, free of other phases, and possessed good flowability for thermal spraying purposes.

  16. Aerosol retrieval algorithm for the characterization of local aerosol using MODIS L1B data

    NASA Astrophysics Data System (ADS)

    Wahab, A. M.; Sarker, M. L. R.

    2014-02-01

    Atmospheric aerosol plays an important role in radiation budget, climate change, hydrology and visibility. However, it has immense effect on the air quality, especially in densely populated areas where high concentration of aerosol is associated with premature death and the decrease of life expectancy. Therefore, an accurate estimation of aerosol with spatial distribution is essential, and satellite data has increasingly been used to estimate aerosol optical depth (AOD). Aerosol product (AOD) from Moderate Resolution Imaging Spectroradiometer (MODIS) data is available at global scale but problems arise due to low spatial resolution, time-lag availability of AOD product as well as the use of generalized aerosol models in retrieval algorithm instead of local aerosol models. This study focuses on the aerosol retrieval algorithm for the characterization of local aerosol in Hong Kong for a long period of time (2006-2011) using high spatial resolution MODIS level 1B data (500 m resolution) and taking into account the local aerosol models. Two methods (dark dense vegetation and MODIS land surface reflectance product) were used for the estimation of the surface reflectance over land and Santa Barbara DISORT Radiative Transfer (SBDART) code was used to construct LUTs for calculating the aerosol reflectance as a function of AOD. Results indicate that AOD can be estimated at the local scale from high resolution MODIS data, and the obtained accuracy (ca. 87%) is very much comparable with the accuracy obtained from other studies (80%-95%) for AOD estimation.

  17. Atmospheric oxidation of 1,3-butadiene: characterization of gas and aerosol reaction products and implication for PM2.5

    NASA Astrophysics Data System (ADS)

    Jaoui, M.; Lewandowski, M.; Docherty, K.; Offenberg, J. H.; Kleindienst, T. E.

    2014-06-01

    Secondary organic aerosol (SOA) was generated by irradiating 1,3-butadiene (13BD) in the presence of H2O2 or NOx. Experiments were conducted in a smog chamber operated in either flow or batch mode. A filter/denuder sampling system was used for simultaneously collecting gas- and particle-phase products. The chemical composition of the gas phase and SOA was analyzed using derivative-based methods (BSTFA, BSTFA + PFBHA, or DNPH) followed by gas chromatography-mass spectrometry (GC-MS) or high-performance liquid chromatography (HPLC) analysis of the derivative compounds. The analysis showed the occurrence of more than 60 oxygenated organic compounds in the gas and particle phases, of which 31 organic monomers were tentatively identified. The major identified products include glyceric acid, d-threitol, erythritol, d-threonic acid, meso-threonic acid, erythrose, malic acid, tartaric acid, and carbonyls including glycolaldehyde, glyoxal, acrolein, malonaldehyde, glyceraldehyde, and peroxyacryloyl nitrate (APAN). Some of these were detected in ambient PM2.5 samples and could potentially serve as organic markers of 1,3-butadiene (13BD). Furthermore, a series of oligoesters were detected and found to be produced from esterification reactions among compounds bearing alcoholic groups and compounds bearing acidic groups. Time profiles are provided for selected compounds. SOA was analyzed for organic mass to organic carbon (OM / OC) ratio, effective enthalpy of vaporization (ΔHvapeff), and aerosol yield. The average OM / OC ratio and SOA density were 2.7 ± 0.09 and 1.2 ± 0.05, respectively. The average ΔHvapeff was 26.1 ± 1.5 kJ mol-1, a value lower than that of isoprene SOA. The average laboratory SOA yield measured in this study at aerosol mass concentrations between 22.5 and 140.2 μg m-3 was 0.025 ± 0.011, a value consistent with the literature (0.021-0.178). While the focus of this study has been examination of the particle-phase measurements, the gas

  18. Photochemistry of Model Organic Aerosol Systems

    NASA Astrophysics Data System (ADS)

    Mang, S. A.; Bateman, A. P.; Dailo, M.; Do, T.; Nizkorodov, S. A.; Pan, X.; Underwood, J. S.; Walser, M. L.

    2007-05-01

    Up to 90 percent of urban aerosol particles have been shown to contain organic molecules. Reactions of these particles with atmospheric oxidants and/or sunlight result in large changes in their composition, toxicity, and ability to act as cloud condensation nuclei. For this reason, chemistry of model organic aerosol particles initiated by oxidation and direct photolysis is of great interest to atmospheric, climate, and health scientists. Most studies in this area have focused on identifying the products of oxidation of the organic aerosols, while the products of direct photolysis of the resulting molecules remaining in the aerosol particle have been left mostly unexplored. We have explored direct photolytic processes occurring in selected organic aerosol systems using infrared cavity ringdown spectroscopy to identify small gas phase products of photolysis, and mass-spectrometric and photometric techniques to study the condensed phase products. The first model system was secondary organic aerosol formed from the oxidation of several monoterpenes by ozone in the presence and absence of NOx, under different humidities. The second system modeled after oxidatively aged primary organic aerosol particles was a thin film of either alkanes or saturated fatty acids oxidized in several different ways, with the oxidation initiated by ozone, chlorine atom, or OH. In every case, the general conclusion was that the photochemical processing of model organic aerosols is significant. Such direct photolysis processes are believed to age organic aerosol particles on time scales that are short compared to the particles' atmospheric lifetimes.

  19. Toxicity of atmospheric aerosols on marine phytoplankton

    PubMed Central

    Paytan, Adina; Mackey, Katherine R. M.; Chen, Ying; Lima, Ivan D.; Doney, Scott C.; Mahowald, Natalie; Labiosa, Rochelle; Post, Anton F.

    2009-01-01

    Atmospheric aerosol deposition is an important source of nutrients and trace metals to the open ocean that can enhance ocean productivity and carbon sequestration and thus influence atmospheric carbon dioxide concentrations and climate. Using aerosol samples from different back trajectories in incubation experiments with natural communities, we demonstrate that the response of phytoplankton growth to aerosol additions depends on specific components in aerosols and differs across phytoplankton species. Aerosol additions enhanced growth by releasing nitrogen and phosphorus, but not all aerosols stimulated growth. Toxic effects were observed with some aerosols, where the toxicity affected picoeukaryotes and Synechococcus but not Prochlorococcus. We suggest that the toxicity could be due to high copper concentrations in these aerosols and support this by laboratory copper toxicity tests preformed with Synechococcus cultures. However, it is possible that other elements present in the aerosols or unknown synergistic effects between these elements could have also contributed to the toxic effect. Anthropogenic emissions are increasing atmospheric copper deposition sharply, and based on coupled atmosphere–ocean calculations, we show that this deposition can potentially alter patterns of marine primary production and community structure in high aerosol, low chlorophyll areas, particularly in the Bay of Bengal and downwind of South and East Asia. PMID:19273845

  20. Toxicity of atmospheric aerosols on marine phytoplankton

    USGS Publications Warehouse

    Paytan, A.; Mackey, K.R.M.; Chen, Y.; Lima, I.D.; Doney, S.C.; Mahowald, N.; Labiosa, R.; Post, A.F.

    2009-01-01

    Atmospheric aerosol deposition is an important source of nutrients and trace metals to the open ocean that can enhance ocean productivity and carbon sequestration and thus influence atmospheric carbon dioxide concentrations and climate. Using aerosol samples from different back trajectories in incubation experiments with natural communities, we demonstrate that the response of phytoplankton growth to aerosol additions depends on specific components in aerosols and differs across phytoplankton species. Aerosol additions enhanced growth by releasing nitrogen and phosphorus, but not all aerosols stimulated growth. Toxic effects were observed with some aerosols, where the toxicity affected picoeukaryotes and Synechococcus but not Prochlorococcus.We suggest that the toxicity could be due to high copper concentrations in these aerosols and support this by laboratory copper toxicity tests preformed with Synechococcus cultures. However, it is possible that other elements present in the aerosols or unknown synergistic effects between these elements could have also contributed to the toxic effect. Anthropogenic emissions are increasing atmospheric copper deposition sharply, and based on coupled atmosphere-ocean calculations, we show that this deposition can potentially alter patterns of marine primary production and community structure in high aerosol, low chlorophyll areas, particularly in the Bay of Bengal and downwind of South and East Asia.

  1. Toxicity of atmospheric aerosols on marine phytoplankton.

    PubMed

    Paytan, Adina; Mackey, Katherine R M; Chen, Ying; Lima, Ivan D; Doney, Scott C; Mahowald, Natalie; Labiosa, Rochelle; Post, Anton F

    2009-03-24

    Atmospheric aerosol deposition is an important source of nutrients and trace metals to the open ocean that can enhance ocean productivity and carbon sequestration and thus influence atmospheric carbon dioxide concentrations and climate. Using aerosol samples from different back trajectories in incubation experiments with natural communities, we demonstrate that the response of phytoplankton growth to aerosol additions depends on specific components in aerosols and differs across phytoplankton species. Aerosol additions enhanced growth by releasing nitrogen and phosphorus, but not all aerosols stimulated growth. Toxic effects were observed with some aerosols, where the toxicity affected picoeukaryotes and Synechococcus but not Prochlorococcus. We suggest that the toxicity could be due to high copper concentrations in these aerosols and support this by laboratory copper toxicity tests preformed with Synechococcus cultures. However, it is possible that other elements present in the aerosols or unknown synergistic effects between these elements could have also contributed to the toxic effect. Anthropogenic emissions are increasing atmospheric copper deposition sharply, and based on coupled atmosphere-ocean calculations, we show that this deposition can potentially alter patterns of marine primary production and community structure in high aerosol, low chlorophyll areas, particularly in the Bay of Bengal and downwind of South and East Asia. PMID:19273845

  2. Aerosolization, Chemical Characterization, Hygroscopicity and Ice Formation of Marine Biogenic Particles

    NASA Astrophysics Data System (ADS)

    Alpert, P. A.; Radway, J.; Kilthau, W.; Bothe, D.; Knopf, D. A.; Aller, J. Y.

    2013-12-01

    were enhanced with time compared with larger sizes. In contrast, all particle sizes were equally enhanced when frits were used. Aerosolized particles were hygroscopic, a finding with significance for warm cloud formation and potential liquid-to-ice phase transformations. Aqueous and dry aerosolized particles from biologically active mesocosm water were found to efficiently nucleate ice exposed to supersaturated water vapor. The majority of particles, including those nucleating ice, consisted of a sea salt core coated with organic material dominated by the carboxyl functional group, and corresponded to a particle type commonly found in marine air. Our results provide improved estimates of marine aerosol production, chemical composition, and hygroscopicity, as well as an accurate physical and chemical representation of ice nucleation by marine biogenic aerosol particles for use in cloud and climate models.

  3. Intermediate Volatility Organic Compound Emissions from On-Road Diesel Vehicles: Chemical Composition, Emission Factors, and Estimated Secondary Organic Aerosol Production.

    PubMed

    Zhao, Yunliang; Nguyen, Ngoc T; Presto, Albert A; Hennigan, Christopher J; May, Andrew A; Robinson, Allen L

    2015-10-01

    Emissions of intermediate-volatility organic compounds (IVOCs) from five on-road diesel vehicles and one off-road diesel engine were characterized during dynamometer testing. The testing evaluated the effects of driving cycles, fuel composition and exhaust aftertreatment devices. On average, more than 90% of the IVOC emissions were not identified on a molecular basis, instead appearing as an unresolved complex mixture (UCM) during gas-chromatography mass-spectrometry analysis. Fuel-based emissions factors (EFs) of total IVOCs (speciated + unspeciated) depend strongly on aftertreatment technology and driving cycle. Total-IVOC emissions from vehicles equipped with catalyzed diesel particulate filters (DPF) are substantially lower (factor of 7 to 28, depending on driving cycle) than from vehicles without any exhaust aftertreatment. Total-IVOC emissions from creep and idle operations are substantially higher than emissions from high-speed operations. Although the magnitude of the total-IVOC emissions can vary widely, there is little variation in the IVOC composition across the set of tests. The new emissions data are combined with published yield data to investigate secondary organic aerosol (SOA) formation. SOA production from unspeciated IVOCs is estimated using surrogate compounds, which are assigned based on gas-chromatograph retention time and mass spectral signature of the IVOC UCM. IVOCs contribute the vast majority of the SOA formed from exhaust from on-road diesel vehicles. The estimated SOA production is greater than predictions by previous studies and substantially higher than primary organic aerosol. Catalyzed DPFs substantially reduce SOA formation potential of diesel exhaust, except at low speed operations. PMID:26322746

  4. A 4-D Climatology (1979-2009) of the Monthly Tropospheric Aerosol Optical Depth Distribution over the Mediterranean Region from a Comparative Evaluation and Blending of Remote Sensing and Model Products

    SciTech Connect

    Nabat, P.; Somot, S.; Mallet, M.; Chiapello, I.; Morcrette, J. -J.; Solmon, F.; Szopa, S.; Dulac, F.; Collins, W.; Ghan, Steven J.; Horowitz, L.; Lamarque, J.-F.; Lee, Y. H.; Naik, Vaishali; Nagashima, T.; Shindell, Drew; Skeie, R. B.

    2013-05-17

    Since the 1980s several spaceborne sensors have been used to retrieve the aerosol optical depth (AOD) over the Mediterranean region. In parallel, AOD climatologies coming from different numerical model simulations are now also available, permitting to distinguish the contribution of several aerosol types to the total AOD. In this work, we perform a comparative analysis of this unique multiyear database in terms of total AOD and of its apportionment by the five main aerosol types (soil dust, seasalt, sulfate, black and organic carbon). We use 9 different satellite-derived monthly AOD products: NOAA/AVHRR, SeaWiFS (2 products), TERRA/MISR, TERRA/MODIS, AQUA/MODIS, ENVISAT/MERIS, PARASOL/POLDER and MSG/SEVIRI, as well as 3 more historical datasets: NIMBUS7/CZCS, TOMS (onboard NIMBUS7 and Earth- Probe) and METEOSAT/MVIRI. Monthly model datasets include the aerosol climatology from Tegen et al. (1997), the climate-chemistry models LMDz-OR-INCA and RegCM-4, the multi-model mean coming from the ACCMIP exercise, and the reanalyses GEMS and MACC. Ground-based Level- 2 AERONET AOD observations from 47 stations around the basin are used here to evaluate the model and satellite data. The sensor MODIS (on AQUA and TERRA) has the best average AOD scores over this region, showing a relevant spatiotemporal variability and highlighting high dust loads over Northern Africa and the sea (spring and summer), and sulfate aerosols over continental Europe (summer). The comparison also shows limitations of certain datasets (especially MERIS and SeaWiFS standard products). Models reproduce the main patterns of the AOD variability over the basin. The MACC reanalysis is the closest to AERONET data, but appears to underestimate dust over Northern Africa, where RegCM-4 is found closer to MODIS thanks to its interactive scheme for dust emissions. The vertical dimension is also investigated using the CALIOP instrument. This study confirms differences of vertical distribution between dust aerosols

  5. 40 CFR 82.70 - Nonessential Class II products and exceptions.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... designated as class II in 40 CFR part 82, appendix B to subpart A) are identified as being nonessential and... 21 CFR 2.125(e); (ii) Lubricants, coatings or cleaning fluids for electrical or electronic equipment... aerosol product or other pressurized dispenser which contains a class II substance: (1) Including but...

  6. Investigation of the formation of benzoyl peroxide, benzoic anhydride, and other potential aerosol products from gas-phase reactions of benzoylperoxy radicals

    NASA Astrophysics Data System (ADS)

    Strollo, Christen M.; Ziemann, Paul J.

    2016-04-01

    The secondary organic aerosol (SOA) products of the reaction of benzaldehyde with Cl atoms and with OH radicals in air in the absence of NOx were investigated in an environmental chamber in order to better understand the possible role of organic peroxy radical self-reactions in SOA formation. SOA products and authentic standards were analyzed using mass spectrometry and liquid chromatography, and results show that the yields of benzoyl peroxide (C6H5C(O)OO(O)CC6H5) and benzoic anhydride (C6H5C(O)O(O)CC6H5), two potential products from the gas-phase self-reaction of benzoylperoxy radicals (C6H5C(O)OO·), were less than 0.1%. This is in contrast to results of recent studies that have shown that the gas-phase self-reactions of β-nitrooxyperoxy radicals formed from reactions of isoprene with NO3 radicals form dialkyl peroxides that contribute significantly to gas-phase and SOA products. Such reactions have also been proposed to explain the gas-phase formation of extremely low volatility dimers from autooxidation of terpenes. The results obtained here indicate that, at least for benzoylperoxy radicals, the self-reactions form only benzoyloxy radicals. Analyses of SOA composition and volatility were inconclusive, but it appears that the SOA may consist primarily of oligomers formed through heterogeneous/multiphase reactions possibly involving some combination of phenol, benzaldehyde, benzoic acid, and peroxybenzoic acid.

  7. Fission product retention in TRISCO coated UO sub 2 particle fuels subjected to HTR simulated core heating tests

    SciTech Connect

    Baldwin, C.A.; Kania, M.J.

    1990-11-01

    Results of the examination and analysis of 25,730 individual microspheres from spherical fuel elements HFR-K3/1 and HFR-K3/3 are reported. The parent spheres were irradiated in excess of end-of-life exposure and subsequently subjected to simulated core heating tests in a special high-temperature furnace at Forschungszentrum, Juelich, GmbH (KFA). Following the heating tests, the spheres were electrolytically deconsolidated to obtain unbonded fuel particles for Irradiated Microsphere Gamma Analyzer (IMGA) analysis. For sphere HFR-K3/1, which was heated for 500 h at 1600{degree}C, only four particles were identified as having released fission products. The remaining particles from the sphere showed no statistical evidence of fission product release. Scanning Electron Microscopy (SEM) examination showed that three of the defect particles had large sections of the TRISO coating missing, while the fourth appeared normal. For sphere HFR-K3/3, which was heated for 100 h at 1800{degree}C, the IMGA data revealed that fission product release (cesium) from individual particles was significant and that there was large particle-to-particle variation in retention capabilities. Individual particle release (cesium) averaged ten times the KFA-measured integral spherical fuel element release value. In addition, the bimodal distribution of the individual particle data indicated that two distinct modes of failure at fuel temperatures of 1800{degree}C and above may exist. 6 refs., 6 figs., 4 tabs.

  8. Coating Carbon Nanosphere with Patchy Gold for Production of Highly Efficient Photothermal Agent.

    PubMed

    Wang, Xiaoxiao; Cao, Dongwei; Tang, Xuejiao; Yang, Jingjing; Jiang, Daoyong; Liu, Mei; He, Nongyue; Wang, Zhifei

    2016-08-01

    Gold- or carbon-based photothermal therapy (PTT) agents have shown encouraging therapeutic effects of PTT in the near-infrared region (NIR) in many preclinical animal experiments. It is expected that gold/carbon hybrid nanomaterial will possess combinational NIR light absorption and can achieve further improvement in photothermal conversion efficiency. In this work, we design and construct a novel PTT agent by coating a carbon nanosphere with patchy gold. To synthesize this composite particle with Janus structure, a new versatile approach based on a facile adsorption-reduction method was presented. Different from the conventional fabrication procedures, the formation of patchy gold in this approach is mainly a thermodynamics-driven spontaneous process. The results show that when compared with the conventional PTT agent gold nanorod the obtained nanocomposites not only have higher photothermal conversion efficiency but also perform more thermally stable. On the basis of these outstanding photothermal effects, the in vitro and in vivo photothermal performances in a MCF-7 cells (human breast adenocarcinoma cell line) and mice were investigated separately. Additionally, to further illustrate the advantage of this asymmetric structure, their potential was explored by selective surface functionalization, taking advantage of the affinity of both patchy gold and carbon domain to different functional molecules. These results suggest that this new hybrid nanomaterial can be used as an effective PTT agent for cancer treatment in the future. PMID:27351062

  9. Production of strontium sulfide coatings by metal organic chemical vapor deposition

    SciTech Connect

    Moss, T.S.; Dye, R.C.; Tuenge, R.T.

    1998-11-01

    This work was focused on the MOCVD of the cerium-doped strontium sulfide (SrS:Ce) phosphor for use in thin film electroluminescent displays (TFELs). Following previous research on a small scale reactor, a feasibility scale-up using a commercially available reactor enlarged the size of the deposition area to a 4`` diameter wafer or a 2`` by 2`` glass slide. Films were deposited from the reaction of Sr(thd){sub 2}, Ce(thd){sub 4}, and H{sub 2}S at 450{degrees}C and 5 torr. This system employed a liquid delivery system for the accurate and repeatable delivery of the metal organic reagents. The deposition from this reactor was shown to be crystalline-as-deposited SrS with a (200) orientation, possibly a result of the thin nature of the coating and the involvement of (200) grains in the initial nucleation process. The wafers showed good uniformity, but had some thickness variation near the outer radius of the wafer resulting from the addition of H{sub 2}S from the outer edge. There were eighteen total deposition experiments, of which nine were characterized for EL performance. The highest brightness observed was 5 fL.. The samples were exceedingly thin as a result of the fifteen fold increase in the surface area between the deposition reactors. Increasing the sample thickness to 7,000{angstrom} or higher will dramatically increase the brightness of the emission.

  10. Eugenol wash and chitosan based coating reduces Campylobacter jejuni counts on poultry products

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Campylobacter, a leading cause of foodborne illness globally in humans, is strongly associated with the consumption of contaminated poultry products. Unfortunately, current strategies to reduce Campylobacter counts in poultry have had limited success. Our study investigated the efficacy of eugenol ...

  11. Aerosol Lidar and MODIS Satellite Comparisons for Future Aerosol Loading Forecast

    NASA Technical Reports Server (NTRS)

    DeYoung, Russell; Szykman, James; Severance, Kurt; Chu, D. Allen; Rosen, Rebecca; Al-Saadi, Jassim

    2006-01-01

    Knowledge of the concentration and distribution of atmospheric aerosols using both airborne lidar and satellite instruments is a field of active research. An aircraft based aerosol lidar has been used to study the distribution of atmospheric aerosols in the California Central Valley and eastern US coast. Concurrently, satellite aerosol retrievals, from the MODIS (Moderate Resolution Imaging Spectroradiometer) instrument aboard the Terra and Aqua satellites, were take over the Central Valley. The MODIS Level 2 aerosol data product provides retrieved ambient aerosol optical properties (e.g., optical depth (AOD) and size distribution) globally over ocean and land at a spatial resolution of 10 km. The Central Valley topography was overlaid with MODIS AOD (5x5 sq km resolution) and the aerosol scattering vertical profiles from a lidar flight. Backward air parcel trajectories for the lidar data show that air from the Pacific and northern part of the Central Valley converge confining the aerosols to the lower valley region and below the mixed layer. Below an altitude of 1 km, the lidar aerosol and MODIS AOD exhibit good agreement. Both data sets indicate a high presence of aerosols near Bakersfield and the Tehachapi Mountains. These and other results to be presented indicate that the majority of the aerosols are below the mixed layer such that the MODIS AOD should correspond well with surface measurements. Lidar measurements will help interpret satellite AOD retrievals so that one day they can be used on a routine basis for prediction of boundary layer aerosol pollution events.

  12. Airborne thermal degradation products of polyurethene coatings in car repair shops.

    PubMed

    Karlsson, D; Spanne, M; Dalene, M; Skarping, G

    2000-10-01

    A methodology for workplace air monitoring of aromatic and aliphatic, mono- and polyisocyanates by derivatisation with di-n-butylamine (DBA) is presented. Air sampling was performed using midget impinger flasks containing 10 ml of 0.01 mol l(-1) DBA in toluene and a glass-fibre filter in series after the impinger flask, thereby providing the possibility of collecting and derivatising isocyanates in both the gas and particle phases. Quantification was made by LC-MS, monitoring the molecular ions [MH]+. Air samples taken with this method in car repair shops showed that many different isocyanates are formed during thermal decomposition of polyurethane (PUR) coatings. In addition to isocyanates such as hexamethylene (HDI), isophorone (IPDI), toluene (TDI) and methylenediphenyl diisocyanate (MDI), monoisocyanates such as methyl (MIC), ethyl (EIC), propyl (PIC), butyl (BIC) and phenyl isocyanate (PhI) were found. In many air samples the aliphatic monoisocyanates dominated. During cutting and welding operations, the highest levels of isocyanates were observed. In a single air sample from a welding operation in a car repair shop, the highest concentrations found were: MIC, 290; EIC, 60; PIC, 20; BIC, 9; PhI, 27; HDI, 105; IPDI, 39; MDI, 4; and 2,4-TDI and 2,6-TDI 140 microg m(-3). Monitoring the particle size distribution and concentration during grinding, welding and cutting operations showed that ultrafine particles (< 0.1 microm) were formed at high concentrations. Isocyanates with low volatility were mainly found in the particle phase, but isocyanates with a relatively high volatility such as TDI, were found in both the particle and gas phases. PMID:11254051

  13. Aerosol Direct Radiative Forcing over Delhi NCR, India: Sensitivity to Mixing State and Particle Shape

    NASA Astrophysics Data System (ADS)

    Srivastava, Parul; Dey, Sagnik; Srivastava, Atul; Singh, Sachchidanand; Agarwal, Poornima

    2015-04-01

    Aerosol properties changes with the change in mixing state of aerosols and thus aerosol direct radiative forcing (DRF). The problem is important in the Indo-Gangetic Basin, Northern India, where various aerosol types mix and show strong seasonal variations. A detailed chemical composition analysis of aerosols for Delhi National capital region (NCR) is carried out during 2007-2008. These results were used to examine the sensitivity of optical properties to the aerosol mixing state. Black carbon, BC was measured directly by Aethalometer. The species are grouped into four major components; dust, water soluble (WS), water insoluble (WINS) and BC. To infer the probable mixing state of aerosols in the Delhi NCR, eight different mixing cases, external mixing, internal mixing, and six combinations of core- shell type mixing which includes two modes of dust (accumulation and coarse) have been considered. Core-shell mixing cases are considered to be as follows - BC over dust, WS over dust, BC over WS and, WS over BC. These core shell mixed components are then externally mixed with rest of the aerosol species. The spectral aerosol optical properties - extinction coefficient, single scattering albedo (SSA) and asymmetry parameter (g) for each of the mixing state cases are calculated. These optical properties are utilized to estimate the radiative forcing using a radiative transfer model. The surface-reaching fluxes for each of the cases are compared with MERRA downward shortwave surface flux. MISR aerosol products were also analyzed to understand the seasonal variations of the bulk aerosol properties that may help in interpreting the sensitivity results. We observed that for the pre-monsoon season (MAMJ), core shell mixed case; BC coated over WS (surface DRF is -10.52 Wm-2) and BC over coarse dust (surface DRF is -2.81 Wm-2) are the most probable mixing states. For monsoon season (JAS,) BC coated over coarse dust (often referred to as polluted dust) (surface DRF is -0.60 Wm-2

  14. PhyLM: A Mission Design Concept for an Optical/Lidar Instrument to Measure Ocean Productivity and Aerosols from Space

    NASA Technical Reports Server (NTRS)

    Gervin, Janette C.; Behrenfeld, Michael; McClain, Charles R.; Spinhirne, James; Purves, Lloyd; Wood, H. John; Roberto, Michael R.

    2004-01-01

    The Physiology Lidar-Multispectral Mission (PhyLM) is intended to explore the complex ecosystems of our global oceans. New "inversion" methods and improved understanding of marine optics have opened the door to quantifying a range of critical ocean properties. This new information could revolutionize our understanding of global ocean processes, such as phytoplankton growth, harmful algal blooms, carbon fluxes between major pools and the productivity equation. The new science requires new measurements not addressed by currently planned space missions. PhyLM will combine active and advanced passive remote sensing technologies to quantify standing stocks and fluxes of climate-critical components of the Ocean carbon cycle to meet these science providing multispectral bands from the far UV through the near infrared (340 - 1250 nm) at a ground resolution of 250 m. Improved detectors, filters, mirrors, digitization and focal plane design will offer an overall higher-quality data product. The unprecedented accuracy and precision of the absolute water-leaving radiances will support inversion- based quantification of an expanded set of ocean carbon cycle components. The dual- wavelength (532 & 1064 nm) Nd:Yag Lidar will enhance the accuracy and precision of the passive data by providing aerosol profiles for atmospheric correction and coincident active measurements of backscattering. The Lidar will also examine dark-side fluorescence as an additional approach to quantifying phytoplankton biomass in highly productive regions.

  15. A CLOSURE STUDY OF AEROSOL MASS CONCENTRATION MEASUREMENTS: COMPARISON OF VALUES OBTAINED WITH FILTERS AND BY DIRECT MEASUREMENTS OF MASS DISTRIBUTIONS. (R826372)

    EPA Science Inventory

    We compare measurements of aerosol mass concentrations obtained gravimetrically using Teflon coated glass fiber filters and by integrating mass distributions measured with the differential mobility analyzer–aerosol particle mass analyzer (DMA–APM) technique (Aero...

  16. Atmospheric Aerosols

    NASA Technical Reports Server (NTRS)

    Pueschel, R. F.; Lawless, James G. (Technical Monitor)

    1994-01-01

    Aerosols, defined as particles and droplets suspended in air, are always present in the atmosphere. They are part of the earth-atmosphere climate system, because they interact with both incoming solar and outgoing terrestrial radiation. They do this directly through scattering and absorption, and indirectly through effects on clouds. Submicrometer aerosols usually predominate in terms of number of particles per unit volume of air. They have dimensions close to the wavelengths of visible light, and thus scatter radiation from the sun very effectively. They are produced in the atmosphere by chemical reactions of sulfur-, nitrogen- and carbon-containing gases of both natural and anthropogenic origins. Light absorption is dominated by particles containing elemental carbon (soot), produced by incomplete combustion of fossil fuels and by biomass burning. Light-scattering dominates globally, although absorption can be significant at high latitudes, particularly over highly reflective snow- or ice-covered surfaces. Other aerosol substances that may be locally important are those from volcanic eruptions, wildfires and windblown dust.

  17. Characterization of aerosols produced by surgical procedures

    SciTech Connect

    Yeh, H.C.; Muggenburg, B.A.; Lundgren, D.L.; Guilmette, R.A.; Snipes, M.B.; Jones, R.K.; Turner, R.S.

    1994-07-01

    In many surgeries, especially orthopedic procedures, power tools such as saws and drills are used. These tools may produce aerosolized blood and other biological material from bone and soft tissues. Surgical lasers and electrocautery tools can also produce aerosols when tissues are vaporized and condensed. Studies have been reported in the literature concerning production of aerosols during surgery, and some of these aerosols may contain infectious material. Garden et al. (1988) reported the presence of papilloma virus DNA in the fumes produced from laser surgery, but the infectivity of the aerosol was not assessed. Moon and Nininger (1989) measured the size distribution and production rate of emissions from laser surgery and found that particles were generally less than 0.5 {mu}m diameter. More recently there has been concern expressed over the production of aerosolized blood during surgical procedures that require power tools. In an in vitro study, the production of an aerosol containing the human immunodeficiency virus (HIV) was reported when power tools were used to cut tissues with blood infected with HIV. Another study measured the size distribution of blood aerosols produced by surgical power tools and found blood-containing particles in a number of size ranges. Health care workers are anxious and concerned about whether surgically produced aerosols are inspirable and can contain viable pathogens such as HIV. Other pathogens such as hepatitis B virus (HBV) are also of concern. The Occupational Safety and Health funded a project at the National Institute for Inhalation Toxicology Research Institute to assess the extent of aerosolization of blood and other tissues during surgical procedures. This document reports details of the experimental and sampling approach, methods, analyses, and results on potential production of blood-associated aerosols from surgical procedures in the laboratory and in the hospital surgical suite.

  18. Aerosols and contact insecticides as alternatives to methyl bromide in flour mills, food production facilities, and food warehouses

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The fumigant methyl bromide (MB) is being phased out of production and usage to control stored product insects in flour and rice mills, as well as feed and food production plants, in the United States (US) and other developed countries throughout the world. A phase-out schedule has also been establi...

  19. Comparison of a laboratory and a production coating spray gun with respect to scale-up.

    PubMed

    Mueller, Ronny; Kleinebudde, Peter

    2007-01-01

    A laboratory spray gun and a production spray gun were investigated in a scale-up study. Two Schlick spray guns, which are equipped with a new antibearding cap, were used in this study. The influence of the atomization air pressure, spray gun-to tablet bed distance, polymer solution viscosity, and spray rate were analyzed in a statistical design of experiments. The 2 spray guns were compared with respect to the spray width and height, droplet size, droplet velocity, and spray density. The droplet size, velocity, and spray density were measured with a Phase Doppler Particle Analyzer. A successful scale-up of the atomization is accomplished if similar droplet sizes, droplet velocities, and spray densities are achieved in the production scale as in the laboratory scale. This study gives basic information for the scale-up of the settings from the laboratory spray gun to the production spray gun. Both spray guns are highly comparable with respect to the droplet size and velocity. The scale-up of the droplet size should be performed by an adjustment of the atomization air pressure. The scale-up of the droplet velocity should be performed by an adjustment of the spray gun to tablet bed distance. The presented statistical model and surface plots are convenient and powerful tools for scaling up the spray settings if the spray gun is changed from laboratory spray gun to the production spray gun. PMID:17408226

  20. Production development of organic nonflammable spacecraft potting, encapsulating and conformal coating compounds. Volume 3: Appendices

    NASA Technical Reports Server (NTRS)

    Lieberman, S. L.

    1974-01-01

    Appendices are presented which include: statement of work; material vendor contacts; formulation/processing data sheet; upward propagation test; flammability test conditions/results sheet; odor test; vacuum stability requirements; flammability test facility; determination of offgassing products and carbon monoxide test; and pneumatic and mechanical impact test guidelines.

  1. Physical properties of the stratospheric aerosols

    NASA Technical Reports Server (NTRS)

    Toon, O. B.; Pollack, J. B.

    1973-01-01

    A comparison of the equilibrium vapor pressure over nitric acid solutions with observed water and nitric acid partial pressures in the stratosphere implies that nitric acid cannot be present as an aerosol particle in the lower stratosphere. A similar comparison for sulfuric acid solutions indicates that sulfuric acid aerosol particles are 75% H2SO4 by weight in water, in good agreement with direct observations. The freezing curve of H2SO4 solutions requires that the H2SO4 aerosol particles be solid or supercooled. The equilibrium vapor pressure of H2SO4 in the stratosphere is of the order of 20 picotorr. At stratospheric temperatures, ammonium sulfate is in a ferroelectric phase. As a result, polar molecules may form a surface coating on these aerosols, which may be a fertile ground for further chemical reaction.

  2. Informing Aerosol Transport Models With Satellite Multi-Angle Aerosol Measurements

    NASA Technical Reports Server (NTRS)

    Limbacher, J.; Patadia, F.; Petrenko, M.; Martin, M. Val; Chin, M.; Gaitley, B.; Garay, M.; Kalashnikova, O.; Nelson, D.; Scollo, S.

    2011-01-01

    As the aerosol products from the NASA Earth Observing System's Multi-angle Imaging SpectroRadiometer (MISR) mature, we are placing greater focus on ways of using the aerosol amount and type data products, and aerosol plume heights, to constrain aerosol transport models. We have demonstrated the ability to map aerosol air-mass-types regionally, and have identified product upgrades required to apply them globally, including the need for a quality flag indicating the aerosol type information content, that varies depending upon retrieval conditions. We have shown that MISR aerosol type can distinguish smoke from dust, volcanic ash from sulfate and water particles, and can identify qualitative differences in mixtures of smoke, dust, and pollution aerosol components in urban settings. We demonstrated the use of stereo imaging to map smoke, dust, and volcanic effluent plume injection height, and the combination of MISR and MODIS aerosol optical depth maps to constrain wildfire smoke source strength. This talk will briefly highlight where we stand on these application, with emphasis on the steps we are taking toward applying the capabilities toward constraining aerosol transport models, planet-wide.

  3. Production of Organic Grain Coatings by Surface-Mediated Reactions and the Consequences of This Process for Meteoritic Constituents

    NASA Technical Reports Server (NTRS)

    Nuth, Joseph A., III; Johnson, Natasha M.

    2011-01-01

    When hydrogen, nitrogen and CO are exposed to amorphous iron silicate surfaces at temperatures between 500 - 900K, a carbonaceous coating forms via Fischer-Tropsch type reactions. Under normal circumstances such a catalytic coating would impede or stop further reaction. However, we find that this coating is a better catalyst than the amorphous iron silicates that initiate these reactions. The formation of a self-perpetuating catalytic coating on grain surfaces could explain the rich deposits of macromolecular carbon found in primitive meteorites and would imply that protostellar nebulae should be rich in organic material. Many more experiments are needed to understand this chemical system and its application to protostellar nebulae.

  4. Products and Mechanisms of Aerosol Formation from Reactions of OH Radicals with Linear and Branched Alkenes in the Presence of NOx (Invited)

    NASA Astrophysics Data System (ADS)

    Ziemann, P. J.; Matsunaga, A.

    2009-12-01

    The chemical and physical processes involved in the formation of secondary organic aerosol (SOA) are complex and can include reactions of volatile organic compounds with a number of atmospheric oxidants (the major ones are O3, and OH and NO3 radicals), as well as surface and condensed-phase reactions, homogeneous nucleation, and gas-particle partitioning. It should come as no surprise that understanding and accurately modeling these processes is a major challenge that has not yet been fully addressed. Alkenes emitted from vegetation are the largest source of non-methane hydrocarbons to the global atmosphere and consist mostly of isoprene (C5H8), monoterpenes (C10H16), and sesquiterpenes (C15H24), compounds with a large range of sizes and molecular structures. Their atmospheric oxidation is initiated primarily by reactions with hydroxyl radicals and can lead to a variety of products, some of which can form SOA. Because of the complexity of terpene reactions and the large numbers of products that are formed, there are advantages to studying the chemistry of simpler alkenes in order to gain insights that can be applied to more complex reaction systems. This is the approach we have taken, and in this talk I will report results of studies of the products, SOA yields, and mechanisms of SOA formation from reactions of a variety of linear and branched alkenes with hydroxyl radicals in the presence of nitrogen oxides. Products consist of a large array of multifunctional compounds, including oligomers, containing carbonyl, hydroxy, carboxyl, and nitrate groups. I will demonstrate some of the ways in which changes in molecular structure can alter both gas and SOA products, including those formed through condensed-phase reactions, and also SOA yields, and suggest explanations for these effects based on current understanding of chemical reaction mechanisms.

  5. BEHAVIOR OF CONSTANT RATE AEROSOL REACTORS (JOURNAL VERSION)

    EPA Science Inventory

    An aerosol reactor is a gaseous system in which fine particles are formed by chemical reaction in either a batch or flow process. Such reactors are used to study the aerosol formation process, as in a smog reactor, or to generate a product such as a pigment or a catalytic aerosol...