Science.gov

Sample records for aerosol deposition ad

  1. 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.

  2. Spatial and temporal distributions of aerosol concentrations and depositions in Asia during the year 2010.

    PubMed

    Park, Soon-Ung; Lee, In-Hye; Joo, Seung Jin

    2016-01-15

    Aerosol Modeling System (AMS) that is consisted of the Asian Dust Aerosol Model2 (ADAM2) and the Community Multi-scale Air Quality (CMAQ) modeling system has been employed to document the spatial distributions of the monthly and the annual averaged concentration of both the Asian dust (AD) aerosol and the anthropogenic aerosol (AA), and their total depositions in the Asian region for the year 2010. It is found that the annual mean surface aerosol (PM10) concentrations in the Asian region affect in a wide region as a complex mixture of AA and AD aerosols; they are predominated by the AD aerosol in the AD source region of northern China and Mongolia with a maximum concentration exceeding 300 μg m(-3); AAs are predominated in the high pollutant emission regions of southern and eastern China and northern India with a maximum concentration exceeding 110 μg m(-3); while the mixture of AA and AD aerosols is dominated in the downwind regions extending from the Yellow Sea to the Northwest Pacific Ocean. It is also found that the annual total deposition of aerosols in the model domain is found to be 485 Tg (372 Tg by AD aerosol and 113 Tg by AA), of which 66% (319 Tg) is contributed by the dry deposition (305 Tg by AD aerosol and 14 Tg by AA) and 34% (166 Tg) by the wet deposition (66 Tg by AD aerosol and 100 Tg by AA), suggesting about 77% of the annual total deposition being contributed by the AD aerosol mainly through the dry deposition process and 24% of it by AA through the wet deposition process. The monthly mean aerosol concentration and the monthly total deposition show a significant seasonal variation with high in winter and spring, and low in summer.

  3. Aerosol Deposition and Solar Panel Performance

    NASA Astrophysics Data System (ADS)

    Arnott, W. P.; Rollings, A.; Taylor, S. J.; Parks, J.; Barnard, J.; Holmes, H.

    2015-12-01

    Passive and active solar collector farms are often located in relatively dry desert regions where cloudiness impacts are minimized. These farms may be susceptible to reduced performance due to routine or episodic aerosol deposition on collector surfaces. Intense episodes of wind blown dust deposition may negatively impact farm performance, and trigger need to clean collector surfaces. Aerosol deposition rate depends on size, morphology, and local meteorological conditions. We have developed a system for solar panel performance testing under real world conditions. Two identical 0.74 square meter solar panels are deployed, with one kept clean while the other receives various doses of aerosol deposition or other treatments. A variable load is used with automation to record solar panel maximum output power every 10 minutes. A collocated sonic anemometer measures wind at 10 Hz, allowing for both steady and turbulent characterization to establish a link between wind patterns and particle distribution on the cells. Multispectral photoacoustic instruments measure aerosol light scattering and absorption. An MFRSR quantifies incoming solar radiation. Solar panel albedo is measured along with the transmission spectra of particles collected on the panel surface. Key questions are: At what concentration does aerosol deposition become a problem for solar panel performance? What are the meteorological conditions that most strongly favor aerosol deposition, and are these predictable from current models? Is it feasible to use the outflow from an unmanned aerial vehicle hovering over solar panels to adequately clean their surface? Does aerosol deposition from episodes of nearby forest fires impact performance? The outlook of this research is to build a model that describes environmental effects on solar panel performance. Measurements from summer and fall 2015 will be presented along with insights gleaned from them.

  4. Pulmonary Deposition of Aerosols in Microgravity

    NASA Technical Reports Server (NTRS)

    Prisk, G. Kim

    1997-01-01

    The intrapulmonary deposition of airborne particles (aerosol) in the size range of 0.5 to 5 microns is primarily due to gravitational sedimentation. In the microgravity (muG) environment, sedimentation is no longer active, and thus there should be marked changes in the amount and site of the deposition of these aerosol. We propose to study the total intrapulmonary deposition of aerosol spanning the range 0.5 to 5 microns in the KC-135 at both muG and at 1.8-G. This will be followed by using boli of 1.0 micron aerosol, inhaled at different points in a breath to study aerosol dispersion and deposition as a function of inspired depth. The results of these studies will have application in better understanding of pulmonary diseases related to inhaled particles (pneumoconioses), in studying drugs delivered by inhalation, and in understanding the consequence of long-term exposure to respirable aerosols in long-duration space flight.

  5. Regional aerosol deposition in human upper airways

    SciTech Connect

    Swift, D.L.

    1990-11-01

    During the current reporting period experimental studies of aerosol deposition in replicate NOPL airways have carried out. A replicate model of a 4 week old infant nasal passage was constructed from MR scans. The model completes the age range from newborn'' to 4 years, there now being one child model for 4 different ages. Deposition studies have been performed with unattached radon progeny aerosols in collaboration with ITRI, Albuquerque, NM and NRPB, Chilton, UK. Overall measurements have been performed in adult and child nasal airways indicating that the child nasal passage was slightly more efficient than the adult in removing 1 nm particles at corresponding flow rates. A similar weak dependence on flow rate was observed. Local deposition studies in an adult nasal model indicated predominant deposition in the anterior region during inspiratory flow, but measurable deposition was found throughout the model. The deposition pattern during expiration was reverse, greater deposition being observed in the posterior region. Local deposition studies of attached progeny aerosol size (100--200 nm) were performed in adult and child nasal models using technigas'' and a gamma scintillation camera. Similar to the unattached size, deposition occurred throughout the models, but was greater in the anterior region.

  6. Regional aerosol deposition in human upper airways

    SciTech Connect

    Swift, D.L.

    1991-11-01

    During the current report experimental studies of upper respiratory deposition of radon progeny aerosols and stimulant aerosols were carried out in replicate casts of nasal and oral passages of adults and children. Additionally, preliminary studies of nasal passage deposition of unattached Po{sup 218} particles was carried out in four human subjects. Data on nasal inspiratory deposition in replicate models of adults and infants from three collaborating laboratories were compared and a best-fit curve of deposition efficiency for both attached and unattached particles was obtained, showing excellent inter-laboratory agreement. This curve demonstrates that nasal inspiratory deposition of radon progeny is weakly dependent upon flow rate over physiologically realistic ranges of flow, does not show a significant age effect, and is relatively independent of nasal passage dimensions for a given age range. Improved replicate models of the human adult oral passage extending to the mid-trachea were constructed for medium and higher flow mouth breathing states; these models were used to assess the deposition of unattached Po{sup 218} particles during oronasal breathing in the oral passage and demonstrated lower deposition efficiency than the nasal passage. Measurements of both Po{sup 218} particle and attached fraction particle size deposition were performed in replicate nasal passage of a four week old infant. 5 refs., 1 fig.

  7. 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.

  8. METHODS OF CALCULATINAG LUNG DELIVERY AND DEPOSITION OF AEROSOL PARTICLES

    EPA Science Inventory


    Lung deposition of aerosol is measured by a variety of methods. Total lung deposition can be measured by monitoring inhaled and exhaled aerosols in situ by laser photometry or by collecting the aerosols on filters. The measurements can be performed accurately for stable monod...

  9. Chamber for Aerosol Deposition of Bioparticles

    NASA Technical Reports Server (NTRS)

    Kern, Roger; Kirschner, Larry

    2008-01-01

    Laboratory apparatus is depicted that is a chamber for aerosol deposition of bioparticles on surfaces of test coupons. It is designed for primary use in inoculating both flat and three-dimensional objects with approximately reproducible, uniform dispersions of bacterial spores of the genus Bacillus so that the objects could be used as standards for removal of the spores by quantitative surface sampling and/or cleaning processes. The apparatus is also designed for deposition of particles other than bacterial spores, including fungal spores, viruses, bacteriophages, and standard micron-sized beads. The novelty of the apparatus lies in the combination of a controllable nebulization system with a settling chamber large enough to contain a significant number of test coupons. Several companies market other nebulizer systems, but none are known to include chambers for deposition of bioparticles to mimic the natural fallout of bioparticles. The nebulization system is an expanded and improved version of commercially available aerosol generators that include nebulizers and drying columns. In comparison with a typical commercial aerosol generator, this system includes additional, higher-resolution flowmeters and an additional pressure regulator. Also, unlike a typical commercial aerosol generator, it includes stopcocks for separately controlling flows of gases to the nebulizer and drying column. To maximize the degree of uniformity of dispersion of bioaerosol, the chamber is shaped as an axisymmetrical cylinder and the aerosol generator is positioned centrally within the chamber and aimed upward like a fountain. In order to minimize electric charge associated with the aerosol particles, the drying column is made of aluminum, the drying column is in direct contact with an aluminum base plate, and three equally spaced Po-210 antistatic strips are located at the exit end of the drying column. The sides and top of the chamber are made of an acrylic polymer; to prevent

  10. Aerosol deposition in the human respiratory tract

    NASA Astrophysics Data System (ADS)

    Winchester, John W.; Jones, Donald L.; Mu-tian, Bi

    1984-04-01

    Rising sulfur dioxide emissions from increased coal combustion present risks, not only of acid rain, but also to health by inhalation of the SO 2 and acid to the lung. We are investigating human inhalation of ppm SO 2 concentrations mixed with aerosol of submicrometer aqueous salt droplets to determine the effects on lung function and body chemistry. Unlike some investigators, we emphasize ammonium sulfate and trace element aerosol composition which simulates ambient air; aerosol pH, relative humidity, and temperature control to reveal gas-particle reaction mechanisms; and dose estimates from length of exposure, SO 2 concentration, and a direct measurement of respiratory deposition of aerosol as a function of particle size by cascade impactor sampling and elemental analysis by PIXE. Exposures, at rest or during exercise, are in a walk-in chamber at body temperature and high humidity to simulate Florida's summer climate. Lung function measurement by spirometry is carried out immediately after exposure. The results are significant in relating air quality to athletic performance and to public health in the southeastern United States.

  11. Aerosol deposition in bends with turbulent flow

    SciTech Connect

    McFarland, A.R.; Gong, H.; Wente, W.B.

    1997-08-01

    The losses of aerosol particles in bends were determined numerically for a broad range of design and operational conditions. Experimental data were used to check the validity of the numerical model, where the latter employs a commercially available computational fluid dynamics code for characterizing the fluid flow field and Lagrangian particle tracking technique for characterizing aerosol losses. Physical experiments have been conducted to examine the effect of curvature ratio and distortion of the cross section of bends. If it curvature ratio ({delta} = R/a) is greater than about 4, it has little effect on deposition, which is in contrast with the recommendation given in ANSI N13.1-1969 for a minimum curvature ratio of 10. Also, experimental results show that if the tube cross section is flattened by 25% or less, the flattening also has little effect on deposition. Results of numerical tests have been used to develop a correlation of aerosol penetration through a bend as a function of Stokes number (Stk), curvature ratio ({delta}) and the bend angle ({theta}). 17 refs., 10 figs., 2 tabs.

  12. Formation and deposition of volcanic sulfate aerosols on Mars

    NASA Technical Reports Server (NTRS)

    Settle, M.

    1979-01-01

    The paper considers the formation and deposition of volcanic sulfate aerosols on Mars. The rate limiting step in sulfate aerosol formation on Mars is the gas phase oxidation of SO2 by chemical reactions with O, OH, and HO2; submicron aerosol particles would circuit Mars and then be removed from the atmosphere by gravitational forces, globally dispersed, and deposited over a range of equatorial and mid-latitudes. Volcanic sulfate aerosols on Mars consist of liquid droplets and slurries containing sulfuric acid; aerosol deposition on a global or hemispheric scale could account for the similar concentrations of sulfur within surficial soils at the two Viking lander sites.

  13. Mechanisms of pharmaceutical aerosol deposition in the respiratory tract.

    PubMed

    Cheng, Yung Sung

    2014-06-01

    Aerosol delivery is noninvasive and is effective in much lower doses than required for oral administration. Currently, there are several types of therapeutic aerosol delivery systems, including the pressurized metered-dose inhaler, the dry powder inhaler, the medical nebulizer, the solution mist inhaler, and the nasal sprays. Both oral and nasal inhalation routes are used for the delivery of therapeutic aerosols. Following inhalation therapy, only a fraction of the dose reaches the expected target area. Knowledge of the amount of drug actually deposited is essential in designing the delivery system or devices to optimize the delivery efficiency to the targeted region of the respiratory tract. Aerosol deposition mechanisms in the human respiratory tract have been well studied. Prediction of pharmaceutical aerosol deposition using established lung deposition models has limited success primarily because they underestimated oropharyngeal deposition. Recent studies of oropharyngeal deposition of several drug delivery systems identify other factors associated with the delivery system that dominates the transport and deposition of the oropharyngeal region. Computational fluid dynamic simulation of the aerosol transport and deposition in the respiratory tract has provided important insight into these processes. Investigation of nasal spray deposition mechanisms is also discussed.

  14. Deposition of Aerosols in the Lung: Physiological Factors

    EPA Science Inventory

    Ventilation and mechanics of breathing are an integral part of respiratory physiology that directly affect aerosol transport and deposition in the lung. Although natural breathing pattern varies widely among individuals, breathing pattern is controllable, and by using an appropri...

  15. Deposition of graphene nanomaterial aerosols in human upper airways.

    PubMed

    Su, Wei-Chung; Ku, Bon Ki; Kulkarni, Pramod; Cheng, Yung Sung

    2016-01-01

    Graphene nanomaterials have attracted wide attention in recent years on their application to state-of-the-art technology due to their outstanding physical properties. On the other hand, the nanotoxicity of graphene materials also has rapidly become a serious concern especially in occupational health. Graphene naomaterials inevitably could become airborne in the workplace during manufacturing processes. The inhalation and subsequent deposition of graphene nanomaterial aerosols in the human respiratory tract could potentially result in adverse health effects to exposed workers. Therefore, investigating the deposition of graphene nanomaterial aerosols in the human airways is an indispensable component of an integral approach to graphene occupational health. For this reason, this study carried out a series of airway replica deposition experiments to obtain original experimental data for graphene aerosol airway deposition. In this study, graphene aerosols were generated, size classified, and delivered into human airway replicas (nasal and oral-to-lung airways). The deposition fraction and deposition efficiency of graphene aerosol in the airway replicas were obtained by a novel experimental approach. The experimental results acquired showed that the fractional deposition of graphene aerosols in airway sections studied were all less than 4%, and the deposition efficiency in each airway section was generally lower than 0.03. These results indicate that the majority of the graphene nanomaterial aerosols inhaled into the human respiratory tract could easily penetrate through the head airways as well as the upper part of the tracheobronchial airways and then transit down to the lower lung airways, where undesired biological responses might be induced.

  16. Regional aerosol deposition in human upper airways. Final report

    SciTech Connect

    Swift, D.L.

    1997-11-01

    During the award period, a number of studies have been carried out related to the overall objective of the project which is to elucidate important factors which influence the upper airway deposition and dose of particles in the size range 0.5 nm - 10 {mu}m, such as particle size, breathing conditions, age, airway geometry, and mode of breathing. These studies are listed below. (1) A high voltage electrospray system was constructed to generate polydispersed 1-10 {mu}m diameter di-ethylhexyl sebacate aerosol for particle deposition studies in nasal casts and in human subjects. (2) The effect of nostril dimensions, nasal passage geometry, and nasal resistance on particle deposition efficiency in forty healthy, nonsmoking adults at a constant flowrate were studied. (3) The effect of nostril dimensions, nasal passage dimensions and nasal resistance on the percentage of particle deposition in the anterior 3 cm of the nasal passage of spontaneously breathing humans were studied. (4) The region of deposition of monodispersed aerosols were studied using replicate casts. (5) Ultrafine aerosol deposition using simulated breath holding path and natural path was compared. (6) An experimental technique was proposed and tested to measure the oral deposition of inhaled ultrafine particles. (7) We have calculated the total deposition fraction of ultrafine aerosols from 5 to 200 n in the extrathoracic airways and in the lung. (8) The deposition fraction of radon progeny in the head airways was studied using several head airway models.

  17. Urban emission hot spots as sources for remote aerosol deposition

    NASA Astrophysics Data System (ADS)

    Kunkel, D.; Lawrence, M. G.; Tost, H.; Kerkweg, A.; Jöckel, P.; Borrmann, S.

    2012-01-01

    Large point sources such as major population centers (MPCs) emit pollutants which can be deposited nearby or transported over long distances before deposition. We have used tracer simulations of aerosols emitted from MPCs worldwide to assess the fractions which are deposited at various distances away from their source location. Considering only source location, prevailing meteorology, and the aerosol size and solubility, we show that fine aerosol particles have a high potential to pollute remote regions. About half of the emitted mass of aerosol tracers with an ambient diameter ≤1.0 μm is typically deposited in regions more than 1000 km away from the source. Furthermore, using the Köppen-Geiger climate classification to categorize the sources into various climate classes we find substantial differences in the deposition potential between these classes. Tracers originating in arid regions show the largest remote deposition potentials, with values more than doubled compared to the smallest potentials from tracers in tropical regions. Seasonal changes in atmospheric conditions lead to variations in the remote deposition potentials. On average the remote deposition potentials in summer correspond to about 70-80% of the values in winter, with a large spread among the climate classes. For tracers from tropical regions the summer remote deposition values are only about 31% of the winter values, while they are about 95% for tracers from arid regions.

  18. A 20-year simulated climatology of global dust aerosol deposition.

    PubMed

    Zheng, Yu; Zhao, Tianliang; Che, Huizheng; Liu, Yu; Han, Yongxiang; Liu, Chong; Xiong, Jie; Liu, Jianhui; Zhou, Yike

    2016-07-01

    Based on a 20-year (1991-2010) simulation of dust aerosol deposition with the global climate model CAM5.1 (Community Atmosphere Model, version 5.1), the spatial and temporal variations of dust aerosol deposition were analyzed using climate statistical methods. The results indicated that the annual amount of global dust aerosol deposition was approximately 1161±31Mt, with a decreasing trend, and its interannual variation range of 2.70% over 1991-2010. The 20-year average ratio of global dust dry to wet depositions was 1.12, with interannual variation of 2.24%, showing the quantity of dry deposition of dust aerosol was greater than dust wet deposition. High dry deposition was centered over continental deserts and surrounding regions, while wet deposition was a dominant deposition process over the North Atlantic, North Pacific and northern Indian Ocean. Furthermore, both dry and wet deposition presented a zonal distribution. To examine the regional changes of dust aerosol deposition on land and sea areas, we chose the North Atlantic, Eurasia, northern Indian Ocean, North Pacific and Australia to analyze the interannual and seasonal variations of dust deposition and dry-to-wet deposition ratio. The deposition amounts of each region showed interannual fluctuations with the largest variation range at around 26.96% in the northern Indian Ocean area, followed by the North Pacific (16.47%), Australia (9.76%), North Atlantic (9.43%) and Eurasia (6.03%). The northern Indian Ocean also had the greatest amplitude of interannual variation in dry-to-wet deposition ratio, at 22.41%, followed by the North Atlantic (9.69%), Australia (6.82%), North Pacific (6.31%) and Eurasia (4.36%). Dust aerosol presented a seasonal cycle, with typically strong deposition in spring and summer and weak deposition in autumn and winter. The dust deposition over the northern Indian Ocean exhibited the greatest seasonal change range at about 118.00%, while the North Atlantic showed the lowest seasonal

  19. Pulmonary deposition of aerosols by different mechanical devices.

    PubMed

    Matthys, H; Köhler, D

    1985-01-01

    With a new method for easy labeling of beta 2-agonists we measured intra- and extrapulmonary aerosol deposition after the administration of a bolus from a metered-dose inhaler at residual volume (RV) inhaling after a pause of 2 s and after immediate administration into the inspiratory flow at functional residual capacity (FRC). Immediate administration during a slow inspiratory vital capacity maneuver gives the highest intrapulmonary deposition (30-40%). Compressed air and ultrasonic nebulizers with a particle distribution pattern of 2-5 micron aerodynamic mass median diameter (AMMD) allow in normal subjects to achieve an intrapulmonary deposition of 30-60% during standardized tidal breathing at rest, the magnitude of the deposition depending mainly on each subject's larynx geometry. The outlet system leads to different deposition patterns in aerosol generators with the same AMMD. Many commercially available aerosol generators do not fulfill the criteria for any intrapulmonary aerosol deposition. For drug administration into the lungs, condensation aerosol generators ('steam boiler nebulizers') are useless as well as compressed-air, ultrasonic and steam driven nebulizers with a particle size of more than 10 micron AMMD.

  20. Aerosol deposition in human respiratory-tract casts

    SciTech Connect

    Martonen, T.B.

    1981-09-01

    To assess the health hazard to the human presented by airborne particulate matter in the mining and industrial work environment, information is needed concerning total dose deposition and its distribution. Data has been obtained by depositing monodisperse ammonium fluorscein aerosols in respiratory system simulators consisting of combined human replica larynx casts and single-pathway trachebronchial (TB) tue models. Since they have only two airways in each generation distal to the trachea, airflow rates and patterns could be controlled in a practical manner with rotometers. Larynx configurations correspond to inspiratory flow rates of 15, 30 and 60 lmin. The mass median aerodynamic diameters of the aerosols ranged from 3.0 ..mu..m to 10.6 ..mu..m with geometric standard deviations of 1.11 to 1.16. Total larynx and TB deposition measurements could be expressed in terms of a single parameter, the particle Stokes number. Intrabronchial dose distribution results indicated relatively large tracheal losses, attributed to the laryngeal jet. Some airway bifurcations were sites of enhanced deposition. Such hot spots would indicate very high dosage to epithelial cells of workers' airways and have important implications regarding the establishment of threshold exposure values. Findings are in agreement with aerosol deposition data from replica TB casts. Inhalation exposure tests support the use of the single-pathway TB model as a suitable surrogate in studies of factors affecting aerosol behavior and deposition in the human.

  1. FACTORS AFFECTING THE DEPOSITION OF AEROSOLIZED INSULIN

    EPA Science Inventory

    Abstract
    Background
    The inhalation of insulin for absorption into the bloodstream via the lung seems to be a promising technique for the treatment of diabetes mellitus. A fundamental issue to be resolved in the development of such insulin aerosol delivery systems is their...

  2. Formation of Thick Dense Yttrium Iron Garnet Films Using Aerosol Deposition.

    PubMed

    Johnson, Scooter D; Glaser, Evan R; Kub, Fritz J; Eddy, Charles R

    2015-05-15

    Aerosol deposition (AD) is a thick-film deposition process that can produce layers up to several hundred micrometers thick with densities greater than 95% of the bulk. The primary advantage of AD is that the deposition takes place entirely at ambient temperature; thereby enabling film growth in material systems with disparate melting temperatures. This report describes in detail the processing steps for preparing the powder and for performing AD using the custom-built system. Representative characterization results are presented from scanning electron microscopy, profilometry, and ferromagnetic resonance for films grown in this system. As a representative overview of the capabilities of the system, focus is given to a sample produced following the described protocol and system setup. Results indicate that this system can successfully deposit 11 µm thick yttrium iron garnet films that are  > 90% of the bulk density during a single 5 min deposition run. A discussion of methods to afford better control of the aerosol and particle selection for improved thickness and roughness variations in the film is provided.

  3. 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.

  4. Deposition of aerosols in sampling tubes

    NASA Astrophysics Data System (ADS)

    Stenger, J. B.; Bajura, R. A.

    1982-05-01

    The particulate loading in the process stream of coal conversion and gasification plants must be accurately determined for reasons of environmental health and safety and the protection of operating equipment such as gas turbines. A common method of obtaining these measurements is with aspiration probes. Deposition of particulate on the probe walls is a source of significant error in these measurements. Literature on deposition in sampling tubes for laminar and turbulent flows, the effects of the entrance region and bends in the sampling lines are reviewed. A research plan is proposed for additional work in the analysis of deposition. Experimental work is also proposed to verify the analytical studies. Methods to correct for the effects of deposition in sampling lines are developed.

  5. 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).

  6. 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.

  7. Inspiratory and expiratory aerosol deposition in the upper airway.

    PubMed

    Verbanck, S; Kalsi, H S; Biddiscombe, M F; Agnihotri, V; Belkassem, B; Lacor, C; Usmani, O S

    2011-02-01

    Aerosol deposition efficiency (DE) in the extrathoracic airways during mouth breathing is currently documented only for the inspiratory phase of respiration, and there is a need for quantification of expiratory DE. Our aim was to study both inspiratory and expiratory DE in a realistic upper airway geometry. This was done experimentally on a physical upper airway cast by scintigraphy, and numerically by computational fluid dynamic simulations using a Reynolds Averaged Navier?Stokes (RANS) method with a k-? SST turbulence model coupled with a stochastic Lagrangian approach. Experiments and simulations were carried out for particle sizes (3 and 6 μm) and flow rates (30 and 60 L/min) spanning the ranges of Stokes (Stk) and Reynolds (Re) number pertinent to therapeutic and environmental aerosols. We showed that inspiratory total deposition data obtained by scintigraphy fell onto a previously published deposition curve representative of a range of upper airway geometries. We also found that expiratory and inspiratory DE curves were almost identical. Finally, DE in different compartments of the upper airway model showed a very different distribution pattern of aerosol deposition during inspiration and expiration, with preferential deposition in oral and pharyngeal compartments, respectively. These compartmental deposition patterns were very consistent and only slightly dependent on particle size or flow rate. Total deposition for inspiration and expiration was reasonably well-mimicked by the RANS simulation method we employed, and more convincingly so in the upper range of the Stk and Re number. However, compartmental deposition patterns showed discrepancies between experiments and RANS simulations, particularly during expiration.

  8. Aerosol chemical vapor deposition of metal oxide films

    DOEpatents

    Ott, Kevin C.; Kodas, Toivo T.

    1994-01-01

    A process of preparing a film of a multicomponent metal oxide including: forming an aerosol from a solution comprised of a suitable solvent and at least two precursor compounds capable of volatilizing at temperatures lower than the decomposition temperature of said precursor compounds; passing said aerosol in combination with a suitable oxygen-containing carrier gas into a heated zone, said heated zone having a temperature sufficient to evaporate the solvent and volatilize said precursor compounds; and passing said volatilized precursor compounds against the surface of a substrate, said substrate having a sufficient temperature to decompose said volatilized precursor compounds whereby metal atoms contained within said volatilized precursor compounds are deposited as a metal oxide film upon the substrate is disclosed. In addition, a coated article comprising a multicomponent metal oxide film conforming to the surface of a substrate selected from the group consisting of silicon, magnesium oxide, yttrium-stabilized zirconium oxide, sapphire, or lanthanum gallate, said multicomponent metal oxide film characterized as having a substantially uniform thickness upon said FIELD OF THE INVENTION The present invention relates to the field of film coating deposition techniques, and more particularly to the deposition of multicomponent metal oxide films by aerosol chemical vapor deposition. This invention is the result of a contract with the Department of Energy (Contract No. W-7405-ENG-36).

  9. Quantitative deposition of aerosolized gentamicin in cystic fibrosis

    SciTech Connect

    Ilowite, J.S.; Gorvoy, J.D.; Smaldone, G.C.

    1987-12-01

    In cystic fibrosis (CF), the clinical effectiveness of aerosolized antibiotics is controversial. Previous investigators have not considered the type of nebulizer, droplet size, and dose to the lung in assessing the results of aerosol therapy. The present study tests the importance of these factors by standardizing an aerosol system for delivery of antibiotics and other agents to patients with CF. Particle size, distribution, and output from a commercially available nebulizer were measured. Thirteen patients with CF inhaled aerosol (MMAD = 1.1 micron) containing gentamicin (160 mg in nebulizer) and /sup 99m/Tc-labeled human serum albumin. Patients' sputum and serum were analyzed for gentamicin levels by immunoenzymatic assay. Using a gamma camera and suitable filters, central versus peripheral deposition (C/P ratio) and whole lung deposition were measured and related to sputum gentamicin levels. Gentamicin deposit averaged 12.3 mg +/- 5.9 (SD) or 7.69% of the original amount placed in the nebulizer. Peak sputum levels averaged 376.6 micrograms/ml +/- 275, whereas serum levels were undetectable in all patients. When peak sputum levels were normalized for the amount deposited, a close correlation with C/P ratio was obtained (r = 0.88, p less than 0.05). Furthermore, an inverse relationship was found between the C/P ratio and the %FEV1 (r = 0.76, p less than 0.05). Finally, a bell-shaped relationship between deposited dose and minute ventilation was seen in the patients (r = 0.88, p less than 0.05), i.e., an optimal minute ventilation was shown. These relationships may be important when designing future clinical studies.

  10. Aerosol assisted chemical vapour deposition control parameters for selective deposition of tungsten oxide nanostructures.

    PubMed

    Vallejos, S; Umek, P; Blackman, C

    2011-09-01

    Tungsten oxide films were deposited via Aerosol Assisted Chemical Vapour Deposition (AACVD) from the single-source precursor W(OPh)6. Film morphology and optimum deposition temperatures for formation of quasi-one-dimensional structures is influenced by the solvent 'carrier' used for deposition of the films with bulk porous films and nanostructured needles, hollow tubes and fibres obtained dependent on the solvent used and the deposition temperature. This influence of solvent could be exploited for the synthesis of other nanomaterials, and so provide a new and versatile route to develop and integrate nanostructured materials for device applications. PMID:22097557

  11. Lung physiology and aerosol deposition imaged with positron emission tomography.

    PubMed

    Venegas, Jose; Winkler, Tilo; Harris, R Scott

    2013-02-01

    Physiological conditions and pathophysiological changes in the lungs may affect many applications in aerosol medicine and pulmonary drug delivery. In the diseased lung, spatial heterogeneity in function and structure may cause substantial changes in aerosol transport and local deposition among different lung regions. Non-uniform aerosol deposition affects airway or tissue pharmacological dosing, which could reduce the therapeutic effectiveness of inhalation therapy. This review article presents examples of pulmonary imaging using PET and PET-CT in lung physiology with an emphasis on their implications for aerosol medicine. Measurements of regional ventilation, perfusion, and ventilation/perfusion ratio, by imaging local kinetics of intravenously injected Nitrogen-13 in saline solution, and of pulmonary inflammation, by assessing the regional uptake of the radiotracer (18)F-FDG, are presented. These examples demonstrate that it is possible to access both preexisting conditions, such as heterogeneity of ventilation, perfusion, and/or inflammatory stimuli, which may affect inhalation therapy, and the functional effects of inhaled medications or inflammatory agents on lung regional function. The imaging techniques described could be efficient tools to evaluate quantitatively and noninvasively these processes in vivo. Furthermore, it can be expected that imaging of respiratory structure and function will yield sensitive biomarkers of disease, which will help and speed drug discovery, and the evaluation of novel inhalation therapies.

  12. Aerosol assisted depositions of polymers using an atomiser delivery system.

    PubMed

    Crick, Colin R; Clausen-Thue, Victoria; Parkin, Ivan P

    2011-09-01

    The hydrophobicity, robustness and anti-microbial properties of Sylgard 184 polymer films deposited via AACVD were optimised by using aerosol droplets from an atomiser delivery system, polymer coating substrates and the swell encapsulation of methylene blue. By using an atomiser deposition system (average droplet size 0.35 microm) rather than a misting aerosol system (45 microm) lead to a surface with smaller surface features, which improved hydrophobicity (water contact angle 165 degrees) in addition to increasing the films transparency from ca 10 to 65%. Pre-treating the substrates with the same Sylgard 184 elastomer lead to a highly consistent surface hydrophobicity and an increase in average water contact angle measured (169 degrees). This paper shows the first example of dye incorporation in a CVD derived polymer film-these films have potential as antimicrobial surfaces. PMID:22097584

  13. Aerosol assisted depositions of polymers using an atomiser delivery system.

    PubMed

    Crick, Colin R; Clausen-Thue, Victoria; Parkin, Ivan P

    2011-09-01

    The hydrophobicity, robustness and anti-microbial properties of Sylgard 184 polymer films deposited via AACVD were optimised by using aerosol droplets from an atomiser delivery system, polymer coating substrates and the swell encapsulation of methylene blue. By using an atomiser deposition system (average droplet size 0.35 microm) rather than a misting aerosol system (45 microm) lead to a surface with smaller surface features, which improved hydrophobicity (water contact angle 165 degrees) in addition to increasing the films transparency from ca 10 to 65%. Pre-treating the substrates with the same Sylgard 184 elastomer lead to a highly consistent surface hydrophobicity and an increase in average water contact angle measured (169 degrees). This paper shows the first example of dye incorporation in a CVD derived polymer film-these films have potential as antimicrobial surfaces.

  14. The Asian Dust and Aerosol Lidar Observation Network (AD-NET): Strategy and Progress

    NASA Astrophysics Data System (ADS)

    Nishizawa, Tomoaki; Sugimoto, Nobuo; Matsui, Ichiro; Shimizu, Atsushi; Higurashi, Akiko; Jin, Yoshitaka

    2016-06-01

    We have operated a ground-based lidar network AD-Net using dual wavelength (532, 1064nm) depolarization Mie lidar continuously and observed movement of Asian dust and air pollution aerosols in East Asia since 2001. This lidar network observation contributed to understanding of the occurrence and transport mechanisms of Asian dust, validation of chemical transport models, data assimilation and epidemiologic studies. To better understand the optical and microphysical properties, externally and internally mixing states, and the movements of Asian dust and airpollution aerosols, we go forward with introducing a multi-wavelength Raman lidar to the AD-Net and developing a multi-wavelength technique of HSRL in order to evaluate optical concentrations of more aerosol components. We will use this evolving AD-Net for validation of Earth-CARE satellite observation and data assimilation to evaluate emissions of air pollution and dust aerosols in East Asia. We go forward with deploying an in-situ instrument polarization optical particle counter (POPC), which can measure size distributions and non-sphericity of aerosols, to several main AD-Net sites and conducting simultaneous observation of POPC and lidar to clarify internally mixed state of Asian dust and air pollution aerosols transported from the Asian continent to Japan.

  15. 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

  16. Deposition of biological aerosols on HVAC heat exchangers

    SciTech Connect

    Siegel, Jeffrey; Walker, Ian

    2001-09-01

    Many biologically active materials are transported as bioaerosols 1-10 {micro}m in diameter. These particles can deposit on cooling and heating coils and lead to serious indoor air quality problems. This paper investigates several of the mechanisms that lead to aerosol deposition on fin and tube heat exchangers. A model has been developed that incorporates the effects of several deposition mechanisms, including impaction, Brownian and turbulent diffusion, turbophoresis, thermophoresis, diffusiophoresis, and gravitational settling. The model is applied to a typical range of air velocities that are found in commercial and residential HVAC systems 1 - 6 m/s (200 - 1200 ft/min), particle diameters from 1 - 8 {micro}m, and fin spacings from 3.2 - 7.9 fins/cm (8 - 16 fins/inch or FPI). The results from the model are compared to results from an experimental apparatus that directly measures deposition on a 4.7 fins/cm (12 FPI) coil. The model agrees reasonably well with this measured data and suggests that cooling coils are an important sink for biological aerosols and consequently a potential source of indoor air quality problems.

  17. Aerosol transport and deposition efficiency in the respiratory airways

    NASA Astrophysics Data System (ADS)

    Nicolaou, Laura; Zaki, Tamer

    2015-11-01

    Prediction of aerosol deposition in the respiratory system is important for improving the efficiency of inhaled drug delivery and for assessing the toxicity of airborne pollutants. Particle deposition in the airways is typically described as a function of the Stokes number based on a reference flow timescale. This choice leads to significant scatter in deposition data since the velocity and length scales experienced by the particles as they are advected through the flow deviate considerably from the reference values in many sections of the airways. Therefore, the use of an instantaneous Stokes number based on the local properties of the flow field is proposed instead. We define the effective Stokes number as the time-average of the instantaneous value. Our results demonstrate that this average, or effective, Stokes number can deviate significantly from the reference value particularly in the intermediate Stokes number range. In addition, the effective Stokes number shows a very clear correlation with deposition efficiency, and is therefore a more appropriate parameter to describe aerosol transport.

  18. 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

  19. Characterization of aerosols in East Asia with the Asian Dust and Aerosol Lidar Observation Network (AD-Net)

    NASA Astrophysics Data System (ADS)

    Sugimoto, Nobuo; Nishizawa, Tomoaki; Shimizu, Atsushi; Matsui, Ichiro; Jin, Yoshitaka

    2014-11-01

    Continuous observations of aerosols are being conducted with the Asian Dust and aerosol lidar observation Network (AD-Net). Currently, two-wavelength (1064 nm and 532 nm) polarization-sensitive (532 nm) lidars are operated at 20 stations in East Asia. At the primary stations (6 stations), nitrogen vibrational Raman scattering is also measured to obtain the extinction coefficient at 532 nm. Recently, continuous observations with a three-wavelength (1064 nm, 532 nm and 355 nm) lidar having a high-spectral-resolution receiver at 532 nm and a Raman receiver at 355 nm and polarization-sensitive receivers at 532 nm and 355 nm) was started in Tsukuba. Also, continuous observations with multi-wavelength Raman lidars are being prepared in Fukuoka, Okinawa Hedo, and Toyama. A data analysis method for deriving distributions of aerosol components (weak absorption fine (such as sulfate), weak absorption coarse (sea salt), strong absorption fine (black carbon), non-spherical (dust)) has been developed for these multi-parameter lidars. Major subjects of the current studies with AD-Net include data assimilation of multi-parameter lidars, mixing states of Asian dust with air pollution particulate matter, and validation of EarthCARE ATLID based on the aerosol component analysis method.

  20. Putative cryomagma interaction with aerosols deposit at Titan's surface

    NASA Astrophysics Data System (ADS)

    Coll, Patrice; Navarro-Gonzalez, Rafael; Raulin, Francois; Coscia, David; Ramirez, Sandra I.; Buch, Arnaud; Szopa, Cyril; Poch, Olivier; Cabane, Michel; Brassé, Coralie

    The largest moon of Saturn, Titan, is known for its dense, nitrogen-rich atmosphere. The organic aerosols which are produced in Titan’s atmosphere are of great astrobiological interest, particularly because of their potential evolution when they reach the surface and may interact with putative ammonia-water cryomagma [1]. In this context we have followed the evolution of alkaline pH hydrolysis (25wt% ammonia-water) of Titan aerosol analogues, that have been qualified as representative of Titan’s aerosols [2]. Indeed the first results obtained by the ACP experiment onboard Huygens probe revealed that the main products obtained after thermolysis of Titan’s collected aerosols, were ammonia (NH3) and hydrogen cyanide (HCN). Then performing a direct comparison of the volatiles produced after a thermal treatment done in conditions similar to the ones used by the ACP experiment, we may estimate that the tholins we used are relevant to chemical analogues of Titan’s aerosols, and to note free of oxygen. Taking into account recent studies proposing that the subsurface ocean may contain a lower fraction of ammonia (about 5wt% or less [3]), and assuming the presence of specific gas species [4, 5], in particular CO2 and H2S, trapped in likely internal ocean, we determine a new probable composition of the cryomagma which could potentially interact with deposited Titan’s aerosols. We then carried out different hydrolyses, taking into account this composition, and we established the influence of the hydrolysis temperature on the organic molecules production. References: [1] Mitri et al., 2008. Resurfacing of Titan by ammonia-water cryomagma. Icarus. 196, 216-224. [2] Coll et al. 2013, Can laboratory tholins mimic the chemistry producing Titan's aerosols? A review in light of ACP experimental results, Planetary and Space Science 77, 91-103. [3] Tobie et al. 2012. Titan’s Bulk Composition Constrained by Cassini-Huygens: implication for internal outgassing. The

  1. Sulfuric acid deposition from stratospheric geoengineering with sulfate aerosols

    NASA Astrophysics Data System (ADS)

    Kravitz, Ben; Robock, Alan; Oman, Luke; Stenchikov, Georgiy; Marquardt, Allison B.

    2009-07-01

    We used a general circulation model of Earth's climate to conduct geoengineering experiments involving stratospheric injection of sulfur dioxide and analyzed the resulting deposition of sulfate. When sulfur dioxide is injected into the tropical or Arctic stratosphere, the main additional surface deposition of sulfate occurs in midlatitude bands, because of strong cross-tropopause flux in the jet stream regions. We used critical load studies to determine the effects of this increase in sulfate deposition on terrestrial ecosystems by assuming the upper limit of hydration of all sulfate aerosols into sulfuric acid. For annual injection of 5 Tg of SO2 into the tropical stratosphere or 3 Tg of SO2 into the Arctic stratosphere, neither the maximum point value of sulfate deposition of approximately 1.5 mEq m-2 a-1 nor the largest additional deposition that would result from geoengineering of approximately 0.05 mEq m-2 a-1 is enough to negatively impact most ecosystems.

  2. Aerosol chemical vapor deposition of metal oxide films

    DOEpatents

    Ott, K.C.; Kodas, T.T.

    1994-01-11

    A process of preparing a film of a multicomponent metal oxide including: forming an aerosol from a solution comprised of a suitable solvent and at least two precursor compounds capable of volatilizing at temperatures lower than the decomposition temperature of said precursor compounds; passing said aerosol in combination with a suitable oxygen-containing carrier gas into a heated zone, said heated zone having a temperature sufficient to evaporate the solvent and volatilize said precursor compounds; and passing said volatilized precursor compounds against the surface of a substrate, said substrate having a sufficient temperature to decompose said volatilized precursor compounds whereby metal atoms contained within said volatilized precursor compounds are deposited as a metal oxide film upon the substrate is disclosed. In addition, a coated article comprising a multicomponent metal oxide film conforming to the surface of a substrate selected from the group consisting of silicon, magnesium oxide, yttrium-stabilized zirconium oxide, sapphire, or lanthanum gallate, said multicomponent metal oxide film characterized as having a substantially uniform thickness upon said substrate.

  3. Deposition flux of aerosol particles and 15 polycyclic aromatic hydrocarbons in the North China Plain.

    PubMed

    Wang, Xilong; Liu, Shuzhen; Zhao, Jingyu; Zuo, Qian; Liu, Wenxin; Li, Bengang; Tao, Shu

    2014-04-01

    The present study examined deposition fluxes of aerosol particles and 15 polycyclic aromatic hydrocarbons (PAHs) associated with the particles in the North China Plain. The annual mean deposition fluxes of aerosol particles and 15 PAHs were 0.69 ± 0.46 g/(m(2) ×d) and 8.5 ± 6.2 μg/(m(2) ×d), respectively. Phenanthrene, fluoranthene, pyrene, chrysene, benzo[b]fluoranthene, and benzo[k]fluoranthene were the dominant PAHs bound to deposited aerosol particles throughout the year. The total concentration of 15 PAHs in the deposited aerosol particles was the highest in winter but lowest in spring. The highest PAH concentration in the deposited aerosol particles in winter was because the heating processes highly increased the concentration in atmospheric aerosol particles. Low temperature and weak sunshine in winter reduced the degradation rate of deposited aerosol particle-bound PAHs, especially for those with low molecular weight. The lowest PAH concentration in deposited aerosol particles in spring resulted from the frequently occurring dust storms, which diluted PAH concentrations. The mean deposition flux of PAHs with aerosol particles in winter (16 μg/[m(2) ×d]) reached 3 times to 5 times that in other seasons (3.5-5.0 μg/[m(2) ×d]). The spatial variation of the deposition flux of PAHs with high molecular weight (e.g., benzo[a]pyrene) was consistent with their concentrations in the atmospheric aerosol particles, whereas such a phenomenon was not observed for those with low molecular weight (e.g., phenanthrene) because of their distinct hydrophobicity, Henry's law constant, and the spatially heterogeneous meteorological conditions.

  4. Amorphous Carbon Deposited by a Novel Aerosol-Assisted Chemical Vapor Deposition for Photovoltaic Solar Cells

    NASA Astrophysics Data System (ADS)

    Ahmad, Nurfadzilah; Kamaruzzaman, Dayana; Rusop, Mohamad

    2012-06-01

    Amorphous carbon (a-C) solar cells were successfully prepared using a novel and self-designed aerosol-assisted chemical vapor deposition (AACVD) method using camphor oil as a precursor. The fabricated solar cell with the configuration of Au/p-C/n-Si/Au achieved an efficiency of 0.008% with a fill factor of 0.15 for the device deposited at 0.5 h. The current-voltage (I-V) graph emphasized on the linear graph (ohmic) for the a-C thin films, whereas for the p-n device structure, a rectifying curve was obtained. The rectifying curves signify the heterojunction between the p-type a-C film and the n-Si substrate and designate the generation of electron-hole pair of the samples under illumination. Photoresponse characteristics of the deposited a-C was highlighted when being illuminated (AM 1.5 illumination: 100 mW/cm2, 25 °C). Transmittance spectrum exhibit a large transmittance value (>85%) and absorption coefficient value of 103-104 cm-1 at the visible range of 390 to 790 nm. The atomization of a liquid precursor solution into fine sub-micrometre-sized aerosol droplets in AACVD induced the smooth surface of a-C films. To the best of our knowledge, fabrication of a-C solar cell using this AACVD method has not yet been reported.

  5. Physiological and pathological considerations for aerosol deposition: expiration and models of deposition.

    PubMed

    Smaldone, G C

    2000-01-01

    Theoretical models are often used to predict fractional and regional deposition of inhaled particles in the respiratory tract. The distribution of particle diameters in the aerosol, airway geometry, breathing pattern, and local flow profiles are major determinants of deposition in the lung. However, most models predicting deposition consider airway geometry to be fixed and concentrate on inspiratory events in their calculations. When particle losses during expiration are estimated, inspiratory and expiratory flow patterns and airspace geometry are usually considered to be similar with similar effects on deposition. The theme of this presentation will be the analysis of events during expiration that influence particle deposition. In the normal lung, during quiet breathing, experiments performed on excised lungs have suggested that convective forces may be different between inspiration and expiration that significantly affect deposition. Bennett and Smaldone, in excised dog lungs, by regulating the duty cycle of tidal breathing found that more particles deposited during inspiration than expiration and that the effects were density dependent. In human subjects with obstructive lung disease, the situation is reversed. Major differences in large airway geometry between inspiration and expiration can occur with each tidal breath. Once the FEV(1) decreases to about 60% of the FVC, flow-limiting segments (FLS) are known to form in central airways. Large pressure drops can occur over short lengths of airway indicating disturbed regions of convective streamlines that are not present during inspiration. Using radiolabeled monodisperse particles, Smaldone and Messina have determined that FLS can be a major determinant of deposition in central airways. Theoretical predictive models of particle deposition and clearance should consider inspiratory and expiratory differences in airway physiology in health and disease.

  6. Phase-contrast helium-3 MRI of aerosol deposition in human airways.

    PubMed

    Sarracanie, Mathieu; Grebenkov, Denis; Sandeau, Julien; Coulibaly, Soulé; Martin, Andrew R; Hill, Kyle; Pérez Sánchez, José Manuel; Fodil, Redouane; Martin, Lionel; Durand, Emmanuel; Caillibotte, Georges; Isabey, Daniel; Darrasse, Luc; Bittoun, Jacques; Maître, Xavier

    2015-02-01

    One of the key challenges in the study of health-related aerosols is predicting and monitoring sites of particle deposition in the respiratory tract. The potential health risks of ambient exposure to environmental or workplace aerosols and the beneficial effects of medical aerosols are strongly influenced by the site of aerosol deposition along the respiratory tract. Nuclear medicine is the only current modality that combines quantification and regional localization of aerosol deposition, and this technique remains limited by its spatial and temporal resolutions and by patient exposure to radiation. Recent work in MRI has shed light on techniques to quantify micro-sized magnetic particles in living bodies by the measurement of associated static magnetic field variations. With regard to lung MRI, hyperpolarized helium-3 may be used as a tracer gas to compensate for the lack of MR signal in the airways, so as to allow assessment of pulmonary function and morphology. The extrathoracic region of the human respiratory system plays a critical role in determining aerosol deposition patterns, as it acts as a filter upstream from the lungs. In the present work, aerosol deposition in a mouth-throat phantom was measured using helium-3 MRI and compared with single-photon emission computed tomography. By providing high sensitivity with high spatial and temporal resolutions, phase-contrast helium-3 MRI offers new insights for the study of particle transport and deposition.

  7. Research of transport and deposition of aerosol in human airway replica

    NASA Astrophysics Data System (ADS)

    Lizal, Frantisek; Jedelsky, Jan; Elcner, Jakub; Durdina, Lukas; Halasova, Tereza; Mravec, Filip; Jicha, Miroslav

    2012-04-01

    Growing concern about knowledge of aerosol transport in human lungs is caused by great potential of use of inhaled pharmaceuticals. Second substantial motive for the research is an effort to minimize adverse effects of particular matter emitted by traffic and industry on human health. We created model geometry of human lungs to 7th generation of branching. This model geometry was used for fabrication of two physical models. The first one is made from thin walled transparent silicone and it allows a measurement of velocity and size of aerosol particles by Phase Doppler Anemometry (PDA). The second one is fabricated by stereolithographic method and it is designed for aerosol deposition measurements. We provided a series of measurements of aerosol transport in the transparent model and we ascertained remarkable phenomena linked with lung flow. The results are presented in brief. To gather how this phenomena affects aerosol deposition in human lungs we used the second model and we developed a technique for deposition fraction and deposition efficiency assessment. The results confirmed that non-symmetric and complicated shape of human airways essentially affects transport and deposition of aerosol. The research will now focus on deeper insight in aerosol deposition.

  8. Characteristics and Mechanism of Cu Films Fabricated at Room Temperature by Aerosol Deposition.

    PubMed

    Lee, Dong-Won; Kwon, Oh-Yun; Cho, Won-Ju; Song, Jun-Kwang; Kim, Yong-Nam

    2016-12-01

    We were successful in growing a dense Cu film on Al2O3 substrates at room temperature using an aerosol deposition (AD) method. The characteristics of Cu films were investigated through electrical resistivity and X-ray photoelectron spectroscopy (XPS). The resistivity of Cu films was low (9.2-12.5 μΩ cm), but it was five to seven times higher than that of bulk copper. The deterioration of the resistivity indicates that a Cu2O phase with CuO occurs due to a particle-to-particle collision. Moreover, the growth of Cu films was investigated by observing their microstructures. At the initial stage in the AD process, the impacted particles were flattened and deformed on a rough Al2O3 substrate. The continuous collision of impacted particles leads to the densification of deposited coating layers due to the plastic deformation of particles. The bonding between the Cu particles and the rough Al2O3 substrate was explained in terms of the adhesive properties on the surface roughness of Al2O3 substrates. It was revealed that the roughness of substrates was considerably associated with the mechanical interlocking between Cu particles and rough Al2O3 substrate. PMID:27009529

  9. Characteristics and Mechanism of Cu Films Fabricated at Room Temperature by Aerosol Deposition

    NASA Astrophysics Data System (ADS)

    Lee, Dong-Won; Kwon, Oh-Yun; Cho, Won-Ju; Song, Jun-Kwang; Kim, Yong-Nam

    2016-03-01

    We were successful in growing a dense Cu film on Al2O3 substrates at room temperature using an aerosol deposition (AD) method. The characteristics of Cu films were investigated through electrical resistivity and X-ray photoelectron spectroscopy (XPS). The resistivity of Cu films was low (9.2-12.5 μΩ cm), but it was five to seven times higher than that of bulk copper. The deterioration of the resistivity indicates that a Cu2O phase with CuO occurs due to a particle-to-particle collision. Moreover, the growth of Cu films was investigated by observing their microstructures. At the initial stage in the AD process, the impacted particles were flattened and deformed on a rough Al2O3 substrate. The continuous collision of impacted particles leads to the densification of deposited coating layers due to the plastic deformation of particles. The bonding between the Cu particles and the rough Al2O3 substrate was explained in terms of the adhesive properties on the surface roughness of Al2O3 substrates. It was revealed that the roughness of substrates was considerably associated with the mechanical interlocking between Cu particles and rough Al2O3 substrate.

  10. COMPARISON OF MONODISPERSE AND POLYDISPERSE AEROSOL DEPOSITION IN A PACKED BED

    EPA Science Inventory

    COMPARISON OF MONODISPERSE AND POLYDISPERSE AEROSOL DEPOSITION IN A PACKED BED. Jacky A. Rosati, Dept. of Environmental Sciences and Engineering, University of North Carolina, Chapel Hill, NC 27599; Chong S. Kim, USEPA National Health and Environmental Effects Research Laboratory...

  11. 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.

  12. 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.

  13. Deposition of aerosol particles in human lungs: in vivo measurements and modeling

    EPA Science Inventory

    The deposition dose and site of inhaled particles within the lung are the key determinants in health risk assessment of particulate pollutants. Accurate dose estimation, however, is a formidable task because aerosol transport and deposition in the lung are governed by many factor...

  14. Aerosol deposition favors red tide phytoplankton in the East China Sea

    NASA Astrophysics Data System (ADS)

    Mackey, K. R.; Chien, C.; Chen, Y.; Glover, D. M.; Paytan, A.

    2013-12-01

    Chinese marginal seas support vast fisheries and vital economies, but their productivity is threatened by eutrophication from runoff and atmospheric deposition. The East China Sea is inundated with nitrogen from the Yangtze River and anthropogenic emissions, leading to elevated N:P ratios. We show that aerosol additions approximating one week of moderate deposition to offshore waters favor the growth of red tide phytoplankton, such as Skeletonema costatum, by providing nutrients and trace metals (iron and zinc) needed for growth. In contrast toxin-producing Pseudonitzchia does not benefit from aerosols in this region, possibly due to its preference for lower N:P ratios. A dose-dependent toxic response was observed in Synechococcus at high aerosol loads approximating a week of heavy deposition in the region. In contrast, phytoplankton growth at an onshore station was light limited, and aerosol additions did not have an appreciable effect on phytoplankton growth. Aerosol and chlorophyll observations from the Moderate Resolution Imaging Spectroradiometer (MODIS) satellite have the potential to explore the effect of aerosols on phytoplankton blooms over longer time scales and seasons. This study shows the potential for aerosols to control N:P ratios in offshore waters and to shape the phytoplankton community through fertilization and toxicity, contributing to the occurrence of red tides.

  15. Inhalation deposition and retention patterns of a U-Pu chain aggregate aerosol.

    PubMed

    Briant, J K; Sanders, C L

    1987-10-01

    Chain aggregate aerosol particles are normally formed during many high-temperature combustion and vaporization processes. The shape of chain aggregate aerosol particles could have an effect on the pattern of inhalation deposition and retention of the particles in the respiratory tract. A chain aggregate aerosol of nuclear reactor fuel could be present as an inhalation hazard if it were released to the atmosphere after a meltdown, core-disruptive accident. Rats were exposed to a chain aggregate U-Pu aerosol made by laser vaporization of mixed-oxide, breeder reactor fuel (20% plutonium dioxide and 80% uranium dioxide), then sacrificed to measure the clearance and retention of the fuel aerosol particles. Deposition of the 0.7-micron (activity median aerodynamic equivalent diameter) aerosol particles resulted in an average initial lung burden of 4140 Bq alpha activity. The chain aggregate particle shape was not a major factor in the total deposition; however, it may have influenced the regional distribution of the activity deposited. Retention of the particles in the upper airways of the tracheobronchial tree was on the order of 1% of the concurrent lung burden, which is consistent with recent data of other investigations. This study indicates that insoluble chain aggregate particles are retained in the tracheobronchial airways to a degree similar to simple spherically shaped particles of equivalent volume diameter.

  16. A Study of Morphology and Magnetic Properties of Doped Barium Ferrite Films Formed by Aerosol Deposition

    NASA Astrophysics Data System (ADS)

    Johnson, Scooter; Gonzalez, Christopher; Robinson, Zachary; Ellsworth, David; Wu, Mingzhong

    Aerosol deposition is a room-temperature thick film deposition technique that produces polycrystalline films that have > 95% of theoretical density and are up to several hundred microns thick. In addition to depositing films at room temperature another distinct advantage of aerosol deposition is the ability to produce films with the same resulting stoichiometry as the starting material. For this work, we deposited a proprietary doped barium ferrite (BaFe12O19) film from powder produced by Temex Ceramics. This material is designed for microwave absorption near 18 GHz via ferromagnetic resonance. We compare the structural and magnetic properties of the as-deposited film, bulk material, and starting powder. For this purpose, we employed scanning electron microscopy, x-ray photoemission spectroscopy, x-ray diffraction, vibrating sample magnetometry, and broad-band ferromagnetic resonance characterization techniques.

  17. ZnS/diamond composite coatings for infrared transmission applications formed by the aerosol deposition method

    NASA Astrophysics Data System (ADS)

    Johnson, Scooter D.; Kub, Fritz J.; Eddy, Charles R.

    2013-06-01

    The deposition of nano-crystalline ZnS/diamond composite protective coatings on silicon, sapphire, and ZnS substrates, as a preliminary step to coating infrared transparent ZnS substrates from powder mixtures by the aerosol deposition method is presented. Advantages of the aerosol deposition method include the ability to form dense, nanocrystalline lms up to hundreds of microns thick at room temperature and at a high deposition rate on a variety of substrates. Deposition is achieved by creating a pressure gradient that accelerates micrometer- scale particles in an aerosol to high velocity. Upon impact with the target substrate the particles fracture and embed. Continued deposition forms the thick compacted lm. Deposition from an aerosolized mixture of ZnS and diamond powders onto all targets results in linear trend from apparent sputter erosion of the substrate at 100% diamond to formation of a lm with increasing fractions of ZnS. The crossover from abrasion to lm formation on sapphire occurs above about 50% ZnS and a mixture of 90% ZnS and 10% diamond forms a well-adhered lm of about 0.7 μm thickness at a rate of 0.14 μm/min. Resulting lms are characterized by scanning electron microscopy, pro lometry, infrared transmission spectroscopy, and x-ray photoemission spectroscopy. These initial lms mark progress toward the future goal of coating ZnS substrates for abrasion resistance.

  18. Aerosol dry deposition on vegetative canopies. Part II: A new modelling approach and applications

    NASA Astrophysics Data System (ADS)

    Petroff, Alexandre; Mailliat, Alain; Amielh, Muriel; Anselmet, Fabien

    2008-05-01

    This paper presents a new approach for the modelling of aerosol dry deposition on vegetation. It follows a companion article, in which a review of the current knowledge highlights the need for a better description of the aerosol behaviour within the canopy [Petroff, A., Mailliat, A., Amielh, M., Anselmet, F., 2008. Aerosol dry deposition on vegetative canopies. Part I: Review of present knowledge. Atmospheric Environment, in press, doi:10.1016/j.atmosenv.2007.09.043]. Concepts from multi-phase flow studies are used for describing the canopy medium and deriving a time and space-averaged aerosol balance equation and the associated deposition terms. The closure of the deposition terms follows an up-scaling procedure based on the statistical distribution of the collecting elements. This aerosol transport model is then applied in a stationary and mono-dimensional configuration and takes into account the properties of the vegetation, the aerosol and the turbulent flow. Deposition mechanisms are Brownian diffusion, interception, inertial and turbulent impactions, and gravitational settling. For each of them, a parameterisation of the particle collection is derived and the quality of their predictions is assessed by comparison with wind-tunnel deposition measurements on coniferous twigs [Belot, Y., Gauthier, D., 1975. Transport of micronic particles from atmosphere to foliar surfaces. In: De Vries, D.A., Afgan, N.H. (Eds.), Heat and Mass Transfer in the Biosphere. Scripta Book, Washington, DC, pp. 583-591; Belot, Y., 1977. Etude de la captation des polluants atmosphériques par les végétaux. CEA, R-4786, Fontenay-aux-Roses; Belot, Y., Camus, H., Gauthier, D., Caput, C., 1994. Uptake of small particles by canopies. The Science of the Total Environment 157, 1-6]. Under a real canopy configuration, the predictions of the aerosol transport model compare reasonably well with detailed on-site deposition measurements of Aitken mode particles [Buzorius, G., Rannik, Ü., M

  19. Aerosol deposition in the human lung periphery is increased by reduced-density gas breathing.

    PubMed

    Peterson, Jonathan B; Prisk, G Kim; Darquenne, Chantal

    2008-06-01

    Aerosol mixing resulting from turbulent flows is thought to be a major mechanism of deposition in the upper respiratory tract (URT). Because turbulence levels are a function of gas density, the use of a low-density carrier gas should reduce deposition in the URT allowing the aerosol to reach more peripheral airways of the lung. We performed aerosol bolus tests on 11 healthy subjects to investigate the effect of reduced gas density on regional aerosol deposition in the human lung. Using both air and heliox (80% helium, 20% oxygen) as carrier gas, boluses of 1 and 2 microm-diameter particles were inhaled to five volumetric lung depths (V(p)) between 150 and 1200 mL during an inspiration from residual volume (RV) to 1 liter above functional residual capacity at a constant flow rate of approximately 0.50 L/sec, which was immediately followed by an expiration to RV at the same flow rate. Aerosol deposition and axial dispersion were calculated from aerosol concentration and flow rate measured at the mouth. For 1 microm-diameter particles, deposition was significantly reduced by 29 +/- 28% (mean +/- SD, p < 0.05) when breathing heliox instead of air at shallow V(p) (150 mL) and significantly increased by 11 +/- 9% at deep V(p) (1200 mL). For 2 microm-diameter particles, deposition was significantly higher at V(p) = 500 mL by 6 +/- 7% and the predicted V(p) to achieve 100% deposition was significantly lower with heliox (834 +/- 146 mL) compared to air (912 +/- 128 mL) (p < 0.05). Despite a decrease in deposition at shallow V(p), there was no change in axial dispersion, suggesting that other factors such as radial turbulent mixing result in decreased aerosol deposition. Our results suggested that heliox reduces upper airway deposition of 1 and 2 microm-diameter particles allowing more particles to penetrate and subsequently deposit in the peripheral lung.

  20. Deposition of Particles in the Alveolar Airways: Inhalation and Breath-Hold with Pharmaceutical Aerosols.

    PubMed

    Khajeh-Hosseini-Dalasm, Navvab; Longest, P Worth

    2015-01-01

    Previous studies have demonstrated that factors such as airway wall motion, inhalation waveform, and geometric complexity influence the deposition of aerosols in the alveolar airways. However, deposition fraction correlations are not available that account for these factors in determining alveolar deposition. The objective of this study was to generate a new space-filling model of the pulmonary acinus region and implement this model to develop correlations of aerosol deposition that can be used to predict the alveolar dose of inhaled pharmaceutical products. A series of acinar models was constructed containing different numbers of alveolar duct generations based on space-filling 14-hedron elements. Selected ventilation waveforms were quick-and-deep and slow-and-deep inhalation consistent with the use of most pharmaceutical aerosol inhalers. Computational fluid dynamics simulations were used to predict aerosol transport and deposition in the series of acinar models across various orientations with gravity where ventilation was driven by wall motion. Primary findings indicated that increasing the number of alveolar duct generations beyond 3 had a negligible impact on total acinar deposition, and total acinar deposition was not affected by gravity orientation angle. A characteristic model containing three alveolar duct generations (D3) was then used to develop correlations of aerosol deposition in the alveolar airways as a function of particle size and particle residence time in the geometry. An alveolar deposition parameter was determined in which deposition correlated with d(2)t over the first half of inhalation followed by correlation with dt(2), where d is the aerodynamic diameter of the particles and t is the potential particle residence time in the alveolar model. Optimal breath-hold times to allow 95% deposition of inhaled 1, 2, and 3 μm particles once inside the alveolar region were approximately >10, 2.7, and 1.2 s, respectively. Coupling of the deposition

  1. Soluble Nutrient and Trace Metal Fluxes from Aerosol Dry Deposition to Elkhorn Slough, CA

    NASA Astrophysics Data System (ADS)

    Gray, E. T.; Paytan, A.; Haskins, J.

    2009-12-01

    Atmospheric deposition has been widely recognized as a source of pollutants and nutrients to coastal ecosystems. Specifically, deposition includes nitrogen compounds, sulfur compounds, mercury, pesticides, phosphate, trace metals and other toxic compounds that can travel great distances in aerosols. These components can come from both natural (volcanoes, mineral dust, forest fires) and anthropogenic (fossil fuels, chemical byproducts, incineration of waste) sources. These pollutants may affect ecosystem health and water quality with environmental impacts such as eutrophication, contaminated fish and harmful algal blooms. In this study we focus on dry deposition to Elkhorn Slough, California. Size fractionated aerosol samples (PM 2.5 and PM 10) collected continuously over a seven day period using a cascade impactor are used along with a deposition model to determine the soluble nutrient and trace metal fluxes on the Elkhorn Slough ecosystem. Atmospheric deposition inputs will be compared to other sources and their potential impact evaluated.

  2. Aerosol assisted chemical vapor deposition of superconducting YBa 2Cu 3O 7-χ

    NASA Astrophysics Data System (ADS)

    Salazar, K. V.; Ott, K. C.; Dye, R. C.; Hubbard, K. M.; Peterson, E. J.; Coulter, J. Y.; Kodas, T. T.

    1992-08-01

    A hybrid process, aerosol-assisted chemical vapor deposotion (AACVD), is described for reproducible preparation of superconducting thin films of YBa 2Cu 3O 7-χ. The process consists of atomizing a toluene solution of the Y, Ba, and Cu tetramethylheptanedionato complexes using an aerosol generator. The aerosol is transported into a CVD reactor where solvent and precursor evaporation and deposition occur at atmospheric pressure on heated substrates. The process provides stable evaporation rates for all three precursors, yielding constant film stoichiometry throughout the deposition period and from film to film. Superconducting films may be deposited in-situ at substrate heater temperatures above 825°C, or may be formed at lower temperatures by deposition followed by post-deposition annealing at higher temperatures. The microstructure and quality of films are highly dependent on the conditions employed in deposition and in the case of films deposited below 825°C, the post-deposition annealing conditions. Superconducting films prepared by the AACVD/post-annealing process have a metallic normal state resistivity signature with a zero resistance temperature typically above 88K, and are highly c-axis oriented. Transport critical current densities measured at 75 K on polycrystalline films prepared by the AACVD process are 220 000 A/cm 2 and 84 000 A/cm 2 at self-field and 0.1 T, respectively.

  3. Solubility of aerosol trace elements: sources and deposition fluxes in the Canary Region

    NASA Astrophysics Data System (ADS)

    Gelado-Caballero, María Dolores; López-García, Patricia; Patey, Matthew; Prieto, Sandra; Collado, Cayetano; Santana, Desire; Hernández-Brito, Joaquín

    2013-04-01

    To date there have been no long-term aerosol studies in the Canary Basin, and current estimates of soluble fluxes of Al, Mn, Fe, P and N for the region are based on limited data available from several oceanographic research cruises which have crossed the region during large transects of the Atlantic Ocean. In this study, aerosol samples have been collected at two stations on the island of Gran Canaria regularly since 2006 (Taliarte, at sea level, and Pico de la Gorra, at 1930 m altitude). Samples have been analysed for total and soluble trace metals (Al, Mn, Fe, Co, Cu and Ti). The high temporal resolution of this dataset represents a valuable contribution to the understanding of aerosol deposition of trace metals to the region. Solubility measurements from acetate buffer leaching experiments showed the same tendency in the percentage of soluble metals in the samples: a higher percentage solubility of metals in anthropogenic aerosols and at low dust loading. Moreover, categorisation of aerosol samples with a continental African origin according to air-mass back-trajectories (North of Africa, Central and Western Sahara and Sahel) showed a decreasing tendency in the percentage of soluble Al and Fe to the south. In addition, factors that can affect the percentage solubility values for crustal elements and comparisons with different methods were studied. Freezing the samples stored affects the measurements of Al and Fe solubility. This last result is important for the design of future aerosol sampling programmes and aerosol solubility experiments. Flux estimates for aerosol-derived soluble metals reveal that phosphate is highly depleted relative to Fe and N when compared with Redfield values. It appears that aerosol deposition is an important source of N and trace metals (Fe, Co, Mn and Al) to the NE subtropical Atlantic Ocean. This work has been supported by the European Commission FEDER funds (PCT MAC 2007-2013, ESTRAMAR Mac/3/C177).

  4. Aerosol deposition characteristics in distal acinar airways under cyclic breathing conditions.

    PubMed

    Ma, Baoshun; Darquenne, Chantal

    2011-05-01

    Although the major mechanisms of aerosol deposition in the lung are known, detailed quantitative data in anatomically realistic models are still lacking, especially in the acinar airways. In this study, an algorithm was developed to build multigenerational three-dimensional models of alveolated airways with arbitrary bifurcation angles and spherical alveolar shape. Using computational fluid dynamics, the deposition of 1- and 3-μm aerosol particles was predicted in models of human alveolar sac and terminal acinar bifurcation under rhythmic wall motion for two breathing conditions (functional residual capacity = 3 liter, tidal volume = 0.5 and 0.9 liter, breathing period = 4 s). Particles entering the model during one inspiration period were tracked for multiple breathing cycles until all particles deposited or escaped from the model. Flow recirculation inside alveoli occurred only during transition between inspiration and expiration and accounted for no more than 1% of the whole cycle. Weak flow irreversibility and convective transport were observed in both models. The average deposition efficiency was similar for both breathing conditions and for both models. Under normal gravity, total deposition was ~33 and 75%, of which ~67 and 96% occurred during the first cycle, for 1- and 3-μm particles, respectively. Under zero gravity, total deposition was ~2-5% for both particle sizes. These results support previous findings that gravitational sedimentation is the dominant deposition mechanism for micrometer-sized aerosols in acinar airways. The results also showed that moving walls and multiple breathing cycles are needed for accurate estimation of aerosol deposition in acinar airways.

  5. ANALYSIS OF RESPIRATORY DEPOSITION OF INHALED AMBIENT AEROSOLS FOR DIFFERENT DOSE METRICS

    EPA Science Inventory

    ANALYSIS OF RESPIRATORY DEPOSITION OF INHALED AMBIENT AEROSOLS FOR DIFFERENT DOSE METRICS.
    Chong S. Kim, SC. Hu**, PA Jaques*, US EPA, National Health and Environmental Effects Research Laboratory, Research Triangle Park, NC 27711; **IIT Research Institute, Chicago, IL; *South...

  6. Aerosol Deposition in the Human Respiratory Tract Breathing Air and 80:20 Heliox

    PubMed Central

    DARQUENNE, CHANTAL; PRISK, G. KIM

    2005-01-01

    Aerosol mixing resulting from turbulent flows is thought to be an important mechanism of deposition in the upper respiratory tract (URT). Since turbulence levels are a function of gas density, the use of a low density carrier gas would be expected to reduce deposition in the URT. We measured aerosol deposition in the respiratory tract of 8 healthy subjects using both air and heliox, a low density gas mixture containing 80% helium and 20% oxygen, as the carrier gas. The subjects breathed 0.5, 1, and 2 μm-diameter monodisperse polystyrene latex particles from a reservoir at a constant flow rate (~450 mL/sec) and tidal volume (~900 mL). Aerosol concentration and flow rate were measured at the mouth using a photometer and a pneumotachograph, respectively. Deposition was 17.0%, 20.3%, and 38.9% in air and 16.8%, 18.5%, and 36.9% in heliox for 0.5, 1, and 2 μm-diameter particles, respectively. There was a small but statistically significant decrease in deposition when using heliox compared to air for 1 and 2 μm-diameter particles (p < 0.05). While it could not be directly measured from these data, it is likely that when breathing heliox instead of air, deposition is reduced in the URT and increased in the small airways and alveoli. PMID:15625820

  7. Supersonic jet deposition of silver nanoparticle aerosols: Correlations of impact conditions and film morphologies

    SciTech Connect

    Huang, Chong; Nichols, William T.; O'Brien, Daniel T.; Becker, Michael F.; Kovar, Desiderio; Keto, John W.

    2007-03-15

    We describe experiments and modeling for the deposition of silver lines and films via the impaction of a silver nanoparticle aerosol delivered through a supersonic jet. The aerosol gas dynamics of the jet flow field, nanoparticle acceleration in the jet, and deposition by impaction onto the substrate were modeled for both a flat-plate nozzle and for a conical nozzle designed to obtain higher impaction velocities. We modeled nanoparticle dynamics for He, Ar, and N{sub 2} gasses, all initially at room temperature and 1 atm pressure, flowing through a 250 {mu}m orifice into vacuum with a pressure ratio of {approx}5000. Experiments were conducted to deposit silver nanoparticle aerosols under the same conditions as were modeled. The silver nanoparticles were generated by laser ablation of a flowing microparticle aerosol entrained in either He or Ar that produced nanoparticles 5-10 and 15-20 nm in diameter, respectively. Deposition was made onto an unheated substrate in vacuum. The morphology of the deposited films was determined by scanning electron microscope cross-section images and crystallite size was determined by x-ray diffraction analysis. The morphological features and crystallite size were correlated with the nanoparticle impaction velocity and impaction energy derived from the model. We found that, for a given gas type, the size of the grains and morphological features within the impacted films were similar to the size of the nanoparticles from which the films were formed. The density and the degree of consolidation of the films were highly dependent on the nanoparticle impaction velocity/energy and were highest for helium. Control of film morphology, grain size, and film density during supersonic impaction of nanoparticle aerosols are discussed in light of these results.

  8. Indoor aerosol modeling for assessment of exposure and respiratory tract deposited dose

    NASA Astrophysics Data System (ADS)

    Hussein, Tareq; Wierzbicka, Aneta; Löndahl, Jakob; Lazaridis, Mihalis; Hänninen, Otto

    2015-04-01

    Air pollution is one of the major environmental problems that influence people's health. Exposure to harmful particulate matter (PM) occurs both outdoors and indoors, but while people spend most of their time indoors, the indoor exposures tend to dominate. Moreover, higher PM concentrations due to indoor sources and tightness of indoor environments may substantially add to the outdoor originating exposures. Empirical and real-time assessment of human exposure is often impossible; therefore, indoor aerosol modeling (IAM) can be used as a superior method in exposure and health effects studies. This paper presents a simple approach in combining available aerosol-based modeling techniques to evaluate the real-time exposure and respiratory tract deposited dose based on particle size. Our simple approach consists of outdoor aerosol data base, IAM simulations, time-activity pattern data-base, physical-chemical properties of inhaled aerosols, and semi-empirical deposition fraction of aerosols in the respiratory tract. These modeling techniques allow the characterization of regional deposited dose in any metric: particle mass, particle number, and surface area. The first part of this presentation reviews recent advances in simple mass-balance based modeling methods that are needed in analyzing the health relevance of indoor exposures. The second part illustrates the use of IAM in the calculations of exposure and deposited dose. Contrary to previous methods, the approach presented is a real-time approach and it goes beyond the exposure assessment to provide the required information for the health risk assessment, which is the respiratory tract deposited dose. This simplified approach is foreseen to support epidemiological studies focusing on exposures originating from both indoor and outdoor sources.

  9. Extraction of Aerosol-Deposited Yersinia pestis from Indoor Surfaces To Determine Bacterial Environmental Decay

    PubMed Central

    Bartlett, Ryan A.; Yeager, John J.; Leroux, Brian; Ratnesar-Shumate, Shanna; Dabisch, Paul

    2016-01-01

    ABSTRACT Public health and decontamination decisions following an event that causes indoor contamination with a biological agent require knowledge of the environmental persistence of the agent. The goals of this study were to develop methods for experimentally depositing bacteria onto indoor surfaces via aerosol, evaluate methods for sampling and enumerating the agent on surfaces, and use these methods to determine bacterial surface decay. A specialized aerosol deposition chamber was constructed, and methods were established for reproducible and uniform aerosol deposition of bacteria onto four coupon types. The deposition chamber facilitated the control of relative humidity (RH; 10 to 70%) following particle deposition to mimic the conditions of indoor environments, as RH is not controlled by standard heating, ventilation, and air conditioning (HVAC) systems. Extraction and culture-based enumeration methods to quantify the viable bacteria on coupons were shown to be highly sensitive and reproducible. To demonstrate the usefulness of the system for decay studies, Yersinia pestis persistence as a function of surface type at 21°C and 40% RH was determined to be >40%/min for all surfaces. Based upon these results, at typical indoor temperature and RH, a 6-log reduction in titer would expected to be achieved within 1 h as the result of environmental decay on surfaces without active decontamination. The developed approach will facilitate future persistence and decontamination studies with a broad range of biological agents and surfaces, providing agent decay data to inform both assessments of risk to personnel entering a contaminated site and decontamination decisions following biological contamination of an indoor environment. IMPORTANCE Public health and decontamination decisions following contamination of an indoor environment with a biological agent require knowledge of the environmental persistence of the agent. Previous studies on Y. pestis persistence have

  10. Dynamics of Particle Size on Inhalation of Environmental Aerosol and Impact on Deposition Fraction.

    PubMed

    Haddrell, Allen E; Davies, James F; Reid, Jonathan P

    2015-12-15

    Inhalation of elevated levels of particulate air pollution has been shown to elicit the onset of adverse health effects in humans, where the magnitude of the response is a product of where in the lung the particulate dose is delivered. At any point in time during inhalation the depositional flux of the aerosol is a function of the radius of the droplet, thus a detailed understanding of the rate and magnitude of the mass flux of water to the droplet during inhalation is crucial. In this study, we assess the impact of aerosol hygroscopicity on deposited dose through the inclusion of a detailed treatment of the mass flux of water to account for the dynamics of particle size in a modified version of the standard International Commission on Radiological Protection (ICRP) whole lung deposition model. The ability to account for the role of the relative humidity (RH) of the aerosol prior to, and during, inhalation on the deposition pattern is explored, and found to have a significant effect on the deposition pattern. The model is verified by comparison to previously published measurements, and used to demonstrate that ambient RH affects where in the lung indoor particulate air pollution is delivered.

  11. Alveolar duct expansion greatly enhances aerosol deposition: a three-dimensional computational fluid dynamics study

    PubMed Central

    Darquenne, C.; Harrington, L.; Prisk, G.K.

    2009-01-01

    Obtaining in vivo data of particle transport in the human lung is often difficult, if not impossible. Computational fluid dynamics (CFD) can provide detailed information on aerosol transport in realistic airway geometries. This paper provides a review of the key CFD studies of aerosol transport in the acinar region of the human lung. It also describes the first ever three-dimensional model of a single fully alveolated duct with moving boundaries allowing for the cyclic expansion and contraction that occurs during breathing. Studies of intra-acinar aerosol transport performed in models with stationary walls (SWs) showed that flow patterns were influenced by the geometric characteristics of the alveolar aperture, the presence of the alveolar septa contributed to the penetration of the particles into the lung periphery and there were large inhomogeneities in deposition patterns within the acinar structure. Recent studies have now used acinar models with moving walls. In these cases, particles penetrate the alveolar cavities not only as a result of sedimentation and diffusion but also as a result of convective transport, resulting in a much higher deposition prediction than that in SW models. Thus, models that fail to incorporate alveolar wall motions probably underestimate aerosol deposition in the acinar region of the lung. PMID:19414458

  12. Aerodynamics and deposition effects of inhaled submicron drug aerosol in airway diseases.

    PubMed

    Faiyazuddin, Md; Mujahid, Md; Hussain, Talib; Siddiqui, Hefazat H; Bhatnagar, Aseem; Khar, Roop K; Ahmad, Farhan J

    2013-01-01

    Particle engineering is the prime focus to improve pulmonary drug targeting with the splendor of nanomedicines. In recent years, submicron particles have emerged as prettyful candidate for improved fludisation and deposition. For effective deposition, the particle size must be in the range of 0.5-5 μm. Inhalers design for the purpose of efficient delivery of powders to lungs is again a crucial task for pulmonary scientists. A huge number of DPI devices exist in the market, a significant number are awaiting FDA approval, some are under development and a large number have been patented or applied for patent. Even with superior design, the delivery competence is still deprived, mostly due to fluidisation problems which cause poor aerosol generation and deposition. Because of the cohesive nature and poor flow characteristics, they are difficult to redisperse upon aerosolization with breath. These problems are illustrious in aerosol research, much of which is vastly pertinent to pulmonary therapeutics. A technical review is presented here of advances that have been utilized in production of submicron drug particles, their in vitro/in vivo evaluations, aerosol effects and pulmonary fate of inhaled submicron powders.

  13. Increasing Ca2+ deposition in the western US: The role of mineral aerosols

    NASA Astrophysics Data System (ADS)

    Brahney, J.; Ballantyne, A. P.; Sievers, C.; Neff, J. C.

    2013-09-01

    Considerable research has focused on the role of industrial emissions in controlling the acidity of precipitation; however, much less research has focused on the role of mineral aerosols emitted from soils. According to data published by the National Atmospheric Deposition Network (NADP), over the past 17 years Ca2+ deposition has increased over large regions of the US. A trend analysis to determine regions of significant change in Ca2+ deposition revealed statistically significant increases in three broad regions within the western half of the country: the inter-mountain west, the midwest, and the northwest. We evaluated potential changes in sources of calcium to the atmosphere including soil erosion, industrial emissions, forest fires, and sea-salt aerosols to determine the cause of rising atmospheric calcium deposition. Based on our evaluation, the most parsimonious explanation for increased Ca2+ deposition is an increase in mineral aerosol emissions from within the western US. This explanation is corroborated by independent evidence showing increases in the frequency of dust storms and low-visibility days across regions of the western US. Furthermore, our analysis indicates that the increase in mineral aerosol emissions is most likely due to (1) increased aridity and wind transport and (2) increased area and intensity of upwind human activities. Changes in atmospheric dust concentrations can have important ecological implications through the contribution of acid neutralizing capacity to both precipitation and regions of deposition. Thus increased dust emissions have the potential to ameliorate the detrimental effects of acid precipitation on terrestrial ecosystems, though dust may exacerbate the impacts of air quality on human health.

  14. Analysis of Three-Dimensional Aerosol Deposition in Pharmacologically Relevant Terms: Beyond Black or White ROIs

    PubMed Central

    Greenblatt, Elliot Eliyahu; Winkler, Tilo; Harris, Robert Scott; Kelly, Vanessa Jane; Kone, Mamary

    2015-01-01

    Abstract Background: This article presents a novel methodological approach to evaluate images of aerosol deposition taken with PET-CT cameras. Traditionally, Black-or-White (BW) Regions of Interest (ROIs) are created to cover Anatomical Regions (ARs) segmented from the high-resolution CT. Such ROIs do not usually consider blurring effects due to limited spatial resolution or breathing motion, and do not consider uncertainty in the AR position within the PET image. The new methodology presented here (Grayscale) addresses these issues, allows estimates of aerosol deposition within ARs, and expresses the deposition in terms of Tissue Dosing (in the lung periphery) and Inner Surface Concentration (in the larger airways). Methods: Imaging data included a PET deposition image acquired during breathing and two CT scans acquired during breath holds at different lung volumes. The lungs were segmented into anatomically consistent ARs to allow unbiased comparisons across subjects and across lobes. The Grayscale method involves defining Voxel Influence Matrices (VIMs) to consider how average activity within each AR influences the measured activity within each voxel. The BW and Grayscale methods were used to analyze aerosol deposition in 14 bronchoconstricted asthmatics. Results: Grayscale resulted in a closer description of the PET image than BW (p<0.0001) and exposed a seven-fold underestimation in measures of specific deposition. The Average Tissue Dosing was 2.11×10−6 Total Lung Dose/mg. The average Inner Surface Concentration was 45×10−6 Total Lung Dose/mm2, with the left lower lobe having a lower ISC than lobes of the right lung (p<0.05). There was a strong lobar heterogeneity in these measures (COV=0.3). Conclusion: The Grayscale approach is an improvement over the BW approach and provides a closer description of the PET image. It can be used to characterize heterogeneous concentrations throughout the lung and may be important in translational research and in the

  15. The influence of aerosol retention and pattern of deposition on bronchial responsiveness to atropine and methacholine in humans

    SciTech Connect

    Gillett, M.K.; Briggs, B.A.; Snashall, P.D. )

    1989-12-01

    We have examined the influence of total intrapulmonary deposition and its pattern on the bronchial response to aerosolized methacholine and atropine in 10 normal and 12 asthmatic subjects. On Day 1 we performed a dose-response challenge to methacholine and defined responsiveness as the provocative dose (PD35) needed to cause a 35% decrease in specific airway conductance (SGaw). On Day 2 we repeated methacholine challenge after premedication with aerosolized atropine, and we defined the response to atropine as dose ratio-1 (DR-1) where DR = PD35 after atropine/PD35 without atropine. On Day 3 we imaged intrapulmonary aerosol deposition by mixing 99mtechnetium with methacholine aerosol and scanning the thorax with a gamma camera during the development of bronchoconstriction. Total pulmonary aerosol deposition varied considerably between individuals (1.2 to 23.6% of nebulized dose) but there was no difference between normal and asthmatic subjects, and no correlation between deposition and baseline SGaw or PD35; there was a significant positive correlation between deposition and DR-1. Deposition of aerosol in central lung zones was inversely related to SGaw and correlated positively with DR-1; there was no significant relationship with PD35. Total intrapulmonary aerosol deposition and its pattern partially determine bronchial responsiveness to atropine, but we have not demonstrated any significant effect on responsiveness to methacholine.

  16. AEROSOL TRANSPORT AND DEPOSITION IN SEQUENTIALLY BIFURCATING AIRWAYS

    EPA Science Inventory

    Deposition patterns and efficiencies of a dilute suspension of inhaled particles in three-dimensional double bifurcating airway models for both in-plane and 90 deg out-of-plane configurations have been numerically simulated assuming steady, laminar, constant-property air flow wit...

  17. In vivo deposition of ultrafine aerosols in human nasal and oral airways

    SciTech Connect

    Yeh, Hsu-Chi; Swift, D.L.; Simpson, S.Q.

    1995-12-01

    The extrathoracic airways, including the nasal passage, oral passage, pharynx, and larynx, are the first targets for inhaled particles and provide an important defense for the lung. Understanding the deposition efficiency of the nasal and oral passages is therefore crucial for assessing doses of inhaled particles to the extrathoracic airways and the lung. Significant inter-subject variability in nasal deposition has been shown in recent studies by Rasmussen, T.R. et al, using 2.6 {mu}m particles in 10 human subjects and in our preliminary studies using 0.004-0.15 {mu}m particles in four adult volunteers. No oral deposition was reported in either of these studies. Reasons for the intersubject variations have been frequently attributed to the geometry of the nasal passages. The aims of the present study were to measure in vivo the nasal airway dimensions and the deposition of ultrafine aerosols in both the nasal and oral passages, and to determine the relationship between nasal airway dimensions and aerosol deposition. A statistical procedure incorporated with the diffusion theory was used to model the dimensional features of the nasal airways which may be responsible for the biological variability in particle deposition. In summary, we have correlated deposition of particles in the size range of 0.004 to 0.15 {mu}m with the nasal dimensions of each subject.

  18. Deposition of ultrafine aerosols and thoron progeny in replicas of nasal airways of children

    SciTech Connect

    Cheng, Y.S.; Smith, S.M.; Yeh, H.C.; Kim, D.B.; Cheng, K.H.; Swift, D.L.

    1995-11-01

    The deposition efficiencies of ultrafine aerosols and thoron progeny were measured in youth nasal replicas. Clear polyester-resin casts of the upper airways of 1.5-yr-old (Cast G), 2.5-yr-old (Cast H), and 4-yr-old (Cast I) children were used. These casts were constructed from series of coronal magnetic resonance images of healthy children. Total deposition was measured for monodisperse NaCl or Ag aerosols between 0.0046 and 0.20 {mu}m in diameter at inspiratory and expiratory flow rates of 3, 7, and 16 L min{sup -1} (covering a near normal range of breathing rates for children of different ages). Deposition efficiency decreased with increasing particle size and flow rate, indicating that diffusion was the main deposition mechanism. Deposition efficiency also decreased with increasing age at a given flow rate and particle size. Based on information obtained and information on minute volumes for different age groups, we predicted nasal deposition in age groups ranging from 1.5- to 20-yr-old at resting breathing rates. Our results showed that the nasal deposition increases with decreasing age for a given particle size between 0.001 to 0.2 {mu}m. This information will be useful in deriving future population-wide models of respiratory tract dosimetry. 24 refs., 12 figs., 3 tabs.

  19. Sea salt aerosol deposition in the coastal zone: A large eddy simulation study

    NASA Astrophysics Data System (ADS)

    Liang, Tinghao; Chamecki, Marcelo; Yu, Xiping

    2016-11-01

    Inland deposition of sea salt aerosol (SSA) particles emitted over the ocean is studied via numerical and theoretical models. The focus is on the large particles that contribute most to the total mass deposition. Large eddy simulations of idealized sea wind are used to investigate the development of the particle plume over land for different particle sizes and to validate some of the assumptions in the theoretical model. An existing theoretical modeling framework for particle dispersion in the atmospheric boundary layer is adapted to the problem of SSA deposition and it is shown to be adequate for the large particles of interest here. The decay of monodisperse SSA particle deposition flux with distance from the shoreline is shown to have a power-law behavior far from the shoreline. A complete model for predicting mass deposition as a function of distance is formulated and shown to present reasonable agreement with existing data.

  20. Room-temperature growth of Ni-Zn-Cu ferrite/PTFE composite thick films on PET via aerosol deposition

    NASA Astrophysics Data System (ADS)

    Kim, Hyung-Jun; Kwon, Oh-Yun; Jang, Chan-Ick; Kim, Tae Kyoung; Oh, Jun Rok; Yoon, Young Joon; Kim, Jong-Hee; Nam, Song-Min; Koh, Jung-Hyuk

    2013-11-01

    Ni-Zn-Cu ferrite and Ni-Zn-Cu ferrite/poly-tetra-fluoro-ethylene (PTFE) composite-thick-films were grown at room temperature on polyethylene terephthalate (PET) sheets via aerosol deposition (AD) as a magnetic shielding sheet for near-field communication. An 80 µm-thick Ni-Zn-Cu ferrite/PTFE composite-thick-film was grown on the PET sheet when 2.0 wt. % PTFE starting powder was used. The real relative permeability µ r ' and the imaginary permeability µ r ″ of the Ni-Zn-Cu ferrite thick film were 10.1 and 2.1 at 13.56 MHz, respectively. In the case of the composite thick film, µ r ' and µ r ″ decreased to 3.9 and 1.3, respectively, at 13.56 MHz; with the addition of the PTFE.

  1. In vitro monodisperse aerosol deposition in a mouth and throat with six different inhalation devices.

    PubMed

    DeHaan, W H; Finlay, W H

    2001-01-01

    Experiments were performed to determine the effect of different pharmaceutical aerosol inhalation devices on the deposition of monodisperse aerosols in an idealized mouth and throat geometry. The devices included two dry powder inhalers (Diskus and Turbuhaler), two nebulizers (Pari LC STAR and Hudson T-Updraft), and a metered dose inhaler with attached holding chamber (Aerochamber), in addition to a straight tube (1.7 cm inner diameter). Aerosol particles (DL-alpha tocopheryl acetate) of diameters of 2.5, 5, and 7 microm generated by a vibrating orifice generator were inhaled at steady air flow rates of Q = 5-90 L/min through the devices and into the mouth-throat. Deposition in the mouth-throat and after-filter were determined by ultraviolet (UV) spectrophotometric assay. The amount of deposition in the mouth and throat region was found to depend on the type of device that the aerosol entered through. Deposition in the extrathoracic region with the two types of jet nebulizers did not differ significantly (p > 0.1) from that of a straight tube or each other over their entire tested range of 590 > or = pd2Q > or = 11,375, where p is particle density (in g/cm3), d is particle diameter (in microm), and Q is flow rate (in cm3/s). The metered dose inhaler with attached holding chamber was found to differ from the straight tube only at two intermediate values of pd2Q = 5,145 and 16,033. The deposition occurring for the dry powder inhalers was found to be significantly greater than for the straight tube for all values of pd2Q > or = 10,954 for the Diskus and pd2Q > or = 9,435 for the Turbuhaler. Deposition with the dry powder inhalers was found to be up to 14 times greater than that with the straight tube. Thus, the inhaler geometry that the aerosol passes through prior to entering the mouth and throat region can greatly affect the deposition in the mouth-throat.

  2. Growth of BaTiO3-PVDF composite thick films by using aerosol deposition

    NASA Astrophysics Data System (ADS)

    Cho, Sung Hwan; Yoon, Young Joon

    2016-01-01

    Barium titanate (BaTiO3)-polyvinylidene fluoride (PVDF) composite thick films were grown by using aerosol deposition at room temperature with BaTiO3 and PVDF powders. To produce a uniform composition in ceramic and polymer composite films, which show a substantial difference in specific gravity, we used PVDF-coated BaTiO3 powders as the starting materials. An examination of the microstructure confirmed that the BaTiO3 were well distributed in the PVDF matrix in the form of a 0 - 3 compound. The crystallite size in the BaTiO3-PVDF composite thick films was 5 ˜ 50 times higher than that in pure BaTiO3 thick films. PVDF plays a role in suppressing the fragmentation of BaTiO3 powder during the aerosol deposition process and in controlling the relative permittivity.

  3. Development of the aerosol generation system for simulating the dry deposition behavior of radioaerosol emitted by the accident of FDNPP

    NASA Astrophysics Data System (ADS)

    Zhang, Z.

    2015-12-01

    A large amount of radioactivity was discharged by the accident of FDNPP. The long half-life radionuclide, 137Cs was transported through the atmosphere mainly as the aerosol form and deposited to the forests in Fukushima prefecture. After the dry deposition of the 137Cs, the foliar uptake process would occur. To evaluate environmental transfer of radionuclides, the dry deposition and following foliar uptake is very important. There are some pioneering studies for radionuclide foliar uptake with attaching the solution containing stable target element on the leaf, however, cesium oxide aerosols were used for these deposition study [1]. In the FDNPP case, 137Cs was transported in sulfate aerosol form [2], so the oxide aerosol behaviors could not represent the actual deposition behavior in this accident. For evaluation of whole behavior of 137Cs in vegetation system, fundamental data for deposition and uptake process of sulfate aerosol was desired. In this study, we developed aerosol generation system for simulating the dry deposition and the foliar uptake behaviors of aerosol in the different chemical constitutions. In this system, the method of aerosol generation based on the spray drying. Solution contained 137Cs was send to a nozzle by a syringe pump and spraying with a high speed air flow. The sprayed mist was generated in a chamber in the relatively high temperature. The solution in the mist was dried quickly, and micro size solid aerosols consisting 137Cs were generated. The aerosols were suctioned by an ejector and transported inside a tube by the dry air flow, then were directly blown onto the leaves. The experimental condition, such as the size of chamber, chamber temperature, solution flow rate, air flow rate and so on, were optimized. In the deposition experiment, the aerosols on leaves were observed by a SEM/EDX system and the deposition amount was evaluated by measuring the stable Cs remaining on leaf. In the presentation, we will discuss the detail

  4. Quantitative assessment of inhalation exposure and deposited dose of aerosol from nanotechnology-based consumer sprays†

    PubMed Central

    Nazarenko, Yevgen; Lioy, Paul J.; Mainelis, Gediminas

    2015-01-01

    This study provides a quantitative assessment of inhalation exposure and deposited aerosol dose in the 14 nm to 20 μm particle size range based on the aerosol measurements conducted during realistic usage simulation of five nanotechnology-based and five regular spray products matching the nano-products by purpose of application. The products were also examined using transmission electron microscopy. In seven out of ten sprays, the highest inhalation exposure was observed for the coarse (2.5–10 μm) particles while being minimal or below the detection limit for the remaining three sprays. Nanosized aerosol particles (14–100 nm) were released, which resulted in low but measurable inhalation exposures from all of the investigated consumer sprays. Eight out of ten products produced high total deposited aerosol doses on the order of 101–103 ng kg−1 bw per application, ~85–88% of which were in the head airways, only <10% in the alveolar region and <8% in the tracheobronchial region. One nano and one regular spray produced substantially lower total deposited doses (by 2–4 orders of magnitude less), only ~52–64% of which were in the head while ~29–40% in the alveolar region. The electron microscopy data showed nanosized objects in some products not labeled as nanotechnology-based and conversely did not find nano-objects in some nano-sprays. We found no correlation between nano-object presence and abundance as per the electron microscopy data and the determined inhalation exposures and deposited doses. The findings of this study and the reported quantitative exposure data will be valuable for the manufacturers of nanotechnology-based consumer sprays to minimize inhalation exposure from their products, as well as for the regulators focusing on protecting the public health. PMID:25621175

  5. Carbon dioxide accumulation during small animal, whole body plethysmography: effects on ventilation, indices of airway function, and aerosol deposition.

    PubMed

    Kimmel, Edgar C; Whitehead, Gregory S; Reboulet, James E; Carpenter, Robert L

    2002-01-01

    Barometric (whole body) plethysmography is used to examine changes in ventilation and breathing pattern in unrestrained animals during exposure to therapeutic or toxic aerosols. Whole body plethysmographs (WBP) may be operated with a bias flow in order to maintain an adequate supply of oxygen and remove expired CO(2). However, some aerosol generation and delivery methods may require operation of the WBP without bias flow, which would artificially deplete aerosol concentration. Under these conditions, expired CO(2) accumulates in the plethysmograph and stimulates ventilation, increasing total aerosol deposition, shifting regional deposition, and significantly altering some airway function indices. We characterized these effects in guinea pigs using a commercially available 4.5-L WBP, with and without a 1 L/min bias flow. CO(2)-induced changes in breathing frequency (f), tidal volume (Vt), minute ventilation (Ve), and indices of airway function -- including enhanced pause (penh), flow derived parameter (FDP), and respiratory duty cycle -- were measured. Without bias flow, CO(2) in the plethysmograph increased steadily to 5.4% after 30 min compared to a steady state 0.9% with bias flow. This resulted in a moderate suppression of f, and significant increases in Vt and Ve by factors of 1.5 and 1.4, respectively. Changes in regional deposition were stimulated for 300 mg/m(3) polydisperse aerosols with mass median aerodynamic diameters of 0.3, 1, 3, or 7 microm and geometric standard deviations of 1.7. Percent increase in aerosol deposition from CO(2) inhalation ranged from 24% to 90%, by mass, depending on aerosol size distribution and respiratory tract region. In addition, fractional deposition shifted toward the pulmonary region. Empirical indices of airway constriction, penh and FDP, also were increased significantly to 1.7 and 1.3 times their respective baseline values. The study quantifies the effect of inadvertent coexposure to CO(2) on ventilation, aerosol

  6. Development of aerosol assisted chemical vapor deposition for thin film fabrication

    NASA Astrophysics Data System (ADS)

    Maulana, Dwindra Wilham; Marthatika, Dian; Panatarani, Camellia; Mindara, Jajat Yuda; Joni, I. Made

    2016-02-01

    Chemical vapor deposition (CVD) is widely used to grow a thin film applied in many industrial applications. This paper report the development of an aerosol assisted chemical vapor deposition (AACVD) which is one of the CVD methods. Newly developed AACVD system consists of a chamber of pyrex glass, two wire-heating elements placed to cover pyrex glass, a substrate holder, and an aerosol generator using an air brush sprayer. The temperature control system was developed to prevent condensation on the chamber walls. The control performances such as the overshoot and settling time were obtained from of the developed temperature controller. Wire-heating elements were controlled at certain setting value to heat the injected aerosol to form a thin film in the substrate. The performance of as-developed AACVD system tested to form a thin film where aerosol was sprayed into the chamber with a flow rate of 7 liters/minutes, and vary in temperatures and concentrations of precursor. The temperature control system have an overshoot around 25 °C from the desired set point temperature, very small temperature ripple 2 °C and a settling time of 20 minutes. As-developed AACVD successfully fabricated a ZnO thin film with thickness of below 1 µm. The performances of system on formation of thin films influenced by the generally controlled process such as values of setting temperature and concentration where the aerosol flow rate was fixed. Higher temperature was applied, the more uniform ZnO thin films were produced. In addition, temperature of the substrate also affected on surface roughness of the obtained films, while concentration of ZnO precursor determined the thickness of produce films. It is concluded that newly simple AACVD can be applied to produce a thin film.

  7. Variability of Black Carbon Deposition to the East Antarctic Plateau, 1800-2000 AD

    NASA Technical Reports Server (NTRS)

    Bisiaux, M. M.; Edwards, R.; McConnell, J. R.; Albert, M. R.; Anschutz, H.; Neumann, T. A.; Isaksson, E.; Penner, J. E.

    2012-01-01

    Refractory black carbon aerosols (rBC) from biomass burning and fossil fuel combustion are deposited to the Antarctic ice sheet and preserve a history of emissions and long-range transport from low- and mid-latitudes. Antarctic ice core rBC records may thus provide information with respect to past combustion aerosol emissions and atmospheric circulation. Here, we present six East Antarctic ice core records of rBC concentrations and fluxes covering the last two centuries with approximately annual resolution (cal. yr. 1800 to 2000). The ice cores were drilled in disparate regions of the high East Antarctic ice sheet, at different elevations and net snow accumulation rates. Annual rBC concentrations were log-normally distributed and geometric means of annual concentrations ranged from 0.10 to 0.18 m cro-g/kg. Average rBC fluxes were determined over the time periods 1800 to 2000 and 1963 to 2000 and ranged from 3.4 to 15.5 m /a and 3.6 to 21.8 micro-g/sq m/a, respectively. Geometric mean concentrations spanning 1800 to 2000 increased linearly with elevation at a rate of 0.025 micro-g/kg/500 m. Spectral analysis of the records revealed significant decadal-scale variability, which at several sites was comparable to decadal ENSO variability.

  8. Enhanced Deposition by Electrostatic Field-Assistance Aggravating Diesel Exhaust Aerosol Toxicity for Human Lung Cells.

    PubMed

    Stoehr, Linda C; Madl, Pierre; Boyles, Matthew S P; Zauner, Roland; Wimmer, Monika; Wiegand, Harald; Andosch, Ancuela; Kasper, Gerhard; Pesch, Markus; Lütz-Meindl, Ursula; Himly, Martin; Duschl, Albert

    2015-07-21

    Air pollution is associated with increased risk of cardiovascular and pulmonary diseases, but conventional air quality monitoring gives no information about biological consequences. Exposing human lung cells at the air-liquid interface (ALI) to ambient aerosol could help identify acute biological responses. This study investigated electrode-assisted deposition of diesel exhaust aerosol (DEA) on human lung epithelial cells (A549) in a prototype exposure chamber. A549 cells were exposed to DEA at the ALI and under submerged conditions in different electrostatic fields (EFs) and were assessed for cell viability, membrane integrity, and IL-8 secretion. Qualitative differences of the DEA and its deposition under different EFs were characterized using scanning mobility particle sizer (SMPS) measurements, transmission electron microscopy (TEM), and electron energy loss spectroscopy (EELS). Upon exposure to DEA only, cell viability decreased and membrane impairment increased for cells at the ALI; submerged cells were unaffected. These responses were enhanced upon application of an EF, as was DEA deposition. No adverse effects were observed for filtered DEA or air only, confirming particle-induced responses. The prototype exposure chamber proved suitable for testing DEA-induced biological responses of cells at the ALI using electrode-assisted deposition and may be useful for analysis of other air pollutants. PMID:26083946

  9. Aerosol-Assisted Chemical Vapor Deposited Thin Films for Space Photovoltaics

    NASA Technical Reports Server (NTRS)

    Hepp, Aloysius F.; McNatt, Jeremiah; Dickman, John E.; Jin, Michael H.-C.; Banger, Kulbinder K.; Kelly, Christopher V.; AquinoGonzalez, Angel R.; Rockett, Angus A.

    2006-01-01

    Copper indium disulfide thin films were deposited via aerosol-assisted chemical vapor deposition using single source precursors. Processing and post-processing parameters were varied in order to modify morphology, stoichiometry, crystallography, electrical properties, and optical properties in order to optimize device-quality material. Growth at atmospheric pressure in a horizontal hot-wall reactor at 395 C yielded best device films. Placing the susceptor closer to the evaporation zone and flowing a more precursor-rich carrier gas through the reactor yielded shinier, smoother, denser-looking films. Growth of (112)-oriented films yielded more Cu-rich films with fewer secondary phases than growth of (204)/(220)-oriented films. Post-deposition sulfur-vapor annealing enhanced stoichiometry and crystallinity of the films. Photoluminescence studies revealed four major emission bands (1.45, 1.43, 1.37, and 1.32 eV) and a broad band associated with deep defects. The highest device efficiency for an aerosol-assisted chemical vapor deposited cell was 1.03 percent.

  10. Dry Lung as a Physical Model in Studies of Aerosol Deposition.

    PubMed

    Morozov, Victor N; Kanev, Igor L

    2015-10-01

    A new physical model was developed to evaluate the deposition of micro- and nanoaerosol particles (NAPs) into the lungs as a function of size and charges. The model was manufactured of a dry, inflated swine lung produced by Nasco company (Fort Atkinson, WI). The dry lung was cut into two lobes and a conductive tube was glued into the bronchial tube. The upper 1-2-mm-thick layer of the lung lobe was removed with a razor blade to expose the alveoli. The lobe was further enclosed into a plastic bag and placed within a metalized plastic box. The probability of aerosol deposition was calculated by comparing the size distribution of NAPs passed through the lung with that of control, where aerosol passed through a box bypassing the lung. Using this new lung model, it was demonstrated that charged NAPs are deposited inside the lung substantially more efficiently than neutral ones. It was also demonstrated that deposition of neutral NAPs well fits prediction of the Multiple-Path Particle Dosimetry (MPPD) model developed by the Applied Research Associates, Inc. (ARA).

  11. Enhanced Deposition by Electrostatic Field-Assistance Aggravating Diesel Exhaust Aerosol Toxicity for Human Lung Cells.

    PubMed

    Stoehr, Linda C; Madl, Pierre; Boyles, Matthew S P; Zauner, Roland; Wimmer, Monika; Wiegand, Harald; Andosch, Ancuela; Kasper, Gerhard; Pesch, Markus; Lütz-Meindl, Ursula; Himly, Martin; Duschl, Albert

    2015-07-21

    Air pollution is associated with increased risk of cardiovascular and pulmonary diseases, but conventional air quality monitoring gives no information about biological consequences. Exposing human lung cells at the air-liquid interface (ALI) to ambient aerosol could help identify acute biological responses. This study investigated electrode-assisted deposition of diesel exhaust aerosol (DEA) on human lung epithelial cells (A549) in a prototype exposure chamber. A549 cells were exposed to DEA at the ALI and under submerged conditions in different electrostatic fields (EFs) and were assessed for cell viability, membrane integrity, and IL-8 secretion. Qualitative differences of the DEA and its deposition under different EFs were characterized using scanning mobility particle sizer (SMPS) measurements, transmission electron microscopy (TEM), and electron energy loss spectroscopy (EELS). Upon exposure to DEA only, cell viability decreased and membrane impairment increased for cells at the ALI; submerged cells were unaffected. These responses were enhanced upon application of an EF, as was DEA deposition. No adverse effects were observed for filtered DEA or air only, confirming particle-induced responses. The prototype exposure chamber proved suitable for testing DEA-induced biological responses of cells at the ALI using electrode-assisted deposition and may be useful for analysis of other air pollutants.

  12. Growth of ultra long multiwall carbon nanotube arrays by aerosol-assisted chemical vapor deposition.

    PubMed

    Byeon, Heejun; Kim, Sang Yong; Koh, Ken Ha; Lee, Soonil

    2010-09-01

    Using a home-made aerosol nebulizer, we developed a new aerosol-assisted chemical vapor deposition (AACVD) process that made it possible to synthesize vertically-aligned carbon nanotube (VACNT) arrays with heights over a few millimeters routinely. An essential part of this technique was in-situ formation of metal catalyst nanoparticles via pyrolysis of ferrocene-ethanol aerosol right before CNT synthesis. Through the optimization of aerosol supply and CVD process parameters, we were able to synthesize clean VACNT arrays as long as 4.38 mm with very low metal contents in 20 min. Furthermore, it is worthy noting that such an outstanding height is achieved very quickly without supporting materials and water-assistance. By taking advantage of almost complete inhibition of CNT growth on low melting-temperature metals, we were able to fabricate patterned VACNT arrays by combining AACVD process with a conventional photolithograpic patterning of gold lines. Characterizations of as-grown nanotubes such as morphology, purity, and metal contents are presented. PMID:21133158

  13. CuInS2 Films Deposited by Aerosol-Assisted Chemical Vapor Deposition Using Ternary Single-Source Precursors

    NASA Technical Reports Server (NTRS)

    Jin, Michael; Banger, Kal; Harris, Jerry; Hepp, Aloysius

    2003-01-01

    Polycrystalline CuInS2 films were deposited by aerosol-assisted chemical vapor deposition using both solid and liquid ternary single-source precursors (SSPs) which were prepared in-house. Films with either (112) or (204/220) preferred orientation, had a chalcopyrite structure, and (112)-oriented films contained more copper than (204/220)-oriented films. The preferred orientation of the film is likely related to the decomposition and reaction kinetics associated with the molecular structure of the precursors at the substrate. Interestingly, the (204/220)-oriented films were always In-rich and were accompanied by a secondary phase. From the results of post-growth annealing, etching experiments, and Raman spectroscopic data, the secondary phase was identified as an In-rich compound. On the contrary, (112)-oriented films were always obtained with a minimal amount of the secondary phase, and had a maximum grain size of about 0.5 micron. Electrical and optical properties of all the films grown were characterized. They all showed p-type conduction with an electrical resistivity between 0.1 and 30 Omega-cm, and an optical band gap of approximately 1.46 eV +/- 0.02, as deposited. The material properties of deposited films revealed this methodology of using SSPs for fabricating chalcopyrite-based solar cells to be highly promising.

  14. CuInS2 Films Deposited by Aerosol-Assisted Chemical Vapor Deposition Using Ternary Single-Source Precursors

    NASA Technical Reports Server (NTRS)

    Jin, Michael H.-C.; Banger, Kulbinder K.; Harris, Jerry D.; Hepp, Aloysius F.

    2004-01-01

    Polycrystalline CuInS2 films were deposited by aerosol-assisted chemical vapor deposition using both solid and liquid ternary single-source precursors (SSPs) prepared in-house. Films with either (112) or (204/220) preferred orientation were obtained, and compositional analysis showed that (112)-oriented films contained more copper than (204/220)-oriented films. Using X-ray diffraction, the signature of chalcopyrite structure was often confirmed for (112)-oriented films. The preferred orientation of the film is likely related to the decomposition and reaction kinetics associated with the molecular structure of the precursors at the substrate. Interestingly, the (204/220)-oriented films were always accompanied by a secondary phase, which was identified as an unknown In-rich compound from the results of post-growth annealing, etching experiments, and Raman spectroscopic data. By increasing Cu to In ratio in the film, (112)-oriented films were obtained with a maximum grain size of about 0.5 micrometers, and their X-ray diffractions did not show any observable signature of the In secondary phase. Electrical and optical properties of all the films grown were characterized. They all showed p-type conduction with an electrical resistivity between 0.1 omega cm and 30 omega cm, and an optical band gap of 1.46eV +/- 0.02, as deposited. The material properties of deposited films revealed this methodology of using SSPs for fabricating chalcopyrite-based solar cells to be highly promising.

  15. Limited influence of dry deposition of semivolatile organic vapors on secondary organic aerosol formation in the urban plume

    NASA Astrophysics Data System (ADS)

    Hodzic, A.; Madronich, S.; Aumont, B.; Lee-Taylor, J.; Karl, T.; Camredon, M.; Mouchel-Vallon, C.

    2013-06-01

    The dry deposition of volatile organic compounds (VOCs) and its impact on secondary organic aerosols (SOA) are investigated in the Mexico City plume. Gas-phase chemistry and gas-particle partitioning of oxygenated VOCs are modeled with the Generator of Explicit Chemistry and Kinetics of Organics in the Atmosphere (GECKO-A) from C3 to C25 alkanes, alkenes, and light aromatics. Results show that dry deposition of oxidized gases is not an efficient sink for SOA, as it removes <5% of SOA within the city's boundary layer and ~15% downwind. Dry deposition competes with the gas-particle uptake, and only gases with fewer than ~12 carbons dry deposit while longer species partition to SOA. Because dry deposition of submicron aerosols is slow, condensation onto particles protects organic gases from deposition, thus increasing their atmospheric burden and lifetime. In the absence of this condensation, ~50% of the regionally produced mass would have been dry deposited.

  16. Use of ceilometers for aerosol profile measurements: a comment from AD-Net

    NASA Astrophysics Data System (ADS)

    Jin, Yoshitaka; Kai, Kenji; Kawai, Kei; Sugimoto, Nobuo; Nishizawa, Tomoaki; Matsui, Ichiro; Shimizu, Atsushi; Batdorj, Dashdondog

    2014-11-01

    Ceilometer instruments are simple backscatter lidar systems and are usually set in airports for detecting the base of clouds. The instrument can also measure aerosol vertical distribution. Since ceilometers barely detect the molecular backscatter signals, retrieval of aerosol optical properties is an issue. This study investigates applicability of ceilometers to retrieval of optical properties. We make an idealized signal profile with the lidar ratio of 50 sr and calculate the retrieval errors caused by 30% errors of lidar ratio. In the forward inversion, useable (small error) optical properties are backscattering coefficients and the retrieval errors are less than 15% if the aerosol optical depth (AOD) is less than 0.2. The initial backscattering coefficients must be determined from other instruments (e.g., multi-wavelength lidar). Whereas in the backward inversion, if the AOD of idealized signals is larger than 1.5, extinction coefficients converge to the true value (within 5% errors), regardless of lidar ratios and initial conditions. Since there is no need for the system constant or molecular backscatter in this method, ceilometers can be an effective tool for retrieving extinction coefficients of dense aerosols in East Asia.

  17. Impact of aerosol composition and foliage characteristics on forest canopy deposition rates: A laboratory study

    NASA Astrophysics Data System (ADS)

    Hornsby, K. E.; Pryor, S. C.

    2013-12-01

    Forests are a major sink for atmospheric aerosols. Hence it has been suggested that (i) increased tree planting in urban areas might lead to a reduction in aerosol particle concentrations and thus a reduction in respiratory conditions and heart complications, and (ii) forests may be responsible for removing a disproportionately large fraction of potentially climate-relevant fine and ultra-fine aerosol particles from the atmosphere. However, larger uncertainties remain with respect to controls on uptake rates for forests. E.g. the deposition flux partitioning between foliage and non-foliage elements, the influence of particle size and composition, the role of leaf surface morphology and stomatal aperture in surface uptake. Improved understanding of the relative importance of these factors and the variability across different tree species should help determine how much of a sink naturally occurring and planted forests can provide downstream of fine particle production. In this study, a sample of trees native to southern Indiana were exposed to ultra-fine aerosol particle populations in a 1.5 m x 1.5 m x 1.5 m Teflon chamber. Stable particle size distributions (PSD) with geometric mean diameters (GMD) ranging from 40 to 80 nm were generated from sodium chloride, ammonium nitrate, ammonium sulfate and sodium sulfite solutions using a TSI model 3940 Aerosol Generation System (AGS). The aerosol stream was diluted using scrubbed and dried zero air to allow a variation of total number concentration across two orders of magnitude. PSD in the chamber are continuously measured using a TSI Scanning Mobility Particle Spectrometer (SMPS) comprising an Electrostatic Classifier (EC model 3080) attached to a Long DMA (LDMA model 3081) and a TSI model 3025A Butanol Condensation Particle Counter (CPC) operated with both the internal diffusion loss and multiple charge corrections turned on. The composition of the chamber air was also monitored for carbon dioxide (CO2) and water vapor

  18. Assessment of dry and wet atmospheric deposits of radioactive aerosols: application to Fukushima radiocaesium fallout.

    PubMed

    Gonze, Marc-André; Renaud, Philippe; Korsakissok, Irène; Kato, Hiroaki; Hinton, Thomas G; Mourlon, Christophe; Simon-Cornu, Marie

    2014-10-01

    The Fukushima Dai-ichi nuclear accident led to massive atmospheric deposition of radioactive substances onto the land surfaces. The spatial distribution of deposits has been estimated by Japanese authorities for gamma-emitting radionuclides through either airborne monitoring surveys (since April 2011) or in situ gamma-ray spectrometry of bare soil areas (since summer 2011). We demonstrate that significant differences exist between the two surveys for radiocaesium isotopes and that these differences can be related to dry deposits through the use of physically based relationships involving aerosol deposition velocities. The methodology, which has been applied to cesium-134 and cesium-137 deposits within 80-km of the nuclear site, provides reasonable spatial estimations of dry and wet deposits that are discussed and compared to atmospheric numerical simulations from the Japanese Atomic Energy Agency and the French Institute of Radioprotection and Nuclear Safety. As a complementary approach to numerical simulations, this field-based analysis has the possibility to contribute information that can be applied to the understanding and assessment of dose impacts to human populations and the environment around Fukushima. PMID:25196232

  19. Enhancement effect of relative humidity on the formation and regional respiratory deposition of secondary organic aerosol.

    PubMed

    Yu, Kuo-Pin; Lin, Chi-Chi; Yang, Shang-Chun; Zhao, Ping

    2011-07-15

    In this study, we investigated the effect of relative humidity (RH) on the formation of secondary organic aerosol (SOA) generated from the ozonolysis of d-limonene in an environmental chamber. The mass yield and the number concentration of SOA increased seven and eight times, respectively, when the RH increased from 18% to 82%. The measured total loss rates (apparent loss rates) of the number and mass concentration of SOA in the chamber ranged from 1.70 to 1.77 h(-1) and from 2.51 to 2.61 h(-1), respectively, at a controlled ventilation rate of 0.72±0.04 h(-1). The wall-deposition-loss-rate coefficient observed (1.00±0.02 h(-1)) was approximate to the estimated value based on Zhao and Wu's model which includes the factors of turbulence, Brownian diffusion, turbophoresis and surface roughness. According to the ICRP (International Commission on Radiological Protection) model, the inhaled SOA particles are deposited primarily in the alveoli of the lung. The integrated alveolar deposited dose of the mass (surface area) of SOA over 3h accounted for 74.0-74.8% (74.3-74.9%) of the total deposited dose at the investigated RH. Raising the RH resulted in the growth of SOA particle sizes and increment of the deposition dose but did not cause significant changes in the ratio of regional to the total respiratory deposition of SOA. PMID:21570180

  20. Aerosol Deposition of Molybdenum: A Control on Nitrogen-Fixation and Tropical Forest Function

    NASA Astrophysics Data System (ADS)

    Wong, M.; Howarth, R. W.; Marino, R. M.; Mahowald, N. M.; Williams, E. R.

    2015-12-01

    Nitrogen fixation, the primary source of new nitrogen (N) to tropical forests, is exclusively catalyzed by the nitrogenase enzyme, which almost always requires molybdenum (Mo). Increasing evidence in recent years suggests that Mo availability may be low in highly weathered soils and can constrain N-fixation rates. Mo is generally either present in a highly soluble form (MoO42-) that is susceptible to leaching or tightly bound in minerals unavailable for biological uptake. To address how Mo is retained in highly weathered tropical systems to support N-fixation, atmospheric transport through dust and sea-salt aerosol spray were examined. Using a global atmospheric transport model computed from modeled meteorological fields, extrapolated dust and sea-salt aerosol Mo sources were used to calculate global distribution of Mo deposition. Dust deposition occurs across the entirety of some tropical forests, particularly the world's largest tropical forest in the Amazon Basin. The model indicates that the Amazon Basin receives substantial inputs of dust, especially the entire northern Amazon Basin, while the southern half receives less. Most of the dust reaching the Amazon originates from the Sahara Desert, and about half of this dust originates from one part of the Sahara, the Bodélé Depression. Mo in dust from the Bodélé Depression was measured with an average concentration of 1.14 ± 0.05 μg/g, similar to the crustal abundance. The model predicts Mo inputs from sea-salt aerosols in coastal regions up to 0.002 mg m-2yr-1. Significant sea-salt deposition occurs up to 300 km inland. Mo from fossil fuel combustion and biomass burning were also evaluated to determine the potential influence of anthropogenic emissions on releasing Mo into the environment.

  1. [Aerosol deposition in nasal passages of burrowing and ground rodents when breathing dust-laden air].

    PubMed

    Moshkin, M P; Petrovskiĭ, D V; Akulov, A E; Romashchenko, A V; Gerlinskaia, L A; Muchnaia, M I; Ganimedov, V L; Sadovskiĭ, A S; Savelov, A A; Koptiug, I V; Troitskiĭ, S Iu; Bukhtiiarov, V I; Kolchanov, N A; Sagdeev, R Z; Fomin, V M

    2014-01-01

    In subterranean rodents, which dig down the passages with frontal teeth, adaptation to the underground mode of life presumes forming of mechanisms that provide protection against inhaling dust particles of different size when digging. One of such mechanisms can be specific pattern of air flow organization in the nasal cavity. To test this assumption, comparative study of geometry and aerodynamics of nasal passages has been conducted with regard to typical representative of subterranean rodents, the mole vole, and a representative of ground rodents, the house mouse. Numerical modeling of air flows and deposition of micro- and nanoparticle aerosols indicates that sedimentation of model particles over the whole surface of nasal cavity is higher in mole vole than in house mouse. On the contrary, particles deposition on the surface of olfactory epithelium turns out to be substantially less in the burrowing rodent as compared to the ground one. Adaptive significance of the latter observation has been substantiated by experimental study on the uptake ofnanoparticles of hydrated manganese oxide MnO x (H2O)x and Mn ions from nasal cavity into brain. It has been shown with use of magnetic resonance tomography method that there is no difference between studied species with respect to intake of particles or ions by olfactory bulb when they are introduced intranasally. Meanwhile, when inhaling nanoparticle aerosol of MnCl2, deposition of Mn in mouse's olfactory bulbs surpasses markedly that in vole's bulbs. Thereby, the morphology of nasal passages as a factor determining the aerodynamics of upper respiratory tract ensures for burrowing rodents more efficient protection of both lungs and brain against inhaled aerosols than for ground ones. PMID:25771679

  2. Lung deposition analyses of inhaled toxic aerosols in conventional and less harmful cigarette smoke: a review.

    PubMed

    Kleinstreuer, Clement; Feng, Yu

    2013-09-23

    Inhaled toxic aerosols of conventional cigarette smoke may impact not only the health of smokers, but also those exposed to second-stream smoke, especially children. Thus, less harmful cigarettes (LHCs), also called potential reduced exposure products (PREPs), or modified risk tobacco products (MRTP) have been designed by tobacco manufacturers to focus on the reduction of the concentration of carcinogenic components and toxicants in tobacco. However, some studies have pointed out that the new cigarette products may be actually more harmful than the conventional ones due to variations in puffing or post-puffing behavior, different physical and chemical characteristics of inhaled toxic aerosols, and longer exposure conditions. In order to understand the toxicological impact of tobacco smoke, it is essential for scientists, engineers and manufacturers to develop experiments, clinical investigations, and predictive numerical models for tracking the intake and deposition of toxicants of both LHCs and conventional cigarettes. Furthermore, to link inhaled toxicants to lung and other diseases, it is necessary to determine the physical mechanisms and parameters that have significant impacts on droplet/vapor transport and deposition. Complex mechanisms include droplet coagulation, hygroscopic growth, condensation and evaporation, vapor formation and changes in composition. Of interest are also different puffing behavior, smoke inlet conditions, subject geometries, and mass transfer of deposited material into systemic regions. This review article is intended to serve as an overview of contributions mainly published between 2009 and 2013, focusing on the potential health risks of toxicants in cigarette smoke, progress made in different approaches of impact analyses for inhaled toxic aerosols, as well as challenges and future directions.

  3. Lung Deposition Analyses of Inhaled Toxic Aerosols in Conventional and Less Harmful Cigarette Smoke: A Review

    PubMed Central

    Kleinstreuer, Clement; Feng, Yu

    2013-01-01

    Inhaled toxic aerosols of conventional cigarette smoke may impact not only the health of smokers, but also those exposed to second-stream smoke, especially children. Thus, less harmful cigarettes (LHCs), also called potential reduced exposure products (PREPs), or modified risk tobacco products (MRTP) have been designed by tobacco manufacturers to focus on the reduction of the concentration of carcinogenic components and toxicants in tobacco. However, some studies have pointed out that the new cigarette products may be actually more harmful than the conventional ones due to variations in puffing or post-puffing behavior, different physical and chemical characteristics of inhaled toxic aerosols, and longer exposure conditions. In order to understand the toxicological impact of tobacco smoke, it is essential for scientists, engineers and manufacturers to develop experiments, clinical investigations, and predictive numerical models for tracking the intake and deposition of toxicants of both LHCs and conventional cigarettes. Furthermore, to link inhaled toxicants to lung and other diseases, it is necessary to determine the physical mechanisms and parameters that have significant impacts on droplet/vapor transport and deposition. Complex mechanisms include droplet coagulation, hygroscopic growth, condensation and evaporation, vapor formation and changes in composition. Of interest are also different puffing behavior, smoke inlet conditions, subject geometries, and mass transfer of deposited material into systemic regions. This review article is intended to serve as an overview of contributions mainly published between 2009 and 2013, focusing on the potential health risks of toxicants in cigarette smoke, progress made in different approaches of impact analyses for inhaled toxic aerosols, as well as challenges and future directions. PMID:24065038

  4. Environmental controls on coastal coarse aerosols: implications for microbial content and deposition in the near-shore environment.

    PubMed

    Dueker, M Elias; Weathers, Kathleen C; O'Mullan, Gregory D; Juhl, Andrew R; Uriarte, Maria

    2011-04-15

    Coarse aerosols (particle diameter (D(p)) > 2 μm) produced in coastal surf zones carry chemical and microbial content to shore, forming a connection between oceanic, atmospheric, and terrestrial systems that is potentially relevant to coastal ecology and human health. In this context, the effects of tidal height, wind speed, and fog on coastal coarse aerosols and microbial content were quantified on the southern coast of Maine, USA. Aerosols at this site displayed clear marine influence and had high concentrations of ecologically relevant nutrients. Coarse aerosol concentrations significantly increased with tidal height (i.e., decreasing distance from waterline), onshore wind speed, and fog presence. As onshore wind speeds rose above 3 m s(-1), the mean half-deposition distance of coarse aerosols increased to an observed maximum of 47.6 ± 10.9 m from the water's edge at wind speeds from 5.5-8 m s(-1). Tidal height and fog presence did not significantly influence total microbial aerosol concentrations but did have a significant effect on culturable microbial aerosol fallout. At low wind speeds, culturable microbial aerosols falling out near-shore decreased by half at a distance of only 1.7 ± 0.4 m from the water's edge, indicating that these microbes may be associated with large coarse aerosols with rapid settling rates.

  5. High T(sub c) superconductors fabricated by plasma aerosol mist deposition technique

    NASA Technical Reports Server (NTRS)

    Wang, X. W.; Vuong, K. D.; Leone, A.; Shen, C. Q.; Williams, J.; Coy, M.

    1995-01-01

    We report new results on high T(sub c) superconductors fabricated by a plasma aerosol mist deposition technique, in atmospheric environment. Materials fabricated are YBaCuO, BiPbSrCaCuO, BaCaCuO precursor films for TlBaCaCuO, and other buffers such as YSZ. Depending on processing conditions, sizes of crystallites and/or particles are between dozens of nano-meters and several micrometers. Superconductive properties and other material characteristics can also be tailored.

  6. Influence of agricultural biomass burning on aerosol size distribution and dry deposition in southeastern Brazil.

    PubMed

    Rocha, Gisele O; Allen, Andrew G; Cardoso, Arnaldo A

    2005-07-15

    The size distributed composition of ambient aerosols is used to explore seasonal differences in particle chemistry and to show that dry deposition fluxes of soluble species, including important plant nutrients, increase during periods of biomass (sugar cane trash) burning in São Paulo State, Brazil. Measurements were made at a single site centrally located in the State's sugar cane growing region but away from the immediate vicinity of burns, so that the airsampled was representative of the regional background. Calculation of ion equivalent balances showed that during burning periods smaller particles (Aitken and accumulation modes) were more acidic, containing higher concentrations of SO4(2-), oxalate, NO3-, HCOO-, CH3COO-, and CI-, but insufficient NH4+ and K+ to achieve neutrality. Larger particles showed an anion deficit due to the presence of unmeasured ions and comprised resuspended dusts modified by accumulation of nitrate, chloride, and organic anions. Increases of resuspended particles during the burning season were attributed to release of earlier deposits from the surfaces of burning vegetation as well as increased vehicle movement on unsurfaced roads. During winter months the relative contribution of combined emissions from road transport and industry diminished due to increased emissions from biomass combustion and other activities specifically associated with the harvest period. Positive increments in annual particulate dry deposition fluxes due to higher fluxes during the sugar cane harvest were 44.3% (NH4+), 42.1% (K+), 31.8% (Mg2+), 30.4% (HCOO-), 12.8% (CI-), 6.6% (CH3COO-), 5.2% (Ca2+), 3.8% (SO4(2-)), and 2.3% (NO3-). Na+ and oxalate fluxes were seasonally invariant. Annual aerosol dry deposition fluxes (kg ha(-1)) were 0.5 (Na+), 0.25 (NH4+), 0.39 (K+), 0.51 (Mg2+), 3.19 (Ca2+), 1.34 (Cl-), 4.47 (NO3-), 3.59 (SO4(2-)), 0.58 (oxalate), 0.71 (HCOO-), and 1.38 (CH3COO-). Contributions of this mechanism to combined aerosol dry deposition and

  7. Single-Species Aerosol Coagulation and Deposition with Arbitrary Size Resolution.

    SciTech Connect

    SAJO, ERNO

    2012-07-31

    Version 00 SAEROSA solves the dynamic aerosol coagulation and deposition problem with arbitrary computational precision under a variety of conditions. The code includes numerous user-selectable coagulation kernels, alone or in combinations, and permits an arbitrary initial size distribution. Many parameter combinations and what-if scenarios under user control are possible. The output gives the particle size distribution suspended in the carrier fluid initially and after the desired aerosol aging time in terms of both differential and integral aerosol volume concentrations. An auxiliary routine designed for the Mac OSX environment provides plotting capability. The output can be further processed by e.g., spreadsheets. The code has been benchmarked against three computer models, including MAEROS, and analytical models with excellent agreement. The test cases also included scenarios where previously published computational coagulation models lack capabilities or exhibit numerical instabilities. These included narrow, delta function, and non-lognormal initial size distributions, and further conditions, such as the presence of simultaneous coagulation mechanisms, including electrostatic effects, spanning multiple flow-regimes.

  8. Single-Species Aerosol Coagulation and Deposition with Arbitrary Size Resolution.

    2012-07-31

    Version 00 SAEROSA solves the dynamic aerosol coagulation and deposition problem with arbitrary computational precision under a variety of conditions. The code includes numerous user-selectable coagulation kernels, alone or in combinations, and permits an arbitrary initial size distribution. Many parameter combinations and what-if scenarios under user control are possible. The output gives the particle size distribution suspended in the carrier fluid initially and after the desired aerosol aging time in terms of both differential andmore » integral aerosol volume concentrations. An auxiliary routine designed for the Mac OSX environment provides plotting capability. The output can be further processed by e.g., spreadsheets. The code has been benchmarked against three computer models, including MAEROS, and analytical models with excellent agreement. The test cases also included scenarios where previously published computational coagulation models lack capabilities or exhibit numerical instabilities. These included narrow, delta function, and non-lognormal initial size distributions, and further conditions, such as the presence of simultaneous coagulation mechanisms, including electrostatic effects, spanning multiple flow-regimes.« less

  9. The dynamics of nonspherical aerosol particles. 5: The wall effect in orderly deposition; Brownian diffusion

    NASA Astrophysics Data System (ADS)

    Gallily, I.

    1981-12-01

    The effect of the wall on the motion of elongated aerosol particles was calculated on the basis of the (powerful) slender body theory for a quiet and flowing medium. The cases treated were those of cylindrical particles moving in a quiet environment or a Couette or a Poiseuille flow near plannar surfaces with various inclinations to the horizontal. Experiments of trajectory photographing were performed in a liquid-tank under creeping flow conditions and typical (aerosol) Reynolds numbers whereby very good correspondence with computations was obtained. The Brownian diffusion of (very small) cylindrical or discoidal aerosol particles was also studied while being based on Brenners' formal structure. To evaluate the significant orientation density function, the (mid-diameter) rotational diffusion coefficient of the particles was calculated by a statistical-mechanical method. The values of the coefficients were found to be larger than those computed on the basis of continuum theory by a factor of about 30. The typical diffusion situation of deposition on a plane within a quiet air was treated.

  10. Mathematical model for aerosol deposition in the respiratory tract of the guinea pig

    SciTech Connect

    Martonen, T.B.; Yang, Y.

    1994-02-01

    Laboratory animals are used as surrogates in inhalation exposure studies for (1) risk assessments of air pollutants and (2) evaluations of pharmacologic drugs. Herein, a mathematical model is presented that identifies factors affecting the regional distributions of inhaled aerosols within the complete respiratory system of the guinea pig. The model couples empirical and deterministic techniques. An original empirical formula is presented to describe particle losses in airways of the head and throat. Regarding the lung, its structure is defined using the asymmetric morphology of Schreider and Hutchens (1980), and deposition is calculated in a deterministic manner using the protocol of Martonen et al. (1992a, 1992b). Results of our deposition model are compared separately with the theory of Schreider and Hutchens (1979) and the experimental data of Raabe et al. (1988). Results of the deposition model presented herein are in qualitative agreement with the laboratory data of Raabe et al. (1988). Quantitative differences in desposition values may be attributable to different strains of guinea pig being used in the repective morphological and deposition studies. By identifying the factors that most affect the behavior of inhaled particles, our deposition model can aid in the design of inhalation exposure experiments and interpretation of data.

  11. Synthesis of carbon containing TiO2 nano powders by aerosol flame deposition for photocatalyst.

    PubMed

    Lim, Gyeong-Taek; Kim, Yeon-Hong; Jeong, Hyung-Gon; Woo, Hee-Gweon; Ohk, Seung-Ho; Kim, Do-Heyoung

    2008-09-01

    In-situ carbon-doped-TiO2 nano-powder was prepared by an AFD (aerosol flame deposition) technique using ethanol and isopropanol, and the photocatalytic activity of the prepared powder was examined. There were no significant effect of the solvents on the phase of the prepared TiO2, but the level of carbon in the deposits prepared with ethanol was lower than that prepared with isopropanol. Also, the average sizes of the particles prepared with ethanol were slightly smaller than that formed with isopropanol. All the samples showed excellent photocatalytic activity in the decomposing of methylene blue (MB). We even observed photocatalytic activity of the powder under visible light irradiation, although the decomposition rate of MB under this irradiation was slightly slower than under UV-A light irradiation. PMID:19049067

  12. Aerosol deposition doses in the human respiratory tree of electronic cigarette smokers.

    PubMed

    Manigrasso, Maurizio; Buonanno, Giorgio; Fuoco, Fernanda Carmen; Stabile, Luca; Avino, Pasquale

    2015-01-01

    Aerosols from eight e-cigarettes at different nicotine levels and flavoring were characterized as particle number size distributions in the range 5.6-560 nm by FMPS and CPC. Results were used to provided osimetry estimates applying the MMPD model.Particle number concentrations varied between 3.26 x 10(9) and 4.09 x 10(9) part cm(-3) for e-liquids without nicotine and between 5.08 x 10(9) and 5.29 x 10(9) part cm(-3) for e-liquids with nicotine. No flavor effects were detected on particle concentration data. Particle size distributions were unimodal with modes between 107-165 nm and 165-255 nm, for number and volume metrics, respectively. Averagely, 6.25 x 10(10) particles were deposited in respiratory tree after a single puff. Highest deposition densities and mean layer thickness of e-cigarette liquid on the lung epithelium were estimated at lobar bronchi. Our study shows that e-cigarette aerosol is source of high particle dose in respiratory system, from 23%to 35% of the daily dose of a no-smoking individual. PMID:25463721

  13. Sensitivity of depositions to the size and hygroscopicity of Cs-bearing aerosols released from the Fukushima nuclear accident

    NASA Astrophysics Data System (ADS)

    Kajino, Mizuo; Adachi, Kouji; Sekiyama, Tsuyoshi; Zaizen, Yuji; Igarashi, Yasuhito

    2014-05-01

    We recently revealed that the microphysical properties of aerosols carrying the radioactive Cs released from the Fukushima Daiichi Nuclear Power Plant (FDNPP) at an early stage (March 14-15, 2011) of the accident could be very different from what we assumed previously: super-micron and non-hygroscopic at the early stage, whereas sub-micron and hygroscopic afterwards (at least later than March 20-22). In the study, two sensitivity simulations with the two different aerosol microphysical properties were conducted using a regional scale meteorology- chemical transport model (NHM-Chem). The impact of the difference was quite significant. 17% (0.001%) of the radioactive Cs fell onto the ground by dry (wet) deposition processes, and the rest was deposited into the ocean or was transported out of the model domain, which is central and northern part of the main land of Japan, under the assumption that Cs-bearing aerosols are non-hygroscopic and super-micron. On the other hand, 5.7% (11.3%) fell onto the ground by dry (wet) deposition, for the cases under the assumption that the Cs-bearing aerosols are hygroscopic and sub-micron. For the accurate simulation of the deposition of radionuclides, knowledge of the aerosol microphysical properties is essential as well as the accuracy of the simulated wind fields and precipitation patterns.

  14. Predicting Reaction Mechanisms and Potentials in Acid and Base from Self-Consistent Quantum Theory: H(ads) and OH(ads) Deposition on the Pt(111) Electrode.

    PubMed

    Zhao, Meng; Anderson, Alfred B

    2016-02-18

    It has been shown recently that when reactants and products are well modeled within a comprehensive self-consistent theory for the electrochemical interface, accurate predictions are possible for reversible potentials, Urev, in acid electrolyte for reactions such as reduction of H(+)(aq) to form under potential deposited H(ads) and oxidation of an OH bond of H2O(ads) to deposit OH(ads). Predictions are based on calculated Gibbs energies for the reactant and product being equal at the reversible potential, which is the potential at the crossing point for reaction and product Gibbs energies, plotted as functions of electrode potential. In this Letter, it is demonstrated that the same capability holds for these reactions in basic electrolyte. This demonstration opens up the opportunity for predictions of reversible potentials and mechanisms for other electrocatalytic reactions in base.

  15. Mechanical and in vitro biological performances of hydroxyapatite-carbon nanotube composite coatings deposited on Ti by aerosol deposition.

    PubMed

    Hahn, Byung-Dong; Lee, Jung-Min; Park, Dong-Soo; Choi, Jong-Jin; Ryu, Jungho; Yoon, Woon-Ha; Lee, Byoung-Kuk; Shin, Du-Sik; Kim, Hyoun-Ee

    2009-10-01

    Hydroxyapatite (HA)-carbon nanotube (CNT) composite coatings on Ti plate, produced by aerosol deposition using HA-CNT powders, were developed for biomedical applications. For the deposition process HA-CNT powder mixtures with CNT contents of 1 and 3 wt.% were used. Dense coatings with a thickness of 5 microm were fabricated, irrespective of the content of CNTs. No pores or microcracks were observed in the coatings. The coatings had good adhesion to the substrate, exhibiting a high adhesion strength, ranging from 27.3 to 29.0 MPa. Microstructural observation using field-emission gun scanning electron microscopy and transmission electron microscopy showed that CNTs with a typical tubular structure were found in the HA-CNT composite coatings. Nanoindentation tests revealed that the mechanical properties, such as the hardness and elastic modulus, were significantly improved by the addition of the CNTs to the HA coating. In addition, the proliferation and alkaline phosphatase (ALP) activity of MC3T3-E1 pre-osteoblast cells grown on the HA-CNT composite coatings were higher than those on the bare Ti and pure HA coating. The ALP activity of the composite coatings considerably improved as the CNT content increased. These results suggest that CNTs would be an effective reinforcing agent to enhance both the mechanical and biological performances of HA coatings.

  16. Enhanced Bactericidal Activity of Silver Thin Films Deposited via Aerosol-Assisted Chemical Vapor Deposition.

    PubMed

    Ponja, Sapna D; Sehmi, Sandeep K; Allan, Elaine; MacRobert, Alexander J; Parkin, Ivan P; Carmalt, Claire J

    2015-12-30

    Silver thin films were deposited on SiO2-barrier-coated float glass, fluorine-doped tin oxide (FTO) glass, Activ glass, and TiO2-coated float glass via AACVD using silver nitrate at 350 °C. The films were annealed at 600 °C and analyzed by X-ray powder diffraction, X-ray photoelectron spectroscopy, UV/vis/near-IR spectroscopy, and scanning electron microscopy. All the films were crystalline, and the silver was present in its elemental form and of nanometer dimension. The antibacterial activity of these samples was tested against Escherichia coli and Staphylococcus aureus in the dark and under UV light (365 nm). All Ag-deposited films reduced the numbers of E. coli by 99.9% within 6 h and the numbers of S. aureus by 99.9% within only 2 h. FTO/Ag reduced bacterial numbers of E. coli to below the detection limit after 60 min and caused a 99.9% reduction of S. aureus within only 15 min of UV irradiation. Activ/Ag reduced the numbers of S. aureus by 66.6% after 60 min and TiO2/Ag killed 99.9% of S. aureus within 60 min of UV exposure. More remarkably, we observed a 99.9% reduction in the numbers of E. coli within 6 h and the numbers of S. aureus within 4 h in the dark using our novel TiO2/Ag system. PMID:26632854

  17. Massive volcanic SO(2) oxidation and sulphate aerosol deposition in Cenozoic North America.

    PubMed

    Bao, Huiming; Yu, Shaocai; Tong, Daniel Q

    2010-06-17

    Volcanic eruptions release a large amount of sulphur dioxide (SO(2)) into the atmosphere. SO(2) is oxidized to sulphate and can subsequently form sulphate aerosol, which can affect the Earth's radiation balance, biologic productivity and high-altitude ozone concentrations, as is evident from recent volcanic eruptions. SO(2) oxidation can occur via several different pathways that depend on its flux and the atmospheric conditions. An investigation into how SO(2) is oxidized to sulphate-the oxidation product preserved in the rock record-can therefore shed light on past volcanic eruptions and atmospheric conditions. Here we use sulphur and triple oxygen isotope measurements of atmospheric sulphate extracted from tuffaceous deposits to investigate the specific oxidation pathways from which the sulphate was formed. We find that seven eruption-related sulphate aerosol deposition events have occurred during the mid-Cenozoic era (34 to 7 million years ago) in the northern High Plains, North America. Two extensively sampled ash beds display a similar sulphate mixing pattern that has two distinct atmospheric secondary sulphates. A three-dimensional atmospheric sulphur chemistry and transport model study reveals that the observed, isotopically discrete sulphates in sediments can be produced only in initially alkaline cloudwater that favours an ozone-dominated SO(2) oxidation pathway in the troposphere. Our finding suggests that, in contrast to the weakly acidic conditions today, cloudwater in the northern High Plains may frequently have been alkaline during the mid-Cenozoic era. We propose that atmospheric secondary sulphate preserved in continental deposits represents an unexploited geological archive for atmospheric SO(2) oxidation chemistry linked to volcanism and atmospheric conditions in the past.

  18. Application of both a physical theory and statistical procedure in the analyses of an in vivo study of aerosol deposition

    SciTech Connect

    Cheng, K.H.; Swift, D.L.; Yang, Y.H.

    1995-12-01

    Regional deposition of inhaled aerosols in the respiratory tract is a significant factor in assessing the biological effects from exposure to a variety of environmental particles. Understanding the deposition efficiency of inhaled aerosol particles in the nasal and oral airways can help evaluate doses to the extrathoracic region as well as to the lung. Dose extrapolation from laboratory animals to humans has been questioned due to significant physiological and anatomical variations. Although human studies are considered ideal for obtaining in vivo toxicity information important in risk assessment, the number of subjects in the study is often small compared to epidemiological and animal studies. This study measured in vivo the nasal airway dimensions and the extrathoracic deposition of ultrafine aerosols in 10 normal adult males. Variability among individuals was significant. The nasal geometry of each individual was characterized at a resolution of 3 mm using magnetic resonance imaging (MRI) and acoustic rhinometry (AR). The turbulent diffusion theory was used to describe the nonlinear nature of extrathoracic aerosol deposition. To determine what dimensional features of the nasal airway were responsible for the marked differences in particle deposition, the MIXed-effects NonLINear Regression (MIXNLIN) procedure was used to account for the random effort of repeated measurements on the same subject. Using both turbulent diffusion theory and MIXNLIN, the ultrafine particle deposition is correlated with nasal dimensions measured by the surface area, minimum cross-sectional area, and complexity of the airway shape. The combination of MRI and AR is useful for characterizing both detailed nasal dimensions and temporal changes in nasal patency. We conclude that a suitable statistical procedure incorporated with existing physical theories must be used in data analyses for experimental studies of aerosol deposition that involve a relatively small number of human subjects.

  19. Validating CFD predictions of respiratory aerosol deposition: effects of upstream transition and turbulence.

    PubMed

    Worth Longest, P; Vinchurkar, Samir

    2007-01-01

    A number of computational fluid dynamics (CFD) studies have explored local deposition patterns of inhaled aerosols in the respiratory tract. These studies have highlighted the effects of multiple physiologic, geometric, and particle characteristics on deposition. However, very few studies have reported local or sub-branch quantitative comparisons to in vitro particle deposition data. The objective of this study is to numerically investigate the effects of transition and turbulence on highly localized particle deposition in a respiratory double bifurcation model in order to quantitatively validate CFD results. To perform the validations, local comparisons have been made to a specific in vitro case study of 10 microm particles depositing in a model of respiratory generations G3-G5. To achieve this objective, two geometric cases have been considered. The first case includes only the double bifurcation model. The second case includes a portion of the experimental particle delivery geometry, where transitional flow is expected. To evaluate the effectiveness of two-equation turbulence models in this system, the flow field solutions have been computed using laminar, standard k-omega, and low Reynolds number (LRN) k-omega approximations. Results indicate that even though the Reynolds number remained below the critical limit required for full turbulence, transition and turbulence have a significant impact on the flow field and local particle deposition patterns. For the experimental case considered, turbulence impacted the local deposition of 10 microm particles primarily by influencing the initial velocity and particle profiles. As such, both the laminar and LRN k-omega flow models provided good local quantitative matches to the in vitro deposition data, provided that the correct initial particle profile was specified. Implications of this study include the need for local quantitative validations of particle deposition results, the importance of correct inlet conditions

  20. Aerosol assisted chemical vapour deposition of Cu-ZnO composite from single source precursors.

    PubMed

    Shahid, Muhammad; Mazhar, Muhammad; Hamid, Mazhar; O'Brien, Paul; Malik, Mohammad A; Helliwell, Madeleine; Raftery, James

    2009-07-28

    Two heterobimetallic precursors [Zn(TFA)3(micro-OH)Cu3(dmae)3Cl].THF (1) and [Zn(TFA)4Cu3(dmae)4] (2) [dmae=N,N-dimethylaminoethanolate and TFA=trifluoroacetate], have been synthesized and characterized by their melting points, elemental analysis, FT-IR spectroscopy, mass spectrometry, TGA and single crystal X-ray diffraction methods. Both complexes were used to deposit thin films of Cu-ZnO composite on glass substrates by aerosol assisted chemical vapor deposition (AACVD) method. The films were characterized by "scotch tape" test for adhesion, thickness measurement as a function of temperature, EDX for composition, SEM for surface morphology and XRD for crystalline phases. Thin film deposition studies at 250, 325, 400, 475 degrees C indicated the increase in thickness with temperature reaching a maximum at 400 degrees C and then decreasing. EDX and PXRD results showed the uniform distribution of cubic metallic copper and hexagonal zinc oxide phases which make them useful for nanocatalysis on structured surfaces. PMID:19587992

  1. Simplified route to multi-walled carbon nanotube synthesis by aerosol assisted chemical vapor deposition.

    PubMed

    Antúnez-Flores, W; Valenzuela-Muñiz, A M; Amézaga-Madrid, P; Alonso-Nuñez, G; Verde, Y; Martínez-Sánchez, R; Miki-Yoshida, M

    2008-12-01

    Uniform multi-walled carbon nanotubes (MWCNTs) were obtained decomposing toluene inside of fused silica tubing previously covered with Co oxide thin film. The two-step process, ruled successively in the same aerosol assisted chemical vapor deposition (AACVD) set up, constitutes a simplified route to the synthesis of MWCNTs. First, Co oxide thin film was deposited inside of fused silica tubing at 723 K, using a precursor solution of Co acetate in absolute methanol. After Co oxide deposition, the covered tubing was heated up to 1173 K under Ar flow, then a mist of toluene was injected inside the tubing, using also Ar as carrier gas, consequently MWCNTs were obtained in the internal wall of the tubing. The Co oxide film and the MWCNTs were analyzed by scanning electron microscopy (SEM), high resolution transmission electron microscopy (HRTEM) and atomic force microscopy (AFM). Uniform and very long MWCNTs (several tens of microm) with diameters around 20 to 100 nm were observed, with the advantage that the content of Co particles inside the nanotube was very low. PMID:19205220

  2. Deposition and resuspension of selected aerosols particles on electrically charged filter materials for respiratory protective devices.

    PubMed

    Makowski, Krzysztof

    2005-01-01

    The primary aim of the study was to analyse the non-steady state of filtration for selected electrostatic filter materials designed for use in respiratory protective devices. The obtained results showed that the filtration process in electrostatic filters was dependent in the main on the following factors: type of the filter material, electrostatic field strength of the material, and the charge of the aerosol. To a lesser degree the filtration process depended on the sign of the charge and the relative humidity of the air. A significant correlation was found between the increase in the penetration and the decrease in breathing resistance while the filter was being loaded. The effect of resuspension (tearing off and re-deposition of dust agglomerates inside the filter) on the filtration process very significant. It was also observed that under certain conditions electrostatic filter materials lost their protection properties.

  3. Superhydrophobic photocatalytic surfaces through direct incorporation of titania nanoparticles into a polymer matrix by aerosol assisted chemical vapor deposition.

    PubMed

    Crick, Colin R; Bear, Joseph C; Kafizas, Andreas; Parkin, Ivan P

    2012-07-10

    A new class of superhydrophobic photocatalytic surfaces that are self-cleaning through light-induced photodegradation and the Lotus effect are presented. The films are formed in a single-step aerosol-assisted chemical vapor deposition (AACVD) process. The films are durable and show no degradation on continuous exposure to UV-C radiation. PMID:22706974

  4. AEROSOL DEPOSITION EFFICIENCIES AND UPSTREAM RELEASE POSITIONS FOR DIFFERENT INHALATION MODES IN AN UPPER BRONCHIAL AIRWAY MODELS

    EPA Science Inventory

    Aerosol Deposition Efficiencies and Upstream Release Positions for Different Inhalation Modes in an Upper Bronchial Airway Model

    Zhe Zhang, Clement Kleinstreuer, and Chong S. Kim

    Center for Environmental Medicine and Lung Biology, University of North Carolina at Ch...

  5. Effects of substrate materials on piezoelectric properties of BaTiO3 thick films deposited by aerosol deposition

    NASA Astrophysics Data System (ADS)

    Kawakami, Yoshihiro; Watanabe, Masato; Arai, Ken-Ichi; Sugimoto, Satoshi

    2016-10-01

    Piezoelectric properties were evaluated for annealed BaTiO3 (BT) films formed by aerosol deposition on yttria-stabilized zirconia (YSZ) and Fe-Cr-Al-based heat-resistant stainless steel (SS). The piezoelectric constants d 31 of BT films annealed at 1200 °C formed on YSZ and SS were -71 and -41 pm/V, respectively. The effects of different substrates on piezoelectric properties were investigated. The grain sizes of the films formed on YSZ and SS were 1.5 and 1.0 µm, respectively. X-ray diffraction analysis using a two-dimensional stress method revealed that the respective residual stresses of the films formed on YSZ and SS were -55 ± 8 and -32 ± 7 MPa, respectively, as compressive stresses. The c-domain structure was formed preferentially in the films on SS because of its larger compressive stress. These results suggest that differences in piezoelectric properties attributable to substrates result from differences in compressive stress magnitude and the volume fraction between the c- and a-domains.

  6. Effect of tubing deposition, breathing pattern, and temperature on aerosol mass distribution measured by cascade impactor.

    PubMed

    Gurses, Burak K; Smaldone, Gerald C

    2003-01-01

    Aerosols produced by nebulizers are often characterized on the bench using cascade impactors. We studied the effects of connecting tubing, breathing pattern, and temperature on mass-weighted aerodynamic particle size aerosol distributions (APSD) measured by cascade impaction. Our experimental setup consisted of a piston ventilator, low-flow (1.0 L/min) cascade impactor, two commercially available nebulizers that produced large and small particles, and two "T"-shaped tubes called "Tconnector(cascade)" and "Tconnector(nebulizer)" placed above the impactor and the nebulizer, respectively. Radiolabeled normal saline was nebulized using an airtank at 50 PSIG; APSD, mass balance, and Tconnector(cascade) deposition were measured with a gamma camera and radioisotope calibrator. Flow through the circuit was defined by the air tank (standing cloud, 10 L/min) with or without a piston pump, which superimposed a sinusoidal flow on the flow from the air tank (tidal volume and frequency of breathing). Experiments were performed at room temperature and in a cooled environment. With increasing tidal volume and frequency, smaller particles entered the cascade impactor (decreasing MMAD; e.g., Misty-Neb, 4.2 +/- 0.9 microm at lowest ventilation and 2.7 +/- 0.1 microm at highest, p = 0.042). These effects were reduced in magnitude for the nebulizer that produced smaller particles (AeroTech II, MMAD 1.8 +/- 0.1 to 1.3 +/- 0.1 microm; p = 0.0044). Deposition on Tconnector(cascade) increased with ventilation but was independent of cascade impactor flow. Imaging of the Tconnector(cascade) revealed a pattern of deposition unaffected by cascade impactor flow. These measurements suggest that changes in MMAD with ventilation were not artifacts of tubing deposition in the Tconnector(cascade). At lower temperatures, APSD distributions were more polydisperse. Our data suggest that, during patient inhalation, changes in particle distribution occur that are related to conditions in the tubing and

  7. Evaluation of nose-only aerosol inhalation chamber and comparison of experimental results with mathematical simulation of aerosol deposition in mouse lungs.

    PubMed

    Nadithe, Venkatareddy; Rahamatalla, Muhib; Finlay, Warren H; Mercer, John R; Samuel, John

    2003-05-01

    In vivo small rodent efficacy testing of new synthetic and biological molecules for the pulmonary route requires an efficient delivery device. For this purpose, a nose-only inhalation chamber was used to deliver aerosolized aqueous compounds to the respiratory tract of mice. The aim of the study was to determine the efficiency of dose delivery and deposition in the lungs of the mice using this chamber. A secondary goal was to compare the experimental lung deposition results with values predicted from mathematical simulation. Experimental tests were conducted by generating aerosols of a radiolabeled formulation of human serum albumin (HSA) with a mass median aerodynamic diameter (MMAD) of 3.9 +/- 0.5 microm and a geometric standard deviation (GSD) of 1.43 +/- 0.05 using PARI LC STAR jet nebulizers. Based on the total activity placed in the nebulizer, the chamber delivered 0.108 +/- 0.027% to the mice and 0.0087 +/- 0.0021% to the lungs of the mice. In vivo lung deposition was found to be 8.19 +/- 3.56% of total activity deposited in the mouse. Mathematical simulation predictions ranged between 5.89 and 4.40% for various breathing patterns, and did not differ significantly from the in vivo results (p > 0.10). These results provide important quantitative information relevant to aerosol delivery experiments in mouse models. Our results also suggest that the nose-only inhalation chamber would benefit from significant changes to increase the efficiency of deposition in mice such that it can be used for nebulization of expensive therapeutic drugs.

  8. Influence of elastase-induced emphysema and the inhalation of an irritant aerosol on deposition and retention of an inhaled insoluble aerosol in Fischer-344 rats

    SciTech Connect

    Damon, E.G.; Mokler, B.V.; Jones, R.K.

    1983-01-01

    The purpose of this study was to assess the effects of elastase-induced pulmonary emphysema and the inhalation of an irritant aerosol (Triton X-100, a nonionic surfactant similar to those used in a number of pressurized consumer products) on pulmonary deposition and retention of an insoluble test aerosol, /sup 59/FE-labeled Fe/sub 2/O/sub 3/. Untreated rats or rats pretreated by intratracheal in stillation with elastase were exposed to an aerosol of /sup 59/Fe-labeled Fe/sub 2/O/sub 3/ either 18 hr or 7 days after exposure to aerosslized Triton X-100 which was administered in doses of 20, 100, or 200 ..mu..g/g of lung. Rats pretreated with elastase had significantly lower pulmonary deposition of /sup 59/Fe than the untreated controls (p < 0.005). Pulmonary deposition of Fe/sub 2/O/sub 3/ was unaffected by pretreatment with Triton X-100. Elastase treatment alone had no effect on retention of Fe/sub 2/O/sub 3/. Triton X-100 administered 18 hr prior to exposure of rats to Fe/sub 2/O/sub 3/ aerosol resulted in dose-related increases in whole-body retention of /sup 59/Fe. When rats were exposed to Triton X-100 7 days before exposure to Fe/sub 2/O/sub 3/, increased retention of /sup 59/Fe was noted only in those treated at the highest Triton X-100 dose level (200 ..mu..g/g). 20 references, 5 tables.

  9. Chemical relations between atmospheric aerosols, deposition and stone decay layers on historic buildings at the mediterranean coast

    NASA Astrophysics Data System (ADS)

    Torfs, K.; Van Grieken, R.

    To evaluate the effects of the environment on weathering of historical buildings in the Mediterranean Basin, an elaborate study has been carried out at four monuments, with specific interest directed on the action of air pollution and marine salts. The composition of the atmosphere around the monuments has been investigated by monitoring the aerosols and the total deposition. These results are combined with the stone decay phenomena to interpret the deterioration at the respective monuments. In Eleusis, Greece, a highly industrialized area, high concentrations of heavy metals and sulphate are found in the aerosols and deposition and in the decay layers of the stone, while the marine influence is obscured, in spite of its location close to the sea. In Malta and in Cadiz (Spain), the influence of the sea dominates in the stone weathering process. In Bari (Italy), next to the effects of marine aerosols on the stone decay inside and outside the building, high concentrations of sulphate are observed on the outside stones. The aerosols and depositions reflect a relatively small influence of anthropogenic derived elements; this points out the action of gaseous SO 2 on the stones.

  10. Fate of inhaled monoclonal antibodies after the deposition of aerosolized particles in the respiratory system.

    PubMed

    Guilleminault, L; Azzopardi, N; Arnoult, C; Sobilo, J; Hervé, V; Montharu, J; Guillon, A; Andres, C; Herault, O; Le Pape, A; Diot, P; Lemarié, E; Paintaud, G; Gouilleux-Gruart, V; Heuzé-Vourc'h, N

    2014-12-28

    Monoclonal antibodies (mAbs) are usually delivered systemically, but only a small proportion of the drug reaches the lung after intravenous injection. The inhalation route is an attractive alternative for the local delivery of mAbs to treat lung diseases, potentially improving tissue concentration and exposure to the drug while limiting passage into the bloodstream and adverse effects. Several studies have shown that the delivery of mAbs or mAb-derived biopharmaceuticals via the airways is feasible and efficient, but little is known about the fate of inhaled mAbs after the deposition of aerosolized particles in the respiratory system. We used cetuximab, an anti-EGFR antibody, as our study model and showed that, after its delivery via the airways, this mAb accumulated rapidly in normal and cancerous tissues in the lung, at concentrations twice those achieved after intravenous delivery, for early time points. The spatial distribution of cetuximab within the tumor was heterogeneous, as reported after i.v. injection. Pharmacokinetic (PK) analyses were carried out in both mice and macaques and showed aerosolized cetuximab bioavailability to be lower and elimination times shorter in macaques than in mice. Using transgenic mice, we showed that FcRn, a key receptor involved in mAb distribution and PK, was likely to make a greater contribution to cetuximab recycling than to the transcytosis of this mAb in the airways. Our results indicate that the inhalation route is potentially useful for the treatment of both acute and chronic lung diseases, to boost and ensure the sustained accumulation of mAbs within the lungs, while limiting their passage into the bloodstream. PMID:25451545

  11. The effect of large anthropogenic particulate emissions on atmospheric aerosols, deposition and bioindicators in the eastern Gulf of Finland region.

    PubMed

    Jalkanen, L; Mäkinen, A; Häsänen, E; Juhanoja, J

    2000-10-30

    The effect of the emissions from large oil shale fuelled power plants and a cement factory in Estonia on the elemental concentration of atmospheric aerosols, deposition, elemental composition of mosses and ecological effects on mosses, lichens and pine trees in the eastern Gulf of Finland region has been studied. In addition to chemical analysis, fly ash, moss and aerosol samples were analysed by a scanning electron microscope with an energy dispersive X-ray spectrometer (SEM/EDS). The massive particulate calcium emissions, approximately 60 kton/year (1992), is clearly observed in the aerosols, deposition and mosses. The calcium deposition is largest next to the Russian border downwind from the power plants and in south-eastern part of Finland. This deposition has decreased due to the application of dust removal systems at the particulate emission sources. At the Virolahti EMEP station approximately 140 km north from the emission sources, elevated elemental atmospheric aerosol concentrations are observed for Al, Ca, Fe, K and Si and during episodes many trace elements, such as As, Br, Mo, Ni, Pb and V. The acidification of the soil is negligible because of the high content of basic cations in the deposition. Visible symptoms on pine trees are negligible. However, in moss samples close to the power plants, up to 25% of the leaf surface was covered by particles. Many epiphytic lichen species do not tolerate basic stemflow and on the other hand most species are also very sensitive for the SO2 content in air. Consequently a large lichen desert is found in an area of 2500 km2 in the vicinity of the power plants with only one out of the investigated 12 species growing.

  12. GENERATION, TRANSPORT AND DEPOSITION OF TUNGSTEN-OXIDE AEROSOLS AT 1000 C IN FLOWING AIR-STEAM MIXTURES.

    SciTech Connect

    GREENE,G.A.; FINFROCK,C.C.

    2001-10-01

    Experiments were conducted to measure the rates of oxidation and vaporization of pure tungsten rods in flowing air, steam and air-steam mixtures in laminar flow. Also measured were the downstream transport of tungsten-oxide condensation aerosols and their region of deposition, including plateout in the superheated flow tube, rainout in the condenser and ambient discharge which was collected on an array of sub-micron aerosol filters. The nominal conditions of the tests, with the exception of the first two tests, were tungsten temperatures of 1000 C, gas mixture temperatures of 200 C and wall temperatures of 150 C to 200 C. It was observed that the tungsten oxidation rates were greatest in all air and least in all steam, generally decreasing non-linearly with increasing steam mole fraction. The tungsten oxidation rates in all air were more than five times greater than the tungsten oxidation rates in all steam. The tungsten vaporization rate was zero in all air and increased with increasing steam mole fraction. The vaporization rate became maximum at a steam mole fraction of 0.85 and decreased thereafter as the steam mole fraction was increased to unity. The tungsten-oxide was transported downstream as condensation aerosols, initially flowing upwards from the tungsten rod through an 18-inch long, one-inch diameter quartz tube, around a 3.5-inch radius, 90{sup o} bend and laterally through a 24-inch horizontal run. The entire length of the quartz glass flow path was heated by electrical resistance clamshell heaters whose temperatures were individually controlled and measured. The tungsten-oxide plateout in the quartz tube was collected, nearly all of which was deposited at the end of the heated zone near the entrance to the condenser which was cold. The tungsten-oxide which rained out in the condenser as the steam condensed was collected with the condensate and weighed after being dried. The aerosol smoke which escaped the condenser was collected on the sub

  13. In Vitro Surfactant and Perfluorocarbon Aerosol Deposition in a Neonatal Physical Model of the Upper Conducting Airways

    PubMed Central

    Goikoetxea, Estibalitz; Murgia, Xabier; Serna-Grande, Pablo; Valls-i-Soler, Adolf; Rey-Santano, Carmen; Rivas, Alejandro; Antón, Raúl; Basterretxea, Francisco J.; Miñambres, Lorena; Méndez, Estíbaliz; Lopez-Arraiza, Alberto; Larrabe-Barrena, Juan Luis; Gomez-Solaetxe, Miguel Angel

    2014-01-01

    Objective Aerosol delivery holds potential to release surfactant or perfluorocarbon (PFC) to the lungs of neonates with respiratory distress syndrome with minimal airway manipulation. Nevertheless, lung deposition in neonates tends to be very low due to extremely low lung volumes, narrow airways and high respiratory rates. In the present study, the feasibility of enhancing lung deposition by intracorporeal delivery of aerosols was investigated using a physical model of neonatal conducting airways. Methods The main characteristics of the surfactant and PFC aerosols produced by a nebulization system, including the distal air pressure and air flow rate, liquid flow rate and mass median aerodynamic diameter (MMAD), were measured at different driving pressures (4–7 bar). Then, a three-dimensional model of the upper conducting airways of a neonate was manufactured by rapid prototyping and a deposition study was conducted. Results The nebulization system produced relatively large amounts of aerosol ranging between 0.3±0.0 ml/min for surfactant at a driving pressure of 4 bar, and 2.0±0.1 ml/min for distilled water (H2Od) at 6 bar, with MMADs between 2.61±0.1 µm for PFD at 7 bar and 10.18±0.4 µm for FC-75 at 6 bar. The deposition study showed that for surfactant and H2Od aerosols, the highest percentage of the aerosolized mass (∼65%) was collected beyond the third generation of branching in the airway model. The use of this delivery system in combination with continuous positive airway pressure set at 5 cmH2O only increased total airway pressure by 1.59 cmH2O at the highest driving pressure (7 bar). Conclusion This aerosol generating system has the potential to deliver relatively large amounts of surfactant and PFC beyond the third generation of branching in a neonatal airway model with minimal alteration of pre-set respiratory support. PMID:25211475

  14. Characteristics of mineral aerosol deposited on the glaciers of Mt. Elbrus, Caucasus, Russia.

    NASA Astrophysics Data System (ADS)

    Kutuzov, Stanislav; Shahgedanova, Maria; Mikhalenko, Vladimir; Ginot, Patrick; Lavrentiev, Ivan; Popov, Gregory

    2014-05-01

    Records of mineral aerosol (desert dust) stored in glaciers provide data on frequency and intensity of deposition events, source regions and atmospheric pathways of mineral dust. We present and discuss a chronology of dust deposition events recorded in the shallow firn and ice cores extracted on the Western Plateau, Mt. Elbrus (5150 m a.s.l.), Caucasus Mountains, Russia and covering the period of 2009-2013. Particle size distribution and chemical analysis (major ions, trace elements) were peformed using Coulter Counter Multisizer III, Abacus particle counter, IC and ICPMS analysis. Sampling was performed using continuous flow analysis (CFA) system. Annual average dust flux (264 μg/cm2 a-1) and average mass concentration (1.7 mg/kg) over the period 2007-2013 were calculated for the first time for this region. A combination of satellite imagery (MSG SEVIRI), trajectory models (FLEXTA, HYSPLIT) and meteorological data were used to accurately date each of the dust layers observed in shallow cores and investigate provenance of the dust and its pathways. Desert dust originating from the Middle East and Sahara was deposited on the Caucasus glaciers 3-6 times a year. Although less frequent, Saharan events are characterized by considerably higher dust loads than the more frequent Middle Eastern events. The mass median diameter of dust particles ranged between 2 and 9 μm. The deposition of dust resulted in elevated concentrations of most ions, especially Ca2+, Mg2+, K+, and sulphates. Dust originated from or passing over the Middle East was characterised by the elevated concentrations of nitrates and ammonia. This may be related to dust emissions from agricultural fields which, if abandoned due to droughts, become important sources of dust. By contrast, samples of the Saharan dust originated from natural sources showed lower concentrations of ammonium. The mean values of crustal enrichment factors for the measured trace elements including metals were calculated. Overall

  15. Insights into anthropogenic nitrogen deposition to the North Atlantic investigated using the isotopic composition of aerosol and rainwater nitrate

    NASA Astrophysics Data System (ADS)

    Gobel, Amy R.; Altieri, Katye E.; Peters, Andrew J.; Hastings, Meredith G.; Sigman, Daniel M.

    2013-11-01

    the dominant sources of atmospheric reactive nitrogen (Nr) is critical for determining the influence of anthropogenic emissions on Nr deposition, especially in marine ecosystems. To test the influence of anthropogenic versus marine air masses, samples were collected in Bermuda, where seasonal atmospheric circulation patterns lead to greater continental transport during the cool season. The 15N/14N of aerosol nitrate (NO3-) indicates changes in Nr sources and its 18O/16O indicates a seasonal shift in the relative strength of pathways of NO3- formation. The aerosol δ15N-NO3- was consistently lower than or equal to the rainwater from the same sampling period, the opposite trend of that observed in polluted systems. We propose that this is due to HNO3(g) uptake onto aerosol particles with a kinetic isotope effect, lowering the aerosol δ15N-NO3- relative to residual HNO3(g). The aerosol δ18O-NO3- was higher than that in rainwater during the cool season, but was not different during the warm season, which we tentatively attribute to the increased importance of heterogeneous halogen chemistry on the formation of NO3- during the cool season.

  16. Determinants of aerosol lung-deposited surface area variation in an urban environment.

    PubMed

    Reche, Cristina; Viana, Mar; Brines, Mariola; Pérez, Noemí; Beddows, David; Alastuey, Andrés; Querol, Xavier

    2015-06-01

    Ultrafine particles are characterized by a high surface area per mass. Particle surface has been reported to play a significant role in determining the toxicological activity of ultrafine particles. In light of this potential role, the time variation of lung deposited surface area (LDSA) concentrations in the alveolar region was studied at the urban background environment of Barcelona (Spain), aiming to asses which processes and sources govern this parameter. Simultaneous data on Black Carbon (BC), total particle number (N) and particle number size distribution were correlated with LDSA. Average LDSA concentrations in Barcelona were 37 ± 26 μm(2)cm(-3), levels which seem to be characteristic for urban environments under traffic influence across Europe. Results confirm the comparability between LDSA data provided by the online monitor and those calculated based on particle size distributions (by SMPS), and reveal that LDSA concentrations are mainly influenced by particles in the size range 50-200 nm. A set of representative daily cycles for LDSA concentrations was obtained by means of a k-means cluster technique. The contribution of traffic emissions to daily patterns was evidenced in all the clusters, but was quantitatively different. Traffic events under stable atmospheric conditions increased mean hourly background LDSA concentrations up to 6 times, attaining levels higher than 200 μm(2)cm(-3). However, under warm and relatively clean atmospheric conditions, the traffic rush hour contribution to the daily LDSA mean appeared to be lower and the contribution of new urban particle formation events (by photochemically induced nucleation) was detected. These nucleation events were calculated to increase average background LDSA concentrations by 15-35% (maximum LDSA levels=45-50 μm(2)cm(-3)). Thereby, it may be concluded that in the urban background of Barcelona road traffic is the main source increasing the aerosol surface area which can deposit on critical

  17. Aerosol-assisted chemical vapor deposition (AACVD) of binary alloy films: Studies of film composition

    SciTech Connect

    Xu, C.; Hampden-Smith, M.J.; Kodas, T.T.

    1995-08-01

    The chemical vapor deposition (CVD) of Cu-Ag and Cu-Pd alloys using aerosol precursor delivery over a range of preheating temperatures, 70 {approximately} 80 C and substrate temperatures, 250 {approximately} 300 C is described. The precursors used include Cu(hfac){sub 2}, (hfac)Ag(SEt{sub 2}) and Pd(hfac){sub 2} dissolved in toluene and 10% H{sub 2} in Ar as carrier gas. The films were characterized by SEM, EDS and X-ray diffraction (XRD). The X-ray diffraction results showed the Cu/Ag films were composed of {alpha}- and {beta}-phases of Cu-Ag alloys, the Cu/Pd films were Cu-Pd and Pd-Ag alloy, solid solutions, under these conditions. Compositional variation studies in Cu-Pd and Pd-Ag alloy systems were also conducted by mixing Cu(hfac){sub 2}/Pd(hfac){sub 2} and (hfac) Ag(SEt{sub 2})/Pd(hfac){sub 2} in toluene solution in different ratios. The films were characterized by X-ray diffraction and the results showed the composition of films was affected by the solution stoichiometry.

  18. High loading of nanostructured ceramics in polymer composite thick films by aerosol deposition

    PubMed Central

    2012-01-01

    Low temperature fabrication of Al2O3-polyimide composite substrates was carried out by an aerosol deposition process using a mixture of Al2O3 and polyimide starting powders. The microstructures and dielectric properties of the composite thick films in relation to their Al2O3 contents were characterized by X-ray diffraction analysis. As a result, the crystallite size of α-Al2O3 calculated from Scherrer's formula was increased from 26 to 52 nm as the polyimide ratio in the starting powders increased from 4 to 12 vol.% due to the crushing of the Al2O3 powder being reduced by the shock-absorbing effect of the polyimide powder. The Al2O3-polyimide composite thick films showed a high loss tangent with a large frequency dependence when a mixed powder of 12 vol.% polyimide was used due to the nonuniform microstructure with a rough surface. The Al2O3-polyimide composite thick films showed uniform composite structures with a low loss tangent of less than 0.01 at 1 MHz and a high Al2O3 content of more than 75 vol.% when a mixed powder of 8 vol.% polyimide was used. Moreover, the Al2O3-polyimide composite thick films had extremely high Al2O3 contents of 95 vol.% and showed a dense microstructure close to that of the Al2O3 thick films when a mixed powder of 4 vol.% polyimide was used. PMID:22283973

  19. Effect of InspirEase on the deposition of metered-dose aerosols in the human respiratory tract

    SciTech Connect

    Newman, S.P.; Woodman, G.; Clarke, S.W.; Sackner, M.A.

    1986-04-01

    A radiotracer technique has been used to assess the effects of a 700-ml collapsible holding chamber (InspirEase, Key Pharmaceuticals Inc.) on the deposition of metered-dose aerosols in ten patients with obstructive airways disease (mean forced expiratory volume in one second (FEV1), 64.5 percent of predicted). Patterns of deposition obtained by patients' usual techniques with the metered-dose inhaler (MDI) were compared with those by correct MDI technique (actuation coordinated with slow deep inhalation and followed by ten seconds of breath-holding) and with those by InspirEase. Deposition of aerosol was assessed by placing Teflon particles labelled with 99mTc inside placebo canisters, and inhaling maneuvers were monitored by respiratory inductive plethysmography (Respitrace). Nine of the ten patients had imperfect technique with the MDI, the most prevalent errors being rapid inhalation and failure to hold their breath adequately. With patients' usual MDI techniques, 6.5 +/- 1.2 percent (mean +/- SE) of the dose reached the lungs. This was increased to 11.2 +/- 1.3 percent (p less than 0.02) with correct technique and increased further to 14.8 +/- 1.4 percent (p less than 0.05) with InspirEase. Oropharyngeal deposition exceeded 80 percent of the dose for the MDI alone but was only 9.5 +/- 0.9 percent with InspirEase (p less than 0.01); 59.2 +/- 2.1 percent of the dose was retained within InspirEase itself. It is concluded that InspirEase gives whole lung deposition of metered-dose aerosols greater than that from a correctly used MDI, while oropharyngeal deposition is reduced approximately nine times.

  20. Nanoparticulate cerium dioxide and cerium dioxide-titanium dioxide composite thin films on glass by aerosol assisted chemical vapour deposition

    NASA Astrophysics Data System (ADS)

    Qureshi, Uzma; Dunnill, Charles W.; Parkin, Ivan P.

    2009-11-01

    Two series of composite thin films were deposited on glass by aerosol assisted chemical vapour deposition (AACVD)—nanoparticulate cerium dioxide and nanoparticulate cerium dioxide embedded in a titanium dioxide matrix. The films were analysed by a range of techniques including UV-visible absorption spectroscopy, X-ray diffraction, scanning electron microscopy and energy dispersive analysis by X-rays. The AACVD prepared films showed the functional properties of photocatalysis and super-hydrophilicity. The CeO 2 nanoparticle thin films displaying photocatalysis and photo-induced hydrophilicity almost comparable to that of anatase titania.

  1. Surface Plasmon Resonance in Novel Nanocomposite Gold/Lead Zirconate Titanate Films Prepared by Aerosol Deposition Method

    NASA Astrophysics Data System (ADS)

    Park, Jae-Hyuk; Akedo, Jun; Nakada, Masafumi

    2006-09-01

    We prepared gold/lead zirconate titanate (PZT) nanocomposite thick films by the aerosol deposition method (ADM) for the first time and report their enhanced surface plasmon resonance (SPR) properties. ADM has been attracting much attention for its ability to deposit complex composite films at a high deposition rate and a low process temperature. Composite metal-dielectric powders are prepared from submicron particles of PZT and nano particles of gold (10-40 nm) with concentrations below 1 wt %. Nanocomposite gold/PZT 3-μm-thick film acquired enhanced SPR at approximately 640 nm as a result of annealing. The SPR position in nanocomposite films deposited by ADM can be precisely controlled by adjusting the dielectric constant of the host matrix by annealing. Moreover, nanogold particles were spatially very well distributed in the PZT matrix and showed no growth in spite of annealing at 600 °C.

  2. Effects of starting powder and thermal treatment on the aerosol deposited BaTiO3 thin films toward less leakage currents

    PubMed Central

    2014-01-01

    To prepare high-density integrated capacitors with low leakage currents, 0.2-μm-thick BaTiO3 thin films were successfully deposited on integrated semiconductor substrates at room temperature by the aerosol deposition (AD) method. In this study, the effects of starting powder size were considered in an effort to remove macroscopic defects. A surface morphology of 25.3 nm and an interface roughness of less than 50 nm were obtained using BT-03B starting powder. The nano-crystalline thin films achieved after deposition were annealed at various temperatures to promote crystallization and densification. Moreover, the influence of rapid thermal annealing process on the surface morphology and crystal growth was evaluated. As the annealing temperature increased from room temperature to 650°C, the root mean square (RMS) roughness decreased from 25.3 to 14.3 nm. However, the surface was transformed into rough performance at 750°C, which agreed well with the surface microstructure trend. Moreover, the crystal growth also reveals the changes in surface morphology via surface energy analysis. PMID:25246860

  3. Concentration, size-distribution and deposition of mineral aerosol over Chinese desert regions

    NASA Astrophysics Data System (ADS)

    Zhang, Xiao Y.; Arimoto, R.; Zhu, G. H.; Chen, T.; Zhang, G. Y.

    1998-09-01

    The mass-particle size distributions (MSDs) of 9 elements in ground-based aerosol samples from dust storm (DS) and non-dust storm (N-DS) periods were determined for 12 sites in 9 major desert regions in northern China. The masses of the 9 elements (Al, Fe, K, Mg, Mn, Sc, Si, Sr and Ti) in the atmosphere were dominated by local mineral dust that averaged 270μg m-3, and the MSDs for the elements were approximately log-normal. On the basis of Al data, the<10μm particles account for ~84% of the total dust mass over the deserts. Model-calculated ("100-step" method) dry deposition velocities (Vd) for the 9 dust-derived elements during N-DS periods ranged from 4.4 to 6.8cms-1, with a median value of 5.6cms-1. On the basis of a statistical relationship between D99% (the dust particle diameter corresponding to the uppermost 1% of the cumulative mass distribution) and Vd, one can also predict dry velocities, especially when D99% ranges from 30 to 70μm. This provides a simple way to reconstruct Vd for dust deposits (like aeolian loess sediments in the Loess Plateau). The estimated daily dry deposition fluxes were higher during DS vs. N-DS periods, but in most cases, the monthly averaged fluxes were mainly attributable to N-DS dust. Two regions with high dust loading and fluxes are identified: the "Western High-Dust Desert" and the "Northern High-Dust Desert", with Taklimakan Desert and Badain Juran Desert as their respective centers. These are energetic regions in which desert-air is actively exchanged, and these apparently are the major source areas for Asian dust.

  4. PAK Inactivation Impairs Social Recognition in 3xTg-AD Mice without Increasing Brain Deposition of Tau and Aβ

    PubMed Central

    Arsenault, Dany; Dal-Pan, Alexandre; Tremblay, Cyntia; Bennett, David A.; Guitton, Matthieu J.; De Koninck, Yves; Tonegawa, Susumu

    2013-01-01

    Defects in p21-activated kinase (PAK) are suspected to play a role in cognitive symptoms of Alzheimer's disease (AD). Dysfunction in PAK leads to cofilin activation, drebrin displacement from its actin-binding site, actin depolymerization/severing, and, ultimately, defects in spine dynamics and cognitive impairment in mice. To determine the role of PAK in AD, we first quantified PAK by immunoblotting in homogenates from the parietal neocortex of subjects with a clinical diagnosis of no cognitive impairment (n = 12), mild cognitive impairment (n = 12), or AD (n = 12). A loss of total PAK, detected in the cortex of AD patients (−39% versus controls), was correlated with cognitive impairment (r2 = 0.148, p = 0.027) and deposition of total and phosphorylated tau (r2 = 0.235 and r2 = 0.206, respectively), but not with Aβ42 (r2 = 0.056). Accordingly, we found a decrease of total PAK in the cortex of 12- and 20-month-old 3xTg-AD mice, an animal model of AD-like Aβ and tau neuropathologies. To determine whether PAK dysfunction aggravates AD phenotype, 3xTg-AD mice were crossed with dominant-negative PAK mice. PAK inactivation led to obliteration of social recognition in old 3xTg-AD mice, which was associated with a decrease in cortical drebrin (−25%), but without enhancement of Aβ/tau pathology or any clear electrophysiological signature. Overall, our data suggest that PAK decrease is a consequence of AD neuropathology and that therapeutic activation of PAK may exert symptomatic benefits on high brain function. PMID:23804095

  5. Measuring the emission rate of an aerosol source placed in a ventilated room using a tracer gas: influence of particle wall deposition.

    PubMed

    Bémer, D; Lecler, M T; Régnier, R; Hecht, G; Gerber, J M

    2002-04-01

    A method to measure the emission rate of an airborne pollutant source using a tracer gas was tested in the case of an aerosol source. The influence of particle deposition on the walls of a test room of 72 m3 was studied. The deposition rate of an aerosol of MgCl2 was determined by means of two methods: one based on measuring the aerosol concentration decay inside the ventilated room, the other based on calculation of the material mass balance. The concentration decay was monitored by optical counting and the aerosol mass concentration determined by means of sampling on a filter and analysis of the mass deposited by atomic absorption spectrometry. Four series of measurements were carried out. The curve giving the deposition rate according to the particle aerodynamic diameter (d(ae)) was established and shows deposition rates higher than those predicted using the model of Corner. The decay method gives the best results. The study carried out has shown that the phenomenon of deposition has little effect on the measurement of the aerosol source emission rate using a tracer gas for particles of aerodynamic diameter < 5 microm (underestimation < 25%). For particles of a greater diameter, wall deposition is an extremely limiting factor for the method, the influence of which can, however, be limited by using a test booth of small volume and keeping the sampling duration as short as possible.

  6. Recent advances in the development of a novel aerosol sorting and deposition system for bio-threat sensing applications

    NASA Astrophysics Data System (ADS)

    Pletcher, Timothy; McGinn, Joseph; Keller, David; Huston, Alan; Eversole, Jay; Sivaprakasum, Vasanthi

    2007-10-01

    Sarnoff Corporation and the Naval Research Laboratory, through support of the U.S. Department of Homeland Security, are developing an automated, high throughput bio-aerosol physical enrichment system designed for use as part of a biological-threat protection system. The Biological Aerosol-Capture-Enrichment (BioACE) system is a bio-aerosol collection system that combines three unique technologies to create physically enriched aerosol samples that can be subsequently interrogated by any number of bio-threat detection systems for the presence of threat agents. An air-to-air concentrator uses an inertial separation technique to highly concentrate an aerosol sample presented to a dual wavelength ultra-violet laser induced fluorescence (UVLIF) optical trigger used to discriminate potential threat particles from non-threat particles conveyed in a collimated particle stream. This particle classification information is used to trigger an electrostatic deposition mechanism to deposit only those particles determined to be potential bio-threats onto a stainless steel substrate. Non-threat particles are discarded with the exiting airflow. The goal for the most recent development effort has been the integration and optimization of these technologies into a unit capable of producing highly enriched particulate samples from ambient air containing variable background aerosol loading and type. Several key technical and engineering challenges were overcome during the course of this development including a unique solution for compensating particle velocity dispersion within the airflow, development of a real-time signal acquisition and detection algorithm for determining material type on a particle by particle basis at rates greater than 2000 particles per second, and the introduction of a robust method for transferring deposited particulate into a 50ul wet sample suitable for most advanced bio-detection techniques. This paper will briefly describe the overall system architecture and

  7. Pre-tuned resonant marker for iMRI using aerosol deposition on polymer catheters

    NASA Astrophysics Data System (ADS)

    Will, Karl; Schimpf, Stefan; Brose, Andreas; Fischbach, Frank; Ricke, Jens; Schmidt, Bertram; Rose, Georg

    2010-02-01

    New advances in MRI technology enable fast acquisition of high-resolution images. In combination with the new open architecture this scanners are entering the surgical suite being used as intra-operative imaging modality for minimally invasive interventions. However, for a usage on a large scale the major issue of availability of appropriate surgical tools is still unsolved. Such instruments, i.e. needles and catheters have to be MR-safe and -compatible but in contrast still have to be visible within the MRI image. This usually is solved by integration of markers onto non-magnetic devices. For reasons of MR-safety, work-flow and cost effectiveness semi-active markers without any connection to the outside are preferable. The challenge in development and integration of such resonant markers is to precisely meet the MRI frequency by keeping the geometrical dimensions of the interventional tool constant. This paper focuses on the reliable integration and easy fabrication of such resonant markers on the tip of an interventional instrument. Starting with a theoretical background for resonant labels a self-sufficient pre-tuned marker consisting of a standard capacitor and a thin-film inductor is presented. A prototype is built using aerosol deposition for the inductor on a 6-F polymer catheter and by integration of an off-the-shelf capacitor into the lumen of the catheter. Due to the fact that the dielectric materials of some capacitors lead to artifacts in the MRI image different capacitor technologies are investigated. The prototypes are scanned by an interventional MRI device proving the proper functionality of the tools.

  8. Criteria for significance of simultaneous presence of both condensible vapors and aerosol particles on mass transfer (deposition) rates

    NASA Technical Reports Server (NTRS)

    Gokoglu, S. A.

    1986-01-01

    The simultaneous presence of aerosol particles and condensible vapors in a saturated boundary layer which may affect deposition rates to subcooled surfaces because of vapor-particle interactions is discussed. Scavenging of condensible vapors by aerosol particles may lead to increased particle size and decreased vapor mass fraction, which alters both vapor and particle deposition rates. Particles, if sufficiently concentrated, may also coagulate. Criteria are provided to assess the significance of such phenomena when particles are already present in the mainstream and are not created inside the boundary layer via homogeneous nucleation. It is determined that there is direct proportionality with: (1) the mass concentration of both condensible vapors and aerosol particles; and (2) the square of the boundary layer thickness to particle diameter ratio (delta d sub p) square. Inverse proportionality was found for mainstream to surface temperature difference if thermophoresis dominates particle transport. It is concluded that the square of the boundary layer thickness to particle diameter ratio is the most critical factor to consider in deciding when to neglect vapor-particle interactions.

  9. Is dry deposition of semi-volatile organic gases a significant loss of secondary organic aerosols (SOA)?

    NASA Astrophysics Data System (ADS)

    Hodzic, A.; Aumont, B.; Knote, C. J.; Lee-Taylor, J. M.; Madronich, S.

    2013-12-01

    Dry deposition removal of semi-volatile organic compounds from the atmosphere and its impact on organic aerosol mass is currently under-explored and not well represented in chemistry-climate models, especially for the many complex partly oxidized organics involved in particle formation. The main reason for this omission is that current models use simplified SOA mechanisms that lump precursors and their products into volatility bins, therefore losing information on important properties of individual molecules (or groups) that are needed to calculate dry deposition. In this study, we apply the Generator of Explicit Chemistry and Kinetics of Organics in the Atmosphere (GECKO-A) to simulate SOA formation and estimate the influence of dry deposition of gas-phase organics on SOA concentrations downwind of an urban area (Mexico City), as well as over a pine forest. SOA precursors considered here include short- and long-chain alkanes (C3-25), alkenes, light aromatics, isoprene and monoterpenes. We show that dry deposition of oxidized gases is not an efficient sink for anthropogenic SOA, as it removes <5% of SOA within the city's boundary layer and ~15% downwind. The effect on biogenic SOA is however significantly larger. We discuss reasons for these differences, and investigate separately the impacts on short and long-chain species. We show that the dry deposition is competing with the uptake of gases to the aerosol phase. In the absence of this condensation, ~50% of the regionally produced mass downwind of Mexico City would have been dry-deposited. However, because dry deposition of submicron aerosols is slow, condensation onto particles protects organic gases from deposition and therefore increases their atmospheric burden and lifetime. We use the explicit GECKO-A model to build an empirical parameterization for use in 3D models. Removal (dry and wet) of organic vapors depends on their solubility, and required Henry's law solubility coefficients were estimated for

  10. Efficacy and Immunogenicity of Single-Dose AdVAV Intranasal Anthrax Vaccine Compared to Anthrax Vaccine Absorbed in an Aerosolized Spore Rabbit Challenge Model

    PubMed Central

    Krishnan, Vyjayanthi; Andersen, Bo H.; Shoemaker, Christine; Sivko, Gloria S.; Tordoff, Kevin P.; Stark, Gregory V.; Zhang, Jianfeng; Feng, Tsungwei; Duchars, Matthew

    2015-01-01

    AdVAV is a replication-deficient adenovirus type 5-vectored vaccine expressing the 83-kDa protective antigen (PA83) from Bacillus anthracis that is being developed for the prevention of disease caused by inhalation of aerosolized B. anthracis spores. A noninferiority study comparing the efficacy of AdVAV to the currently licensed Anthrax Vaccine Absorbed (AVA; BioThrax) was performed in New Zealand White rabbits using postchallenge survival as the study endpoint (20% noninferiority margin for survival). Three groups of 32 rabbits were vaccinated with a single intranasal dose of AdVAV (7.5 × 107, 1.5 × 109, or 3.5 × 1010 viral particles). Three additional groups of 32 animals received two doses of either intranasal AdVAV (3.5 × 1010 viral particles) or intramuscular AVA (diluted 1:16 or 1:64) 28 days apart. The placebo group of 16 rabbits received a single intranasal dose of AdVAV formulation buffer. All animals were challenged via the inhalation route with a targeted dose of 200 times the 50% lethal dose (LD50) of aerosolized B. anthracis Ames spores 70 days after the initial vaccination and were followed for 3 weeks. PA83 immunogenicity was evaluated by validated toxin neutralizing antibody and serum anti-PA83 IgG enzyme-linked immunosorbent assays (ELISAs). All animals in the placebo cohort died from the challenge. Three of the four AdVAV dose cohorts tested, including two single-dose cohorts, achieved statistical noninferiority relative to the AVA comparator group, with survival rates between 97% and 100%. Vaccination with AdVAV also produced antibody titers with earlier onset and greater persistence than vaccination with AVA. PMID:25673303

  11. Efficacy and immunogenicity of single-dose AdVAV intranasal anthrax vaccine compared to anthrax vaccine absorbed in an aerosolized spore rabbit challenge model.

    PubMed

    Krishnan, Vyjayanthi; Andersen, Bo H; Shoemaker, Christine; Sivko, Gloria S; Tordoff, Kevin P; Stark, Gregory V; Zhang, Jianfeng; Feng, Tsungwei; Duchars, Matthew; Roberts, M Scot

    2015-04-01

    AdVAV is a replication-deficient adenovirus type 5-vectored vaccine expressing the 83-kDa protective antigen (PA83) from Bacillus anthracis that is being developed for the prevention of disease caused by inhalation of aerosolized B. anthracis spores. A noninferiority study comparing the efficacy of AdVAV to the currently licensed Anthrax Vaccine Absorbed (AVA; BioThrax) was performed in New Zealand White rabbits using postchallenge survival as the study endpoint (20% noninferiority margin for survival). Three groups of 32 rabbits were vaccinated with a single intranasal dose of AdVAV (7.5 × 10(7), 1.5 × 10(9), or 3.5 × 10(10) viral particles). Three additional groups of 32 animals received two doses of either intranasal AdVAV (3.5 × 10(10) viral particles) or intramuscular AVA (diluted 1:16 or 1:64) 28 days apart. The placebo group of 16 rabbits received a single intranasal dose of AdVAV formulation buffer. All animals were challenged via the inhalation route with a targeted dose of 200 times the 50% lethal dose (LD50) of aerosolized B. anthracis Ames spores 70 days after the initial vaccination and were followed for 3 weeks. PA83 immunogenicity was evaluated by validated toxin neutralizing antibody and serum anti-PA83 IgG enzyme-linked immunosorbent assays (ELISAs). All animals in the placebo cohort died from the challenge. Three of the four AdVAV dose cohorts tested, including two single-dose cohorts, achieved statistical noninferiority relative to the AVA comparator group, with survival rates between 97% and 100%. Vaccination with AdVAV also produced antibody titers with earlier onset and greater persistence than vaccination with AVA.

  12. Effect of hydrogen addition on the deposition of titanium nitride thin films in nitrogen added argon magnetron plasma

    NASA Astrophysics Data System (ADS)

    Saikia, P.; Bhuyan, H.; Diaz-Droguett, D. E.; Guzman, F.; Mändl, S.; Saikia, B. K.; Favre, M.; Maze, J. R.; Wyndham, E.

    2016-06-01

    The properties and performance of thin films deposited by plasma assisted processes are closely related to their manufacturing techniques and processes. The objective of the current study is to investigate the modification of plasma parameters occurring during hydrogen addition in N2  +  Ar magnetron plasma used for titanium nitride thin film deposition, and to correlate the measured properties of the deposited thin film with the bulk plasma parameters of the magnetron discharge. From the Langmuir probe measurements, it was observed that the addition of hydrogen led to a decrease of electron density from 8.6 to 6.2  ×  (1014 m-3) and a corresponding increase of electron temperature from 6.30 to 6.74 eV. The optical emission spectroscopy study reveals that with addition of hydrogen, the density of argon ions decreases. The various positive ion species involving hydrogen are found to increase with increase of hydrogen partial pressure in the chamber. The thin films deposited were characterized using standard surface diagnostic tools such as x-ray photoelectron spectroscopy (XPS), secondary ion mass spectrometry (SIMS), x-ray diffraction (XRD), Raman spectroscopy (RS), scanning electron microscopy (SEM) and energy dispersive x-ray spectroscopy (EDS). Although it was possible to deposit thin films of titanium nitride with hydrogen addition in nitrogen added argon magnetron plasma, the quality of the thin films deteriorates with higher hydrogen partial pressures.

  13. Organic aerosols in the Miami area, USA: temporal variability of atmospheric particles and wet/dry deposition.

    PubMed

    Lang, Qingyong; Zhang, Qian; Jaffé, Rudolf

    2002-04-01

    Atmospheric particulate matter and both wet and dry deposition was collected over a period of nine months at one location in the metropolitan area of Miami, Florida. Molecular distributions and concentrations of n-alkanes, fatty acids, polycyclic aromatic hydrocarbons (PAHs) and hopanes were determined using weekly composite samples over this time period in order to determine temporal variability, and their possible dependence on climatic parameters such as temperature, rainfall and wind direction and frequency. Based on molecular distributions of the compounds studied, potential emission sources for the atmospheric particles were assessed and suggested to be mainly derived from automobile exhaust and natural sources. Although wet and dry deposition processes were observed to remove about equal amounts of organic aerosols from the Miami atmosphere, dry deposition was dominant in the removal of anthropogenically derived compounds such as PAHs and hopanes. Only very limited seasonal trends were observed, while wind direction and frequency was found to be the most important meteorological parameter controlling the temporal variability of the organic aerosols. This is the first detailed report of this nature for the Miami area.

  14. The impact of atmospheric mineral aerosol deposition on the albedo of snow & sea ice: are snow and sea ice optical properties more important than mineral aerosol optical properties?

    NASA Astrophysics Data System (ADS)

    Lamare, M. L.; Lee-Taylor, J.; King, M. D.

    2016-01-01

    Knowledge of the albedo of polar regions is crucial for understanding a range of climatic processes that have an impact on a global scale. Light-absorbing impurities in atmospheric aerosols deposited on snow and sea ice by aeolian transport absorb solar radiation, reducing albedo. Here, the effects of five mineral aerosol deposits reducing the albedo of polar snow and sea ice are considered. Calculations employing a coupled atmospheric and snow/sea ice radiative-transfer model (TUV-snow) show that the effects of mineral aerosol deposits are strongly dependent on the snow or sea ice type rather than the differences between the aerosol optical characteristics. The change in albedo between five different mineral aerosol deposits with refractive indices varying by a factor of 2 reaches a maximum of 0.0788, whereas the difference between cold polar snow and melting sea ice is 0.8893 for the same mineral loading. Surprisingly, the thickness of a surface layer of snow or sea ice loaded with the same mass ratio of mineral dust has little effect on albedo. On the contrary, the surface albedo of two snowpacks of equal depth, containing the same mineral aerosol mass ratio, is similar, whether the loading is uniformly distributed or concentrated in multiple layers, regardless of their position or spacing. The impact of mineral aerosol deposits is much larger on melting sea ice than on other types of snow and sea ice. Therefore, the higher input of shortwave radiation during the summer melt cycle associated with melting sea ice accelerates the melt process.

  15. Deposition, retention, and biological fate of inhaled benzo(a)pyrene adsorbed onto ultrafine particles and as a pure aerosol

    SciTech Connect

    Sun, J.D.; Wolff, R.K.; Kanapilly, G.M.

    1982-01-01

    The effect of ultrafine, airborne, carrier particles on the deposition, retention, and biological fate of inhaled polycyclic aromatic hydrocarbons (PAHs) was studied. Using a radiolabeled model PAH, (/sup 3/H)benzo(a)pyrene ((/sup 3/H)BaP), Fischer-344 rats were exposed by nose-only inhalation (30 min) to this compound, as a coating (15% by mass) on insoluble /sup 67/Ga/sub 2/O/sub 3/ particles or as a pure aerosol. These aerosols were produced by vapor condensation methods in a dynamic aerosol generation system. The concentrations of (/sup 3/H)BaP in the coated and homogeneous aerosols were 0.6 and 1.0 ..mu..g/liter of air, respectively, while the mass median diameter of both these aerosols was approximately 0.1 ..mu..m. Pulmonary retention of /sup 3/H radioactivity was longer in animals exposed to the (/sup 3/H)BaP coated on the /sup 67/Ga/sub 2/O/sub 3/ particles. The time required to clear 90% of the initial lung burden of /sup 67/Ga/sub 2/O/sub 3/-associated /sup 3/H radioactivity detected 30 min postexposure was approximately 1 day as compared to 4 hr for animals ex Tracheal clearance of 90% of the /sup 67/Ga/sub 2/O/sub 3/-associated /sup 3/H radioactivity required 1 day, while only 1.5 hr were required to clear the same percentage of /sup 3/H radioactivity from the tracheas of rats exposed to the pure (/sup 3/H)BaP aerosol. The rates of clearance of this /sup 3/H material to other tissues suggested that a substantial amount of the (/sup 3/H)BaP coated on /sup 67/Ga/sub 2/O/sub 3/ was cleared from lungs by mucociliary clearance and subsequent ingestion, whereas the majority of the pure (/sup 3/H)BaP aerosol was cleared by direct absorption into blood. In both cases, the ultimate fate of the majority of the (/sup 3/H)BaP and its metabolites was excretion in feces.

  16. Saharan versus local influence on atmospheric aerosol deposition in the southern Iberian Peninsula: Significance for N and P inputs

    NASA Astrophysics Data System (ADS)

    Morales-Baquero, Rafael; Pérez-Martínez, Carmen

    2016-03-01

    A novel methodology was used to evaluate the contribution of Saharan dust to the atmospheric deposition of particulate material (PM), total phosphorus (TP), and total nitrogen (TN) in the southeastern Iberian Peninsula. Dry and wet aerosol depositions were measured weekly during two 1 year periods at one site and simultaneously during spring-summer of the same years at two other sites (intersite distance of ~ 40 km). Statistical relationships among depositions at the different sites permitted differentiation of Saharan dust inputs from locally derived dust. PM and TP depositions were synchronous among the three study sites; the synchrony was elevated during periods of Saharan intrusions (evaluated by air mass retrotrajectories analyses), but no temporal correlation was observed during periods without Saharan intrusions. According to analysis of variance results, PM and TP depositions were both significantly affected by Saharan intrusions. During weeks with Saharan intrusions, PM deposition increased around 85% above background levels, with no differences among the three sites, while TP deposition increased by 1.1 µmol TP m-2 d-1, i.e., 29% to 81% above background levels depending on the site. There were no correlations or differences in TN deposition among sites or as a function of Saharan intrusion periods. The annual contribution of PM and TP from Saharan dust was 75 kg ha-1 and 0.07 kg P ha-1, respectively, which can be considered a genuine input for the ecosystems in this area. This novel approach is likely to be valid in any area in the world under atmospheric deposition of long-range transported material.

  17. Direct Deposition of Gas Phase Generated Aerosol Gold Nanoparticles into Biological Fluids - Corona Formation and Particle Size Shifts

    PubMed Central

    Svensson, Christian R.; Messing, Maria E.; Lundqvist, Martin; Schollin, Alexander; Deppert, Knut; Pagels, Joakim H.; Rissler, Jenny; Cedervall, Tommy

    2013-01-01

    An ongoing discussion whether traditional toxicological methods are sufficient to evaluate the risks associated with nanoparticle inhalation has led to the emergence of Air-Liquid interface toxicology. As a step in this process, this study explores the evolution of particle characteristics as they move from the airborne state into physiological solution. Airborne gold nanoparticles (AuNP) are generated using an evaporation-condensation technique. Spherical and agglomerate AuNPs are deposited into physiological solutions of increasing biological complexity. The AuNP size is characterized in air as mobility diameter and in liquid as hydrodynamic diameter. AuNP:Protein aggregation in physiological solutions is determined using dynamic light scattering, particle tracking analysis, and UV absorption spectroscopy. AuNPs deposited into homocysteine buffer form large gold-aggregates. Spherical AuNPs deposited in solutions of albumin were trapped at the Air-Liquid interface but was readily suspended in the solutions with a size close to that of the airborne particles, indicating that AuNP:Protein complex formation is promoted. Deposition into serum and lung fluid resulted in larger complexes, reflecting the formation of a more complex protein corona. UV absorption spectroscopy indicated no further aggregation of the AuNPs after deposition in solution. The corona of the deposited AuNPs shows differences compared to AuNPs generated in suspension. Deposition of AuNPs from the aerosol phase into biological fluids offers a method to study the protein corona formed, upon inhalation and deposition in the lungs in a more realistic way compared to particle liquid suspensions. This is important since the protein corona together with key particle properties (e.g. size, shape and surface reactivity) to a large extent may determine the nanoparticle effects and possible translocation to other organs. PMID:24086363

  18. Effects of mechanical properties of polymer on ceramic-polymer composite thick films fabricated by aerosol deposition.

    PubMed

    Kwon, Oh-Yun; Na, Hyun-Jun; Kim, Hyung-Jun; Lee, Dong-Won; Nam, Song-Min

    2012-01-01

    Two types of ceramic-polymer composite thick films were deposited on Cu substrates by an aerosol deposition process, and their properties were investigated to fabricate optimized ceramic-based polymer composite thick films for application onto integrated substrates with the advantage of plasticity. When polymers with different mechanical properties, such as polyimide (PI) and poly(methyl methacrylate) (PMMA), are used as starting powders together with α-Al2O3 powder, two types of composite films are formed with different characteristics - surface morphologies, deposition rates, and crystallite size of α-Al2O3. Through the results of micro-Vickers hardness testing, it was confirmed that the mechanical properties of the polymer itself are associated with the performances of the ceramic-polymer composite films. To support and explain these results, the microstructures of the two types of polymer powders were observed after planetary milling and an additional modeling test was carried out. As a result, we could conclude that the PMMA powder is distorted by the impact of the Al2O3 powder, so that the resulting Al2O3-PMMA composite film had a very small amount of PMMA and a low deposition rate. In contrast, when using PI powder, the Al2O3-PI composite film had a high deposition rate due to the cracking of PI particles. Consequently, it was revealed that the mechanical properties of polymers have a considerable effect on the properties of the resulting ceramic-polymer composite thick films.

  19. Influence of seed aerosol surface area and oxidation rate on vapor wall deposition and SOA mass yields: a case study with α-pinene ozonolysis

    NASA Astrophysics Data System (ADS)

    Nah, Theodora; McVay, Renee C.; Zhang, Xuan; Boyd, Christopher M.; Seinfeld, John H.; Ng, Nga L.

    2016-07-01

    Laboratory chambers, invaluable in atmospheric chemistry and aerosol formation studies, are subject to particle and vapor wall deposition, processes that need to be accounted for in order to accurately determine secondary organic aerosol (SOA) mass yields. Although particle wall deposition is reasonably well understood and usually accounted for, vapor wall deposition is less so. The effects of vapor wall deposition on SOA mass yields in chamber experiments can be constrained experimentally by increasing the seed aerosol surface area to promote the preferential condensation of SOA-forming vapors onto seed aerosol. Here, we study the influence of seed aerosol surface area and oxidation rate on SOA formation in α-pinene ozonolysis. The observations are analyzed using a coupled vapor-particle dynamics model to interpret the roles of gas-particle partitioning (quasi-equilibrium vs. kinetically limited SOA growth) and α-pinene oxidation rate in influencing vapor wall deposition. We find that the SOA growth rate and mass yields are independent of seed surface area within the range of seed surface area concentrations used in this study. This behavior arises when the condensation of SOA-forming vapors is dominated by quasi-equilibrium growth. Faster α-pinene oxidation rates and higher SOA mass yields are observed at increasing O3 concentrations for the same initial α-pinene concentration. When the α-pinene oxidation rate increases relative to vapor wall deposition, rapidly produced SOA-forming oxidation products condense more readily onto seed aerosol particles, resulting in higher SOA mass yields. Our results indicate that the extent to which vapor wall deposition affects SOA mass yields depends on the particular volatility organic compound system and can be mitigated through the use of excess oxidant concentrations.

  20. Addressing the ice nucleating abilities of marine aerosol: A combination of deposition mode laboratory and field measurements

    NASA Astrophysics Data System (ADS)

    Ladino, L. A.; Yakobi-Hancock, J. D.; Kilthau, W. P.; Mason, R. H.; Si, M.; Li, J.; Miller, L. A.; Schiller, C. L.; Huffman, J. A.; Aller, J. Y.; Knopf, D. A.; Bertram, A. K.; Abbatt, J. P. D.

    2016-05-01

    This study addresses, through two types of experiments, the potential for the oceans to act as a source of atmospheric ice-nucleating particles (INPs). The INP concentration via deposition mode nucleation was measured in situ at a coastal site in British Columbia in August 2013. The INP concentration at conditions relevant to cirrus clouds (i.e., -40 °C and relative humidity with respect to ice, RHice = 139%) ranged from 0.2 L-1 to 3.3 L-1. Correlations of the INP concentrations with levels of anthropogenic tracers (i.e., CO, SO2, NOx, and black carbon) and numbers of fluorescent particles do not indicate a significant influence from anthropogenic sources or submicron bioaerosols, respectively. Additionally, the INPs measured in the deposition mode showed a poor correlation with the concentration of particles with sizes larger than 500 nm, which is in contrast with observations made in the immersion freezing mode. To investigate the nature of particles that could have acted as deposition INP, laboratory experiments with potential marine aerosol particles were conducted under the ice-nucleating conditions used in the field. At -40 °C, no deposition activity was observed with salt aerosol particles (sodium chloride and two forms of commercial sea salt: Sigma-Aldrich and Instant Ocean), particles composed of a commercial source of natural organic matter (Suwannee River humic material), or particle mixtures of sea salt and humic material. In contrast, exudates from three phytoplankton (Thalassiosira pseudonana, Nanochloris atomus, and Emiliania huxleyi) and one marine bacterium (Vibrio harveyi) exhibited INP activity at low RHice values, down to below 110%. This suggests that the INPs measured at the field site were of marine biological origins, although we cannot rule out other sources, including mineral dust.

  1. Aerosol assisted chemical vapor deposition of In2O3 films from Me3In and donor functionalized alcohols.

    PubMed

    Basharat, Siama; Carmalt, Claire J; Barnett, Sarah A; Tocher, Derek A; Davies, Hywel O

    2007-10-29

    The reaction of Me3In and ROH (R = CH2CH2NMe2, CH(CH3)CH2NMe2, C(CH3)2CH2OMe, CH2CH2OMe) in toluene under aerosol assisted chemical vapor deposition (AACVD) conditions leads to the production of indium oxide thin films on glass. The indium oxide films were deposited at 550 degrees C and analyzed by scanning electron microscopy (SEM), X-ray powder diffraction, wavelength dispersive analysis of X-rays (WDX), X-ray photoelectron spectroscopy (XPS), and Raman spectroscopy. This CVD technique offers a rapid, convenient route to In2O3, which presumably involves the in situ formation of dimethylindium alkoxides, of the type [Me2InOR]2. In order to identify compounds present in the aerosol mist, the solution-phase reaction between Me3In and ROH (R = CH2CH2NMe2, C(CH3)2CH2OMe, CH(CH3)CH2NMe2, CH(CH2NMe2)2) at room temperature in toluene was carried out. Dimeric indium alkoxides, of the type [Me2In(OR)]2, were isolated, and their structures were determined by X-ray crystallography. PMID:17914814

  2. Impact of absorbing aerosol deposition on snow albedo reduction over the southern Tibetan plateau based on satellite observations

    NASA Astrophysics Data System (ADS)

    Lee, Wei-Liang; Liou, K. N.; He, Cenlin; Liang, Hsin-Chien; Wang, Tai-Chi; Li, Qinbin; Liu, Zhenxin; Yue, Qing

    2016-07-01

    We investigate the snow albedo variation in spring over the southern Tibetan Plateau induced by the deposition of light-absorbing aerosols using remote sensing data from moderate resolution imaging spectroradiometer (MODIS) aboard Terra satellite during 2001-2012. We have selected pixels with 100 % snow cover for the entire period in March and April to avoid albedo contamination by other types of land surfaces. A model simulation using GEOS-Chem shows that aerosol optical depth (AOD) is a good indicator for black carbon and dust deposition on snow over the southern Tibetan Plateau. The monthly means of satellite-retrieved land surface temperature (LST) and AOD over 100 % snow-covered pixels during the 12 years are used in multiple linear regression analysis to derive the empirical relationship between snow albedo and these variables. Along with the LST effect, AOD is shown to be an important factor contributing to snow albedo reduction. We illustrate through statistical analysis that a 1-K increase in LST and a 0.1 increase in AOD indicate decreases in snow albedo by 0.75 and 2.1 % in the southern Tibetan Plateau, corresponding to local shortwave radiative forcing of 1.5 and 4.2 W m-2, respectively.

  3. Use of the electrical aerosol detector as an indicator of the surface area of fine particles deposited in the lung.

    PubMed

    Wilson, William E; Stanek, John; Han, Hee-Siew Ryan; Johnson, Tim; Sakurai, Hiromu; Pui, David Y H; Turner, Jay; Chen, Da-Ren; Duthie, Scott

    2007-02-01

    Because of recent concerns about the health effects of ultrafine particles and the indication that particle toxicity is related to surface area, we have been examining techniques for measuring parameters related to the surface area of fine particles, especially in the 0.003- to 0.5-microm size range. In an earlier study, we suggested that the charge attached to particles, as measured by a prototype of the Electrical Aerosol Detector (EAD, TSI Inc., Model 3070), was related to the 1.16 power of the mobility diameter. An inspection of the pattern of particle deposition in the lung as a function of particle size suggested that the EAD measurement might be a useful indicator of the surface area of particles deposited in the lung. In this study, we calculate the particle surface area (micrometer squared) deposited in the lung per cubic centimeter of air inhaled as a function of particle size using atmospheric particle size distributions measured in Minneapolis, MN, and East St. Louis, IL. The correlations of powers of the mobility diameter, Dx, were highest for X = 1.1-1.6 for the deposited surface area and for X = 1.25 with the EAD signal. This overlap suggested a correspondence between the EAD signal and the deposited surface area. The correlation coefficients of the EAD signal and particle surface area deposited in the alveolar and tracheobronchial regions of the lung for three breathing patterns are in the range of Pearson's r = 0.91-0.95 (coefficient of determination, R2 = 0.82-0.90). These statistical relationships suggest that the EAD could serve as a useful indicator of particle surface area deposited in the lung in exposure and epidemiologic studies of the human health effects of atmospheric particles and as a measure of the potential surface area dose for the characterization of occupational environments.

  4. Effect of microgravity and hypergravity on deposition of 0.5- to 3-micron-diameter aerosol in the human lung

    NASA Technical Reports Server (NTRS)

    Darquenne, C.; Paiva, M.; West, J. B.; Prisk, G. K.

    1997-01-01

    We measured intrapulmonary deposition of 0. 5-, 1-, 2-, and 3-micron-diameter particles in four subjects on the ground (1 G) and during parabolic flights both in microgravity (microG) and at approximately 1.6 G. Subjects breathed aerosols at a constant flow rate (0.4 l/s) and tidal volume (0.75 liter). At 1 G and approximately 1.6 G, deposition increased with increasing particle size. In microG, differences in deposition as a function of particle size were almost abolished. Deposition was a nearly linear function of the G level for 2- and 3-micron-diameter particles, whereas for 0.5- and 1.0-micron-diameter particles, deposition increased less between microG and 1 G than between 1 G and approximately 1.6 G. Comparison with numerical predictions showed good agreement for 1-, 2-, and 3-micron-diameter particles at 1 and approximately 1.6 G, whereas the model consistently underestimated deposition in microG. The higher deposition observed in microG compared with model predictions might be explained by a larger deposition by diffusion because of a higher alveolar concentration of aerosol in microG and to the nonreversibility of the flow, causing additional mixing of the aerosols.

  5. Massive Volcanic SO2 Oxidation and Sulphate Aerosol Deposition in Cenozoic North America

    EPA Science Inventory

    Volcanic eruptions release a large amount of sulphur dioxide (SO2) into the atmosphere. SO2 is oxidized to sulphate and can subsequently form sulphate aerosol, which can affect the Earth's radiation balance, biologic productivity and high-altitude ozone co...

  6. Deposition and dispersion of 1-micrometer aerosol boluses in the human lung: effect of micro- and hypergravity.

    PubMed

    Darquenne, C; West, J B; Prisk, G K

    1998-10-01

    We performed bolus inhalations of 1-micrometer particles in four subjects on the ground (1 G) and during parabolic flights both in microgravity (microG) and in approximately 1.6 G. Boluses of approximately 70 ml were inhaled at different points in an inspiration from residual volume to 1 liter above functional residual capacity. The volume of air inhaled after the bolus [the penetration volume (Vp)] ranged from 200 to 1,500 ml. Aerosol concentration and flow rate were continuously measured at the mouth. The deposition, dispersion, and position of the bolus in the expired gas were calculated from these data. For Vp >/=400 ml, both deposition and dispersion increased with Vp and were strongly gravity dependent, with the greatest deposition and dispersion occurring for the largest G level. At Vp = 800 ml, deposition and dispersion increased from 33.9% and 319 ml in microG to 56.9% and 573 ml at approximately 1.6 G, respectively (P < 0.05). At each G level, the bolus was expired at a smaller volume than Vp, and this volume became smaller with increasing Vp. Although dispersion was lower in microG than in 1 G and approximately 1.6 G, it still increased steadily with increasing Vp, showing that nongravitational ventilatory inhomogeneity is partly responsible for dispersion in the human lung.

  7. Aerosol-assisted delivery of precursors for chemical vapour deposition: expanding the scope of CVD for materials fabrication.

    PubMed

    Marchand, Peter; Hassan, Iman A; Parkin, Ivan P; Carmalt, Claire J

    2013-07-14

    The production of thin films of materials has become the attention of a great deal of research throughout academia and industry worldwide owing to the array of applications which utilise them, including electronic devices, gas sensors, solar cells, window coatings and catalytic systems. Whilst a number of deposition techniques are in common use, chemical vapour deposition (CVD) is an attractive process for the production of a wide range of materials due to the control it offers over film composition, coverage and uniformity, even on large scales. Conventional CVD processes can be limited, however, by the need for suitably volatile precursors. Aerosol-assisted (AA)CVD is a solution-based process which relies on the solubility of the precursor, rather than its volatility and thus vastly extends the range of potentially applicable precursors. In addition, AACVD offers extra means to control film morphology and concurrently the properties of the deposited materials. In this perspective we discuss the AACVD process, the influence of deposition conditions on film characteristics and a number of materials and applications to which AACVD has been found beneficial. PMID:23629474

  8. Deposition and dispersion of 1-micrometer aerosol boluses in the human lung: effect of micro- and hypergravity

    NASA Technical Reports Server (NTRS)

    Darquenne, C.; West, J. B.; Prisk, G. K.

    1998-01-01

    We performed bolus inhalations of 1-micrometer particles in four subjects on the ground (1 G) and during parabolic flights both in microgravity (microG) and in approximately 1.6 G. Boluses of approximately 70 ml were inhaled at different points in an inspiration from residual volume to 1 liter above functional residual capacity. The volume of air inhaled after the bolus [the penetration volume (Vp)] ranged from 200 to 1,500 ml. Aerosol concentration and flow rate were continuously measured at the mouth. The deposition, dispersion, and position of the bolus in the expired gas were calculated from these data. For Vp >/=400 ml, both deposition and dispersion increased with Vp and were strongly gravity dependent, with the greatest deposition and dispersion occurring for the largest G level. At Vp = 800 ml, deposition and dispersion increased from 33.9% and 319 ml in microG to 56.9% and 573 ml at approximately 1.6 G, respectively (P < 0.05). At each G level, the bolus was expired at a smaller volume than Vp, and this volume became smaller with increasing Vp. Although dispersion was lower in microG than in 1 G and approximately 1.6 G, it still increased steadily with increasing Vp, showing that nongravitational ventilatory inhomogeneity is partly responsible for dispersion in the human lung.

  9. Estimation of sulfate trends at selected national park service sites: Does the wet deposition record parallel the aerosol record?

    SciTech Connect

    Shealy, R.T.; Bowersox, V.C.

    1997-12-31

    Recently temporal trends in sulfate concentration in fine-particle aerosols have been measured at a set of twelve National Park Service (NPS) sites using the Interagency Monitoring of Visual Environments (IMPROVE) network. Trends were computed for each climatological season over the period 1982-1993. The distribution of trend direction was nearly symmetric; of the 48 possible site-season combinations, 11 were negative, 8 positive, and the remainder exhibited no trend. These are surprising findings in the context of nearly constant SO{sub 2} emissions in the East over this period (EPA, 1991) and generally-decreasing trends over the entire US computed from wet deposition sulfate concentrations collected by the National Atmospheric Deposition Program/National Trends Network (NADP/NTN). Of particular interest are the three largest positive trends: Grand Canyon exhibited a 4.2% increase in winter, Great Smoky Mountains had an increase of 3.9% in summer, and Shenandoah had an increase of 3.7% in summer, Recently, the latter two sites have been studied over a period more recent than the original study (1982-1995) and the trends are smaller, but they remain positive. It has been suggested that these findings are a statistical artifact: that in a large set of trend tests over many sites and seasons, a few will by chance be found to have statistically significant positive trends, even under the condition of no trends.A special study was undertaken using the subset of the NPS sites with co-located IMPROVE and NADP/NTN samplers. Direct comparison of aerosol sulfur and wet deposition sulfate trends is done to determine their relationship to each other. The NPS sites that qualify as candidates in the study are: Shenandoah, Great Smoky Mountains, Glacier, Yosemite, Grand Canyon, Mesa Verde, and Big Bend Parks.

  10. Changes in future air quality, deposition, and aerosol-cloud interactions under future climate and emission scenarios

    NASA Astrophysics Data System (ADS)

    Glotfelty, Timothy; Zhang, Yang; Karamchandani, Prakash; Streets, David G.

    2016-08-01

    The prospect of global climate change will have wide scale impacts, such as ecological stress and human health hazards. One aspect of concern is future changes in air quality that will result from changes in both meteorological forcing and air pollutant emissions. In this study, the GU-WRF/Chem model is employed to simulate the impact of changing climate and emissions following the IPCC AR4 SRES A1B scenario. An average of 4 future years (2020, 2030, 2040, and 2050) is compared against an average of 2 current years (2001 and 2010). Under this scenario, by the Mid-21st century global air quality is projected to degrade with a global average increase of 2.5 ppb in the maximum 8-hr O3 level and of 0.3 μg m-3 in 24-hr average PM2.5. However, PM2.5 changes are more regional due to regional variations in primary aerosol emissions and emissions of gaseous precursor for secondary PM2.5. Increasing NOx emissions in this scenario combines with a wetter climate elevating levels of OH, HO2, H2O2, and the nitrate radical and increasing the atmosphere's near surface oxidation state. This differs from findings under the RCP scenarios that experience declines in OH from reduced NOx emissions, stratospheric recovery of O3, and increases in CH4 and VOCs. Increasing NOx and O3 levels enhances the nitrogen and O3 deposition, indicating potentially enhanced crop damage and ecosystem stress under this scenario. The enhanced global aerosol level results in enhancements in aerosol optical depth, cloud droplet number concentration, and cloud optical thickness. This leads to dimming at the Earth's surface with a global average reduction in shortwave radiation of 1.2 W m-2. This enhanced dimming leads to a more moderate warming trend and different trends in radiation than those found in NCAR's CCSM simulation, which does not include the advanced chemistry and aerosol treatment of GU-WRF/Chem and cannot simulate the impacts of changing climate and emissions with the same level of detailed

  11. A novel exposure system for the efficient and controlled deposition of aerosol particles onto cell cultures.

    PubMed

    Savi, Melanie; Kalberer, Markus; Lang, Doris; Ryser, Manuel; Fierz, Martin; Gaschen, Annina; Ricka, Jaroslav; Geiser, Marianne

    2008-08-01

    Epidemiologic studies have shown correlations between morbidity and particles < or = 2.5 microm generated from pollution processes and manufactured nanoparticles. Thereby nanoparticles seem to play a specific role. The interaction of particles with the lung, the main pathway of undesired particle uptake, is poorly understood. In most studies investigating these interactions in vitro, particle deposition differs greatly from the in vivo situation, causing controversial results. We present a nanoparticle deposition chamber to expose lung cells mimicking closely the particle deposition conditions in the lung. In this new deposition chamber, particles are deposited very efficiently, reproducibly, and uniformly onto the cell culture, a key aspect if cell responses are quantified in respect to the deposited particle number. In situ analyses of the lung cells, e.g., the ciliary beat frequency, indicative of the defense capability of the cells, are complemented by off-line biochemical, physiological, and morphological cell analyses.

  12. Gas-phase photoacoustic determination of the total carbon content of aerosol deposits.

    PubMed

    Pleil, J D; Russwurm, G M; McClenny, W A

    1982-01-01

    A prototype system was constructed to determine the total carbon content of ambient aerosols trapped on quartz fiber filters. The measurement technique is based on carbon combustion to CO(2), cryogenic precon-centration, and subsequent photoacoustic monitoring of produced CO(2). A common sample set was independently analyzed by two established combustion method instruments and the photoacoustic system. Statistical comparison of data showed good agreement with accepted carbon values indicating feasibility for photoacoustic application to routine carbon analysis. PMID:20372416

  13. Fabrication of LiCoO 2 cathode powder for thin film battery by aerosol flame deposition

    NASA Astrophysics Data System (ADS)

    Lee, Taewon; Cho, Kihyun; Oh, Jangwon; Shin, Dongwook

    Crystalline LiCoO 2 nano-particles for thin film battery were synthesized and deposited by aerosol flame deposition (AFD). The aqueous precursor solution of the lithium nitrate and cobalt acetate was atomized with an ultrasonic vibrator and subsequently carried into the central tube of the torch by flowing dry Ar gas. LiCoO 2 were formed by oxy-hydrogen flame and deposited on a substrate placed in a heating stage. The deposited soot film composed of nano-sized particles was subsequently consolidated into a dense film by high temperature heat treatment at 500-800 °C for 5 h and characterized by SEM, XRD, and Raman spectroscopy. The crystalline carbonates and oxide were first formed by the deposition and the subsequent heat treatment converted those to LiCoO 2. The FWHMs of the XRD peaks were reduced and their intensity increased as the heat treatment temperature increased, which is due to improved crystallinity. When judged from the low enough cation mixing and well-developed layered structure, it is believed that the LiCoO 2 film satisfied the quality standard for the real application. SEM measurements showed that LiCoO 2 were nano-crystalline structure with the average particle size <70 nm and the particle size increased with the increase of heat treatment temperature. The thickness of thin film LiCoO 2 before the consolidation process was about 15 μm and reduced to about 4 μm after sintering.

  14. Aerosol-assisted chemical vapor deposition of tungsten oxide films and nanorods from oxo tungsten(VI) fluoroalkoxide precursors.

    PubMed

    Kim, Hankook; Bonsu, Richard O; O'Donohue, Christopher; Korotkov, Roman Y; McElwee-White, Lisa; Anderson, Timothy J

    2015-02-01

    Aerosol-assisted chemical vapor deposition (AACVD) of WOx was demonstrated using the oxo tungsten(VI) fluoroalkoxide single-source precursors, WO[OCCH3(CF3)2]4 and WO[OC(CH3)2CF3]4. Substoichiometric amorphous tungsten oxide thin films were grown on indium tin oxide (ITO) substrates in nitrogen at low deposition temperature (100-250 °C). At growth temperatures above 300 °C, the W18O49 monoclinic crystalline phase was observed. The surface morphology and roughness, visible light transmittance, electrical conductivity, and work function of the tungsten oxide materials are reported. The solvent and carrier gas minimally affected surface morphology and composition at low deposition temperature; however, material crystallinity varied with solvent choice at higher temperatures. The work function of the tungsten oxide thin films grown between 150 and 250 °C was determined to be in the range 5.0 to 5.7 eV, according to ultraviolet photoelectron spectroscopy (UPS). PMID:25569472

  15. Three-dimensional model for aerosol transport and deposition in expanding and contracting alveoli.

    PubMed

    Balásházy, Imre; Hofmann, Werner; Farkas, Arpád; Madas, Balázs G

    2008-04-01

    Particle transport and deposition within a model alveolus, represented by a rhythmically expanding and contracting hemisphere, was modeled by a three-dimensional analytical model for the time-dependent air velocity field as a superposition of uniform and radial flow components, satisfying both the mass and momentum conservation equations. Trajectories of particles entrained in the airflow were calculated by a numerical particle trajectory code to compute simultaneously deposition by inertial impaction, gravitational sedimentation, Brownian diffusion, and interception. Five different orientations of the orifice of the alveolus relative to the direction of gravity were selected. Deposition was calculated for particles from 1 nm to 10 microm, for 3 breathing conditions, and for 5 different entrance times relative to the onset of inspiration. For the analyzed cases, the spatial orientation of the orifice of an alveolus has practically no effect on deposition for particles below about 0.1 microm, where deposition is dominated by Brownian motion. Above about 1 microm, where deposition is governed primarily by gravitational settling, deposition can vary from 0 to 100%, depending on the spatial orientation, while deposition of particles 0.1-1 microm falls between these two extreme cases. Due to the isotropic nature of Brownian motion, deposition of the 10-nm particles is practically uniform for all spatial orientations. However, for larger particles, deposition can be quite inhomogeneous, consistent with the direction of gravity. While nearly all particles are exhaled during the successive expiration phase, there are a few cases where particles still leave the alveolus even after many breathing cycles.

  16. Dielectric and Insulating Properties of Embedded Capacitor for Flexible Electronics Prepared by Aerosol-Type Nanoparticle Deposition

    NASA Astrophysics Data System (ADS)

    Imanaka, Yoshihiko; Amada, Hideyuki; Kumasaka, Fumiaki

    2013-05-01

    The rapid evolution in electronic equipment has created a demand for advanced devices that are flexible, thin, and light in weight. This demand is driving the development of a core technology for flexible and stretchable electronic devices. To produce wearable computers, we need to fabricate functional membranes that contain passive devices, such as capacitors and resistors, on resin sheets at low temperatures. These sheets can then serve as mounting boards for various electronic devices. By improving the technique for room-temperature aerosol-type nanoparticle deposition of a ceramic material, we have established a technology for forming a dielectric inorganic BaTiO3 film with an excellent degree of crystallinity and favorable electric properties for use in the production of flexible and stretchable electronic devices on a polyimide sheet. By this method of forming a homogeneous nanoparticle structure inside a film, we produced a capacitor film with a dielectric constant of 200 on a polyimide sheet at room temperature.

  17. Volatility dependence of Henry's law constants of condensable organics: Application to estimate depositional loss of secondary organic aerosols

    NASA Astrophysics Data System (ADS)

    Hodzic, A.; Aumont, B.; Knote, C.; Lee-Taylor, J.; Madronich, S.; Tyndall, G.

    2014-07-01

    The water solubility of oxidation intermediates of volatile organic compounds that can condense to form secondary organic aerosol (SOA) is largely unconstrained in current chemistry-climate models. We apply the Generator of Explicit Chemistry and Kinetics of Organics in the Atmosphere to calculate Henry's law constants for these intermediate species. Results show a strong negative correlation between Henry's law constants and saturation vapor pressures. Details depend on precursor species, extent of photochemical processing, and NOx levels. Henry's law constants as a function of volatility are made available over a wide range of vapor pressures for use in 3-D models. In an application using the Weather Research and Forecasting model coupled with Chemistry (WRF-Chem) over the U.S. in summer, we find that dry (and wet) deposition of condensable organic vapors leads to major reductions in SOA, decreasing surface concentrations by ~50% (10%) for biogenic and ~40% (6%) for short chain anthropogenic precursors under the considered volatility conditions.

  18. ANALYSIS OF RESPIRATORY DEPOSITION OF INHALED PARTICLES FOR DIFFERENT DOSE METRICS: COMPARISON OF NUMBER, SURFACE AREA AND MASS DOSE OF TYPICAL AMBIENT BI-MODAL AEROSOLS

    EPA Science Inventory

    ANALYSIS OF RESPIRATORY DEPOSITION OF INHALED PARTICLES FOR DIFFERENT DOSE METRICS: COMPARISON OF NUMBER, SURFACE AREA AND MASS DOSE OF TYPICAL AMBIENT BI-MODAL AEROSOLS.
    Chong S. Kim, SC. Hu*, PA Jaques*, US EPA, National Health and Environmental Effects Research Laboratory, ...

  19. Mass movement deposit and Tsunami in Lake Geneva (Switzerland-France) caused by a rockslide in 563 AD

    NASA Astrophysics Data System (ADS)

    Kremer, K.; Simpson, G.; Girardclos, S.

    2012-04-01

    Steep continental margins are known to collapse, producing submarine landslides that can generate Tsunamis. At smaller scale, the same can happen in lake basins. Lake sediments are excellent archives of such events. The study of mass movement deposits in lake sediments allows a better knowledge of past natural hazards in intracontinental regions at historic and prehistoric timescales. In Lake Geneva (Switzerland-France), more than 100 km of high resolution seismic reflection profiles reveal two distinct sequences in the lakes' late Holocene sedimentation history. The first sequence consists mainly of a succession of five large lens-shaped seismic units (A to E), characterized by transparent/chaotic seismic facies with irregular lower boundaries, interpreted as mass-movement deposits. These units are interbedded with parallel, continuous and strong amplitude reflections, interpreted as the 'background' lake sediment. The largest and most recent unit (E) is 5 m thick, covers an area of 50 km2 and has an estimated minimum volume of 0.25 km3, making it the largest sub-lacustrine mass-movement unit in Switzerland. The second sediment sequence consists of 5 m of 'background' seismic facies with parallel geometry, varying at small scale between chaotic/transparent and continuous, high amplitude reflections, which is interpreted as alternating turbidite and hemipelagic layers, respectively. Four 10 m long sediment cores confirm the seismic interpretation and show that the 5 m thick deposit can be described as a co-genetic debrite turbidite (Talling et al., 2004). Radiocarbon dating of plant macro-remains reveals that the unit E deposit may be linked to the Tauredunum rockslide of 563 AD in Rhone delta area. The induced sediment failure in the Rhone delta triggered a tsunami wave destroying parts of the Geneva Burgudian city and other villages at the lake borders as described in historical records. Numerical simulations, based on the shallow water equations, performed here

  20. Phreatomagmatic and phreatic fall and surge deposits from explosions at Kilauea volcano, Hawaii, 1790 a.d.: Keanakakoi Ash Member

    USGS Publications Warehouse

    McPhie, J.; Walker, G.P.L.; Christiansen, R.L.

    1990-01-01

    In or around 1790 a.d. an explosive eruption took place in the summit caldera of Kilauea shield volcano. A group of Hawaiian warriors close to the caldera at the time were killed by the effects of the explosions. The stratigraphy of pyroclastic deposits surrounding Kilauea (i.e., the Keanakakoi Ash Member) suggests that the explosions referred to in the historic record were the culmination of a prolonged hydrovolcanic eruption consisting of three main phases. The first phase was phreatomagmatic and generated well-bedded, fine fallout ash rich in glassy, variably vesiculated, juvenile magmatic and dense, lithic pyroclasts. The ash was mainly dispersed to the southwest of the caldera by the northeasterly trade winds. The second phase produced a Strombolian-style scoria fall deposit followed by phreatomagmatic ash similar to that of the first phase, though richer in accretionary lapilli and lithics. The third and culminating phase was phreatic and deposited lithic-rich lapilli and block fall layers, interbedded with cross-bedded surge deposits, and accretionary lapilli-rich, fine ash beds. These final explosions may have been responsible for the deaths of the warriors. The three phases were separated by quiescent spells during which the primary deposits were eroded and transported downwind in dunes migrating southwestward and locally excavated by fluvial runoff close to the rim. The entire hydrovolcanic eruption may have lasted for weeks or perhaps months. At around the same time, lava erupted from Kilauea's East Rift Zone and probably drained magma from the summit storage. The earliest descriptions of Kilauea (30 years after the Keanakakoi eruption) emphasize the great depth of the floor (300-500 m below the rim) and the presence of stepped ledges. It is therefore likely that the Keanakakoi explosions were deepseated within Kilauea, and that the vent rim was substantially lower than the caldera rim. The change from phreatomagmatic to phreatic phases may reflect the

  1. The effect of dry and wet deposition of condensable vapors on secondary organic aerosols concentrations over the continental US

    DOE PAGES

    Knote, C.; Hodzic, A.; Jimenez, J. L.

    2015-01-06

    The effect of dry and wet deposition of semi-volatile organic compounds (SVOCs) in the gas phase on the concentrations of secondary organic aerosol (SOA) is reassessed using recently derived water solubility information. The water solubility of SVOCs was implemented as a function of their volatility distribution within the WRF-Chem regional chemistry transport model, and simulations were carried out over the continental United States for the year 2010. Results show that including dry and wet removal of gas-phase SVOCs reduces annual average surface concentrations of anthropogenic and biogenic SOA by 48 and 63% respectively over the continental US. Dry deposition ofmore » gas-phase SVOCs is found to be more effective than wet deposition in reducing SOA concentrations (−40 vs. −8% for anthropogenics, and −52 vs. −11% for biogenics). Reductions for biogenic SOA are found to be higher due to the higher water solubility of biogenic SVOCs. The majority of the total mass of SVOC + SOA is actually deposited via the gas phase (61% for anthropogenics and 76% for biogenics). Results are sensitive to assumptions made in the dry deposition scheme, but gas-phase deposition of SVOCs remains crucial even under conservative estimates. Considering reactivity of gas-phase SVOCs in the dry deposition scheme was found to be negligible. Further sensitivity studies where we reduce the volatility of organic matter show that consideration of gas-phase SVOC removal still reduces average SOA concentrations by 31% on average. We consider this a lower bound for the effect of gas-phase SVOC removal on SOA concentrations. A saturation effect is observed for Henry's law constants above 108 M atm−1, suggesting an upper bound of reductions in surface level SOA concentrations by 60% through removal of gas-phase SVOCs. Other models that do not consider dry and wet removal of gas-phase SVOCs would hence overestimate SOA concentrations by roughly 50%. Assumptions about the water solubility

  2. The effect of dry and wet deposition of condensable vapors on secondary organic aerosols concentrations over the continental US

    NASA Astrophysics Data System (ADS)

    Knote, C.; Hodzic, A.; Jimenez, J. L.

    2015-01-01

    The effect of dry and wet deposition of semi-volatile organic compounds (SVOCs) in the gas phase on the concentrations of secondary organic aerosol (SOA) is reassessed using recently derived water solubility information. The water solubility of SVOCs was implemented as a function of their volatility distribution within the WRF-Chem regional chemistry transport model, and simulations were carried out over the continental United States for the year 2010. Results show that including dry and wet removal of gas-phase SVOCs reduces annual average surface concentrations of anthropogenic and biogenic SOA by 48 and 63% respectively over the continental US. Dry deposition of gas-phase SVOCs is found to be more effective than wet deposition in reducing SOA concentrations (-40 vs. -8% for anthropogenics, and -52 vs. -11% for biogenics). Reductions for biogenic SOA are found to be higher due to the higher water solubility of biogenic SVOCs. The majority of the total mass of SVOC + SOA is actually deposited via the gas phase (61% for anthropogenics and 76% for biogenics). Results are sensitive to assumptions made in the dry deposition scheme, but gas-phase deposition of SVOCs remains crucial even under conservative estimates. Considering reactivity of gas-phase SVOCs in the dry deposition scheme was found to be negligible. Further sensitivity studies where we reduce the volatility of organic matter show that consideration of gas-phase SVOC removal still reduces average SOA concentrations by 31% on average. We consider this a lower bound for the effect of gas-phase SVOC removal on SOA concentrations. A saturation effect is observed for Henry's law constants above 108 M atm-1, suggesting an upper bound of reductions in surface level SOA concentrations by 60% through removal of gas-phase SVOCs. Other models that do not consider dry and wet removal of gas-phase SVOCs would hence overestimate SOA concentrations by roughly 50%. Assumptions about the water solubility of SVOCs made in

  3. Multiscale Airflow Model and Aerosol Deposition in Healthy and Emphysematous Rat Lungs

    NASA Astrophysics Data System (ADS)

    Oakes, Jessica; Marsden, Alison; Grandmont, Celine; Darquenne, Chantal; Vignon-Clementel, Irene

    2012-11-01

    The fate of aerosol particles in healthy and emphysematic lungs is needed to determine the toxic or therapeutic effects of inhalable particles. In this study we used a multiscale numerical model that couples a 0D resistance and capacitance model to 3D airways generated from MR images. Airflow simulations were performed using an in-house 3D finite element solver (SimVascular, simtk.org). Seven simulations were performed; 1 healthy, 1 uniform emphysema and 5 different cases of heterogeneous emphysema. In the heterogeneous emphysema cases the disease was confined to a single lobe. As a post processing step, 1 micron diameter particles were tracked in the flow field using Lagrangian particle tracking. The simulation results showed that the inhaled flow distribution was equal for the healthy and uniform emphysema cases. However, in the heterogeneous emphysema cases the delivery of inhaled air was larger in the diseased lobe. Additionally, there was an increase in delivery of aerosol particles to the diseased lobe. This suggests that as the therapeutic particles would reach the diseased areas of the lung, while toxic particles would increasingly harm the lung. The 3D-0D model described here is the first of its kind to be used to study healthy and emphysematic lungs. NSF Graduate Fellowship (Oakes), Burroughs Wellcome Fund (Marsden, Oakes) 1R21HL087805-02 from NHLBI at NIH, INRIA Team Grant.

  4. HCl in rocket exhaust clouds - Atmospheric dispersion, acid aerosol characteristics, and acid rain deposition

    NASA Technical Reports Server (NTRS)

    Pellett, G. L.; Sebacher, D. I.; Bendura, R. J.; Wornom, D. E.

    1983-01-01

    Both measurements and model calculations of the temporal dispersion of peak HCl (g + aq) concentration in Titan III exhaust clouds are found to be well characterized by one-term power-law decay expressions. The respective coefficients and decay exponents, however, are found to vary widely with meteorology. The HCl (g), HCl (g + aq), dewpoint, and temperature-pressure-altitude data for Titan III exhaust clouds are consistent with accurately calculated HCl/H2O vapor-liquid compositions for a model quasi-equilibrated flat surface aqueous aerosol. Some cloud evolution characteristics are also defined. Rapid and extensive condensation of aqueous acid clearly occurs during the first three min of cloud rise. Condensation is found to be intensified by the initial entrainment of relatively moist ambient air from lower levels, that is, from levels below eventual cloud stabilization. It is pointed out that if subsequent dilution air at stabilization altitude is significantly drier, a state of maximum condensation soon occurs, followed by an aerosol evaporation phase.

  5. Numerical simulation of inhaled aerosol particle deposition within 3D realistic human upper respiratory tract

    NASA Astrophysics Data System (ADS)

    Lin, J.; Fan, J. R.; Zheng, Y. Q.; Hu, G. L.; Pan, D.

    2010-03-01

    Computational fluid dynamics (CFD) simulations of airflow and particle deposition in the upper respiratory tract (URT) were conducted in this paper. Based on the CT (Computerized Tomography) scanned images of a 19-years-old healthy boy, a realistic geometric model of URT from oral cavity to the upper six-generation bronchial is rebuilt. To investigate airflow and particle deposition in the obtained realistic human upper respiratory tract, RNG k-ɛ turbulence model was used to describe the primary flow and particle deposition under three breathing intensity such as 15 L/min, 30 L/min and 60 L/min. The particle is tracked and analyzed in the Lagrangian frame. The velocity fields of airflow under different airflow rates were computed and discussed. In order to study the characteristics of particles movement and the effect of particles diameter on the deposition pattern, eleven kinds of sphere particles with different diameters are selected as research object. The diameters of selected particles as follows: 0.1 μm, 0.5 μm, 1 μm, 2.5 μm, 3 μm, 3.5 μm, 4 μm, 4.5 μm, 5 μm, 6.5 μm and 8 μm. The variation of inhalable particles deposition in realistic human upper respiratory tract with respiratory intensity and particle size was researched and compared. Furthermore, the more real inhalable particles with Rosin-Rammler mass distribution are used to study the effect of particles size. The deposition rate of particles with the different diameter scope in the different part of upper respiratory tract was summarized. The geometrical model based images technology promises to provide more real results of airflow field and particle deposition in the URT.

  6. Comparison of methods for evaluation of aerosol deposition in the model of human lungs

    NASA Astrophysics Data System (ADS)

    Belka, Miloslav; Lippay, Josef; Lizal, Frantisek; Jedelsky, Jan; Jicha, Miroslav

    2014-03-01

    It seems to be very convenient to receive a medicine by inhalation instead of injection. Unfortunately transport of particles and targeted delivery of a drug in human respiratory airways is very complicated task. Therefore we carried out experiments and tested different methods for evaluation of particle deposition in a model of human lungs. The model included respiratory airways from oral cavity to 7th generation of branching. Particles were dispersed by TSI Small-scale Powder Disperser 3433 and delivered to the model. The model was disassembled into segments after the deposition of the particles and local deposition was measured. Two methods were used to analyse the samples, fluorescence spectroscopy and optical microscopy. The first method was based on measuring the intensity of luminescence, which represented the particle deposition. The second method used the optical microscope with phase-contrast objective. A dispersion of isopropanol and particles was filtrated using a vacuum filtration unit, a filter was placed on glass slide and made transparent. The particles on the filter were counted manually and the deposition was calculated afterwards. The results of the methods were compared and both methods proved to be useful.

  7. Influence of dust loading on the alpha-particle energy resolution of continuous air monitors for thin deposits of radioactive aerosols.

    PubMed

    Huang, Suilou; Schery, Stephen D; Alcantara, Raul E; Rodgers, John C; Wasiolek, Piotr T

    2002-12-01

    Alpha-particle continuous air monitors must sometimes be operated in dusty environments where significant dust loading of the filter can be anticipated. It is important to understand how this dust loading affects the response of the continuous air monitors. Not only must a filter be changed if there is a reduction in airflow, but a change may be necessary if the energy resolution deteriorates and the continuous air monitor loses sensitivity and specificity for the radioactive aerosols of interest. A series of experiments were conducted to investigate alpha-particle energy resolution of continuous air monitor filters, particularly under dust loading conditions. Aerosol particles of various sizes were tagged with radon decay products to serve as surrogates for radioactive aerosols of interest such as plutonium or uranium. While the size of radioactive aerosols, filter type, and dust type affected the energy resolution, the thickness of an underlying (nonradioactive) dust layer did not show significant effect for the materials studied and a loading range of 0.01-10 mg x cm(-2). Our results indicate that it is possible for continuous air monitors to detect the release of radioactive aerosols with little deterioration in energy resolution under conditions of significant dust loading provided that the deposited layer of radioactive aerosols remains thin (< or = 0.1 mg x cm(-2)).

  8. Synthesis and characterization of LiNbO3 nanocrystals prepared by the aerosol assisted chemical vapor deposition method

    NASA Astrophysics Data System (ADS)

    Ocón, J. A.; Murillo, J. G.; Miki-Yoshida, M.; Cardoza, M. N.; Contreras-López, O. E.

    2014-12-01

    This work reports the synthesis of LiNbO3 nanocrystals by an aerosol assisted chemical vapor deposition method, onto silicon (0 0 1) substrates. Some of the nanocrystals showed a hexagonal morphology and characteristic sizes ranging from a few tens to a few hundreds of nanometers. The nanocrystals with hexagonal structure were obtained at 773 K using a carrier gas flow of 6 L/min and a deposition time of 90 min. Structural, morphological, photoluminescence and cathodoluminescence properties were studied by grazing incidence X-ray diffraction, scanning electron microscopy, high resolution transmission electron microscopy, fluorospectrometry, and cathodoluminescence, respectively. An extraordinary violet luminescence at 396 nm with excitation in UV region (280 nm) was observed in one of the samples. Cathodoluminescence (CL) imaging and spectroscopy studies of the nanocrystals exhibit stimulated emission of light in the near ultraviolet-violet-green spectral region. The emission peaks in CL spectra varied according to the nature of nanoparticles. A red-shift in the CL spectra with a decrease in the particle size was observed. Apparently the size of LiNbO3 typical nanocrystals investigated in this work has tuned the photoluminescence emission. This result encourages the use and integration of LiNbO3 nanocrystals into nanophotonics applications.

  9. Tris(phosphino)borato silver(I) complexes as precursors for metallic silver aerosol-assisted chemical vapor deposition.

    PubMed

    McCain, Matthew N; Schneider, Sven; Salata, Michael R; Marks, Tobin J

    2008-04-01

    A series of light- and air-stable tris(phosphino)borato silver(I) complexes has been synthesized, structurally and spectroscopically characterized, and implemented in the growth of low resistivity metallic silver thin films by aerosol-assisted chemical vapor deposition (AACVD). Of the four complexes in the series, [RB(CH2PR'2) 3]AgPEt3 (R = Ph (1, 3), (n)Bu (2, 4); R' = Ph (1, 2), (i)Pr (3, 4), complexes 1 and 2 have been characterized by single-crystal X-ray diffraction. Complex 2 represents a significant improvement over previously available nonfluorinated Ag precursors, owing to ease of handling and efficient film deposition characteristics. Thermogravimetric analysis (TGA) shows that the thermolytic properties of these complexes can be significantly modified by altering the ligand structure. Polycrystalline cubic-phase Ag thin films were grown on glass, MgO(100), and 52100 steel substrates. Ag films of thicknesses 3 microm, grown at rates of 14-18 nm/min, exhibit low levels of extraneous element contamination by X-ray photoelectron spectroscopy (XPS). Atomic force microscopy (AFM) and scanning electron microscopy (SEM) indicate that film growth proceeds primarily via an island growth (Volmer-Weber) mechanism. PMID:18293915

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

    NASA Astrophysics Data System (ADS)

    Hienola, A. I.; Pietikäinen, J.-P.; Jacob, D.; Pozdun, R.; Petäjä, T.; Hyvärinen, A.-P.; Kerminen, V.-M.; Kulmala, M.; Laaksonen, A.

    2012-09-01

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

  11. Cellular response to the deposition of diesel exhaust particle aerosols onto human lung cells grown at the air-liquid interface by inertial impaction.

    PubMed

    Cooney, Daniel J; Hickey, Anthony J

    2011-12-01

    The pathogenesis of disease resulting from exposure to diesel exhaust particles (DEP) is often studied using cultured lung cells. Frequently, researchers expose cells to DEP by spiking a suspension of particles in liquid onto the apical surface. This is not representative of in vivo exposure, where aerosols are deposited onto cell surfaces at the air-liquid interface (ALI). Inertial impaction provides an opportunity to deliver high doses of particles with aerodynamic diameters>∼1 μm to the surface of cells in seconds in a reproducible and predictable manner. A custom device was constructed to deposit DEP aerosols onto the surface of Calu-3 and A549 cells grown at the ALI. The pro-inflammatory and toxic cellular response to exposure to the deposited DEP aerosols was measured and compared to the response of cells exposed to DEP as suspensions. Calu-3 cells showed evidence of an oxidative stress response for both exposure types, while there was strong evidence to suggest that the method of aerosol delivery was harmful to the A549 cells.

  12. 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

  13. Influence of dry deposition of semi-volatile organic compounds (VOC) on secondary organic aerosol (SOA) formation in the Mexico City plume

    NASA Astrophysics Data System (ADS)

    Hodzic, Alma; Madronich, Sasha; Aumont, Bernard; Lee-Taylor, Julia; Karl, Thomas

    2013-04-01

    The dry deposition removal of organic compounds from the atmosphere and its impact on organic aerosol mass is currently unexplored and unaccounted for in chemistry-climate models. The main reason for this omission is that current models use simplified SOA mechanisms that lump precursors and their products into volatility bins, therefore losing information on other important properties of individual molecules (or groups) that are needed to calculate dry deposition. In this study, we apply the Generator of Explicit Chemistry and Kinetics of Organics in the Atmosphere (GECKO-A) to simulate SOA formation and estimate the influence of dry deposition of VOCs on SOA concentrations downwind of Mexico City. SOA precursors considered here include short- and long-chain alkanes (C3-25), alkenes, and light aromatics. The results suggest that 90% of SOA produced in Mexico City originates from the oxidation and partitioning of long-chain (C>12) alkanes, while the regionally exported SOA is almost equally produced from long-chain alkanes and from shorter alkanes and light aromatics. We show that dry deposition of oxidized gases is not an efficient sink for SOA, as it removes <5% of SOA within the city's boundary layer and ~15% downwind. We discuss reasons for this limited influence, and investigate separately the impacts on short and long-chain species. We show that the dry deposition is competing with the uptake of gases to the aerosol phase, and because dry deposition of submicron aerosols is slow, condensation onto particles protects organic gases from deposition and therefore increases their atmospheric burden and lifetime. In the absence of this condensation, ~50% of the regionally produced mass would have been dry-deposited.

  14. Bi-directional nasal delivery of aerosols can prevent lung deposition.

    PubMed

    Djupesland, Per Gisle; Skretting, Arne; Winderen, Mette; Holand, Trond

    2004-01-01

    Nasal delivery of drugs and vaccines has important advantages compared to injection and oral administration, and is being considered for a widening range of vaccines and substances with topical and systemic action. Traditional nasal delivery technologies are, however, trapped in the dilemma between achieving improved nasal distribution and limiting deposition in the lower airways. The novel bi-directional nasal delivery concept takes advantage of the posterior connection between the nasal passages persisting when the soft palate automatically closes during oral exhalation. Exhalation into the delivery device triggers release of liquid or powder particles into an airflow, which enters one nostril via a sealing nozzle and exits through the other nostril. In a study of 16 healthy subjects using 99mTc labeled nebulized particles with a mean particle size of 3.5 microm, delivery with this novel concept showed no or minimal lung deposition (0.8 +/- 2.0% (range -4.1% to 5.6%) for bi-directional delivery, whereas significant fractions were deposited in the lungs in all 16 subjects (mean 22.3 +/- 8.1%, range 12.2-39.3%) following conventional nasal inhalation (p < 0.0005). In the latter case, the fraction deposited in the lungs correlated significantly (r2 = 0.47, p < 0.004) with the volume of the nasal passages. The bi-directional nasal delivery concept minimizes the risks and problems related to lung deposition occurring during conventional nasal inhalation from a nebulizer and opens up a new range of opportunities for nasal delivery of drugs and vaccines.

  15. Microstructural, chemical and textural characterization of ZnO nanorods synthesized by aerosol assisted chemical vapor deposition

    SciTech Connect

    Sáenz-Trevizo, A.; Amézaga-Madrid, P.; Fuentes-Cobas, L.; Pizá-Ruiz, P.; Antúnez-Flores, W.; Ornelas-Gutiérrez, C.; Pérez-García, S.A.; Miki-Yoshida, M.

    2014-12-15

    ZnO nanorods were synthesized by aerosol assisted chemical vapor deposition onto TiO{sub 2} covered borosilicate glass substrates. Deposition parameters were optimized and kept constant. Solely the effect of different nozzle velocities on the growth of ZnO nanorods was evaluated in order to develop a dense and uniform structure. The crystalline structure was characterized by conventional X-ray diffraction in grazing incidence and Bragg–Brentano configurations. In addition, two-dimensional grazing incidence synchrotron radiation diffraction was employed to determine the preferred growth direction of the nanorods. Morphology and growth characteristics analyzed by electron microscopy were correlated with diffraction outcomes. Chemical composition was established by X-ray photoelectron spectroscopy. X-ray diffraction results and X-ray photoelectron spectroscopy showed the presence of wurtzite ZnO and anatase TiO{sub 2} phases. Morphological changes noticed when the deposition velocity was lowered to the minimum, indicated the formation of relatively vertically oriented nanorods evenly distributed onto the TiO{sub 2} buffer film. By coupling two-dimensional X-ray diffraction and computational modeling with ANAELU it was proved that a successful texture determination was achieved and confirmed by scanning electron microscopy analysis. Texture analysis led to the conclusion of a preferred growth direction in [001] having a distribution width Ω = 20° ± 2°. - Highlights: • Uniform and pure single-crystal ZnO nanorods were obtained by AACVD technique. • Longitudinal and transversal axis parallel to the [001] and [110] directions, respectively. • Texture was determined by 2D synchrotron diffraction and electron microscopy analysis. • Nanorods have its [001] direction distributed close to the normal of the substrate. • Angular spread about the preferred orientation is 20° ± 2°.

  16. The effect of dry and wet deposition of condensable vapors on secondary organic aerosols concentrations over the continental US

    DOE PAGES

    Knote, C.; Hodzic, A.; Jimenez, J. L.

    2014-05-26

    The effect of dry and wet deposition of semi-volatile organic compounds (SVOC) in the gas-phase on the concentrations of secondary organic aerosol (SOA) is reassessed using recently derived water solubility information. The water solubility of SVOCs was implemented as a function of their volatility distribution within the regional chemistry transport model WRF-Chem, and simulations were carried out over the continental United States for the year 2010. Results show that including dry and wet removal of gas-phase SVOCs reduces annual average surface concentrations of anthropogenic and biogenic SOA by 48% and 63% respectively over the continental US Dry deposition of gas-phasemore » SVOCs is found to be more effective than wet deposition in reducing SOA concentrations (−40% vs. −8% for anthropogenics, −52% vs. −11% for biogenics). Reductions for biogenic SOA are found to be higher due to the higher water solubility of biogenic SVOCs. The majority of the total mass of SVOC + SOA is actually deposited via the gas-phase (61% for anthropogenics, 76% for biogenics). A number of sensitivity studies shows that this is a robust feature of the modeling system. Other models that do not consider dry and wet removal of gas-phase SVOCs would hence overestimate SOA concentrations by roughly 50%. Assumptions about the water solubility of SVOCs made in some current modeling systems (H* = 105 M atm−1; H* = H* (HNO3)) still lead to an overestimation of 25% / 10% compared to our best estimate. A saturation effect is observed for Henry's law constants above 108 M atm−1, suggesting an upper bound of reductions in surface level SOA concentrations by 60% through removal of gas-phase SVOCs. Considering reactivity of gas-phase SVOCs in the dry deposition scheme was found to be negligible. Further sensitivity studies where we reduce the volatility of organic matter show that consideration of gas-phase SVOC removal still reduces average SOA concentrations by 31% on average. We

  17. The effect of dry and wet deposition of condensable vapors on secondary organic aerosols concentrations over the continental US

    NASA Astrophysics Data System (ADS)

    Knote, C.; Hodzic, A.; Jimenez, J. L.

    2014-05-01

    The effect of dry and wet deposition of semi-volatile organic compounds (SVOC) in the gas-phase on the concentrations of secondary organic aerosol (SOA) is reassessed using recently derived water solubility information. The water solubility of SVOCs was implemented as a function of their volatility distribution within the regional chemistry transport model WRF-Chem, and simulations were carried out over the continental United States for the year 2010. Results show that including dry and wet removal of gas-phase SVOCs reduces annual average surface concentrations of anthropogenic and biogenic SOA by 48% and 63% respectively over the continental US Dry deposition of gas-phase SVOCs is found to be more effective than wet deposition in reducing SOA concentrations (-40% vs. -8% for anthropogenics, -52% vs. -11% for biogenics). Reductions for biogenic SOA are found to be higher due to the higher water solubility of biogenic SVOCs. The majority of the total mass of SVOC + SOA is actually deposited via the gas-phase (61% for anthropogenics, 76% for biogenics). A number of sensitivity studies shows that this is a robust feature of the modeling system. Other models that do not consider dry and wet removal of gas-phase SVOCs would hence overestimate SOA concentrations by roughly 50%. Assumptions about the water solubility of SVOCs made in some current modeling systems (H* = 105 M atm-1; H* = H* (HNO3)) still lead to an overestimation of 25% / 10% compared to our best estimate. A saturation effect is observed for Henry's law constants above 108 M atm-1, suggesting an upper bound of reductions in surface level SOA concentrations by 60% through removal of gas-phase SVOCs. Considering reactivity of gas-phase SVOCs in the dry deposition scheme was found to be negligible. Further sensitivity studies where we reduce the volatility of organic matter show that consideration of gas-phase SVOC removal still reduces average SOA concentrations by 31% on average. We consider this a lower

  18. Controlling pyridinic, pyrrolic, graphitic, and molecular nitrogen in multi-wall carbon nanotubes using precursors with different N/C ratios in aerosol assisted chemical vapor deposition.

    PubMed

    Bulusheva, L G; Okotrub, A V; Fedoseeva, Yu V; Kurenya, A G; Asanov, I P; Vilkov, O Y; Koós, A A; Grobert, N

    2015-10-01

    Nitrogen-containing multi-wall carbon nanotubes (N-MWCNTs) were synthesized using aerosol assisted chemical vapor deposition (CVD) techniques in conjunction with benzylamine:ferrocene or acetonitrile:ferrocene mixtures. Different amounts of toluene were added to these mixtures in order to change the N/C ratio of the feedstock. X-ray photoelectron and near-edge X-ray absorption fine structure spectroscopy detected pyridinic, pyrrolic, graphitic, and molecular nitrogen forms in the N-MWCNT samples. Analysis of the spectral data indicated that whilst the nature of the nitrogen-containing precursor has little effect on the concentrations of the different forms of nitrogen in N-MWCNTs, the N/C ratio in the feedstock appeared to be the determining factor. When the N/C ratio was lower than ca. 0.01, all four forms existed in equal concentrations, for N/C ratios above 0.01, graphitic and molecular nitrogen were dominant. Furthermore, higher concentrations of pyridinic nitrogen in the outer shells and N2 molecules in the core of the as-produced N-MWCNTs suggest that the precursors were decomposed into individual atoms, which interacted with the catalyst surface to form CN and NH species or in fact diffused through the bulk of the catalyst particles. These findings are important for a better understanding of possible growth mechanisms for heteroatom-containing carbon nanotubes (CNTs) and therefore paving the way for controlling the spatial distribution of foreign elements in the CNTs using CVD processes. PMID:26104737

  19. Transport and deposition of pyroclastic material from the ˜1000 A.D. caldera-forming eruption of Volcán Ceboruco, Nayarit, Mexico

    NASA Astrophysics Data System (ADS)

    Browne, B. L.; Gardner, J. E.

    2005-06-01

    The complex eruption sequence from the ˜1000 A.D. caldera-forming eruption of Volcán Ceboruco, known as the Jala Pumice, offers an exceptional opportunity to examine how pyroclastic material is transported and deposited from pyroclastic density currents over variable topography. Three main pyroclastic surge deposits (S1, S2, and S3) and two pyroclastic flow deposits (Marquesado and North-Flank PFDs) were emplaced during this eruption. Pyroclastic surge deposits are massive, planar, or cross-bedded, poor-to-well sorted, and display fluctuations in thickness, median diameter, sorting, and lithology as a function of distance, topography, and flow dynamics. Marquesado pyroclastic flow deposits reveal lateral variations from massive, poorly sorted deposits located within 5 km of Ceboruco to planar bedded, moderately well sorted deposits located >15 km away over the nearly horizontal topography to the south of Ceboruco. North-Flank pyroclastic flow deposits also reveal lateral variations from massive, poorly sorted deposits located within 4 km of Ceboruco to planar bedded, moderately well sorted deposits located 8 km away atop an escarpment that steeply rises 230 m from the northern valley floor. Field observations, granulometric analyses, component analyses, and crystal sedimentation calculations along flow-parallel sampling transects all suggest that both surges and flows were density stratified currents, where deposition occurred from a basal region of higher particle concentration that was supplied from an overlying dilute layer that transports particles in suspension. This supports the idea of a transition between “flow” and “surge” end members with variations in particle concentration. Topography greatly affects the transport and depositional capacity of the pyroclastic density currents as a result of “blocking”, either by topographic obstacles or by abrupt breaks at the base of volcano slopes, whereas the origin of Jala Pumice surge deposits

  20. Tungsten Doped TiO2 with Enhanced Photocatalytic and Optoelectrical Properties via Aerosol Assisted Chemical Vapor Deposition

    NASA Astrophysics Data System (ADS)

    Sathasivam, Sanjayan; Bhachu, Davinder S.; Lu, Yao; Chadwick, Nicholas; Althabaiti, Shaeel A.; Alyoubi, Abdulrahman O.; Basahel, Sulaiman N.; Carmalt, Claire J.; Parkin, Ivan P.

    2015-06-01

    Tungsten doped titanium dioxide films with both transparent conducting oxide (TCO) and photocatalytic properties were produced via aerosol-assisted chemical vapor deposition of titanium ethoxide and dopant concentrations of tungsten ethoxide at 500 °C from a toluene solution. The films were anatase TiO2, with good n-type electrical conductivities as determined via Hall effect measurements. The film doped with 2.25 at.% W showed the lowest resistivity at 0.034 Ω.cm and respectable charge carrier mobility (14.9 cm3/V.s) and concentration (×1019 cm-3). XPS indicated the presence of both W6+ and W4+ in the TiO2 matrix, with the substitutional doping of W4+ inducing an expansion of the anatase unit cell as determined by XRD. The films also showed good photocatalytic activity under UV-light illumination, with degradation of resazurin redox dye at a higher rate than with undoped TiO2.

  1. Microstructure and Optical Properties of Erbium Doped Silica-Based Films via Flame Hydrolysis Deposition and Aerosol Doping

    NASA Astrophysics Data System (ADS)

    Sui, Jiehe; Wang, Haibo; Cai, Wei

    Silica-based films on Si fabricated by flame hydrolysis deposition were doped with erbium ions using an aerosol doping technique, and co-doped with GeO2, P2O5 and B2O3. The erbium solution concentration was varied from 4 to 8wt%. The results show that the refractive index of the films is not changed with erbium addition and no OH group is detected for erbium doped silica-based films. An obvious peak was observed at 1.542 µm with the FWHM of 65 nm, which corresponds to the 4I13/2 → 4I15/2 transition. With the increase of Er solution concentration, the photoluminescence (PL) intensity first increases, then decreases above 6wt% Er solution concentration. The decrease in PL intensity with concentration is attributed to concentration quenching caused by Er-Er interaction. The dependence of PL intensity on pump power intensity further confirms the concentration quenching is cooperative upconversion.

  2. Tungsten Doped TiO2 with Enhanced Photocatalytic and Optoelectrical Properties via Aerosol Assisted Chemical Vapor Deposition

    PubMed Central

    Sathasivam, Sanjayan; Bhachu, Davinder S.; Lu, Yao; Chadwick, Nicholas; Althabaiti, Shaeel A.; Alyoubi, Abdulrahman O.; Basahel, Sulaiman N.; Carmalt, Claire J.; Parkin, Ivan P.

    2015-01-01

    Tungsten doped titanium dioxide films with both transparent conducting oxide (TCO) and photocatalytic properties were produced via aerosol-assisted chemical vapor deposition of titanium ethoxide and dopant concentrations of tungsten ethoxide at 500 °C from a toluene solution. The films were anatase TiO2, with good n-type electrical conductivities as determined via Hall effect measurements. The film doped with 2.25 at.% W showed the lowest resistivity at 0.034 Ω.cm and respectable charge carrier mobility (14.9 cm3/V.s) and concentration (×1019 cm−3). XPS indicated the presence of both W6+ and W4+ in the TiO2 matrix, with the substitutional doping of W4+ inducing an expansion of the anatase unit cell as determined by XRD. The films also showed good photocatalytic activity under UV-light illumination, with degradation of resazurin redox dye at a higher rate than with undoped TiO2. PMID:26042724

  3. Evaluation and development of models for resuspension of aerosols at short times after deposition

    NASA Astrophysics Data System (ADS)

    Loosmore, Gwen A.

    Resuspension is known to transport hazardous particles in the natural environment, moving a fraction of deposited material back into the atmosphere. This process is notoriously difficult to model, given the complexity of the turbulent boundary layer and chemistry of the three-phase interface (air, liquid, solid) typically found at the land surface. Wind tunnel studies have demonstrated the importance of resuspension within a short time after deposition, but there exists no robust model for short-term resuspension. Numerical simulations of accidental or terrorist releases of hazardous materials need such a model to accurately predict fate and transport of the materials within hours to days after release. Many accepted conventional models were derived from resuspension data for aged sources, such as former weapons test sites; these data sets, and the associated models, may not be appropriate for short-time resuspension. The study described here reexamined historical wind tunnel data on short-term resuspension, with the goal of developing a model appropriate for numerical simulations. Empirical models are derived from these data using a suite of parameters (friction velocity, particle diameter, surface roughness, particle density, and time). These empirical models, and the wind tunnel data, are compared quantitatively with existing conventional models from the literature. The conventional models underpredict short-time resuspension, resulting in order-of-magnitude errors in predictions of resuspended mass. Only three models perform reasonably well: the empirical models derived from the data and an adaptation of the NCRP 129 model. More data are needed to validate the empirical models and build the physical understanding of the processes involved.

  4. Recent progress on micro-piezoelectric energy harvesters fabricated with aerosol deposition method and the interfacing circuits

    NASA Astrophysics Data System (ADS)

    Yeh, S. P.; Wang, L. T.; Wang, Y. J.; Lin, S. C.; Shih, Y. S.; Wu, W. J.

    2014-04-01

    This paper presents a system integration of micro-piezoelectric energy harvester (MPEH) system based on MPEHs fabricated with an aero-deposited PZT technique, including both the device and the interface circuit design. An in depth look at the deposition method known as aerosol deposition is analyzed. Secondly, various structural designs throughout the years will be introduced and discussed. Thirdly, the non-linear synchronized switching technique interfacing circuit was designed to boost the harvested power in comparison to standard rectifying circuits. The boosting effect in comparison to theoretical expectations will also be presented. The power dissipation effects of self-powered SSHI under low current has also been discussed. Experimental results show that the device based on silicon substrate showed a maximum output power of 21 μW with the output voltage of 2.2 Vrms, excited at 215 Hz under a 1.5 g vibrating source. In comparison, the device based on stainless steel substrate, driven under the same acceleration, had a maximum output power of 34 μW with 1.8 Vrms at the resonant frequency of 202 Hz. The power densities were 4.7 μW mm-2 and 7.6 μW mm-2 for the silicon substrate and the stainless steel substrate based devices, each. The cantilever structured MPEG was later improved to the power output of 200.28 μW. To further improve the output characteristic, the device was tested under vacuumed circumstance, which then gave the output power of 241.60μW, with a 6.02 Vrms under 1.5 g, 104.4Hz. The power boosting circuit gave a power gain of 2.03 times, as the overall system outputs 91.4 μW using the self-powered nonlinear technique under 0.75 g with a similar device. The overall system, using only the standard rectifying circuit was able to light a low consumption red- colored SMD-0805 packaged LED in a duty ratio of approximately 25%.

  5. Deposition and generation of multiple widespread fall units from the c. AD 1314 Kaharoa rhyolitic eruption, Tarawera, New Zealand

    NASA Astrophysics Data System (ADS)

    Sahetapy-Engel, Steve; Self, Stephen; Carey, Rebecca J.; Nairn, Ian A.

    2014-08-01

    The c. AD 1314 Kaharoa eruption from Tarawera volcano, North Island, New Zealand, was a complex, long-duration, multi-episode rhyolitic event. Up to 13 discrete sub-Plinian to Plinian-style phases occurred in two stages from at least two different vents along an 8-km-long fissure. The early explosive stage produced seven pumice lapilli fall units dispersed solely to the southeast of the volcano, while a later stage produced six fall units dispersed almost entirely to the north and northwest. The duration of fallout for these 13 lapilli units is estimated to have totaled about 1.5 days. The presence of massive-textured ash layers between many of the lapilli fall units suggests that longer-duration, pyroclastic density-current producing phases and more quiescent fallout intervals occurred between the intense explosive phases of the eruption (total duration of ash fallout ~ 7.5 days). The ash deposition extended the minimum duration of the explosive episodes to at least 9 days, based on settling rates of the ash. Possibly the explosive phase of eruptive activity lasted for ~ 2 weeks, including some brief hiatuses and pyroclastic density-current deposition, and was followed by ~ 4 years of mainly lava-dome-forming activity. At least 15 km3 (> 7.3 km3 dense rock equivalent, DRE) of tephra was erupted during the main explosive episodes, and at least 9.1 km3 DRE during the whole eruption, more than doubling the previous estimate. This may be an underestimate by up to 50 % of the fallout volume. Eruption column heights for the two most widely dispersed fall units are estimated to have ranged from 25-28 km above the vents and durations of individual lapilli fall unit-forming phases ranged from 1.5 to 4 h, but the ash-producing phases lasted much longer (individually up to 30 h) and represent a longer-lived shut-down to each eruptive episode. Time-averaged mass discharge rates are estimated to have varied by more than one order of magnitude during the main Plinian

  6. Burial of Emperor Augustus' villa at Somma Vesuviana (Italy) by post-79 AD Vesuvius eruptions and reworked (lahars and stream flow) deposits

    NASA Astrophysics Data System (ADS)

    Perrotta, Annamaria; Scarpati, Claudio; Luongo, Giuseppe; Aoyagi, Masanori

    2006-11-01

    A new archaeological site of Roman Age has been recently found engulfed in the products of Vesuvius activity at Somma Vesuviana, on the northern flank of the Somma-Vesuvius, 5 km from the vent. A 9 m deep, 30 by 35 m trench has revealed a monumental edifice tentatively attributed to the Emperor Augustus. Different than Pompeii and Herculaneum sites which were completely buried in the catastrophic eruption of 79 AD, this huge roman villa survived the effects of the 79 AD plinian eruption as suggested by stratigraphic and geochronologic data. It was later completely engulfed in the products of numerous explosive volcanic eruptions ranging from 472 AD to 1631 AD, which were separated by reworked material and paleosols. The exposed burial sequence is comprised of seven stratigraphic units. Four units are composed exclusively of pyroclastic products each emplaced during a unique explosive event. Two units are composed of volcaniclastic material (stream flow and lahars) emplaced during quiescent periods of the volcano. Finally, one unit is composed of both pyroclastic and volcaniclastic deposits. One of the more relevant volcanological results of this study is the detailed reconstruction of the destructive events that buried the Emperor Augustus' villa. Stratigraphic evidence shows the absence of any deposit associated with the 79 AD eruption at this site and that the building was extensively damaged (sacked) before it was engulfed by the products of subsequent volcanic eruptions and lahars. The products of the 472 AD eruption lie directly on the roman structures. They consist of scoria fall layers intercalated with massive and stratified pyroclastic density current deposits that caused limited damage to the structure. The impact on the building of penecontemporaneous lahars was more important; these caused the collapse of some structures. The remaining part of the building was subsequently entombed by the products of explosive eruptions (e.g. 512/536 eruption, 1631

  7. Aqueous glyoxal photooxidation in the presence of inorganic nitrogen: A potential source of organic nitrogen in aerosols and wet deposition

    NASA Astrophysics Data System (ADS)

    Kirkland, J. R.; Tan, Y.; Altieri, K. E.; Seitzinger, S.; Turpin, B. J.

    2010-12-01

    The sources of organic nitrogen in aerosols and atmospheric wet deposition are poorly understood, yet are important when assessing potential anthropogenic impacts on global nitrogen budgets. Nitrogen-containing organics are formed through gas phase photochemistry (e.g., involving NOx and isoprene). Imidazoles have been reported to form during smog chamber experiments involving glyoxal and ammonium sulfate seed particles. We hypothesize that nitrogen-containing organic compounds also form during cloud processing of water-soluble organic gases. Specifically, in this work we examine the possibility that organic nitrogen forms from GLY and inorganic nitrogen (NO3- or NH4+) at conditions found in daytime liquid clouds. We conducted batch aqueous reactions of GLY (1 mM) and OH radical (~10^-12 M) with and without nitric acid (1.7 mM) and ammonium sulfate (0.84 mM). OH radical was formed from the continuous photolysis of H2O2. Products were analyzed by ion chromatography (IC) and electrospray ionization mass spectrometry with pre-separation by IC (IC/ESI-MS). The addition of ammonium or nitrate had little effect on the concentrations of major system species (i.e., oxalate, glycolate) in the presence and absence of OH radical. Concentrations of inorganic nitrate and sulfate showed no significant change throughout light and dark experiments. ESI mass spectra with and without pre-separation by IC and ultra high resolution Fourier transform ion cyclotron resonance mass spectral analysis of samples will be examined and any evidence of organic nitrogen products will be discussed.

  8. Dioxo-Fluoroalkoxide Tungsten(VI) Complexes for Growth of WOx Thin Films by Aerosol-Assisted Chemical Vapor Deposition.

    PubMed

    Bonsu, Richard O; Kim, Hankook; O'Donohue, Christopher; Korotkov, Roman Y; Abboud, Khalil A; Anderson, Timothy J; McElwee-White, Lisa

    2015-08-01

    The soluble bis(fluoroalkoxide) dioxo tungsten(VI) complexes WO2(OR)2(DME) [1, R = C(CF3)2CH3; 2, R = C(CF3)3] have been synthesized by alkoxide-chloride metathesis and evaluated as precursors for aerosol-assisted chemical vapor deposition (AACVD) of WOx. The (1)H NMR and (19)F NMR spectra of 1 and 2 are consistent with an equilibrium between the dimethoxyethane (DME) complexes 1 and 2 and the solvato complexes WO2(OR)2(CD3CN)2 [1b, R = C(CF3)2CH3; 2b, R = C(CF3)3] in acetonitrile-d3 solution. Studies of the fragmentation of 1 and 2 by mass spectrometry and thermolysis resulted in observation of DME and the corresponding alcohols, with hexafluoroisobutylene also generated from 1. DFT calculations on possible decomposition mechanisms for 1 located pathways for hydrogen abstraction by a terminal oxo to form hexafluoroisobutylene, followed by dimerization of the resulting terminal hydroxide complex and dissociation of the alcohol. AACVD using 1 occurred between 100 and 550 °C and produced both substoichiometric amorphous WOx and a polycrystalline W18O49 monoclinic phase, which exhibits 1-D preferred growth in the [010] direction. The work function (4.9-5.6 eV), mean optical transmittance (39.1-91.1%), conductivity (0.4-2.3 S/cm), and surface roughness (3.4-7.9 nm) of the WOx films are suitable for charge injection layers in organic electronics. PMID:26172992

  9. Electrochromic and colorimetric properties of nickel(II) oxide thin films prepared by aerosol-assisted chemical vapor deposition.

    PubMed

    Sialvi, Muhammad Z; Mortimer, Roger J; Wilcox, Geoffrey D; Teridi, Asri Mat; Varley, Thomas S; Wijayantha, K G Upul; Kirk, Caroline A

    2013-06-26

    Aerosol-assisted chemical vapor deposition (AACVD) was used for the first time in the preparation of thin-film electrochromic nickel(II) oxide (NiO). The as-deposited films were cubic NiO, with an octahedral-like grain structure, and an optical band gap that decreased from 3.61 to 3.48 eV on increase in film thickness (in the range 500-1000 nm). On oxidative voltammetric cycling in aqueous KOH (0.1 mol dm(-3)) electrolyte, the morphology gradually changed to an open porous NiO structure. The electrochromic properties of the films were investigated as a function of film thickness, following 50, 100, and 500 conditioning oxidative voltammetric cycles in aqueous KOH (0.1 mol dm(-3)). Light modulation of the films increased with the number of conditioning cycles. The maximum coloration efficiency (CE) for the NiO (transmissive light green, the "bleached" state) to NiOOH (deep brown, the colored state) electrochromic process was found to be 56.3 cm(2) C(-1) (at 450 nm) for films prepared by AACVD for 15 min followed by 100 "bleached"-to-colored conditioning oxidative voltammetric cycles. Electrochromic response times were <10 s and generally longer for the coloration than the bleaching process. The films showed good stability when tested for up to 10 000 color/bleach cycles. Using the CIE (Commission Internationale de l'Eclairage) system of colorimetry the color stimuli of the electrochromic NiO films and the changes that take place on reversibly oxidatively switching to the NiOOH form were calculated from in situ visible spectra recorded under electrochemical control. Reversible changes in the hue and saturation occur on oxidation of the NiO (transmissive light green) form to the NiOOH (deep brown) form, as shown by the track of the CIE 1931 xy chromaticity coordinates. As the NiO film is oxidized, a sharp decrease in luminance was observed. CIELAB L*a*b* coordinates were also used to quantify the electrochromic color states. A combination of a low L* and positive a

  10. On the influence of DC electric fields on the aerosol assisted chemical vapor deposition growth of photoactive titanium dioxide thin films.

    PubMed

    Romero, Luz; Binions, Russell

    2013-11-01

    Titanium dioxide thin films were deposited on fluorine doped tin oxide glass substrate from the electric field assisted aerosol chemical vapor deposition (EACVD) reaction of titanium isopropoxide (TTIP, Ti(OC3H7)4) in toluene on glass substrates at a temperature of 450 °C. DC electric fields were generated by applying a potential difference between the electrodes of the transparent coated oxide coated glass substrates during the deposition. The deposited films were characterized using scanning electron microscopy, X-ray diffraction, atomic force microscopy, Raman spectroscopy, and UV-vis spectroscopy. The photoactivity and hydrophilicity of the deposited films were also analyzed using a dye-ink test and water-contact angle measurements. The characterization work revealed that the incorporation of DC electric fields produced significant reproducible changes in the film microstructure, preferred crystallographic orientation, roughness, and film thickness. Photocatalytic activity was calculated from the half-time (t1/2) or time taken to degrade 50% of the initial resazurin dye concentration. A large improvement in photocatalytic activity was observed for films deposited using an electric field with a strong orientation in the (004) direction (t1/2 17 min) as compared to a film deposited with no electric field (t1/2 40 min). PMID:24160408

  11. Thin films of tin(II) sulphide (SnS) by aerosol-assisted chemical vapour deposition (AACVD) using tin(II) dithiocarbamates as single-source precursors

    NASA Astrophysics Data System (ADS)

    Kevin, Punarja; Lewis, David J.; Raftery, James; Azad Malik, M.; O'Brien, Paul

    2015-04-01

    The synthesis of the asymmetric dithiocarbamates of tin(II) with the formula [Sn(S2CNRR')2] (where R=Et, R'=n-Bu (1); R=Me, R'=n-Bu (2); R=R'=Et (3)) and their use for the deposition of SnS thin films by aerosol-assisted chemical vapour deposition (AACVD) is described. The effects of temperature and the concentration of the precursors on deposition were investigated. The stoichiometry of SnS was best at higher concentrations of precursors (250 mM) and at 450 °C. The direct electronic band gap of the SnS produced by this method was estimated from optical absorbance measurements as 1.2 eV. The composition of films was confirmed by powder X-ray diffraction (p-XRD) and energy dispersive analysis of X-rays (EDAX) spectroscopy.

  12. Regional background aerosols over the Balearic Islands over the last 3 years: ground-based concentrations, atmospheric deposition and sources

    NASA Astrophysics Data System (ADS)

    Cerro, Jose Carlos; Pey, Jorge; Bujosa, Carles; Caballero, Sandra; Alastuey, Andres; Sicard, Michael; Artiñano, Begoña; Querol, Xavier

    2013-04-01

    In the context of the ChArMEx (The Chemistry-Aerosol Mediterranean Experiment, https://charmex.lsce.ipsl.fr) initiative, a 3-year study over a regional background environment (Can Llompart, CLP) in Mallorca has been conducted. Ground-based PM mass concentrations, gaseous pollutants and meteorological parameters were continuously registered from 2010 to 2012. Since the beginning of the campaign, PM10 daily samples for chemical determinations were obtained every 4 days, and dry and wet deposition samples were collected every week. Moreover, additional instruments (condensation particle counter, multi-angle absorption photometer, airpointer, sequential high and low volume samplers) were deployed during intensive filed campaigns in 2011 and 2012, as well as the sampling frequency was intensified. In the laboratory, PM samples were analyzed for inorganic compounds, and organic and elemental carbon following different approaches. In addition, n-alkanes, iso-alkanes, antiso-alkanes, levoglucosan, alkanoic acids and cholesterol were determined by GC-MS chromatography in a selection of 30 samples. Mean PM10, PM2.5 and PM1 concentrations in the period 2010-2012 reached 17, 11, and 8 µg/m3 respectively. Mass concentrations displayed marked seasonal trends, with much higher background levels in summer due to stagnant conditions over the western Mediterranean and increased frequency of Saharan dust events. Likewise, diverse-intensity peaks of coarse PM due to African dust inputs were observed along the year. On average, African dust in PM10 accounted for 1.0-1.5 µg/m3. Sporadic pollution events, characterized by most of the particles in the fine mode, were related to the transport of anthropogenic polluted air masses from central and eastern Europe. Wet and dry atmospheric deposition samples are being analyzed to quantify the deposition fluxes for different soluble and insoluble compounds. On average, PM10 composition is made up of organic matter (23%), mineral components (17

  13. LiNi0.4Co0.3Mn0.3O2 thin film electrode by aerosol deposition

    PubMed Central

    2012-01-01

    LiNi0.4Co0.3Mn0.3O2 thin film electrodes are fabricated from LiNi0.4Co0.3Mn0.3O2 raw powder at room temperature without pretreatments using aerosol deposition that is much faster and easier than conventional methods such as vaporization, pulsed laser deposition, and sputtering. The LiNi0.4Co0.3Mn0.3O2 thin film is composed of fine grains maintaining the crystal structure of the LiNi0.4Co0.3Mn0.3O2 raw powder. In the cyclic voltammogram, the LiNi0.4Co0.3Mn0.3O2 thin film electrode shows a 3.9-V anodic peak and a 3.6-V cathodic peak. The initial discharge capacity is 44.6 μAh/cm2, and reversible behavior is observed in charge-discharge profiles. Based on the results, the aerosol deposition method is believed to be a potential candidate for the fabrication of thin film electrodes. PMID:22222001

  14. Benchmark study on fine-mode aerosol in a big urban area and relevant doses deposited in the human respiratory tract.

    PubMed

    Avino, Pasquale; Protano, Carmela; Vitali, Matteo; Manigrasso, Maurizio

    2016-09-01

    It is well-known that the health effects of PM increase as particle size decreases: particularly, great concern has risen on the role of UltraFine Particles (UFPs). Starting from the knowledge that the main fraction of atmospheric aerosol in Rome is characterized by significant levels of PM2.5 (almost 75% of PM10 fraction is PM2.5), the paper is focused on submicron particles in such great urban area. The daytime/nighttime, work-/weekdays and cold/hot seasonal trends of submicron particles will be investigated and discussed along with NOx and total PAH drifts demonstrating the primary origin of UFPs from combustion processes. Furthermore, moving from these data, the total dose of submicron particles deposited in the respiratory system (i.e., head, tracheobronchial and alveolar regions in different lung lobes) has been estimated. Dosimeter estimates were performed with the Multiple-Path Particle Dosimetry model (MPPD v.2.1). The paper discusses the aerosol doses deposited in the respiratory system of individuals exposed in proximity of traffic. During traffic peak hours, about 6.6 × 10(10) particles are deposited into the respiratory system. Such dose is almost entirely made of UFPs. According to the greater dose estimated, right lung lobes are expected to be more susceptible to respiratory pathologies than left lobes. PMID:27325547

  15. Effect of epicuticular wax crystals on the localization of artificially deposited sub-micron carbon-based aerosols on needles of Cryptomeria japonica.

    PubMed

    Nakaba, Satoshi; Yamane, Kenichi; Fukahori, Mie; Nugroho, Widyanto Dwi; Yamaguchi, Masahiro; Kuroda, Katsushi; Sano, Yuzou; Wuled Lenggoro, I; Izuta, Takeshi; Funada, Ryo

    2016-09-01

    Elucidation of the mechanism of adsorption of particles suspended in the gas-phase (aerosol) to the outer surfaces of leaves provides useful information for understanding the mechanisms of the effect of aerosol particles on the growth and physiological functions of trees. In the present study, we examined the localization of artificially deposited sub-micron-sized carbon-based particles on the surfaces of needles of Cryptomeria japonica, a typical Japanese coniferous tree species, by field-emission scanning electron microscopy. The clusters (aggregates) of carbon-based particles were deposited on the needle surface regions where epicuticular wax crystals were sparsely distributed. By contrast, no clusters of the particles were found on the needle surface regions with dense distribution of epicuticular wax crystals. Number of clusters of carbon-based particles per unit area showed statistically significant differences between regions with sparse epicuticular wax crystals and those with dense epicuticular wax crystals. These results suggest that epicuticular wax crystals affect distribution of carbon-based particles on needles. Therefore, densely distributed epicuticular wax crystals might prevent the deposition of sub-micron-sized carbon-based particles on the surfaces of needles of Cryptomeria japonica to retain the function of stomata.

  16. Effect of epicuticular wax crystals on the localization of artificially deposited sub-micron carbon-based aerosols on needles of Cryptomeria japonica.

    PubMed

    Nakaba, Satoshi; Yamane, Kenichi; Fukahori, Mie; Nugroho, Widyanto Dwi; Yamaguchi, Masahiro; Kuroda, Katsushi; Sano, Yuzou; Wuled Lenggoro, I; Izuta, Takeshi; Funada, Ryo

    2016-09-01

    Elucidation of the mechanism of adsorption of particles suspended in the gas-phase (aerosol) to the outer surfaces of leaves provides useful information for understanding the mechanisms of the effect of aerosol particles on the growth and physiological functions of trees. In the present study, we examined the localization of artificially deposited sub-micron-sized carbon-based particles on the surfaces of needles of Cryptomeria japonica, a typical Japanese coniferous tree species, by field-emission scanning electron microscopy. The clusters (aggregates) of carbon-based particles were deposited on the needle surface regions where epicuticular wax crystals were sparsely distributed. By contrast, no clusters of the particles were found on the needle surface regions with dense distribution of epicuticular wax crystals. Number of clusters of carbon-based particles per unit area showed statistically significant differences between regions with sparse epicuticular wax crystals and those with dense epicuticular wax crystals. These results suggest that epicuticular wax crystals affect distribution of carbon-based particles on needles. Therefore, densely distributed epicuticular wax crystals might prevent the deposition of sub-micron-sized carbon-based particles on the surfaces of needles of Cryptomeria japonica to retain the function of stomata. PMID:27294967

  17. [Aerosol therapy].

    PubMed

    Wildhaber, J H

    1998-08-15

    Aerosol therapy plays a major role in the diagnosis and treatment of various lung diseases. The aim of inhalation therapy is to deposit a reproducible and adequate dose of a specific drug to the airways, in order to achieve a high, local, clinical effect while avoiding serious systemic side effects. To achieve this goal, it is therefore important to have an efficient inhalation device to deliver different medications. However, the currently available therapeutic inhalation devices (nebuliser, pressurised metered-dose inhaler and dry powder inhaler) are not very efficient in aerosol delivery and have several disadvantages. Inhalation devices can be assessed by in vitro studies, filter studies and radiolabelled deposition studies. Several radiolabelled deposition studies have shown that nebulisers and pressurised metered-dose inhalers are not very efficient in aerosol delivery. In children, before 1997, only 0.5% to 15% of the total nebulised or actuated dose from a nebuliser or pressurised metered-dose inhaler actually reached the lungs. These numbers were somewhat improved in adults, 30% of the total nebulised or actuated dose reaching the airways. Aerosol therapy with dry powder inhalers was the most efficient before 1997, 30% of the total dose being deposited in the lungs of adults and children. In 1997, new developments in pressurised metered-dose inhalers much improved their efficiency in aerosol delivery. Lung deposition can be increased by up to 60% with use of a non-electrostatic holding chamber and/or a pressurised metered-dose inhaler with a hydrofluoroalkane propellant possessing superior aerosol characteristics. Several studies comparing the clinical efficiency of different inhalation devices have shown that the choice of an optimal inhalation device is crucial. In addition to the aerosol characteristics, ventilation parameters and airway morphology have an important bearing on deposition patterns. These parameters may be greatly influenced by the

  18. Nano-granulization of gadolinia-doped ceria electrolyte surface by aerosol-assisted chemical vapor deposition for low-temperature solid oxide fuel cells

    NASA Astrophysics Data System (ADS)

    Kim, Jun Woo; Jang, Dong Young; Kim, Manjin; Choi, Hyung Jong; Shim, Joon Hyung

    2016-01-01

    We have fabricated nano-scale gadolinia-doped ceria (GDC) at the electrode-electrolyte boundary by aerosol-assisted chemical vapor deposition (AACVD) for high-performance solid oxide fuel cells (SOFCs) working at low temperatures below 500 °C. In AACVD, temperature is the key factor affecting the grain size. We have confirmed that by nano-granulizing the electrolyte surface using optimized AACVD, the power output of the SOFC is 50% higher than that of the bare GDC SOFC. From the impedance analysis, significant enhancement of the cathodic oxygen reduction reaction is identified from the AACVD-GDC nano-grain surface treatment.

  19. Structural and optical properties of Ni added ZnO thin films deposited by sol-gel method

    SciTech Connect

    Murugan, R.; Vijayaprasath, G.; Anandhan, N. E-mail: gravicrc@gmail.com; Ravi, G. E-mail: gravicrc@gmail.com; Mahalingam, T.

    2014-04-24

    Pure and Ni added zinc oxide thin films were prepared by sol-gel method using spin-coating technique on glass substrates. The influences of nickel on ZnO thin films are characterized by Powder X-ray diffraction study. Pure and Ni added thin films are hexagonal wurtzite structure without any secondary phase in c-axis orientation. The SEM images of thin films show uniform sphere like particles covered completely on glass substrates. All the films exhibit transmittance of 85-95% in the visible range up to 800nm and cut-off wavelength observed at 394 nm corresponding to the fundamental absorption of ZnO. The photoluminescence property for pure and Ni added ZnO thin films has been studied and results are presented in detail.

  20. Structural analysis for metavolcanics and their metapyroclastics at gold deposit of the Mahd Ad Dahab area, Arabian Shield, Saudi Arabia

    NASA Astrophysics Data System (ADS)

    Kassem, Osama M. K.; Al Bassam, Abdel Aziz M.; Zaidi, Faisal K.

    2013-11-01

    The present study focuses on the gold mining in Mahd Ad Dahab region of Saudi Arabia. The study aims to assess the spatial relationship between tectonic contacts in Mahd Ad Dahab area and to provide a meaningful hypothesis relating gold metallogeny to the evolution of the Arabian Shield. Distribution and localization of gold occurrences in the study area was envisaged based on the different styles of microstructures and the major deformation phases affecting the area. The detailed petrographical and mineralogical investigations indicate that the metavolcanic rocks at the Mahd Ad Dahab gold mine area can be classified into metabasalt, metaandesite, and the felsic varieties (metadacite, metarhyodacite and metarhyolite) associating their metapyroclastics (conglomerate and tuffs). Furthermore, quartz forms allotriomorphic crystals which exhibit wavy extinction, deformational lamina and foliation due to subsequent deformations. Furthermore, we conclude that finite strain in the deformed rocks is of the same order of magnitude for all units of metavolcano-sedimentary rocks. Furthermore, contacts formed during intrusion of plutons with some faults in the Mahd Ad Dahab area under brittle to semi-ductile deformation conditions. In this case, finite strain accumulated during superimposed deformation on the already assembled nappe structure. It indicates that the contacts formed during the accumulation of finite strain.

  1. Effects of Properties on S45C Carbon Steel by Electroless NiP Adding Al2O3 Powder of Composite Deposition and Various Heat Treatments

    NASA Astrophysics Data System (ADS)

    Chang, Shih-Hsien; Liang, Cheng; Chang, Chih-Chung

    2014-06-01

    This research studies the effects on the surface microstructure and mechanical properties of S45C carbon steel via electroless Ni-P, by adding αAl2O3 powder via composite deposition and various heat treatments. The plating specimens were treated with pH5 and pH8 baths heated to 350°C and 300°C, respectively, and soaked for 1 hr. Meanwhile, two different particle sizes of Al2O3 powder were added to the electroless Ni-P plating: 0.3 μm of αAl2O3 and 0.05 μm of γAl2O3 powder, respectively. The experimental results show that, after 1 hr of heat treatment at 300°C, the optimal hardness for the specimens using the pH8 of Ni-P with αAl2O3 and γAl2O3 added by composite deposition are HV0.05 1237 and HV0.05 1145, respectively. All of the specimens underwent the main precipitate phase of Ni3P after heat treatment.

  2. Flame Aerosol Deposition of TiO2 Nanoparticle Films on Polymers and Polymeric Microfluidic Devices for On-Chip Phosphopeptide Enrichment.

    PubMed

    Rudin, Thomas; Tsougeni, Katerina; Gogolides, Evangelos; Pratsinis, Sotiris E

    2012-09-01

    Direct and fast (10s of seconds) deposition of flame-made, high surface-area aerosol films on polymers and polymeric microfluidic devices is demonstrated. Uniform TiO2 nanoparticle films were deposited on cooled Poly(methyl methacrylate) (PMMA) substrates by combustion of titanium(IV) isopropoxide (TTIP) - xylene solution sprays. Films were mechanically stabilized by in-situ annealing with a xylene spray flame. Plasma-etched microfluidic chromatography columns, comprising parallel microchannels were also coated with such nanoparticle films without any microchannel deformation. These microcolumns were successfully used in metal-oxide affinity chromatography (MOAC) to selectively trap phosphopeptides on these high surface-area nanostructured films. The chips had a high capacity retaining 1.2 μg of standard phosphopeptide. A new extremely fast method is developed for MOAC microchip stationary phase fabrication with applications in proteomics. PMID:23729946

  3. Flame Aerosol Deposition of TiO2 Nanoparticle Films on Polymers and Polymeric Microfluidic Devices for On-Chip Phosphopeptide Enrichment

    PubMed Central

    Rudin, Thomas; Tsougeni, Katerina; Gogolides, Evangelos; Pratsinis, Sotiris E.

    2013-01-01

    Direct and fast (10s of seconds) deposition of flame-made, high surface-area aerosol films on polymers and polymeric microfluidic devices is demonstrated. Uniform TiO2 nanoparticle films were deposited on cooled Poly(methyl methacrylate) (PMMA) substrates by combustion of titanium(IV) isopropoxide (TTIP) – xylene solution sprays. Films were mechanically stabilized by in-situ annealing with a xylene spray flame. Plasma-etched microfluidic chromatography columns, comprising parallel microchannels were also coated with such nanoparticle films without any microchannel deformation. These microcolumns were successfully used in metal-oxide affinity chromatography (MOAC) to selectively trap phosphopeptides on these high surface-area nanostructured films. The chips had a high capacity retaining 1.2 μg of standard phosphopeptide. A new extremely fast method is developed for MOAC microchip stationary phase fabrication with applications in proteomics. PMID:23729946

  4. Re-examination of Magnitude of the AD 869 Jogan Earthquake, a Possible Predecessor of the 2011 Tohoku Earthquake, from Tsunami Deposit Distribution and Computed Inundation Distances

    NASA Astrophysics Data System (ADS)

    Namegaya, Y.; Satake, K.

    2012-12-01

    We re-examined the magnitude of the AD 869 Jogan earthquake by comparing the inland limit of tsunami deposit and computed inundation distance for various fault models. The 869 tsunami deposit is distributed 3-4 km inland from the estimated past shorelines in Ishinomaki and Sendai plains (Shishikura et al., 2007, Annual Report on Active Fault and Paleoearthquake Researches; Sawai et al., 2007 ibid). In the previous studies (Satake et al., 2008 and Namegaya et al. 2010, ibid), we assumed 14 fault models of the Jogan earthquake including outer-rise normal fault, tsunami earthquake, interplate earthquakes, and an active fault in Sendai bay. The computed inundation area from an interplate earthquake with Mw of 8.4 (length: 200 km, width: 100 km, slip 7 m) covers the distribution of tsunami deposits in Ishinomaki and Sendai plains. However, the previous studies yielded the minimum magnitude, because we assumed that the inland limit of tsunami deposits and the computed inundation limit were the same. A post-2011 field survey indicate that the 2011 tsunami inundation distance was about 1.6 times the inland limit of tsunami deposits (e.g. Goto et al., 2011, Marine Geology). In this study, we computed tsunami inundation areas from interplate earthquake with different magnitude, fault length, and slip amount. The moment magnitude ranges from 8.0 to 8.7, the fault length ranges from 100 to 400 km, and the slip ranged from 3 to 9 m. The fault width is fixed at 100 km. The distance ratios of computed inundation to the inland limit of tsunami deposit (Inundation to Deposit Ratio or IDR) were calculated along 8 transects on Sendai and Ishinomaki plains. The results show that IDR increases with magnitude, up to Mw=8.4, when IDR becomes one, or the computed inundation is almost the same as the inland limit of tsunami deposit. IDR increases for a larger magnitude, but at a much smaller rate. This confirms that the magnitude of the 869 Jogan earthquake was at least 8.4, but it could

  5. 79 AD Vesuvius PDC deposits' temperatures inferred from optical analysis on woods charred in-situ in the Villa dei Papiri at Herculaneum (Italy)

    NASA Astrophysics Data System (ADS)

    Caricchi, C.; Vona, A.; Corrado, S.; Giordano, G.; Romano, C.

    2014-12-01

    Determining the deposit temperature of pyroclastic density currents (PDCs) is a first order priority in the assessment of volcanic hazard. For past eruptions, in which no direct measurements are possible, PDC deposit temperatures have been calculated mainly using magnetic proxies. A more recent and innovative approach consists of the determination of the degree of charring of preserved wood fragments by optical analysis. In this study, we perform optical analyses on wooden beams belonging to the Villa dei Papiri at the archeological site of Herculaneum, which was destroyed by PDCs during the 79 AD eruption of Vesuvius. The new temperature data from this study range between 240 °C and 370 °C, and are in good agreement with literature data for this eruption. The large T variation measured can be interpreted as due to the interaction of the PDCs with the local environment, i.e. the impacted buildings of the villa and the sea shoreline. The study of in situ charred wood allows to constrain the charring kinetics and to evaluate the sensitivity of the reflectance proxy in recording PDC depositional features. We demonstrate that the charcoal reflectance is an excellent proxy for the determination of the PDC deposit temperatures even at a local scale, and it can be used in conjunction with, or in alternative to other more traditional methodologies, especially in case of pre-heating effects which may alter the T determinations by thermoremanent magnetization.

  6. Responses of phytoplankton community to the input of different aerosols in the East China Sea

    NASA Astrophysics Data System (ADS)

    Meng, X.; Chen, Y.; Wang, B.; Ma, Q. W.; Wang, F. J.

    2016-07-01

    Atmospheric deposition can affect marine phytoplankton by supplying macronutrients and trace elements. We conducted mesocosm experiments by adding aerosols with different composition (dominated by mineral dust, biomass burning and high Cu, and secondary aerosol, respectively) to the surface seawater of the East China Sea. Chlorophyll a concentrations were found to be the highest and lowest after adding aerosols containing the highest Fe and dissolved inorganic nitrogen (DIN), respectively. The relative abundance of Haptophyceae increased significantly after adding mineral dust, whereas diatom, Dinophyceae and Cryptophyceae reached the maximum accompanied with the highest DIN. Our results suggest that Fe may be more important than DIN in promoting primary productivity in the sampled seawater. The input of mineral dust and anthropogenic aerosols may result in distinct changes of phytoplankton community structure.

  7. Plutonium-aerosol emission rates and human pulmonary deposition calculations for Nuclear Site 201, Nevada Test Site

    SciTech Connect

    Shinn, J.H.; Homan, D.N.

    1982-06-21

    This study determined the plutonium-aerosol fluxes from the soil to quantify (1) the extent of potential human exposure by deep-lung retention of alpha-emitting particles; (2) the source term should there be any significant, long-term, transport of plutonium aerosols; and (3) the resuspension factor and rate so that, for the first time at any nuclear site, one may calculate how long it will take for wind erosion to carry away a significant amount of the contaminated soil. High-volume air samplers and cascade impactors were used to characterize the plutonium aerosols. Meteorological flux-profile methods were used to calculate dust and plutonium aerosol emission rates. A floorless wind tunnel (10-m long) was used to examine resuspension under steady-state, high wind speed. The resuspension factor was two orders of magnitude lower than the other comparable sites at NTS and elsewhere, and the average resuspension rate of 5.3 x 10/sup -8//d was also very low, so that the half-time for resuspension by wind erosion was about 36,000 y.

  8. Heterocyclic dithiocarbamato-iron(III) complexes: single-source precursors for aerosol-assisted chemical vapour deposition (AACVD) of iron sulfide thin films.

    PubMed

    Mlowe, Sixberth; Lewis, David J; Malik, Mohammad Azad; Raftery, James; Mubofu, Egid B; O'Brien, Paul; Revaprasadu, Neerish

    2016-02-14

    Tris-(piperidinedithiocarbamato)iron(III) (1) and tris-(tetrahydroquinolinedithiocarbamato)iron(iii) (2) complexes have been synthesized and their single-crystal X-ray structures were determined. Thermogravimetric analysis (TGA) of the complexes showed decomposition to iron sulfide. Both complexes were then used as single-source precursors for the deposition of iron sulfide thin films by aerosol-assisted chemical vapour deposition (AACVD). Energy-dispersive X-ray (EDX) spectroscopy confirmed the formation of iron sulfide films. The addition of tert-butyl thiol almost doubled the sulfur content in the deposited films. Scanning electron microscopy (SEM) images of the iron sulfide films from both complexes showed flakes/leaves/sheets, spherical granules and nanofibres. The sizes and shapes of these crystallites depended on the nature of the precursor, temperature, solvent and the amount of tert-butyl thiol used. The observed optical properties are dependent upon the variation of reaction parameters such as temperature and solvent. Powder X-ray diffraction (p-XRD) studies revealed that pyrrhotite, hexagonal (Fe0.975S), marcasite and smythite (Fe3S4) phases were differently deposited. PMID:26732865

  9. Novel multi-functional europium-doped gadolinium oxide nanoparticle aerosols facilitate the study of deposition in the developing rat lung

    NASA Astrophysics Data System (ADS)

    Das, Gautom K.; Anderson, Donald S.; Wallis, Chris D.; Carratt, Sarah A.; Kennedy, Ian M.; van Winkle, Laura S.

    2016-06-01

    Ambient ultrafine particulate matter (UPM), less than 100 nm in size, has been linked to the development and exacerbation of pulmonary diseases. Age differences in susceptibility to UPM may be due to a difference in delivered dose as well as age-dependent differences in lung biology and clearance. In this study, we developed and characterized aerosol exposures to novel metal oxide nanoparticles containing lanthanides to study particle deposition in the developing postnatal rat lung. Neonatal, juvenile and adult rats (1, 3 and 12 weeks old) were nose only exposed to 380 μg m-3 of ~30 nm europium doped gadolinium oxide nanoparticles (Gd2O3:Eu3+) for 1 h. The deposited dose in the nose, extrapulmonary airways and lungs was determined using inductively-coupled plasma mass spectroscopy. The dose of deposited particles was significantly greater in the juvenile rats at 2.22 ng per g body weight compared to 1.47 ng per g and 0.097 ng per g for the adult and neonate rats, respectively. Toxicity was investigated in bronchoalveolar lavage fluid (BALF) by quantifying recovered cell types, and measuring lactate dehydrogenase activity and total protein. The toxicity data suggests that the lanthanide particles were not acutely toxic or inflammatory with no increase in neutrophils or lactate dehydrogenase activity at any age. Juvenile and adult rats had the same mass of deposited NPs per gram of lung tissue, while neonatal rats had significantly less NPs deposited per gram of lung tissue. The current study demonstrates the utility of novel lanthanide-based nanoparticles to study inhaled particle deposition in vivo and has important implications for nanoparticles delivery to the developing lung either as therapies or as a portion of particulate matter air pollution.Ambient ultrafine particulate matter (UPM), less than 100 nm in size, has been linked to the development and exacerbation of pulmonary diseases. Age differences in susceptibility to UPM may be due to a difference in

  10. Decadal trend of black carbon and refractory carbonaceous aerosol in the western rim of the North Pacific Ocean: atmospheric concentration and the retrieved record of deposition flux

    NASA Astrophysics Data System (ADS)

    Kaneyasu, Naoki; Yamaguchi, Takashi; Noguchi, Izumi; Akiyama, Masayuki; Matsumoto, Kiyoshi

    2013-04-01

    The long-term trend of light absorbing carbonaceous aerosols (or black carbon: BC) or refractory carbonaceous aerosol (or elemental carbon: EC) concentration is reported at European background sites such as Mace Head, and that of aerosol absorption coefficient are monitored in many GAW sites. On the contrary, such long-term data are relatively scarce at around the western part of the North Pacific Ocean. Thus, to understand the long-term variation of in the area, BC in fine aerosol fraction has been measured at Chichi-jima Islands, Japan. Chichi-jima Island is located 1000 km south of the Japanese mainland, and 1800 km west of the coast line of the Asian continent. BC has been measured with an Aethalometer (Magee, AE-16 and AE-30) since December, 1998 with 1 hr time resolution. Mass flowmeter embedded inside the Aethalometer is calibrated with a rotational dry gas-meter once a year. Monthly averaged BC concentration shows an obvious seasonal variation, i.e. high concentration during late autumn-winter-spring period resulting from the transport from East Asia, with maximum daily concentration above 500 ng m-3. In summer, daily concentration was usually less than 20 ng m-3, due to the clean background airmass originating from the North Pacific Anticyclone. Decadal trend of the annual averaged BC concentration showed a increasing trend from 2000 to 2007 and started to decrease after 2008, which roughly coincides with the reported emission trend of SO2 in China (Lu et al., 2010). In addition, total (i.e., wet + dry) deposition record of refractory carbon at two sites in the northern Japan (Rishiri Island: a remote island site, and Sapporo City: an urban site) are retrieved. At these sites, the local government have been measuring the chemical components in precipitation water collected by deposition gauges. In the deposition gauge, a membrane filter made of cellulose-acetate is fixed at the bottom of the funnel to remove water-insoluble particles from the precipitated

  11. Novel multi-functional europium-doped gadolinium oxide nanoparticle aerosols facilitate the study of deposition in the developing rat lung.

    PubMed

    Das, Gautom K; Anderson, Donald S; Wallis, Chris D; Carratt, Sarah A; Kennedy, Ian M; Van Winkle, Laura S

    2016-06-01

    Ambient ultrafine particulate matter (UPM), less than 100 nm in size, has been linked to the development and exacerbation of pulmonary diseases. Age differences in susceptibility to UPM may be due to a difference in delivered dose as well as age-dependent differences in lung biology and clearance. In this study, we developed and characterized aerosol exposures to novel metal oxide nanoparticles containing lanthanides to study particle deposition in the developing postnatal rat lung. Neonatal, juvenile and adult rats (1, 3 and 12 weeks old) were nose only exposed to 380 μg m(-3) of ∼30 nm europium doped gadolinium oxide nanoparticles (Gd2O3:Eu(3+)) for 1 h. The deposited dose in the nose, extrapulmonary airways and lungs was determined using inductively-coupled plasma mass spectroscopy. The dose of deposited particles was significantly greater in the juvenile rats at 2.22 ng per g body weight compared to 1.47 ng per g and 0.097 ng per g for the adult and neonate rats, respectively. Toxicity was investigated in bronchoalveolar lavage fluid (BALF) by quantifying recovered cell types, and measuring lactate dehydrogenase activity and total protein. The toxicity data suggests that the lanthanide particles were not acutely toxic or inflammatory with no increase in neutrophils or lactate dehydrogenase activity at any age. Juvenile and adult rats had the same mass of deposited NPs per gram of lung tissue, while neonatal rats had significantly less NPs deposited per gram of lung tissue. The current study demonstrates the utility of novel lanthanide-based nanoparticles to study inhaled particle deposition in vivo and has important implications for nanoparticles delivery to the developing lung either as therapies or as a portion of particulate matter air pollution. PMID:27198643

  12. Contributions of low molecular weight carboxylic acids to aerosols and wet deposition in a natural subtropical broad-leaved forest environment

    NASA Astrophysics Data System (ADS)

    Tsai, Ying I.; Kuo, Su-Ching

    2013-12-01

    The carboxylic acid component of autumn aerosol and wet deposition (fog water and rainwater) in a broad-leaved forest in central Taiwan was investigated. High levels of low molecular weight carboxylic acids (LMWCAs) were noted in all deposition types. Acetic acid, oxalic acid and formic acid were the most prevalent carboxylic acids, together accounting for 72.2% (fog water), 86.7% (rain water), 77.2% (PM2.5) and 88.3% (PM2.5-10) of total carboxylic acid. The forest fog water contained 2453.9 ± 1030.5 ng mL-1 of carboxylic acid, 2.71 times more than was contained in forest rainwater. In PM, most carboxylic acid existed in the fine PM2.5 aerosol (576.6 ± 254.1 ng m-3 or 6.28 times more than was contained in PM2.5-10. Most carboxylic acids in PM had higher concentrations during the day. Pyruvic acid concentration was higher during the night (2.97 times), however, owing to its rapid photodegradation during the day. Citric acid accounted for 9.1% of the total carboxylic acid in fog water compared with just 1.8% in rainwater, confirming its origin from emissions from leaves. Raman spectroscopy was used to observe the photochemical conversion of citric acid into intermediate products and this observation confirmed that the carboxylic acids identified in the forest dry and wet depositions originated directly from biological emissions in the forest environment.

  13. Numerical simulation of emitted particle characteristics and airway deposition distribution of Symbicort(®) Turbuhaler(®) dry powder fixed combination aerosol drug.

    PubMed

    Farkas, Árpád; Jókay, Ágnes; Balásházy, Imre; Füri, Péter; Müller, Veronika; Tomisa, Gábor; Horváth, Alpár

    2016-10-10

    One of the most widespread dry powder fixed combinations used in asthma and chronic obstructive pulmonary disease (COPD) management is Symbicort(®) Turbuhaler(®). The aim of this study was to simulate the deposition distribution of both components of this drug within the airways based on realistic airflow measurements. Breathing parameters of 25 healthy adults (11 females and 14 males) were acquired while inhaling through Turbuhaler(®). Individual specific emitted doses and particle size distributions of Symbicort(®) Turbuhaler(®) were determined. A self-developed particle deposition model was adapted and validated to simulate the deposition of budesonide (inhaled corticosteroid; ICS) and formoterol (long acting β2 agonist; LABA) in the upper airways and lungs of the healthy volunteers. Based on current simulations the emitted doses varied between 50.4% and 92.5% of the metered dose for the ICS, and between 38% and 96.1% in case of LABA component depending on the individual inhalation flow rate. This variability induced a notable inter-individual spread of the deposited lung doses (mean: 33.6%, range: 20.4%-48.8% for budesonide and mean: 29.8%, range: 16.4%-42.9% for formoterol). Significant inter-gender differences were also observed. Average lung dose of budesonide was 29.2% of the metered dose for females and 37% for males, while formoterol deposited with 26.4% efficiency for females and 32.5% for males. Present results also highlighted the importance of breath-holding after inhalation of the drug. About a half of the total lung deposition occurred during breath-hold at 9.6s average breath-hold time. Calculated depositions confirmed appropriate lung deposition of Symbicort(®) Turbuhaler(®) for both genders, however more effort for optimal inhalation technique is advised for persons with low vital capacity. This study demonstrated the possibility of personalized prediction of airway deposition of aerosol drugs by numerical simulations. The methodology

  14. Atomic layer epitaxy of Ruddlesden-Popper SrO(SrTiO{sub 3}){sub n} films by means of metalorganic aerosol deposition

    SciTech Connect

    Jungbauer, M.; Hühn, S.; Moshnyaga, V.; Egoavil, R.; Tan, H.; Verbeeck, J.; Van Tendeloo, G.

    2014-12-22

    We report an atomic layer epitaxial growth of Ruddlesden-Popper (RP) thin films of SrO(SrTiO{sub 3}){sub n} (n = ∞, 2, 3, 4) by means of metalorganic aerosol deposition (MAD). The films are grown on SrTiO{sub 3}(001) substrates by means of a sequential deposition of Sr-O/Ti-O{sub 2} atomic monolayers, monitored in-situ by optical ellipsometry. X-ray diffraction and transmission electron microscopy (TEM) reveal the RP structure with n = 2–4 in accordance with the growth recipe. RP defects, observed by TEM in a good correlation with the in-situ ellipsometry, mainly result from the excess of SrO. Being maximal at the film/substrate interface, the SrO excess rapidly decreases and saturates after 5–6 repetitions of the SrO(SrTiO{sub 3}){sub 4} block at the level of 2.4%. This identifies the SrTiO{sub 3} substrate surface as a source of RP defects under oxidizing conditions within MAD. Advantages and limitations of MAD as a solution-based and vacuum-free chemical deposition route were discussed in comparison with molecular beam epitaxy.

  15. Li-ion conducting Li0.35La0.55TiO3 electrolyte thick films fabricated by aerosol deposition

    NASA Astrophysics Data System (ADS)

    Choi, Jong-Jin; Ahn, Cheol-Woo; Ryu, Jungho; Hahn, Byung-Dong; Kim, Jong-Woo; Yoon, Woon-Ha; Park, Dong-Soo

    2016-01-01

    Lithium lanthanum titanium oxide (Li0.35La0.55TiO3, LLT) films with thickness of 5 ˜ 30 μm were fabricated on a stainless-steel substrates by using aerosol deposition with a micron-sized powder at room temperature, and their Li-ion conductivity values were analyzed and compared with bulk ceramics sintered using the same powder. The crystalline size of the film was controlled by controlling the initial particle size of the LLT powder. The phase formation and the microstructural evolution of the films for different deposition conditions were observed by X-ray diffraction and electron microscopy. The lithium-ion conductivity of the film at room temperature was analyzed by the impedance measurement technique. The LLT bulk ceramic sintered at 1200 °C and LLT film deposited at room-temperature showed total lithium ion conductivity of 8.37 × 10-6 and 6.38 × 10-7 S/cm, respectively.

  16. Tropospheric Aerosols

    NASA Astrophysics Data System (ADS)

    Buseck, P. R.; Schwartz, S. E.

    2003-12-01

    m, PM10=1.1 μg m-3; estimated coefficient of light scattering by particulate matter, σep, at 570 nm=12 Mm-1). (b) High aerosol concentration (PM2.5=43.9 μg m-3; PM10=83.4 μg m-3; estimated σep at 570 nm=245 Mm-1) (reproduced by permission of National Park Service, 2002). Although comprising only a small fraction of the mass of Earth's atmosphere, aerosol particles are highly important constituents of the atmosphere. Special interest has focused on aerosols in the troposphere, the lowest part of the atmosphere, extending from the land or ocean surface typically to ˜8 km at high latitudes, ˜12 km in mid-latitudes, and ˜16 km at low latitudes. That interest arises in large part because of the importance of aerosol particles in geophysical processes, human health impairment through inhalation, environmental effects through deposition, visibility degradation, and influences on atmospheric radiation and climate.Anthropogenic aerosols are thought to exert a substantial influence on Earth's climate, and the need to quantify this influence has sparked much of the current interest in and research on tropospheric aerosols. The principal mechanisms by which aerosols influence the Earth radiation budget are scattering and absorbing solar radiation (the so-called "direct effects") and modifying clouds and precipitation, thereby affecting both radiation and hydrology (the so-called "indirect effects"). Light scattering by aerosols increases the brightness of the planet, producing a cooling influence. Light-absorbing aerosols such as black carbon exert a warming influence. Aerosols increase the reflectivity of clouds, another cooling influence. These radiative influences are quantified as forcings, where a forcing is a perturbation to the energy balance of the atmosphere-Earth system, expressed in units of watts per square meter, W m-2. A warming influence is denoted a positive forcing, and a cooling influence, negative. The radiative direct and indirect forcings by

  17. The Effect of Ultrafine Aerosol (0.5 to 50 NM (0.05 Micrometers)) on the Deposition of Radon Progeny in Human Lungs and Implications for the Measurement of Exposure.

    NASA Astrophysics Data System (ADS)

    Schmalbeck, Linda Michaels

    1995-01-01

    Despite a generally acknowledged public health risk from indoor exposure to airborne radon progeny, measurement techniques in current use do not provide sufficient information to assess risk from exposures in the home. By contrast, a simple, direct, measurement (the working level month) is a reliable starting point for the evaluation of miners' risks from radon progeny exposure. Ultrafine particles (0.5 to 50 nm in diameter) are frequently present in room air, especially during high occupancy times when activities like cooking and cleaning are taking place; but they are virtually absent from mine air. Measurement techniques used to evaluate mine and indoor air exposures do not supply any size-based data. Few studies of ultrafine aerosol deposition in humans have been undertaken, and none of these has specifically examined ultrafine particle deposition in the radiosensitive bronchial region of the respiratory tract. In this research, the effect of ultrafine aerosol on radon progeny deposition in the bronchial airways was studied using: (1) a unique human exposure data base involving 8 men and 4 women volunteers, (2) a mathematical model describing the attachment behavior of radon progeny in the presence of aerosol developed as part of this work, and (3) a human respiratory-tract deposition model. The addition of ultrafine aerosol to the air breathed by human subjects more than doubled the amount of radon progeny activity deposited in the bronchial region of the subjects' lungs, although radon gas concentration was held constant during all exposure experiments. The gamma activity measured in vivo remained higher at all times after exposure to ultrafine aerosol, while the rate of gamma activity clearance from the region was, on average, about 40 percent faster following ultrafine aerosol exposure. The human exposure data demonstrated that some aerosol size information is crucial to the determination of regional lung deposition and, consequently, the calculation of

  18. Polycyclic aromatic hydrocarbon and elemental carbon size distributions in Los Angeles aerosol: Source resolution and deposition velocities

    SciTech Connect

    Venkataraman, C.

    1992-01-01

    Particulate PAH size distributions for several species were measured, for the first time, at three ambient sites in Los Angeles. PAH size distributions in automobile exhaust were also measured by sampling aerosol in two traffic tunnels. A low flow impactor was used to minimize sampling losses in combination with a high resolution analysis method based on HPLC and fluorescence detection. Elemental carbon size distributions were measured using a thermal evolution method and flame ionization detection. Differences in ambient concentrations and size distributions are explained in terms of location within the basin, seasonal variations and differences in species reactivity and volatility. Differences between tunnel and ambient size distributions are explained in terms of gas to particle conversion. A particle morphology study confirmed that the structure of primary particles (0.05-0.5 [mu]m) is similar to soot agglomerates while the accumulation mode particles (0.5-1 [mu]m) are coated with a film of liquid aerosol. PAH profiles were estimated for the automobile source from the traffic tunnel measurements. These were used along with a characteristic PAH profile for meat cooking to apportion ambient aerosol PAH concentrations at Pico Rivera and Upland. Model estimates show that the Pico Rivera site is dominated by auto emissions which account for over 90% of all PAH (exception chrysene, 75%) and CO concentrations measured at the site. 61% of the EC concentration was explained by the model and attributed to auto emissions. In contrast, meat cooking operations contributed significantly (20 to 80%) to the concentrations of 2-4 ring PAH measured at Upland. The 5-ring and larger PAH were attributed to auto emissions at this site as well.

  19. Thermoluminescent aerosol analysis

    NASA Technical Reports Server (NTRS)

    Rogowski, R. S.; Long, E. R., Jr. (Inventor)

    1977-01-01

    A method for detecting and measuring trace amounts of aerosols when reacted with ozone in a gaseous environment was examined. A sample aerosol was exposed to a fixed ozone concentration for a fixed period of time, and a fluorescer was added to the exposed sample. The sample was heated in a 30 C/minute linear temperature profile to 200 C. The trace peak was measured and recorded as a function of the test aerosol and the recorded thermoluminescence trace peak of the fluorescer is specific to the aerosol being tested.

  20. The Studies on Aerosol Transport, Its Deposition, and Its Impact on Climate - the Study on the Surface Material Circulation can Connect from the Past to the Future

    NASA Technical Reports Server (NTRS)

    Yasunari, Teppei

    2012-01-01

    Recently the issue on glacier retreats comes up and many factors should be relevant to the issue. The absorbing aerosols such as dust and black carbon (BC) are considered to be one of the factors. After they deposited onto the snow surface, it will reduce snow albedo (called snow darkening effect) and probably contribute to further melting of glacier. The Goddard Earth Observing System version 5 (GEOS-5) has developed at NASAlGSFC. However, the original snowpack model used in the land surface model in the GEOS-5 did not consider the snow darkening effect. Here we developed the new snow albedo scheme which can consider the snow darkening effect. In addition, another scheme on calculating mass concentrations on the absorbing aerosols in snowpack was also developed, in which the direct aerosol depositions from the chemical transport model in the GEOS-5 were used. The scheme has been validated with the observed data obtained at backyard of the Institute of Low Temperature Science, Hokkaido University, by Dr. Teruo Aoki (Meteorological Research Institute) et al. including me. The observed data was obtained when I was Ph.D. candidate. The original GEOS-5 during 2007-2009 over the Himalayas and Tibetan Plateau region showed more reductions of snow than that of the new GEOS-5 because the original one used lower albedo settings. On snow cover fraction, the new GEOS-5 simulated more realistic snow-covered area comparing to the MODIS snow cover fraction. The reductions on snow albedo, snow cover fraction, and snow water equivalent were seen with statistically significance if we consider the snow darkening effect comparing to the results without the snow darkening effect. In the real world, debris-cover, inside refreezing process, surface flow of lacier, etc. affect glacier mass balance and the simu.latedresults immediately do not affect whole glacier retreating. However, our results indicate that some surface melting over non debris-covered parts of the glacier would be

  1. Inhalational anthrax (Ames aerosol) in naïve and vaccinated New Zealand rabbits: characterizing the spread of bacteria from lung deposition to bacteremia.

    PubMed

    Gutting, Bradford W; Nichols, Tonya L; Channel, Stephen R; Gearhart, Jeffery M; Andrews, George A; Berger, Alan E; Mackie, Ryan S; Watson, Brent J; Taft, Sarah C; Overheim, Katie A; Sherwood, Robert L

    2012-01-01

    There is a need to better understand inhalational anthrax in relevant animal models. This understanding could aid risk assessment, help define therapeutic windows, and provide a better understanding of disease. The aim here was to characterize and quantify bacterial deposition and dissemination in rabbits following exposure to single high aerosol dose (> 100 LD(50)) of Bacillus anthracis (Ames) spores immediately following exposure through 36 h. The primary goal of collecting the data was to support investigators in developing computational models of inhalational anthrax disease. Rabbits were vaccinated prior to exposure with the human vaccine (Anthrax Vaccine Adsorbed, AVA) or were sham-vaccinated, and were then exposed in pairs (one sham and one AVA) so disease kinetics could be characterized in equally-dosed hosts where one group is fully protected and is able to clear the infection (AVA-vaccinated), while the other is susceptible to disease, in which case the bacteria are able to escape containment and replicate uncontrolled (sham-vaccinated rabbits). Between 4-5% of the presented aerosol dose was retained in the lung of sham- and AVA-vaccinated rabbits as measured by dilution plate analysis of homogenized lung tissue or bronchoalveolar lavage (BAL) fluid. After 6 and 36 h, >80% and >96%, respectively, of the deposited spores were no longer detected in BAL, with no detectable difference between sham- or AVA-vaccinated rabbits. Thereafter, differences between the two groups became noticeable. In sham-vaccinated rabbits the bacteria were detected in the tracheobronchial lymph nodes (TBLN) 12 h post-exposure and in the circulation at 24 h, a time point which was also associated with dramatic increases in vegetative CFU in the lung tissue of some animals. In all sham-vaccinated rabbits, bacteria increased in both TBLN and blood through 36 h at which point in time some rabbits succumbed to disease. In contrast, AVA-vaccinated rabbits showed small numbers of CFU in

  2. Inhalational anthrax (Ames aerosol) in naïve and vaccinated New Zealand rabbits: characterizing the spread of bacteria from lung deposition to bacteremia

    PubMed Central

    Gutting, Bradford W.; Nichols, Tonya L.; Channel, Stephen R.; Gearhart, Jeffery M.; Andrews, George A.; Berger, Alan E.; Mackie, Ryan S.; Watson, Brent J.; Taft, Sarah C.; Overheim, Katie A.; Sherwood, Robert L.

    2012-01-01

    There is a need to better understand inhalational anthrax in relevant animal models. This understanding could aid risk assessment, help define therapeutic windows, and provide a better understanding of disease. The aim here was to characterize and quantify bacterial deposition and dissemination in rabbits following exposure to single high aerosol dose (> 100 LD50) of Bacillus anthracis (Ames) spores immediately following exposure through 36 h. The primary goal of collecting the data was to support investigators in developing computational models of inhalational anthrax disease. Rabbits were vaccinated prior to exposure with the human vaccine (Anthrax Vaccine Adsorbed, AVA) or were sham-vaccinated, and were then exposed in pairs (one sham and one AVA) so disease kinetics could be characterized in equally-dosed hosts where one group is fully protected and is able to clear the infection (AVA-vaccinated), while the other is susceptible to disease, in which case the bacteria are able to escape containment and replicate uncontrolled (sham-vaccinated rabbits). Between 4–5% of the presented aerosol dose was retained in the lung of sham- and AVA-vaccinated rabbits as measured by dilution plate analysis of homogenized lung tissue or bronchoalveolar lavage (BAL) fluid. After 6 and 36 h, >80% and >96%, respectively, of the deposited spores were no longer detected in BAL, with no detectable difference between sham- or AVA-vaccinated rabbits. Thereafter, differences between the two groups became noticeable. In sham-vaccinated rabbits the bacteria were detected in the tracheobronchial lymph nodes (TBLN) 12 h post-exposure and in the circulation at 24 h, a time point which was also associated with dramatic increases in vegetative CFU in the lung tissue of some animals. In all sham-vaccinated rabbits, bacteria increased in both TBLN and blood through 36 h at which point in time some rabbits succumbed to disease. In contrast, AVA-vaccinated rabbits showed small numbers of CFU in

  3. Synthesizing organic compounds by photocatalytic oxidation on TiO{sub 2} films deposited in flame aerosol reactors

    SciTech Connect

    Wang, Z.M.; Biswas, P.; Sahle-Demessie, E.; Gonzalez, M.

    1999-07-01

    The partial oxidation of cyclohexane to cyclohexanol and cyclohexanone on uv irradiated titanium dioxide films was studied at ambient temperatures and pressures. The oxidation efficiencies of different film reactors fabricated by three different coating methodologies (dip coating using titanium isopropoxide and commercially available titanium dioxide particles, sol-gel process and flame aerosol process) are compared. Conversions rates, yield of ketone and alcohol, and selectivity for ketone formation are reported for all the film reactors. The film reactor fabricated by the flame coating method showed the highest yield per mass of catalyst used, and showed no coking and deactivation for a total run time of approximately 10 hours (two cycles). The flame aerosol coating resulted in the formation of high surface area aggregates consisting of nanometer sized primary particles with higher particle density, whereas dip coating resulted in formation of bulk crystallites that were more susceptible to coking and deactivation. All the films were characterized by XRD, SEM and TEM to establish the phase compositions and their morphologies. The methodology incorporates the concepts of Green Chemistry and Engineering for the production of oxygenates in an energy efficient, selective manner, and by producing less by products and pollutants in comparison to conventional techniques.

  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. Effect of doping on the Structural and Optical Properties of SnO2 Thin Films fabricated by Aerosol Assisted Chemical Vapor Deposition

    NASA Astrophysics Data System (ADS)

    Mansoor Ali, Syed; Tajammul Hussain, Syed; Abu Bakar, Shahzad; Muhammad, Jan; Rehman, Naeem ur

    2013-06-01

    In order to achieve high conductivity and transmittance of transparent conducting oxide (TCO), we attempted to fabricate Mg doped SnO2 (MgxSn1-xO2) thin films and characterized them for their structural and optical properties. The MgxSn1-xO2 thin films have been deposited on glass substrate by using aero-sole assisted chemical vapor deposition (AACVD). The molar concentration of Mg concentration was changed from 0 to 8%. The confirmation of tetragonal structure and particle size (32 to 87nm) has been calculated of thin films by XRD. The surface roughness is decreased with the increase of the dopant concentration, which has been investigated by atomic force microscopy (AFM). The optical transmission has increased from 54 to 78% and the band gape of pure SnO2 has been found to be in the range of 3.76eV and it is shifted to 3.69eV for 6Wt % Mg doping and then increase on further increasing the Mg doping.

  6. Synergy of multispectral and multisensors satellite observations to evaluate desert aerosol transport and impact of dust deposition on inland waters: study case of Lake Garda

    NASA Astrophysics Data System (ADS)

    Di Nicolantonio, Walter; Cazzaniga, Ilaria; Cacciari, Alessandra; Bresciani, Mariano; Giardino, Claudia

    2015-01-01

    The capabilities of different Earth Observation multispectral satellites are employed for detecting and tracking of desert dust coming from North Africa toward the Northern Italy area and for evaluating the impact of Saharan dust deposition in inland waters, such as those of Lake Garda. Absorbing and scattering spectral optical properties of desert aerosol in the atmospheric windows in the ultraviolet, visible-near-infrared, and infrared spectral ranges are exploited in the dust retrieval performed by OMI/Aura, MODIS/Terra-Aqua, and SEVIRI/MSG satellite sensors. Therefore, the direct link between dust deposition and increase in phytoplankton abundance has been assessed retrieving MERIS-based chlorophyll-a (chl-a) concentration for the desert dust events. Estimates of the increased chl-a in the lake have been derived with values in concentration from 30% to 170%. AERONET sun-photometer measurements, gravimetric particulate matter samplings, in situ chl-a concentration and surface temperature are employed to select events and assess the presence of desert dust and recognize a corresponding increase of the phytoplankton abundance in the analyzed inland waters. The improved observational features that will be provided by the next European Sentinels missions, namely Sentinel-2, 3, 4, 5P, together with MTG-I (Imager) and MTG-S (Sounder) will allow better monitoring atmospheric constituents and studying the environmental impacts of desert dust transport.

  7. The aerosol assisted chemical vapour deposition of SnSe and Cu₂SnSe₃ thin films from molecular precursors.

    PubMed

    Kevin, Punarja; Malik, Sajid N; Malik, Mohammad A; O'Brien, Paul

    2014-11-28

    Tin selenide (SnSe) and copper tin selenide (Cu2SnSe3) thin films have been deposited onto glass substrates by AACVD using [Sn(Ph2PSe2)2] or a mixture of [Sn(Ph2PSe2)2] and [Cu(acac)2] respectively. PMID:25284472

  8. Influence of the voltage waveform during nanocomposite layer deposition by aerosol-assisted atmospheric pressure Townsend discharge

    NASA Astrophysics Data System (ADS)

    Profili, J.; Levasseur, O.; Naudé, N.; Chaneac, C.; Stafford, L.; Gherardi, N.

    2016-08-01

    This work examines the growth dynamics of TiO2-SiO2 nanocomposite coatings in plane-to-plane Dielectric Barrier Discharges (DBDs) at atmospheric pressure operated in a Townsend regime using nebulized TiO2 colloidal suspension in hexamethyldisiloxane as the growth precursors. For low-frequency (LF) sinusoidal voltages applied to the DBD cell, with voltage amplitudes lower than the one required for discharge breakdown, Scanning Electron Microscopy of silicon substrates placed on the bottom DBD electrode reveals significant deposition of TiO2 nanoparticles (NPs) close to the discharge entrance. On the other hand, at higher frequencies (HF), the number of TiO2 NPs deposited strongly decreases due to their "trapping" in the oscillating voltage and their transport along the gas flow lines. Based on these findings, a combined LF-HF voltage waveform is proposed and used to achieve significant and spatially uniform deposition of TiO2 NPs across the whole substrate surface. For higher voltage amplitudes, in the presence of hexamethyldisiloxane and nitrous oxide for plasma-enhanced chemical vapor deposition of inorganic layers, it is found that TiO2 NPs become fully embedded into a silica-like matrix. Similar Raman spectra are obtained for as-prepared TiO2 NPs and for nanocomposite TiO2-SiO2 coating, suggesting that plasma exposure does not significantly alter the crystalline structure of the TiO2 NPs injected into the discharge.

  9. Particle Deposition in Granular Media

    SciTech Connect

    Tien, C.

    1992-01-01

    Objective is to understand aerosol deposition from gas streams flowing through granular media; this is important to the design of granular filtration systems. The following investigations were carried out: transient behavior of granular filtration of aerosols, and stochastic simulation of aerosol deposition in granular media.

  10. Interglacial Greenland aerosol deposition: comparison of continuous high resolution chemical ice core records from the Eemian and Holocene

    NASA Astrophysics Data System (ADS)

    Gfeller, Gideon; Bigler, Matthias; Schüpbach, Simon; Mini, Olivia; Leuenberger, Daiana; Fischer, Hubertus

    2014-05-01

    Earth's climate system has been oscillating over the last million years between cold glacials and warm interglacials, leaving the imprints of their climate states in form of isotopes variations and chemical impurities in polar ice caps. In the course of the North Greenland Eemian Ice Drilling (NEEM) project, the NEEM ice core has been entirely analysed in very high depth resolution with a Continuous Flow Analysis (CFA) system for the concentrations of chemical aerosol tracers in the ice. Only in the brittle ice zone (600-1100 m depth equivalent to the time interval 3000-8000 years before present) most of the ice had to be discarded due to multifractured core material. Based on the unique reconstructed age scale to unfold the stratigraphically disturbed part from about 2200 m depth downwards (NEEM community members, Nature, 2013), we are able to present the first Greenland chemistry record over the entire last interglacial, the so called Eemian period (about 128'000 to 115'000 years ago). As the Eemian is believed to have been 4 to 8 degrees C warmer than the modern climate, it can be used as an analogue for our present warming climate and, thus, contributes to a better understanding of processes causing natural variations. By means of the chemistry records we are able to assess the natural variability of Greenland Eemian climate and gain insight in its biogeochemical state. Here, short-term variability as well as long term trends of soluble chemical impurities in the Eemian are investigated and compared with those in the Holocene. Changes of organic processes in soils and biomass burning for example are assessed through soluble ammonium and nitrate concentrations. In comparison to the Holocene, ammonium concentrations were about 25% higher during the Eemian. Nitrate, on the other hand, shows about 25% lower concentrations. Sodium concentrations, reflecting changes in sea salt aerosol, are about 35% lower during the Eemian than during the Holocene. Calcium

  11. Aerosol deposition (trace elements and black carbon) over the highest glacier of the Eastern European Alps during the last centuries

    NASA Astrophysics Data System (ADS)

    Bertò, Michele; Barbante, Carlo; Gabrieli, Jacopo; Gabrielli, Paolo; Spolaor, Andrea; Dreossi, Giuliano; Laj, Paolo; Zanatta, Marco; Ginot, Patrick; Fain, Xavier

    2016-04-01

    are Li, Na, Mg, Al, K, Ca, Ti, V, Mn, Fe, Ni, Cu, Zn, Rb, Ag, Cd, Sb, I, Ba, Pt, Tl, Pb and U. Trace elements concentrations in the Ortles snow are related to the emissions from the Po Valley, one of the most polluted region of Europe. The results show an increase in the concentration of many heavy metals due to anthropogenic emissions, mainly from the onset of the Industrial Revolution. rBC is one of the most important aerosol species affecting the climate system, particularly the glaciers, by modifying the radiative energy balance. A significant increase of rBC was found in the ice identifying this kind of aerosol as a responsible in forcing the end of the LIA.

  12. Modeling Deposition of Inhaled Particles

    EPA Science Inventory

    The mathematical modeling of the deposition and distribution of inhaled aerosols within human lungs is an invaluable tool in predicting both the health risks associated with inhaled environmental aerosols and the therapeutic dose delivered by inhaled pharmacological drugs. Howeve...

  13. Three air quality studies: Great Lakes ozone formation and nitrogen dry deposition; and Tucson aerosol chemical characterization

    NASA Astrophysics Data System (ADS)

    Foley, Theresa

    (arsenic, beryllium, cadmium, chromium, cobalt, lead, manganese, and nickel) in the southern Tucson metropolitan area. A Tucson company that uses beryllium oxide to manufacture thermally conductive ceramics has prompted strong citizen concern. This study found that the study area has good air quality with respect to PM10 and metals, with ambient concentrations meeting US Environmental Protection Agency and World Health Organization standards. Beryllium was detected only once (during a dust storm) and was ascribed to naturally-occurring beryllium in the suspended soil. The third paper (to be submitted to the Journal of Great Lakes Research) studies nitrogen dry deposition over Lake Michigan and Lake Superior. Numerous studies have shown that wet and dry deposition of nitrogen has contributed to the eutrophication of coastal waters and declining productivity of marine fisheries. Nitrogen dry deposition over the Great Lakes themselves, as opposed to the shorelines, has not been documented in the peer-reviewed literature. This paper calculates nitrogen dry deposition over Lake Michigan and Lake Superior, using aircraft measurements from the LADCO Aircraft Study, and finds that over-water, nitrogen dry deposition is a significant source of nitrogen to Lake Michigan and Lake Superior.

  14. Investigating the impact of aqueous-phase chemistry and wet deposition on organic aerosol formation using a molecular surrogate modeling approach.

    PubMed

    Couvidat, Florian; Sartelet, Karine; Seigneur, Christian

    2013-01-15

    A molecular surrogate representation of secondary organic aerosol (SOA) formation is used to investigate the effect of aqueous-phase (in clouds and particles) chemical processing and wet deposition on SOA atmospheric concentrations. To that end, the hydrophilic/hydrophobic organic (H(2)O) model was augmented to account for several gas/aqueous-phase equilibria and aqueous-phase processes, including the formation of oxalic, glyoxilic and pyruvic acids, the oxidation of methyl vinyl ketone (MVK) and methacrolein (MACR), the formation of tetrols and organosulfates from epoxydiols (IEPOX), and further oxidation of water-soluble SOA (aging). Among those processes, SOA chemical aging and IEPOX reactions led to the most significant increases (up to 1 μg m(-3) in some areas) in SOA concentrations in a one-month summer simulation over Europe. However, large uncertainties remain in the gas/aqueous-phase partitioning of oxalic acid, MVK, and MACR. Below-cloud scavenging of SOA precursor gases and of gas-phase SVOC was found to affect SOA concentrations by up to 20%, which suggests that it should be taken into account in air quality models.

  15. Aerosol assisted chemical vapour deposition of ZnO films on glass with noble metal and p-type dopants; use of dopants to influence preferred orientation

    NASA Astrophysics Data System (ADS)

    Walters, G.; Parkin, I. P.

    2009-04-01

    The use of aerosol assisted chemical vapour deposition (AACVD) for the formation of zinc oxide and doped ZnO films with control of preferred orientation on glass is reported. Undoped and doped ZnO host matrix films were highly transparent with visible transmission >85%. The Cu (CuO/Cu 2O) doped ZnO thin films were highly coloured and opaque. Undoped and noble metal doped ZnO films had mainly spherical morphology. Aluminium oxide/ZnO composite films had a range of morphologies from spherical to cubic. The XRD patterns for both doped and undoped ZnO films grown at substrate temperatures less than 500 °C showed strong preferred (0 0 2) crystal lattice orientation. The undoped ZnO film at 500 °C exhibited a random crystal orientation pattern for hexagonal ZnO. The introduction of small amounts of Al 2O 3 within the ZnO to form a composite significantly altered the preferred crystal orientation to (1 0 1).

  16. The Use of Additives to Control the Morphology of Thin Films Synthesized Using Aerosol Assisted Chemical Vapour Deposition

    NASA Astrophysics Data System (ADS)

    Kaye, Karl; Turner, David; McKenna, David; Cackett, Adam; Hyett, Geoffrey

    This paper identifies and discusses the use of additives to control the morphology of nanoscale crystalline zinc oxide films, grown using AACVD, principally from a solution of zinc acetate in methanol. We will discuss the use of both positively charged additives such as tetramethylammonium bromide and cetyltrimethylammonium bromide as well as negatively charged additives like sodium dodecylsulphate. Additives such as these, combined with other experimental parameters such as deposition time, have allowed us to control the size of the particles (from 100 to 400 nm in diameter), their orientation, and the regularity of their shape, from rough edged plates to well defined hexagons. We will show that the additives can be used to control morphology consistently over a temperature range of 250-400 °C, and that this technique can be applied generally to a number of additives and solvents.

  17. Dispersion of aerosol particles in the atmosphere: Fukushima

    NASA Astrophysics Data System (ADS)

    Haszpra, Tímea; Lagzi, István; Tél, Tamás

    2013-04-01

    Investigation of dispersion and deposition of aerosol particles in the atmosphere is an essential issue, because they have an effect on the biosphere and atmosphere. Moreover, aerosol particles have different transport properties and chemical and physical transformations in the atmosphere compared to gas phase air pollutants. The motion of a particle is described by a set of ordinary differential equations. The large-scale dynamics in the horizontal direction can be described by the equations of passive scalar advection, but in the vertical direction a well-defined terminal velocity should be taken into account as a term added to the vertical wind component. In the planetary boundary layer turbulent diffusion has an important role in the particle dispersion, which is taken into account by adding stochastic terms to the deterministic equations above. Wet deposition is also an essential process in the lower levels of the atmosphere, however, its precise parameterization is a challenge. For the simulations the wind field and other necessary data were taken from the ECMWF ERA-Interim database. In the case of the Fukushima Daiichi nuclear disaster (March-April 2011) radioactive aerosol particles were also released in the planetary boundary layer. Simulations (included the continuous and varying emission from the nuclear power plant) will be presented for the period of 14-23 March. Results show that wet deposition also has to be taken into consideration in the lower levels of the atmosphere. Furthermore, dynamical system characteristics are evaluated for the aerosol particle dynamics. The escape rate of particles was estimated both with and without turbulent diffusion, and in both cases when there was no wet deposition and also when wet deposition was taken into consideration.

  18. Evaluation of the deposition, translocation and pathological response of brake dust with and without added chrysotile in comparison to crocidolite asbestos following short-term inhalation: Interim results

    SciTech Connect

    Bernstein, David M.; Rogers, Rick; Sepulveda, Rosalina; Kunzendorf, Peter; Bellmann, Bernd; Ernst, Heinrich; Phillips, James I.

    2014-04-01

    Chrysotile has been frequently used in the past in manufacturing brakes and continues to be used in brakes in many countries. This study was designed to provide an understanding of the biokinetics and potential toxicology following inhalation of brake dust following short term exposure in rats. The deposition, translocation and pathological response of brake dust derived from brake pads manufactured with chrysotile were evaluated in comparison to the amphibole, crocidolite asbestos. Rats were exposed by inhalation 6 h/day for 5 days to either brake dust obtained by sanding of brake-drums manufactured with chrysotile, a mixture of chrysotile and the brake dust or crocidolite asbestos. No significant pathological response was observed at any time point in either the brake dust or chrysotile/brake dust exposure groups. The long chrysotile fibers (> 20 μm) cleared quickly with T{sub 1/2} estimated as 30 and 33 days, respectively in the brake dust and the chrysotile/brake dust exposure groups. In contrast, the long crocidolite fibers had a T{sub 1/2} > 1000 days and initiated a rapid inflammatory response in the lung following exposure resulting in a 5-fold increase in fibrotic response within 91 days. These results provide support that brake dust derived from chrysotile containing brake drums would not initiate a pathological response in the lung following short term inhalation. - Highlights: • We evaluated brake dust w/wo added chrysotile in comparison to crocidolite asbestos. • Persistence, translocation, pathological response in the lung and pleural cavity. • Chrysotile cleared rapidly from the lung while the crocidolite asbestos persisted. • No significant pathology observed at any time point in the brake-dust groups. • Crocidolite produced pathological response - Wagner 4 interstitial fibrosis by 32d.

  19. A comparison of natural and passive methods to measure nasal deposition of utrafline aerosols using replicate human upper airway casts

    SciTech Connect

    Cheng, Kuo-Hsi; Swift, D.L.; Cheng, Yung-Sung; Yeh, Hsu-Chi

    1994-11-01

    The risk of lung cancer associated with exposure to radon progeny in underground miners has been investigated extensively by epidemiological studies. Results indicate that exposure to relatively high concentrations of radon progeny in mines is closely linked to an increased occurrence of lung cancer. Current risk estimates for the general population exposed to indoor radon are primarily based on extrapolations from studies of underground miners. To extend these data to radon exposures of the general population in homes, dosimetric modeling is being used to assess the differences in exposure-dose relationships between the mining and home environments. The human upper airways are the first filter against inhaled particles that would otherwise penetrate into the more distal respiratory tract. Understanding of nasal and oral filtration efficiency is the first step in evaluating dose to the lung from exposure to radon progeny. Of the many factors considered in assessing health effects from exposure to radon progeny, particle size and breathing rate are two important parameters that influence deposition patterns in the respiratory tract.

  20. Dielectric strength of voidless BaTiO{sub 3} films with nano-scale grains fabricated by aerosol deposition

    SciTech Connect

    Kim, Hong-Ki; Lee, Young-Hie; Lee, Seung-Hwan; In Kim, Soo; Woo Lee, Chang; Rag Yoon, Jung; Lee, Sung-Gap

    2014-01-07

    In order to investigate the dielectric strength properties of the BaTiO{sub 3} films with nano-scale grains with uniform grain size and no voids, BaTiO{sub 3} films were fabricated with a thickness of 1 μm by an AD process, and the fabricated films were sintered at 800, 900, and 1000 °C in air and reducing atmosphere. The films have superior dielectric strength properties due to their uniform grain size and high density without any voids. In addition, based on investigation of the leakage current (intrinsic) properties, it was confirmed that the sintering conditions of the reducing atmosphere largely increase leakage currents due to generated electrons and doubly ionized oxygen vacancies following the Poole-Frenkel emission mechanism, and increased leakage currents flow at grain boundary regions. Therefore, we conclude that the extrinsic breakdown factors should be eliminated for superior dielectric strength properties, and it is important to enhance grain boundaries by doping acceptors and rare-earth elements.

  1. Rapid deposition process for zinc oxide film applications in pyroelectric devices

    NASA Astrophysics Data System (ADS)

    Hsiao, Chun-Ching; Yu, Shih-Yuan

    2012-10-01

    Aerosol deposition (AD) is a rapid process for the deposition of films. Zinc oxide is a low toxicity and environmentally friendly material, and it possesses properties such as semiconductivity, pyroelectricity and piezoelectricity without the poling process. Therefore, AD is used to accelerate the manufacturing process for applications of ZnO films in pyroelectric devices. Increasing the temperature variation rate in pyroelectric films is a useful method for enhancing the responsivity of pyroelectric devices. In the present study, a porous ZnO film possessing the properties of large heat absorption and high temperature variation rate is successfully produced by the AD rapid process and laser annealing for application in pyroelectric devices.

  2. Nondestructive and rapid determination of nitrate in soil, dry deposits and aerosol samples using KBr-matrix with diffuse reflectance Fourier transform infrared spectroscopy (DRIFTS).

    PubMed

    Verma, Santosh Kumar; Deb, Manas Kanti

    2007-01-23

    This paper presents the development of a new, rapid and precise analytical method for submicrogram levels of nitrate (NO3-) in environmental samples like soil, dry deposit samples, and coarse and fine aerosol particles. The determination of submicrogram levels of nitrate is based on the selection of a quantitative analytical peak at 1385 cm(-1) among the three observed vibrational peaks and preparing calibration curves using different known concentrations of nitrate by diffuse reflectance Fourier transform infra red spectrometric (DRIFTS) technique. Pre-weighed and ground infrared (IR) grade KBr was used as substrate over which remarkably wide range of known concentration of nitrate was sprayed and dried. The dried sample was analyzed by DRIFTS and absorbance was measured. Eight calibration curves for four different concentration ranges of nitrate for absorbance as well as peak area were prepared for samples containing lower and relatively higher values of nitrate. The relative standard deviation (n=8) for the nitrate concentration ranges, 0.05-40, 0.05-1.5, 1.5-25, 5-40 microg/0.1 g KBr were in the range 1.6-2.3% for the above calibration curves. The limit of detection (LOD) of the method is 0.07 microg g(-1) NO3-. The F- and t-tests were performed to check the analytical quality assurance test. The noteworthy feature of the reported method is the noninterference of any of the associated cations. The results were compared with that of ion-chromatographic method with high degree of acceptability. The method can be applied in wide concentration ranges. The method is reagent less, nondestructive, very fast, repeatable, and accurate and has high sample throughput value.

  3. Single and multi-layered core-shell structures based on ZnO nanorods obtained by aerosol assisted chemical vapor deposition

    SciTech Connect

    Sáenz-Trevizo, A.; Amézaga-Madrid, P.; Pizá-Ruiz, P.; Antúnez-Flores, W.; Ornelas-Gutiérrez, C.; Miki-Yoshida, M.

    2015-07-15

    Core–shell nanorod structures were prepared by a sequential synthesis using an aerosol assisted chemical vapor deposition technique. Several samples consisting of ZnO nanorods were initially grown over TiO{sub 2} film-coated borosilicate glass substrates, following the synthesis conditions reported elsewhere. Later on, a uniform layer consisting of individual Al, Ni, Ti or Fe oxides was grown onto ZnO nanorod samples forming the so-called single MO{sub x}/ZnO nanorod core–shell structures, where MO{sub x} was the metal oxide shell. Additionally, a three-layer core–shell sample was developed by growing Fe, Ti and Fe oxides alternately, onto the ZnO nanorods. The microstructure of the core–shell materials was characterized by grazing incidence X-ray diffraction, scanning and transmission electron microscopy. Energy dispersive X-ray spectroscopy was employed to corroborate the formation of different metal oxides. X-ray diffraction outcomes for single core–shell structures showed solely the presence of ZnO as wurtzite and TiO{sub 2} as anatase. For the multi-layered shell sample, the existence of Fe{sub 2}O{sub 3} as hematite was also detected. Morphological observations suggested the existence of an outer material grown onto the nanorods and further microstructural analysis by HR-STEM confirmed the development of core–shell structures in all cases. These studies also showed that the individual Al, Fe, Ni and Ti oxide layers are amorphous; an observation that matched with X-ray diffraction analysis where no apparent extra oxides were detected. For the multi-layered sample, the development of a shell consisting of three different oxide layers onto the nanorods was found. Overall results showed that no alteration in the primary ZnO core was produced during the growth of the shells, indicating that the deposition technique used herein was and it is suitable for the synthesis of homogeneous and complex nanomaterials high in quality and purity. In addition

  4. Aerosol assisted chemical vapour deposition of gas sensitive SnO2 and Au-functionalised SnO2 nanorods via a non-catalysed vapour solid (VS) mechanism.

    PubMed

    Vallejos, Stella; Selina, Soultana; Annanouch, Fatima Ezahra; Gràcia, Isabel; Llobet, Eduard; Blackman, Chris

    2016-01-01

    Tin oxide nanorods (NRs) are vapour synthesised at relatively lower temperatures than previously reported and without the need for substrate pre-treatment, via a vapour-solid mechanism enabled using an aerosol-assisted chemical vapour deposition method. Results demonstrate that the growth of SnO2 NRs is promoted by a compression of the nucleation rate parallel to the substrate and a decrease of the energy barrier for growth perpendicular to the substrate, which are controlled via the deposition conditions. This method provides both single-step formation of the SnO2 NRs and their integration with silicon micromachined platforms, but also allows for in-situ functionalization of the NRs with gold nanoparticles via co-deposition with a gold precursor. The functional properties are demonstrated for gas sensing, with microsensors using functionalised NRs demonstrating enhanced sensing properties towards H2 compared to those based on non-functionalised NRs. PMID:27334232

  5. Aerosol assisted chemical vapour deposition of gas sensitive SnO2 and Au-functionalised SnO2 nanorods via a non-catalysed vapour solid (VS) mechanism.

    PubMed

    Vallejos, Stella; Selina, Soultana; Annanouch, Fatima Ezahra; Gràcia, Isabel; Llobet, Eduard; Blackman, Chris

    2016-06-23

    Tin oxide nanorods (NRs) are vapour synthesised at relatively lower temperatures than previously reported and without the need for substrate pre-treatment, via a vapour-solid mechanism enabled using an aerosol-assisted chemical vapour deposition method. Results demonstrate that the growth of SnO2 NRs is promoted by a compression of the nucleation rate parallel to the substrate and a decrease of the energy barrier for growth perpendicular to the substrate, which are controlled via the deposition conditions. This method provides both single-step formation of the SnO2 NRs and their integration with silicon micromachined platforms, but also allows for in-situ functionalization of the NRs with gold nanoparticles via co-deposition with a gold precursor. The functional properties are demonstrated for gas sensing, with microsensors using functionalised NRs demonstrating enhanced sensing properties towards H2 compared to those based on non-functionalised NRs.

  6. Aerosol assisted chemical vapour deposition of gas sensitive SnO2 and Au-functionalised SnO2 nanorods via a non-catalysed vapour solid (VS) mechanism

    PubMed Central

    Vallejos, Stella; Selina, Soultana; Annanouch, Fatima Ezahra; Gràcia, Isabel; Llobet, Eduard; Blackman, Chris

    2016-01-01

    Tin oxide nanorods (NRs) are vapour synthesised at relatively lower temperatures than previously reported and without the need for substrate pre-treatment, via a vapour-solid mechanism enabled using an aerosol-assisted chemical vapour deposition method. Results demonstrate that the growth of SnO2 NRs is promoted by a compression of the nucleation rate parallel to the substrate and a decrease of the energy barrier for growth perpendicular to the substrate, which are controlled via the deposition conditions. This method provides both single-step formation of the SnO2 NRs and their integration with silicon micromachined platforms, but also allows for in-situ functionalization of the NRs with gold nanoparticles via co-deposition with a gold precursor. The functional properties are demonstrated for gas sensing, with microsensors using functionalised NRs demonstrating enhanced sensing properties towards H2 compared to those based on non-functionalised NRs. PMID:27334232

  7. Aerosol assisted chemical vapour deposition of gas sensitive SnO2 and Au-functionalised SnO2 nanorods via a non-catalysed vapour solid (VS) mechanism

    NASA Astrophysics Data System (ADS)

    Vallejos, Stella; Selina, Soultana; Annanouch, Fatima Ezahra; Gràcia, Isabel; Llobet, Eduard; Blackman, Chris

    2016-06-01

    Tin oxide nanorods (NRs) are vapour synthesised at relatively lower temperatures than previously reported and without the need for substrate pre-treatment, via a vapour-solid mechanism enabled using an aerosol-assisted chemical vapour deposition method. Results demonstrate that the growth of SnO2 NRs is promoted by a compression of the nucleation rate parallel to the substrate and a decrease of the energy barrier for growth perpendicular to the substrate, which are controlled via the deposition conditions. This method provides both single-step formation of the SnO2 NRs and their integration with silicon micromachined platforms, but also allows for in-situ functionalization of the NRs with gold nanoparticles via co-deposition with a gold precursor. The functional properties are demonstrated for gas sensing, with microsensors using functionalised NRs demonstrating enhanced sensing properties towards H2 compared to those based on non-functionalised NRs.

  8. Sulfur mass loading of the atmosphere from volcanic eruptions: Calibration of the ice core record on basis of sulfate aerosol deposition in polar regions from the 1982 El Chichon eruption

    NASA Technical Reports Server (NTRS)

    Sigurdsson, Haraldur; Laj, Paolo

    1990-01-01

    Major volcanic eruptions disperse large quantities of sulfur compound throughout the Earth's atmosphere. The sulfuric acid aerosols resulting from such eruptions are scavenged by snow within the polar regions and appear in polar ice cores as elevated acidity layers. Glacio-chemical studies of ice cores can, thus, provide a record of past volcanism, as well as the means for understanding the fate of volcanic sulfur in the atmosphere. The primary objectives of this project are to study the chemistry and physical properties of volcanic fallout in a Greenland Ice Core in order to evaluate the impact of the volcanic gases on the atmospheric chemistry and the total atmospheric mass of volcanic aerosols emitted by major volcanic eruptions. We propose to compare the ice core record to other atmospheric records performed during the last 10 years to investigate transport and deposition of volcanic materials.

  9. Particle Deposition in Granular Media. Final report

    SciTech Connect

    Tien, C.

    1992-12-31

    Objective is to understand aerosol deposition from gas streams flowing through granular media; this is important to the design of granular filtration systems. The following investigations were carried out: transient behavior of granular filtration of aerosols, and stochastic simulation of aerosol deposition in granular media.

  10. 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.

  11. MODELING DEPOSITION OF INHALED PARTICLES

    EPA Science Inventory

    Modeling Deposition of Inhaled Particles: ABSTRACT

    The mathematical modeling of the deposition and distribution of inhaled aerosols within human lungs is an invaluable tool in predicting both the health risks associated with inhaled environmental aerosols and the therapeut...

  12. Hairy AdS solitons

    NASA Astrophysics Data System (ADS)

    Anabalón, Andrés; Astefanesei, Dumitru; Choque, David

    2016-11-01

    We construct exact hairy AdS soliton solutions in Einstein-dilaton gravity theory. We examine their thermodynamic properties and discuss the role of these solutions for the existence of first order phase transitions for hairy black holes. The negative energy density associated to hairy AdS solitons can be interpreted as the Casimir energy that is generated in the dual filed theory when the fermions are antiperiodic on the compact coordinate.

  13. Particle deposition in granular media: Progress report

    SciTech Connect

    Tien, Chi

    1987-01-01

    This paper discusses topics on particle deposition in granular media. The six topics discussed are: experimental determination of initial collection efficiency in granular beds - an assessment of the effect of instrument sensitivity and the extent of particle bounce-off; deposition of polydispersed aerosols in granular media; in situ observation of aerosol deposition in a two-dimensional model filter; solid velocity in cross-flow granular moving bed; aerosol deposition in granular moving bed; and aerosol deposition in a magnetically stabilized fluidized bed. (LSP)

  14. Evaluating model parameterizations of submicron aerosol scattering and absorption with in situ data from ARCTAS 2008

    NASA Astrophysics Data System (ADS)

    Alvarado, Matthew J.; Lonsdale, Chantelle R.; Macintyre, Helen L.; Bian, Huisheng; Chin, Mian; Ridley, David A.; Heald, Colette L.; Thornhill, Kenneth L.; Anderson, Bruce E.; Cubison, Michael J.; Jimenez, Jose L.; Kondo, Yutaka; Sahu, Lokesh K.; Dibb, Jack E.; Wang, Chien

    2016-07-01

    Accurate modeling of the scattering and absorption of ultraviolet and visible radiation by aerosols is essential for accurate simulations of atmospheric chemistry and climate. Closure studies using in situ measurements of aerosol scattering and absorption can be used to evaluate and improve models of aerosol optical properties without interference from model errors in aerosol emissions, transport, chemistry, or deposition rates. Here we evaluate the ability of four externally mixed, fixed size distribution parameterizations used in global models to simulate submicron aerosol scattering and absorption at three wavelengths using in situ data gathered during the 2008 Arctic Research of the Composition of the Troposphere from Aircraft and Satellites (ARCTAS) campaign. The four models are the NASA Global Modeling Initiative (GMI) Combo model, GEOS-Chem v9-02, the baseline configuration of a version of GEOS-Chem with online radiative transfer calculations (called GC-RT), and the Optical Properties of Aerosol and Clouds (OPAC v3.1) package. We also use the ARCTAS data to perform the first evaluation of the ability of the Aerosol Simulation Program (ASP v2.1) to simulate submicron aerosol scattering and absorption when in situ data on the aerosol size distribution are used, and examine the impact of different mixing rules for black carbon (BC) on the results. We find that the GMI model tends to overestimate submicron scattering and absorption at shorter wavelengths by 10-23 %, and that GMI has smaller absolute mean biases for submicron absorption than OPAC v3.1, GEOS-Chem v9-02, or GC-RT. However, the changes to the density and refractive index of BC in GC-RT improve the simulation of submicron aerosol absorption at all wavelengths relative to GEOS-Chem v9-02. Adding a variable size distribution, as in ASP v2.1, improves model performance for scattering but not for absorption, likely due to the assumption in ASP v2.1 that BC is present at a constant mass fraction

  15. Effect of adding sorbitol to the electroplating solution on the process of depositing lead on copper and the morphology of the film produced

    NASA Astrophysics Data System (ADS)

    Siqueira, J. L. P.; Carlos, I. A.

    The electrodeposition of lead on to a copper substrate from a plumbite solution, 0.1 M Pb(NO 3) 2 + 0.2 M sorbitol + NaOH, was investigated over a range of concentrations of the hydroxide. Interactions between the copper electrode surface and the lead deposit were investigated by the voltammetric technique. From these experiments, it was concluded that underpotential deposition (upd) of lead does not occur on copper and that lead nucleation occurs as soon as deposition is operative from -0.78 V. Energy-dispersive X-ray spectroscopy (EDS) and scanning electron microscopy (SEM) of the lead films corroborates this result. Lead films obtained at -0.78 and -0.90 V were adherent and could be used as a support in battery plates, but this adhesion of lead to copper cannot be attributed to upd. SEM analysis showed that films produced at potentials down to -0.90 V were smooth and that this is the critical potential for a transition from dense to pyramidal or dendritic crystals patterns. The dendritic crystallites can be transformed into a high-purity lead powder.

  16. Value Added?

    ERIC Educational Resources Information Center

    UCLA IDEA, 2012

    2012-01-01

    Value added measures (VAM) uses changes in student test scores to determine how much "value" an individual teacher has "added" to student growth during the school year. Some policymakers, school districts, and educational advocates have applauded VAM as a straightforward measure of teacher effectiveness: the better a teacher, the better students…

  17. 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

  18. 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.

  19. Phytoplankton responses to atmospheric metal deposition in the coastal and open-ocean Sargasso Sea.

    PubMed

    Mackey, Katherine R M; Buck, Kristen N; Casey, John R; Cid, Abigail; Lomas, Michael W; Sohrin, Yoshiki; Paytan, Adina

    2012-01-01

    This study investigated the impact of atmospheric metal deposition on natural phytoplankton communities at open-ocean and coastal sites in the Sargasso Sea during the spring bloom. Locally collected aerosols with different metal contents were added to natural phytoplankton assemblages from each site, and changes in nitrate, dissolved metal concentration, and phytoplankton abundance and carbon content were monitored. Addition of aerosol doubled the concentrations of cadmium (Cd), cobalt (Co), copper (Cu), iron (Fe), manganese (Mn), and nickel (Ni) in the incubation water. Over the 3-day experiments, greater drawdown of dissolved metals occurred in the open ocean water, whereas little metal drawdown occurred in the coastal water. Two populations of picoeukaryotic algae and Synechococcus grew in response to aerosol additions in both experiments. Particulate organic carbon increased and was most sensitive to changes in picoeukaryote abundance. Phytoplankton community composition differed depending on the chemistry of the aerosol added. Enrichment with aerosol that had higher metal content led to a 10-fold increase in Synechococcus abundance in the oceanic experiment but not in the coastal experiment. Enrichment of aerosol-derived Co, Mn, and Ni were particularly enhanced in the oceanic experiment, suggesting the Synechococcus population may have been fertilized by these aerosol metals. Cu-binding ligand concentrations were in excess of dissolved Cu in both experiments, and increased with aerosol additions. Bioavailable free hydrated Cu(2+) concentrations were below toxicity thresholds throughout both experiments. These experiments show (1) atmospheric deposition contributes biologically important metals to seawater, (2) these metals are consumed over time scales commensurate with cell growth, and (3) growth responses can differ between distinct Synechococcus or eukaryotic algal populations despite their relatively close geographic proximity and taxonomic similarity.

  20. Phytoplankton responses to atmospheric metal deposition in the coastal and open-ocean Sargasso Sea.

    PubMed

    Mackey, Katherine R M; Buck, Kristen N; Casey, John R; Cid, Abigail; Lomas, Michael W; Sohrin, Yoshiki; Paytan, Adina

    2012-01-01

    This study investigated the impact of atmospheric metal deposition on natural phytoplankton communities at open-ocean and coastal sites in the Sargasso Sea during the spring bloom. Locally collected aerosols with different metal contents were added to natural phytoplankton assemblages from each site, and changes in nitrate, dissolved metal concentration, and phytoplankton abundance and carbon content were monitored. Addition of aerosol doubled the concentrations of cadmium (Cd), cobalt (Co), copper (Cu), iron (Fe), manganese (Mn), and nickel (Ni) in the incubation water. Over the 3-day experiments, greater drawdown of dissolved metals occurred in the open ocean water, whereas little metal drawdown occurred in the coastal water. Two populations of picoeukaryotic algae and Synechococcus grew in response to aerosol additions in both experiments. Particulate organic carbon increased and was most sensitive to changes in picoeukaryote abundance. Phytoplankton community composition differed depending on the chemistry of the aerosol added. Enrichment with aerosol that had higher metal content led to a 10-fold increase in Synechococcus abundance in the oceanic experiment but not in the coastal experiment. Enrichment of aerosol-derived Co, Mn, and Ni were particularly enhanced in the oceanic experiment, suggesting the Synechococcus population may have been fertilized by these aerosol metals. Cu-binding ligand concentrations were in excess of dissolved Cu in both experiments, and increased with aerosol additions. Bioavailable free hydrated Cu(2+) concentrations were below toxicity thresholds throughout both experiments. These experiments show (1) atmospheric deposition contributes biologically important metals to seawater, (2) these metals are consumed over time scales commensurate with cell growth, and (3) growth responses can differ between distinct Synechococcus or eukaryotic algal populations despite their relatively close geographic proximity and taxonomic similarity

  1. Phytoplankton responses to atmospheric metal deposition in the coastal and open-ocean Sargasso Sea

    PubMed Central

    Mackey, Katherine R. M.; Buck, Kristen N.; Casey, John R.; Cid, Abigail; Lomas, Michael W.; Sohrin, Yoshiki; Paytan, Adina

    2012-01-01

    This study investigated the impact of atmospheric metal deposition on natural phytoplankton communities at open-ocean and coastal sites in the Sargasso Sea during the spring bloom. Locally collected aerosols with different metal contents were added to natural phytoplankton assemblages from each site, and changes in nitrate, dissolved metal concentration, and phytoplankton abundance and carbon content were monitored. Addition of aerosol doubled the concentrations of cadmium (Cd), cobalt (Co), copper (Cu), iron (Fe), manganese (Mn), and nickel (Ni) in the incubation water. Over the 3-day experiments, greater drawdown of dissolved metals occurred in the open ocean water, whereas little metal drawdown occurred in the coastal water. Two populations of picoeukaryotic algae and Synechococcus grew in response to aerosol additions in both experiments. Particulate organic carbon increased and was most sensitive to changes in picoeukaryote abundance. Phytoplankton community composition differed depending on the chemistry of the aerosol added. Enrichment with aerosol that had higher metal content led to a 10-fold increase in Synechococcus abundance in the oceanic experiment but not in the coastal experiment. Enrichment of aerosol-derived Co, Mn, and Ni were particularly enhanced in the oceanic experiment, suggesting the Synechococcus population may have been fertilized by these aerosol metals. Cu-binding ligand concentrations were in excess of dissolved Cu in both experiments, and increased with aerosol additions. Bioavailable free hydrated Cu2+ concentrations were below toxicity thresholds throughout both experiments. These experiments show (1) atmospheric deposition contributes biologically important metals to seawater, (2) these metals are consumed over time scales commensurate with cell growth, and (3) growth responses can differ between distinct Synechococcus or eukaryotic algal populations despite their relatively close geographic proximity and taxonomic similarity. PMID

  2. The origin of vein-type copper-lead-zinc deposits Host in Palaeozoic metamorphic rocks at the Southeast Anatolian Orogenic Belt (Küplüce-Adıyaman, Southeastern Turkey)

    NASA Astrophysics Data System (ADS)

    Akyıldız, Mustafa; Yıldırım, Nail; Gören, Burcu; Yıldırım, Esra; Ilhan, Semiha

    2015-02-01

    The study area is located around the town of Küplüce between the Çelikhan and Sincik districts (Adıyaman, Turkey). Mineralisations are located at the Southeast Anatolian Orogenic Belt. Despite many differential units, especially in age and lithology, that coexist in the region, mineralisation and alteration are only developed in partly concordant/partly disconcordant veins/veinlets of quartz within chlorite schists, sericite schists, mica schists/mica gneisses, quartz schists and metadiabases of the Palaeozoic Pütürge metamorphics. Pyrite, chalcopyrite and sphalerite are dominant minerals in mineral paragenesis. Chalcocite, covellite and carollite are also found in trace amounts. Quartz, calcite, sericite and chlorite are the gang minerals. Silicification, sericitisation, chloritisation, epidotisation and limonitisation are widespread in limited areas around ore veins. The estimated Co/Ni (1.8-4.3) ratio in pyrites belonging to mineralisation deposits indicates that mineralisation in the region is related to magmatic hydrothermal deposits. In addition, REE (rare earth element) contents of mineralisation deposits in chondrite-normalised diagrams are enriched and show a similar trend to that of chondritic values. This indicates that metals that form mineralisation deposits are related to magmatic rocks. Values of δ34S estimated in the Küplüce region vary between 1.6‰ and 2.34‰. Values of δ34S close to 0 indicate that the sulphur forming the mineralisation is of magmatic origin. In addition, δ18O values vary between 8‰ and 10.8‰ and are consistent with magmatic water. Analyses of the fluid inclusions in quartz samples from mineralisation deposits were performed, and the homogenisation temperature was estimated to be between 90 and 150 °C. These temperature values can be explained by the mixing of a solution with surface water. It was determined that mineralisation deposits were vein-type hydrothermal deposits that had developed due to Middle Eocene

  3. Effects of sediment-associated copper to the deposit-feeding snail, Potamopyrgus antipodarum: a comparison of Cu added in aqueous form or as nano- and micro-CuO particles.

    PubMed

    Pang, Chengfang; Selck, Henriette; Misra, Superb K; Berhanu, Deborah; Dybowska, Agnieszka; Valsami-Jones, Eugenia; Forbes, Valery E

    2012-01-15

    Increasing use of engineered nanoparticles (NPs) is likely to result in release of these particles to the aquatic environment where the NPs may eventually accumulate in sediment. However, little is known about the potential ecotoxicity of sediment-associated engineered NPs. We here consider the case of metal oxide NPs using CuO to understand if the effects of NPs differ from micron-sized particles of CuO and aqueous Cu (CuCl₂). To address this issue, we compared effects of copper added to the sediment as aqueous Cu, nano- (6 nm) and micro- (<5 μm) CuO particles on the deposit-feeding snail, Potamopyrgus antipodarum. Effects were assessed as mortality, specific growth rate, feeding rate, reproduction, and bioaccumulation after 8 weeks of exposure to nominal concentrations of 0, 30, 60, 120 and 240 μg Cu/g dry weight sediment. The results demonstrate that copper added to sediment as nano-CuO had greater effects on growth, feeding rate, and reproduction of P. antipodarum than copper added as micro-CuO or aqueous Cu. P. antipodarum accumulated more copper in the nano-CuO treatment than in aqueous Cu or micro-CuO treatments, indicating that consideration of metal form may be important when assessing risks of metals to the aquatic environment.

  4. Improvement in understanding the deposition of ambient dust particles on ECAM (environmental continuous air monitor) filters, reduction of the alpha-particle interference of radon progeny and other radioactive aerosols in different particle size ranges on filters, and development of ECAMs with increased sensitivity under dusty outdoor conditions.

    SciTech Connect

    Schery, Stephen D., Wasiolek, Piotr; Rodgers, John

    1999-06-01

    Improvement in understanding the deposition of ambient dust particles on ECAM (environmental continuous air monitor) filters, reduction of the alpha-particle interference of radon progeny and other radioactive aerosols in different particle size ranges on filters, and development of ECAMs with increased sensitivity under dusty outdoor conditions.

  5. Impact of clouds and precipitation on atmospheric aerosol

    NASA Astrophysics Data System (ADS)

    Andronache, Constantin

    2015-04-01

    Aerosols have a significant impact on the dynamics and microphysics of continental mixed-phase convective clouds. High aerosol concentrations provide enhanced cloud condensation nuclei that can lead to the invigoration of convection and increase of surface rainfall. Such effects are dependent on environmental conditions and aerosol properties. Clouds are not only affected by aerosol, they also alter aerosol properties by various processes. Cloud processing of aerosol includes: convective redistribution, modification in the number and size of aerosol particles, chemical processing, new particle formation around clouds, and aerosol removal by rainfall to the surface. Among these processes, the wet removal during intense rain events, in polluted continental regions, can lead to spikes in acidic deposition into environment. In this study, we address the effects of clouds and precipitation on the aerosol distribution in cases of convective precipitation events in eastern US. We examine the effects of clouds and precipitation on various aerosol species, as well as their temporal and spatial variability.

  6. Evaluation of the deposition, translocation and pathological response of brake dust with and without added chrysotile in comparison to crocidolite asbestos following short-term inhalation: interim results.

    PubMed

    Bernstein, David M; Rogers, Rick; Sepulveda, Rosalina; Kunzendorf, Peter; Bellmann, Bernd; Ernst, Heinrich; Phillips, James I

    2014-04-01

    Chrysotile has been frequently used in the past in manufacturing brakes and continues to be used in brakes in many countries. This study was designed to provide an understanding of the biokinetics and potential toxicology following inhalation of brake dust following short term exposure in rats. The deposition, translocation and pathological response of brake dust derived from brake pads manufactured with chrysotile were evaluated in comparison to the amphibole, crocidolite asbestos. Rats were exposed by inhalation 6 h/day for 5 days to either brake dust obtained by sanding of brake-drums manufactured with chrysotile, a mixture of chrysotile and the brake dust or crocidolite asbestos. No significant pathological response was observed at any time point in either the brake dust or chrysotile/brake dust exposure groups. The long chrysotile fibers (>20 μm) cleared quickly with T(½) estimated as 30 and 33 days, respectively in the brake dust and the chrysotile/brake dust exposure groups. In contrast, the long crocidolite fibers had a T(½)>1000 days and initiated a rapid inflammatory response in the lung following exposure resulting in a 5-fold increase in fibrotic response within 91 days. These results provide support that brake dust derived from chrysotile containing brake drums would not initiate a pathological response in the lung following short term inhalation.

  7. Aerosols and past environments: A global investigation into cave aerosol identification, distribution, and contribution to speleothem geochemistry

    NASA Astrophysics Data System (ADS)

    Dredge, J. A.; Fairchild, I. J.; Harrison, R. M.; Woodhead, J. D.; Hellstrom, J.; Mattey, D.

    2013-12-01

    A new sector of interest is developing within cave science regarding the influence of aerosols on the cave environment and the potential speleothem palaeoenvironmental aerosol record which may be preserved. This paper presents the results from a global collaboration project which explored all aspects of aerosols in the cave environment. Cave aerosol identification, introduction and distribution Cave aerosol multivariable environmental monitoring projects were carried out in the UK, Spain, Austria and Australia. Results demonstrate that cave ventilation is the predominant control on the introduction and distribution of aerosols throughout the cave environment (Dredge et al., 2013). Consequently, aerosol transportation processes vary as a result of seasonal ventilation changes and cave morphological features. Cave aerosol contribution to speleothem geochemistry Aerosol contributions to speleothem geochemistry were determined by comparing monitored aerosol deposition to speleothem trace element data. Significant aerosol contribution scenarios were identified as: hiatus events, high aerosol flux situations and secondary microbial concentration processes. Modelling indicates that a >99.9% reduction in drip water flow rates is required to reduce trace element supply quantities to equal that of aerosol supply (Dredge et al., 2013). Aerosol palaeoclimate and palaeoenvironmental records Aerosol contributions and the ability to utilise aerosol records in speleothem are investigated in samples from Gibraltar and Australia. Long range dust sources and past atmospheric circulation over several glacial cycles is studied through Sr isotope analysis of a Flowstone core from Gibraltar. Results of organic fire proxy analysis from Australian speleothem samples indicate an aerosol deposition forest fire record. In addition to primary fire deposition, secondary biological feedbacks and subsequent bioaccumulation processes in the cave environment are explored by microbial analysis

  8. MDIs: physics of aerosol formation.

    PubMed

    Clark, A R

    1996-03-01

    The aerosol clouds produced by metered dose inhalers are very dynamic and dramatic changes in both droplet size and velocity take place within the first few centimeters of the spray plume. It is the interaction of this dynamic cloud with the geometry of the mouth and oropharynx that controls the extent of oral deposition and hence the ability of the MDI to deliver a respiratory therapeutic to the lung. Oral deposition is controlled by inertial mechanisms and in order to develop meaningful in-vitro test methods consideration must be given to both the velocity and droplet size distribution of the cloud. The correct design of the inlet ports used to convey MDI clouds in aerosol sizing instruments is therefore crucial to the development of successful in-vitro methodologies. The use of large sampling chambers or the characterization of residual aerosol droplets is unlikely to produce meaning product comparisons or satisfactory product control data.

  9. Aerosolized Antibiotics.

    PubMed

    Restrepo, Marcos I; Keyt, Holly; Reyes, Luis F

    2015-06-01

    Administration of medications via aerosolization is potentially an ideal strategy to treat airway diseases. This delivery method ensures high concentrations of the medication in the targeted tissues, the airways, with generally lower systemic absorption and systemic adverse effects. Aerosolized antibiotics have been tested as treatment for bacterial infections in patients with cystic fibrosis (CF), non-CF bronchiectasis (NCFB), and ventilator-associated pneumonia (VAP). The most successful application of this to date is treatment of infections in patients with CF. It has been hypothesized that similar success would be seen in NCFB and in difficult-to-treat hospital-acquired infections such as VAP. This review summarizes the available evidence supporting the use of aerosolized antibiotics and addresses the specific considerations that clinicians should recognize when prescribing an aerosolized antibiotic for patients with CF, NCFB, and VAP.

  10. 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 ...

  11. Exposures to acidic aerosols.

    PubMed

    Spengler, J D; Keeler, G J; Koutrakis, P; Ryan, P B; Raizenne, M; Franklin, C A

    1989-02-01

    Ambient monitoring of acid aerosols in four U.S. cities and in a rural region of southern Ontario clearly show distinct periods of strong acidity. Measurements made in Kingston, TN, and Steubenville, OH, resulted in 24-hr H+ ion concentrations exceeding 100 nmole/m3 more than 10 times during summer months. Periods of elevated acidic aerosols occur less frequently in winter months. The H+ determined during episodic conditions in southern Ontario indicates that respiratory tract deposition can exceed the effects level reported in clinical studies. Observed 12-hr H+ concentrations exceeded 550 nmole/m3 (approximately 27 micrograms/m3 H2SO4). The maximum estimated 1-hr concentration exceeded 1500 nmole/m3 for H+ ions. At these concentrations, an active child might receive more than 2000 nmole of H+ ion in 12 hr and in excess of 900 nmole during the hour when H2SO4 exceeded 50 micrograms/m3.

  12. Aerosol Modeling for the Global Model Initiative

    NASA Technical Reports Server (NTRS)

    Weisenstein, Debra K.; Ko, Malcolm K. W.

    2001-01-01

    The goal of this project is to develop an aerosol module to be used within the framework of the Global Modeling Initiative (GMI). The model development work will be preformed jointly by the University of Michigan and AER, using existing aerosol models at the two institutions as starting points. The GMI aerosol model will be tested, evaluated against observations, and then applied to assessment of the effects of aircraft sulfur emissions as needed by the NASA Subsonic Assessment in 2001. The work includes the following tasks: 1. Implementation of the sulfur cycle within GMI, including sources, sinks, and aqueous conversion of sulfur. Aerosol modules will be added as they are developed and the GMI schedule permits. 2. Addition of aerosol types other than sulfate particles, including dust, soot, organic carbon, and black carbon. 3. Development of new and more efficient parameterizations for treating sulfate aerosol nucleation, condensation, and coagulation among different particle sizes and types.

  13. Size Distribution and Estimated Respiratory Deposition of Total Chromium, Hexavalent Chromium, Manganese, and Nickel in Gas Metal Arc Welding Fume Aerosols

    PubMed Central

    Cena, Lorenzo G.; Chisholm, William P.; Keane, Michael J.; Cumpston, Amy; Chen, Bean T.

    2016-01-01

    A laboratory study was conducted to determine the mass of total Cr, Cr(VI), Mn, and Ni in 15 size fractions for mild and stainless steel gas-metal arc welding (GMAW) fumes. Samples were collected using a nano multi orifice uniform deposition impactor (MOUDI) with polyvinyl chloride filters on each stage. The filters were analyzed by inductively coupled plasma mass spectrometry (ICP-MS) and ion chromatography. Limits of detection (LODs) and quantitation (LOQs) were experimentally calculated and percent recoveries were measured from spiked metals in solution and dry, certified welding-fume reference material. The fraction of Cr(VI) in total Cr was estimated by calculating the ratio of Cr(VI) to total Cr mass for each particle size range. Expected, regional deposition of each metal was estimated according to respiratory-deposition models. The weight percent (standard deviation) of Mn in mild steel fumes was 9.2% (6.8%). For stainless steel fumes, the weight percentages were 8.4% (5.4%) for total Cr, 12.2% (6.5%) for Mn, 2.1% (1.5%) for Ni and 0.5% (0.4%) for Cr(VI). All metals presented a fraction between 0.04 and 0.6 μm. Total Cr and Ni presented an additional fraction <0.03 μm. On average 6% of the Cr was found in the Cr(VI) valence state. There was no statistical difference between the smallest and largest mean Cr(VI) to total Cr mass ratio (p-value D 0.19), hence our analysis does not show that particle size affects the contribution of Cr(VI) to total Cr. The predicted total respiratory deposition for the metal particles was ∼25%. The sites of principal deposition were the head airways (7–10%) and the alveolar region (11–14%). Estimated Cr(VI) deposition was highest in the alveolar region (14%). PMID:26848207

  14. The European aerosol budget in 2006

    NASA Astrophysics Data System (ADS)

    Aan de Brugh, J. M. J.; Schaap, M.; Vignati, E.; Dentener, F.; Kahnert, M.; Sofiev, M.; Huijnen, V.; Krol, M. C.

    2011-02-01

    This paper presents the aerosol budget over Europe in 2006 calculated with the global transport model TM5 coupled to the size-resolved aerosol module M7. Comparison with ground observations indicates that the model reproduces the observed concentrations quite well with an expected slight underestimation of PM10 due to missing emissions (e.g. resuspension). We model that a little less than half of the anthropogenic aerosols emitted in Europe are exported and the rest is removed by deposition. The anthropogenic aerosols are removed mostly by rain (95%) and only 5% is removed by dry deposition. For the larger natural aerosols, especially sea salt, a larger fraction is removed by dry processes (sea salt: 70%, mineral dust: 35%). We model transport of aerosols in the jet stream in the higher atmosphere and an import of Sahara dust from the south at high altitudes. Comparison with optical measurements shows that the model reproduces the Ångström parameter very well, which indicates a correct simulation of the aerosol size distribution. However, we underestimate the aerosol optical depth. Because the surface concentrations are close to the observations, the shortage of aerosol in the model is probably at higher altitudes. We show that the discrepancies are mainly caused by an overestimation of wet-removal rates. To match the observations, the wet-removal rates have to be scaled down by a factor of about 5. In that case the modelled ground-level concentrations of sulphate and sea salt increase by 50% (which deteriorates the match), while other components stay roughly the same. Finally, it is shown that in particular events, improved fire emission estimates may significantly improve the ability of the model to simulate the aerosol optical depth. We stress that discrepancies in aerosol models can be adequately analysed if all models would provide (regional) aerosol budgets, as presented in the current study.

  15. The European aerosol budget in 2006

    NASA Astrophysics Data System (ADS)

    Aan de Brugh, J. M. J.; Schaap, M.; Vignati, E.; Dentener, F.; Kahnert, M.; Sofiev, M.; Huijnen, V.; Krol, M. C.

    2010-09-01

    This paper presents the aerosol budget over Europe in 2006 calculated with the global transport model TM5 coupled to the size-resolved aerosol module M7. Comparison with ground observations indicates that the model reproduces the observed concentrations quite well with an expected slight underestimation of PM10 due to missing emissions (e.g. resuspension). We observe that a little less than half of the anthropogenic aerosols emitted in Europe are exported and the rest is removed by deposition. The anthropogenic aerosols are removed mostly by rain (95%) and only 5% is removed by dry deposition. For the larger natural aerosols, especially sea salt, a larger fraction is removed by dry processes (sea salt: 70%, mineral dust: 35%). We observe transport of aerosols in the jet stream in the higher atmosphere and an import of Sahara dust from the south at high altitudes. Comparison with optical measurements shows that the model reproduces the Ångström parameter very well, which indicates a correct simulation of the aerosol size distribution. However, we observe an underestimation of the aerosol optical depth. Because the surface concentrations are close to the observations, the shortage of aerosol in the model is probably at higher altitudes. We show that the discrepancies are mainly caused by an overestimation of wet-removal rates. To match the observations, the wet-removal rates have to be scaled down by a factor of about 5. In that case the modelled ground-level concentrations of sulphate and sea salt increase by 50% (which deteriorates the match), while other components stay roughly the same. Finally, it is shown that in particular events, improved fire emission estimates may significantly improve the ability of the model to simulate the aerosol optical depth. We stress that discrepancies in aerosol models can be adequately analysed if all models would provide (regional) aerosol budgets, as presented in the current study.

  16. DIS in AdS

    SciTech Connect

    Albacete, Javier L.; Kovchegov, Yuri V.; Taliotis, Anastasios

    2009-03-23

    We calculate the total cross section for the scattering of a quark-anti-quark dipole on a large nucleus at high energy for a strongly coupled N = 4 super Yang-Mills theory using AdS/CFT correspondence. We model the nucleus by a metric of a shock wave in AdS{sub 5}. We then calculate the expectation value of the Wilson loop (the dipole) by finding the extrema of the Nambu-Goto action for an open string attached to the quark and antiquark lines of the loop in the background of an AdS{sub 5} shock wave. We find two physically meaningful extremal string configurations. For both solutions we obtain the forward scattering amplitude N for the quark dipole-nucleus scattering. We study the onset of unitarity with increasing center-of-mass energy and transverse size of the dipole: we observe that for both solutions the saturation scale Q{sub s} is independent of energy/Bjorken-x and depends on the atomic number of the nucleus as Q{sub s}{approx}A{sup 1/3}. Finally we observe that while one of the solutions we found corresponds to the pomeron intercept of {alpha}{sub P} = 2 found earlier in the literature, when extended to higher energy or larger dipole sizes it violates the black disk limit. The other solution we found respects the black disk limit and yields the pomeron intercept of {alpha}{sub P} = 1.5. We thus conjecture that the right pomeron intercept in gauge theories at strong coupling may be {alpha}{sub P} = 1.5.

  17. INDUCED SPUTUM DERIVES FROM THE CENTRAL AIRWAYS: CONFIRMATION USING A RADIOLABELED AEROSOL BOLUS DELIVERY TECHNIQUE

    EPA Science Inventory

    Indirect evidence suggests that induced sputum derives from the surfaces of the bronchial airways. To confirm this experimentally, we employed a radiolabeled aerosol bolus delivery technique that preferentially deposits aerosol in the central airways in humans. We hypothesized th...

  18. Trace Element Determination from the Guliya Ice Core to Characterize Aerosol Deposition over the Western Tibetan Plateau during the Last 500 Years

    NASA Astrophysics Data System (ADS)

    Sierra Hernandez, R.; Gabrielli, P.; Beaudon, E.; Wegner, A.; Thompson, L. G.

    2014-12-01

    The Tibetan Plateau or Third Pole covers over 5 million km2, and has ~46,000 glaciers that collectively contain one of the Earth's largest stores of fresh water. The Guliya ice cap located in the western Kunlun Shan on the Qinghai-Tibetan Plateau, China, is the largest (> 200 km2) ice cap in the subtropical zone. In 1992, a 308.6 m ice core to bedrock was recovered from the Guliya ice cap. The deepest 20 meters yielded the first record extending back through the last glacial cycle found outside of the Polar Regions. Because of its continental location on the northwestern side of the Tibetan Plateau, the atmospheric circulation over the Guliya ice cap is dominated by westerly air flow from the Eurasian region. Therefore the site is expected to be unaffected by the fallout of anthropogenic trace metals originating from the inner Asian continent and rather may serve to characterize trace metal emissions from the western countries. Here we present preliminary results of the determination of 29 trace elements, Rb, Sr, Nb, Mo, Ag, Cd, Sn, Sb, Cs, Ba, Ta, Tl, Pb, Bi, U, Li, Al, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Ge, and As, from Guliya ice core samples spanning the period 1500 - 1992 AD at seasonal (1750-1992 AD) and annual (1500-1750 AD) resolution. This Guliya trace element record will complement the developing records from the Dasuopu glacier, central Himalaya, and from the Puruogangri ice cap in the western Tanggula Shan in central Tibetan Plateau, which in contrast to Guliya are influenced by the monsoon. We investigate the possible sources both natural and anthropogenic of atmospheric trace elements and their fluxes over the Tibetan Plateau during the last 500 years.

  19. Use of beryllium-7 as a surrogate to determine the deposition of metal and polycyclic aromatic hydrocarbon through urban aerosols in Nantes, France

    NASA Astrophysics Data System (ADS)

    Percot, Stéphane; Ruban, Véronique; Roupsard, Pierre; Maro, Denis; Millet, Maurice

    2013-08-01

    The aerodynamic size distribution of the natural radionuclide beryllium-7 (7Be) and associated trace metals, pesticides and polycyclic aromatic hydrocarbons (PAHs) in Nantes (France) was determined during 6 campaigns (conducted from June 2010 to March 2012) using a low-pressure impactor. The activity distribution of 7Be, as measured by a gamma ray spectrometer, was associated with the accumulation mode (with around 85% of the mass < 1 μm) and explained by post condensation processes on the airborne particle. The mass size distribution of heavy metals and PAHs was mainly focused on the accumulation mode as well. Trace metals generally show a unimodal distribution, although bimodal distributions for Zn, Cu, As and Cr could also be observed; these were attributed to re-suspension processes. For PAHs, the size distribution remained unimodal with a mass median diameter (MMD) ranging from 0.31 to 0.68 μm, thus confirming the urban origin. Pesticide concentrations in the atmosphere were low and did not allow determining the size distribution. Given their identical aerodynamic distribution as 7Be, trace metals and PAHs are expected to display a similar dry deposition velocity, which will then allow us to calculate the dry deposition fluxes over this urban area.

  20. What We Can Say About the Roles of Natural and Anthropogenic Aerosols in Climate Change

    NASA Astrophysics Data System (ADS)

    Kahn, Ralph

    2016-07-01

    Although particles from natural sources dominate the globally averaged aerosol load, it is widely understood that human activity has added significantly to the atmospheric aerosol inventory in many regions. Anthropogenic contributions include pollution particles from industrial activity, transportation, cook-stoves, and other combustion sources, smoke from agricultural fires and those wildfires that result from land-management practices, soil and mineral dust mobilized in regions where overgrazing, severe tilling, or overuse of surface water resources have occurred, and biogenic particles from vegetation planted and maintained by the populance. The history of human influence is complex - in the 18th and 19th centuries agricultural burning tended to dominate the anthropogenic component in most places, whereas more recently, fossil fuel combustion leads the human contribution is many areas. However, identifying and quantifying the anthropogenic aerosol component on global scales is a challenging endeavor at present. Most estimates of the anthropogenic component come from aerosol transport models that are initialized with aerosol and precursor-gas source locations, emission strengths, and injection heights. The aerosol is then advected based on meteorological modeling, possibly modified chemically or physically, and removed by parameterized wet or dry deposition processes. Aerosol effects on clouds are also represented in some climate models, but with even greater uncertainty than the direct aerosol effects on Earth's radiation balance. Even for present conditions, aerosol source inventories are deduced from whatever constraints can be found, along with much creativity and many assumptions. Aerosol amount (i.e., aerosol optical depth) is routinely measured globally from space, but observational constraints on the anthropogenic component require some knowledge of the aerosol type as well, a much more difficult quantity to derive. As large-swath, multi-spectral, single

  1. A pathway analysis of global aerosol processes

    NASA Astrophysics Data System (ADS)

    Schutgens, Nick; Stier, Philip

    2014-05-01

    Although budgets for aerosol emission and deposition (macrophysical fluxes) have been studied before, much less is known about the budgets of processes e.g. nucleation, coagulation and condensation. A better understanding of their relative importance would improve our understanding of the aerosol system and help model development and evaluation. Aerosols are not only emitted from and deposited to the Earth's surface but are modified during their transport. The processes for these modifications include nucleation of H2SO4 gas into new aerosol, coagulation with other aerosol and condensation of H2SO4 unto existing aerosol. As a result of these processes, aerosol grow in size and change their chemical composition, often becoming hydrophilic where they were hydrophobic before. This affects their characteristics for various deposition processes (sedimentation, dry or wet deposition) as well as their radiative properties and hence climate forcing by aerosol. We present a complete budget of all aerosol processes in the aerosol-climate model ECHAM-HAM including the M7 microphysics. This model treats aerosol as 7 distinct but interacting two-moment modes of mixed species (soot, organic carbons, sulfate, sea salt and dust). We will show both global budgets as well as regional variations in dominant processes. Some of our conclusions are: condensation of H2SO4 gas onto pre-existing particles is an important process, dominating the growth of small particles in the nucleation mode to the Aitken mode and the ageing of hydrophobic matter. Together with in-cloud production of H2SO4, it significantly contributes to (and often dominates) the mass burden (and hence composition) of the hydrophilic Aitken and accumulation mode particles. Particle growth itself is the leading source of number densities in the hydrophilic Aitken and accumulation modes, with their hydrophobic counterparts contributing (even locally) relatively little. However, the coarse mode is mostly decoupled from the

  2. Particle deposition and clearance of atmospheric particles in the human respiratory tract during LACE 98

    NASA Astrophysics Data System (ADS)

    Bundke, U.; Hänel, G.

    2003-04-01

    During the LACE 98footnote{Lindenberg Aerosol Characterization Experiment, (Germany) 1998} experiment microphysical, chemical and optical properties of atmospheric particles were measured by several groups. (Bundke et al.). The particle deposition and clearance of the particles in the human respiratory tract was calculated using the ICRP (International Commission on Radiological Protection) deposition and clearance model (ICRP 1994). Particle growth as function of relative humidity outside the body was calculated from measurement data using the model introduced by Bundke et al.. Particle growth inside the body was added using a non-equilibrium particle growth model. As a result of the calculations, time series of the total dry particle mass and -size distribution were obtained for all compartments of the human respiratory tract defined by ICRP 1994. The combined ICRP deposition and clearance model was initialized for different probationers like man, woman, children of different ages and several circumstances like light work, sitting, sleeping etc. Keeping the conditions observed during LACE 98 constant a approximation of the aerosol burdens of the different compartments was calculated up to 4 years of exposure and compared to the results from Snipes et al. for the "Phoenix" and "Philadelphia" aerosol. References: footnotesize{ Bundke, U. et al.,it{Aerosol Optical Properties during the Lindenberg Aerosol Characterization Experiment (LACE 98)} ,10.1029/2000JD000188, JGR, 2002 ICRP,it{Human Respiratory Tract Model for Radiological Protection, Bd. ICRP Publication 66}, Annals of the ICRP, 24,1-3, Elsevier Science, Ocford, 1994 Snipes et al. ,it{The 1994 ICRP66 Human Respiratory Tract Model as a Tool for predicting Lung Burdens from Exposure to Environmental Aerosols}, Appl. Occup. Environ. Hyg., 12, 547-553,1997}

  3. The effects of mineral aerosol deposits on the BRDF (bidirectional reflectance distribution function) of sea ice for the calibration of satellite remote sensing products: an experimental and modelling study.

    NASA Astrophysics Data System (ADS)

    Lamare, Maxim; Hedley, John; King, Martin

    2016-04-01

    Knowledge of the albedo in the cryosphere is essential to monitor a range of climatic processes that have an impact on a global scale. Optical Earth Observation satellites are ideal for the synoptic observation of expansive and inaccessible areas, providing large datasets used to derive essential products, such as albedo. The application of remote sensing to investigate climate processes requires the combination of data from different sensors. However, although there is significant value in the analysis of data from individual sensors, global observing systems require accurate knowledge of sensor-to-sensor biases. Therefore, the inter-calibration of sensors used for climate studies is essential to avoid inconsistencies, which may mask climate effects. CEOS (Committee on Earth Observing Satellites) has established a number of natural Earth targets to serve as international reference standards, amongst which sea ice has great potential. The reflectance of natural surfaces is not isotropic and reflectance varies with the illumination and viewing geometries, consequently impacting satellite observations. Furthermore, variations in the physical properties (sea ice type, thickness) and the light absorbing impurities deposited in the sea ice have a strong impact on reflectance. Thus, the characterisation of the bi-directional reflectance distribution function (BRDF) of sea ice is a fundamental step toward the inter-calibration of optical satellite sensors. This study provides a characterisation of the effects of mineral aerosol and black carbon deposits on the BRDF of three different sea ice types. BRDF measurements were performed on bare sea ice grown in an experimental ice tank, using a state-of-the-art laboratory goniometer. The sea ice was "poisoned" with concentrations of mineral dust and black carbon varying between 100 and 5 000 ng g-1 deposited uniformly in a 5 cm surface layer. Using measurements from the experimental facility, novel information about sea ice

  4. Measurement of resuspended aerosol in the Chernobyl area. Part III. Size distribution and dry deposition velocity of radioactive particles during anthropogenic enhanced resuspension.

    PubMed

    Garger, E K; Paretzke, H G; Tschiersch, J

    1998-10-01

    During anthropogenic activities, such as agricultural soil management and traffic on unpaved roads, size distribution measurements were performed of atmospheric particulate radionuclides at a site in the Chernobyl 30-km exclusion zone. Analysis of cascade impactor measurements showed an increase of the total atmospheric radioactivity. In the cases of harrowing by a tractor and traffic on unpaved roads, a common shape of the size distribution was found with two maxima, the first in the 2-4 microm range, the second in the 12-20 microm range. The size distributions were compared to measurements during wind-driven resuspension. Particle number concentration measurements with an Aerodynamic Particle Sizer showed a dynamic dependence of the particle concentration in different size ranges on anthropogenic action. The increase of the mean concentration was for the large particles more than one order of magnitude higher than for fine particles during anthropogenic enhanced resuspension. From the measurement of the mass concentration, the radioactive loading could be estimated. An enrichment of radionuclides on resuspended particles (compared to soil particles) was found, with the highest enrichment for large particles. Micrometeorological considerations showed that large particles may frequently be subject to medium range transport. The dry deposition velocity was measured; the mean value of 0.026 m s(-1) +/- 0.016 m s(-1) is typical for 6-9 microm diameter particles.

  5. Droplet Number Concentration Value Added Product

    2015-08-06

    Cloud droplet number concentration is an important factor in understanding aerosol-cloud interactions. As aerosol concentration increases, it is expected that droplet number concentration (Nd) will increase and droplet size will decrease, for a given liquid water path. This will greatly affect cloud albedo as smaller droplets reflect more shortwave radiation; however, the magnitude and variability of these processes under different environmental conditions is still uncertain.McComiskey et al. (2009) have implemented a method, based onBoers andmore » Mitchell (1994), for calculating Nd from ground-based remote sensing measurements of optical depth and liquid water path. They show that the magnitude of the aerosol-cloud interactions (ACI) varies with a range of factors, including the relative value of the cloud liquid water path (LWP), the aerosol size distribution, and the cloud updraft velocity. Estimates of Nd under a range of cloud types and conditions and at a variety of sites are needed to further quantify the impacts of aerosol cloud interactions. In order to provide data sets for studying aerosol-cloud interactions, the McComiskey et al. (2009) method was implemented as the Droplet Number Concentration (NDROP) value-added product (VAP).« less

  6. Droplet Number Concentration Value Added Product

    SciTech Connect

    Chitra Sivaraman, PNNL

    2015-08-06

    Cloud droplet number concentration is an important factor in understanding aerosol-cloud interactions. As aerosol concentration increases, it is expected that droplet number concentration (Nd) will increase and droplet size will decrease, for a given liquid water path. This will greatly affect cloud albedo as smaller droplets reflect more shortwave radiation; however, the magnitude and variability of these processes under different environmental conditions is still uncertain.McComiskey et al. (2009) have implemented a method, based onBoers and Mitchell (1994), for calculating Nd from ground-based remote sensing measurements of optical depth and liquid water path. They show that the magnitude of the aerosol-cloud interactions (ACI) varies with a range of factors, including the relative value of the cloud liquid water path (LWP), the aerosol size distribution, and the cloud updraft velocity. Estimates of Nd under a range of cloud types and conditions and at a variety of sites are needed to further quantify the impacts of aerosol cloud interactions. In order to provide data sets for studying aerosol-cloud interactions, the McComiskey et al. (2009) method was implemented as the Droplet Number Concentration (NDROP) value-added product (VAP).

  7. MELCOR aerosol transport module modification for NSSR-1

    SciTech Connect

    Merrill, B.J.; Hagrman, D.L.

    1996-03-01

    This report describes modifications of the MELCOR computer code aerosol transport module that will increase the accuracy of calculations for safety analysis of the International Thermonuclear Experimental Reactor (ITER). The modifications generalize aerosol deposition models to consider gases other than air, add specialized models for aerosol deposition during high speed gas flows in ducts, and add models for resuspension of aerosols that are entrained in coolants when these coolants flash. Particular attention has been paid to the adhesion of aerosol particles once they are transported to duct walls. The results of calculations with the modified models have been successfully compared to data from Light Water Reactor Aerosol Containment Experiments (LACE) conducted by an international consortium at Hanford, Washington.

  8. 76 FR 41392 - Interest on Deposits; Deposit Insurance Coverage

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-07-14

    ... From the Federal Register Online via the Government Publishing Office FEDERAL DEPOSIT INSURANCE CORPORATION 12 CFR Parts 329 and 330 RIN 3064-AD78 Interest on Deposits; Deposit Insurance Coverage AGENCY: Federal Deposit Insurance Corporation (FDIC). ACTION: Final rule. SUMMARY: The FDIC is issuing a...

  9. 76 FR 21265 - Interest on Deposits; Deposit Insurance Coverage

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-04-15

    ... From the Federal Register Online via the Government Publishing Office FEDERAL DEPOSIT INSURANCE CORPORATION 12 CFR Parts 329 and 330 RIN 3064-AD78 Interest on Deposits; Deposit Insurance Coverage AGENCY: Federal Deposit Insurance Corporation (FDIC). ACTION: Notice of proposed rulemaking (NPR) and request...

  10. Results from simulated upper-plenum aerosol transport and aerosol resuspension experiments

    SciTech Connect

    Wright, A.L.; Pattison, W.L.

    1984-01-01

    Recent calculational results published as part of the Battelle-Columbus BMI-2104 source term study indicate that, for some LWR accident sequences, aerosol deposition in the reactor primary coolant system (PCS) can lead to significant reductions in the radionuclide source term. Aerosol transport and deposition in the PCS have been calculated in this study using the TRAP-MELT 2 computer code, which was developed at Battelle-Columbus; the status of validation of the TRAP-MELT 2 code has been described in an Oak Ridge National Laboratory (ORNL) report. The objective of the ORNL TRAP-MELT Validation Project, which is sponsored by the Fuel Systems Behavior Research Branch of the US Nuclear Regulatory Commission, is to conduct simulated reactor-vessel upper-plenum aerosol deposition and transport tests. The results from these tests will be used in the ongoing effort to validate TRAP-MELT 2. The TRAP-MELT Validation Project includes two experimental subtasks. In the Aerosol Transport Tests, aerosol transport in a vertical pipe is being studied; this geometry was chosen to simulate aerosol deposition and transport in the reactor-vessel upper-plenum. To date, four experiments have been performed; the results from these tests are presented in this paper. 7 refs., 4 figs., 4 tabs.

  11. Aerosol indirect effect on biogeochemical cycles and climate.

    PubMed

    Mahowald, Natalie

    2011-11-11

    The net effect of anthropogenic aerosols on climate is usually considered the sum of the direct radiative effect of anthropogenic aerosols, plus the indirect effect of these aerosols through aerosol-cloud interactions. However, an additional impact of aerosols on a longer time scale is their indirect effect on climate through biogeochemical feedbacks, largely due to changes in the atmospheric concentration of CO(2). Aerosols can affect land and ocean biogeochemical cycles by physical forcing or by adding nutrients and pollutants to ecosystems. The net biogeochemical effect of aerosols is estimated to be equivalent to a radiative forcing of -0.5 ± 0.4 watts per square meter, which suggests that reaching lower carbon targets will be even costlier than previously estimated.

  12. Targeted Lung Delivery of Nasally Administered Aerosols

    PubMed Central

    Tian, Geng; Hindle, Michael; Longest, P. Worth

    2014-01-01

    Using the nasal route to deliver pharmaceutical aerosols to the lungs has a number of advantages including co-administration during non-invasive ventilation. The objective of this study was to evaluate the growth and deposition characteristics of nasally administered aerosol throughout the conducting airways based on delivery with streamlined interfaces implementing two forms of controlled condensational growth technology. Characteristic conducting airways were considered including a nose-mouth-throat (NMT) geometry, complete upper tracheobronchial (TB) model through the third bifurcation (B3), and stochastic individual path (SIP) model to the terminal bronchioles (B15). Previously developed streamlined nasal cannula interfaces were used for the delivery of submicrometer particles using either enhanced condensational growth (ECG) or excipient enhanced growth (EEG) techniques. Computational fluid dynamics (CFD) simulations predicted aerosol transport, growth and deposition for a control (4.7 μm) and three submicrometer condensational aerosols with budesonide as a model insoluble drug. Depositional losses with condensational aerosols in the cannula and NMT were less than 5% of the initial dose, which represents an order-of-magnitude reduction compared to the control. The condensational growth techniques increased the TB dose by a factor of 1.1–2.6x, delivered at least 70% of the dose to the alveolar region, and produced final aerosol sizes ≥2.5 μm. Compared to multiple commercial orally inhaled products, the nose-to-lung delivery approach increased dose to the biologically important lower TB region by factors as large as 35x. In conclusion, nose-to-lung delivery with streamlined nasal cannulas and condensational aerosols was highly efficient and targeted deposition to the lower TB and alveolar regions. PMID:24932058

  13. Modelling the surface deposition of meteoric smoke particles

    NASA Astrophysics Data System (ADS)

    Brooke, James S. A.; Feng, Wuhu; Mann, Graham W.; Dhomse, Sandip S.; Bardeen, Charles G.; Plane, John M. C.

    2016-04-01

    The flux of meteoric smoke particles (MSPs) in Greenland and Antarctica has been measured using Ir and Pt observations in ice cores, by Gabrielli et al. [1,2]. They obtained MSP deposition fluxes of 1.5 ± 0.45 × 10-4 g m-2 yr-1 (209 ± 63 t d-1) in Greenland and 3.9 ± 1.4 × 10-5 g m-2 yr-1 (55 ± 19 t d-1) in Antarctica, where the values in parentheses are total atmospheric inputs, assuming a uniform global deposition rate. These results show reasonable agreement with those of Lanci et al. [3], who used ice core magnetisation measurements, resulting in MSP fluxes of 1.7 ± 0.23 × 10-4 g m-2 yr-1 (236 ± 50 t d-1) (Greenland) and 2.0 ± 0.52 × 10-5 g m-2 yr-1 (29 ± 5.0 t d-1) (Antarctica). Atmospheric modelling studies have been performed to assess the transport and deposition of MSPs, using WACCM (Whole Atmosphere Community Climate Model), and the CARMA (Community Aerosol and Radiation Model) aerosol microphysics package. An MSP input function totalling 44 t d-1 was added between about 80 and 105 km. Several model runs have been performed in which the aerosol scavenging by precipitation was varied. Wet deposition is expected (and calculated here) to be the main deposition process; however, rain and snow aerosol scavenging coefficients have uncertainties spanning up to two and three orders of magnitude, respectively [4]. The model experiments that we have carried out include simple adjustments of the scavenging coefficients, full inclusion of a parametrisation reported by Wang et al. [4], and a scheme based on aerosol removal where relative humidity > 100 %. The MSP fluxes obtained vary between 1.4 × 10-5 and 2.6 × 10-5 g m-2 yr-1 for Greenland, and 5.1 × 10-6 and 1.7 × 10-5 g m-2 yr-1 for Antarctica. These values are about an order of magnitude lower than the Greenland observations, but show reasonable agreement for Antarctica. The UM (Unified Model), UKCA (United Kingdom Chemistry and Aerosols Model), and GLOMAP (GLObal Model of Aerosol Processes) have

  14. Segmented strings in AdS 3

    NASA Astrophysics Data System (ADS)

    Callebaut, Nele; Gubser, Steven S.; Samberg, Andreas; Toldo, Chiara

    2015-11-01

    We study segmented strings in flat space and in AdS 3. In flat space, these well known classical motions describe strings which at any instant of time are piecewise linear. In AdS 3, the worldsheet is composed of faces each of which is a region bounded by null geodesics in an AdS 2 subspace of AdS 3. The time evolution can be described by specifying the null geodesic motion of kinks in the string at which two segments are joined. The outcome of collisions of kinks on the worldsheet can be worked out essentially using considerations of causality. We study several examples of closed segmented strings in AdS 3 and find an unexpected quasi-periodic behavior. We also work out a WKB analysis of quantum states of yo-yo strings in AdS 5 and find a logarithmic term reminiscent of the logarithmic twist of string states on the leading Regge trajectory.

  15. Polarised black holes in AdS

    NASA Astrophysics Data System (ADS)

    Costa, Miguel S.; Greenspan, Lauren; Oliveira, Miguel; Penedones, João; Santos, Jorge E.

    2016-06-01

    We consider solutions in Einstein-Maxwell theory with a negative cosmological constant that asymptote to global AdS 4 with conformal boundary {S}2× {{{R}}}t. At the sphere at infinity we turn on a space-dependent electrostatic potential, which does not destroy the asymptotic AdS behaviour. For simplicity we focus on the case of a dipolar electrostatic potential. We find two new geometries: (i) an AdS soliton that includes the full backreaction of the electric field on the AdS geometry; (ii) a polarised neutral black hole that is deformed by the electric field, accumulating opposite charges in each hemisphere. For both geometries we study boundary data such as the charge density and the stress tensor. For the black hole we also study the horizon charge density and area, and further verify a Smarr formula. Then we consider this system at finite temperature and compute the Gibbs free energy for both AdS soliton and black hole phases. The corresponding phase diagram generalizes the Hawking-Page phase transition. The AdS soliton dominates the low temperature phase and the black hole the high temperature phase, with a critical temperature that decreases as the external electric field increases. Finally, we consider the simple case of a free charged scalar field on {S}2× {{{R}}}t with conformal coupling. For a field in the SU(N ) adjoint representation we compare the phase diagram with the above gravitational system.

  16. Fractal morphology, imaging and mass spectrometry of single aerosol particles in flight (CXIDB ID 16)

    DOE Data Explorer

    Loh, N. Duane

    2012-06-20

    This deposition includes the aerosol diffraction images used for phasing, fractal morphology, and time-of-flight mass spectrometry. Files in this deposition are ordered in subdirectories that reflect the specifics.

  17. Global Atmospheric Aerosol Modeling

    NASA Technical Reports Server (NTRS)

    Hendricks, Johannes; Aquila, Valentina; Righi, Mattia

    2012-01-01

    Global aerosol models are used to study the distribution and properties of atmospheric aerosol particles as well as their effects on clouds, atmospheric chemistry, radiation, and climate. The present article provides an overview of the basic concepts of global atmospheric aerosol modeling and shows some examples from a global aerosol simulation. Particular emphasis is placed on the simulation of aerosol particles and their effects within global climate models.

  18. Effects of African dust deposition on phytoplankton in the western tropical Atlantic Ocean off Barbados

    NASA Astrophysics Data System (ADS)

    Chien, Chia-Te; Mackey, Katherine R. M.; Dutkiewicz, Stephanie; Mahowald, Natalie M.; Prospero, Joseph M.; Paytan, Adina

    2016-05-01

    Bioassay incubation experiments conducted with nutrients and local atmospheric aerosol amendments indicate that phosphorus (P) availability limited phytoplankton growth in the low-nutrient low-chlorophyll (LNLC) ocean off Barbados. Atmospheric deposition provides a relatively large influx of new nutrients and trace metals to the surface ocean in this region in comparison to other nutrient sources. However, the impact on native phytoplankton is muted due to the high ratio of nitrogen (N) to P (NO3:SRP > 40) and the low P solubility of these aerosols. Atmospheric deposition induces P limitation in this LNLC region by adding more N and iron (Fe) relative to P. This favors the growth of Prochlorococcus, a genus characterized by low P requirements and highly efficient P acquisition mechanisms. A global three-dimensional marine ecosystem model that includes species-specific phytoplankton elemental quotas/stoichiometry and the atmospheric deposition of N, P, and Fe supports this conclusion. Future increases in aerosol N loading may therefore influence phytoplankton community structure in other LNLC areas, thereby affecting the biological pump and associated carbon sequestration.

  19. Lead Isotopic Composition and Trace Metals in Aerosols for Source Apportionment

    NASA Astrophysics Data System (ADS)

    Chien, C. T.; Paytan, A.

    2014-12-01

    Transported thousands of miles away from their source, aerosols can be dispersed and deposition throughout the Earth's surface. Aerosols from natural and industrial sources have different characteristics and health impacts thus it is important to identify their sources. The lead isotopic composition and trace metals in aerosol samples collected in different regions and periods around the world can help us better understand spatial and seasonal variation of aerosol sources. Aerosol samples collected in California, Bermuda, China and the Red Sea have been analyzed. The trace metal and Pb isotopes in these samples provide information regarding the various sources of aerosols to these sites.

  20. Direct impact aerosol sampling by electrostatic precipitation

    DOEpatents

    Braden, Jason D.; Harter, Andrew G.; Stinson, Brad J.; Sullivan, Nicholas M.

    2016-02-02

    The present disclosure provides apparatuses for collecting aerosol samples by ionizing an air sample at different degrees. An air flow is generated through a cavity in which at least one corona wire is disposed and electrically charged to form a corona therearound. At least one grounded sample collection plate is provided downstream of the at least one corona wire so that aerosol ions generated within the corona are deposited on the at least one grounded sample collection plate. A plurality of aerosol samples ionized to different degrees can be generated. The at least one corona wire may be perpendicular to the direction of the flow, or may be parallel to the direction of the flow. The apparatus can include a serial connection of a plurality of stages such that each stage is capable of generating at least one aerosol sample, and the air flow passes through the plurality of stages serially.

  1. Sulfur speciation in individual aerosol particles

    NASA Astrophysics Data System (ADS)

    Neubauer, Kenneth R.; Sum, Stephen T.; Johnston, Murray V.; Wexler, Anthony S.

    1996-08-01

    Sulfur aerosols play an important role in acid deposition and the Earth's energy balance. Important species in these aerosols include methanesulfonates, hydroxymethanesulfonates, sulfates, and sulfites. Because the relative amounts of these species indicate different sources and atmospheric processes, it is important to distinguish them in single-aerosol particles. To accomplish this task, we use rapid single-particle mass spectrometry (RSMS), a technique that permits individual particles to be analyzed in an online mode. Each sulfur species produces a characteristic set of ions in the mass spectra. In simulated marine and urban aerosols the relative amounts of methanesulfonic acid (MSA) and sodium hydroxymethanesulfonate (NaHMSA) in a single particle can be determined from peak area ratios in the mass spectra. Improved quantitation is possible by application of the classification and regression tree (CART) algorithm to distinguish the mass spectra of particles having different compositions. Factors that influence speciation include particle size, morphology, and laser fluence.

  2. 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.

  3. A numerical determination of the evolution of cloud drop spectra due to condensation on natural aerosol particles

    NASA Technical Reports Server (NTRS)

    Lee, I. Y.; Haenel, G.; Pruppacher, H. R.

    1980-01-01

    The time variation in size of aerosol particles growing by condensation is studied numerically by means of an air parcel model which allows entrainment of air and aerosol particles. Particles of four types of aerosols typically occurring in atmospheric air masses were considered. The present model circumvents any assumption about the size distribution and chemical composition of the aerosol particles by basing the aerosol particle growth on actually observed size distributions and on observed amounts of water taken up under equilibrium by a deposit of the aerosol particles. Characteristic differences in the drop size distribution, liquid water content and supersaturation were found for the clouds which evolved from the four aerosol types considered.

  4. Recent Rainfall and Aerosol Chemistry From Bermuda

    NASA Astrophysics Data System (ADS)

    Landing, W. M.; Shelley, R.; Kadko, D. C.

    2014-12-01

    This project was devoted to testing the use of Be-7 as a tracer for quantifying trace element fluxes from the atmosphere to the oceans. Rainfall and aerosol samples were collected between June 15, 2011 and July 27, 2013 at the Bermuda Institute of Ocean Sciences (BIOS) located near the eastern end of the island of Bermuda. Collectors were situated near ground level, clear of surrounding vegetation, at a meteorological monitoring station in front of the BIOS laboratory, about 10 m above sea level. This is a Bermuda Air Quality Program site used for ambient air quality monitoring. To quantify the atmospheric deposition of Be-7, plastic buckets were deployed for collection of fallout over ~3 week periods. Wet deposition was collected for trace element analysis using a specially modified "GEOTRACES" N-CON automated wet deposition collector. Aerosol samples were collected with a Tisch TE-5170V-BL high volume aerosol sampler, modified to collect 12 replicate samples on acid-washed 47mm diameter Whatman-41 filters, using procedures identical to those used for the US GEOTRACES aerosol program (Morton et al., 2013). Aerosol and rainfall samples were analyzed for total Na, Mg, Al, P, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Rb, Sr, Zr, Cd, Sb, Ba, La, Ce, Nd, Pb, Th, and U using ICPMS. Confirming earlier data from Bermuda, strong seasonality in rainfall and aerosol loading and chemistry was observed, particularly for aerosol and rainfall Fe concentrations when Saharan dust arrives in July/August with SE trajectories.

  5. Copper oxide aerosol: generation and characterization.

    PubMed

    Peoples, S M; McCarthy, J F; Chen, L C; Eppelsheimer, D; Amdur, M O

    1988-06-01

    Effluent gases from high temperature systems such as fossil fuel combustion and pyrometallurgical processes contain inorganic material which has the potential to interact with sulfur dioxide (SO2) on the surface of particles to form an irritant aerosol. The submicron fraction of this inorganic material is especially important as the fine particles may penetrate deep into the lung and cause serious health effects. A laboratory furnace was designed to produce a submicrometer copper oxide aerosol to stimulate emissions from copper smelters and other pyrometallurgical operations. The ultimate aim of this research is to investigate the interaction of SO2 and the copper oxide aerosol at different temperatures and humidities in order to determine the reaction products and their potential health effects upon inhalation. The initial work, as presented in this paper, was to reproducibly generate a submicrometer copper oxide aerosol and to characterize it in terms of size, morphology and composition. Two experimental regimes were set up. One admitted filtered air, without water vapor, into the furnace, and the other admitted filtered air and water vapor. The size and morphology of the aerosols were determined using an electrical aerosol analyzer and transmission electron microscopy. The particles appear as chain aggregates with a count median diameter of 0.026 micron when no water vapor was added and 0.031 micron when water vapor was added into the furnace. Composition of the aerosol was determined using x-ray photoelectron spectroscopy. The aerosol, with or without water in the furnace, consists of a mixture of copper(I) oxide and copper(II) hydroxide. PMID:3400592

  6. 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

  7. Age-dependent inverse correlations in CSF and plasma amyloid-β(1–42) concentrations prior to amyloid plaque deposition in the brain of 3xTg-AD mice

    PubMed Central

    Cho, Soo Min; Lee, Sejin; Yang, Seung-Hoon; Kim, Hye Yun; Lee, Michael Jisoo; Kim, Hyunjin Vincent; Kim, Jiyoon; Baek, Seungyeop; Yun, Jin; Kim, Dohee; Kim, Yun Kyung; Cho, Yakdol; Woo, Jiwan; Kim, Tae Song; Kim, YoungSoo

    2016-01-01

    Amyloid-β (Aβ) plays a critical role as a biomarker in Alzheimer’s disease (AD) diagnosis. In addition to its diagnostic potential in the brain, recent studies have suggested that changes of Aβ level in the plasma can possibly indicate AD onset. In this study, we found that plasma Aβ(1–42) concentration increases with age, while the concentration of Aβ(1–42) in the cerebrospinal fluid (CSF) decreases in APPswe, PS1M146V and TauP301L transgenic (3xTg-AD) mice, if measurements were made before formation of ThS-positive plaques in the brain. Our data suggests that there is an inverse correlations between the plasma and CSF Aβ(1–42) levels until plaques form in transgenic mice’s brains and that the plasma Aβ concentration possesses the diagnostic potential as a biomarker for diagnosis of early AD stages. PMID:26830653

  8. Investigating Types and Sources of Organic Aerosol in Rocky Mountain National Park Using Aerosol Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Schurman, M. I.; Lee, T.; Sun, Y.; Schichtel, B. A.; Kreidenweis, S. M.; Collett, J. L.

    2011-12-01

    The Rocky Mountain Atmospheric Nitrogen and Sulfur Study (RoMANS) focuses on identifying pathways and sources of nitrogen deposition in Rocky Mountain National Park (RMNP). Past work has combined measurements from a range of instrumentation such as annular denuders, PILS-IC, Hi-Vol samplers, and trace gas analyzers. Limited information from early RoMANS campaigns is available regarding organic aerosol. While prior measurements have produced a measure of total organic carbon mass, high time resolution measures of organic aerosol concentration and speciation are lacking. One area of particular interest is characterizing the types, sources, and amounts of organic nitrogen aerosol. Organic nitrogen measurements in RMNP wet deposition reveal a substantial contribution to the total reactive nitrogen deposition budget. In this study an Aerodyne High Resolution Time-of-Flight Aerosol Mass Spectrometer (HR-ToF-AMS) was deployed in summer 2010 at RMNP to investigate organic aerosol composition and its temporal variability. The species timeline and diurnal species variations are combined with meteorological data to investigate local transport events and chemistry; transport from the Colorado Front Range urban corridor appears to be more significant for inorganic species than for the overall organic aerosol mass. Considerable variation in organic aerosol concentration is observed (0.5 to 20 μg/m3), with high concentration episodes lasting between hours and two days. High resolution AMS data are analyzed for organic aerosol, including organic nitrogen species that might be expected from local biogenic emissions, agricultural activities, and secondary reaction products of combustion emissions. Positive matrix factorization reveals that semi-volatile oxidized OA, low-volatility oxidized OA, and biomass burning OA comprise most organic mass; the diurnal profile of biomass burning OA peaks at four and nine pm and may arise from local camp fires, while constant concentrations of

  9. Characterization of Speciated Aerosol Direct Radiative Forcing Over California

    SciTech Connect

    Zhao, Chun; Leung, Lai-Yung R.; Easter, Richard C.; Hand, Jenny; Avise, J.

    2013-03-16

    A fully coupled meteorology-chemistry model (WRF-Chem) with added capability of diagnosing the spatial and seasonal distribution of radiative forcings for individual aerosol species over California is used to characterize the radiative forcing of speciated aerosols in California. Model simulations for the year of 2005 are evaluated with various observations including meteorological data from California Irrigation Management Information System (CIMIS), aerosol mass concentrations from US EPA Chemical Speciation Network (CSN) and Interagency Monitoring of Protected Visual Environments (IMPROVE), and aerosol optical depth from AErosol RObotic NETwork (AERONET) and satellites. The model well captures the observed seasonal meteorological conditions over California. Overall, the simulation is able to reproduce the observed spatial and seasonal distribution of mass concentration of total PM2.5 and the relative contribution from individual aerosol species, except the model significantly underestimates the surface concentrations of organic matter (OM) and elemental carbon (EC), potentially due to uncertainty in the anthropogenic emissions of OM and EC and the outdated secondary organic aerosol mechanism used in the model. A sensitivity simulation with anthropogenic EC emission doubled significantly reduces the model low bias of EC. The simulation reveals high anthropogenic aerosol loading over the Central Valley and the Los Angeles metropolitan regions and high natural aerosol (dust) loading over southeastern California. The seasonality of aerosol surface concentration is mainly determined by vertical turbulent mixing, ventilation, and photochemical activity, with distinct characteristics for individual aerosol species and between urban and rural areas. The simulations show that anthropogenic aerosols dominate the aerosol optical depth (AOD). The ratio of AOD to AAOD (aerosol absorption optical depth) shows distinct seasonality with a winter maximum and a summer minimum

  10. Light Absorbing Aerosols in Mexico City

    NASA Astrophysics Data System (ADS)

    Marley, N. A.; Kelley, K. L.; Kilaparty, P. S.; Gaffney, J. S.

    2008-12-01

    The direct effects of aerosol radiative forcing has been identified by the IPCC as a major uncertainty in climate modeling. The DOE Megacity Aerosol Experiment-Mexico City (MAX-Mex), as part of the MILAGRO study in March of 2006, was undertaken to reduce these uncertainties by characterization of the optical, chemical, and physical properties of atmospheric aerosols emitted from this megacity environment. Aerosol samples collected during this study using quartz filters were characterized in the uv-visible-infrared by using surface spectroscopic techniques. These included the use of an integrating sphere approach combined with the use of Kubelka-Munk theory to obtain aerosol absorption spectra. In past work black carbon has been assumed to be the only major absorbing species in atmospheric aerosols with an broad band spectral profile that follows a simple inverse wavelength dependence. Recent work has also identified a number of other absorbing species that can also add to the overall aerosol absorption. These include primary organics from biomass and trash burning and secondary organic aerosols including nitrated PAHs and humic-like substances, or HULIS. By using surface diffuse reflection spectroscopy we have also obtained spectra in the infrared that indicate significant IR absorption in the atmospheric window-region. These data will be presented and compared to spectra of model compounds that allow for evaluation of the potential importance of these species in adding strength to the direct radiative forcing of atmospheric aerosols. This work was supported by the Office of Science (BER), U.S. Department of Energy, Grant No. DE-FG02-07ER64327 as part of the Atmospheric Science Program.

  11. Observation of rates and products in the reaction of NO3 with submicron squalane and squalene aerosol.

    PubMed

    Lee, Lance; Wooldridge, Paul; Nah, Theodora; Wilson, Kevin; Cohen, Ronald

    2013-01-21

    The reactive uptake coefficients γ, for nitrate radical, NO(3), on ∼100 nm diameter squalane and squalene aerosol were measured (1 atm pressure of N(2) and 293 K). For squalane, a branched alkane, γ(NO(3)) of 2.8 × 10(-3) was estimated. For squalene which contains 6 double bonds, γ(NO(3)) was found to be a function of degree of oxidation with an initial value of 0.18 ± 0.03 on fresh particles increasing to 0.82 ± 0.11 on average of over 3 NO(3) reactions per squalene molecule in the aerosol. Synchrotron VUV-ionization aerosol mass spectrometry was used to detect the particle phase oxidation products that include as many as 3 NO(3) subunits added to the squalene backbone. The fraction of squalene remaining in the aerosol follows first order kinetics under oxidation, even at very high oxidation equivalents, which suggests that the matrix remains a liquid upon oxidation. Our calculation indicates a much shorter chemical lifetime for squalene-like particle with respect to NO(3) than its atmospheric lifetime to deposition or wet removal.

  12. Aerosol mobility size spectrometer

    DOEpatents

    Wang, Jian; Kulkarni, Pramod

    2007-11-20

    A device for measuring aerosol size distribution within a sample containing aerosol particles. The device generally includes a spectrometer housing defining an interior chamber and a camera for recording aerosol size streams exiting the chamber. The housing includes an inlet for introducing a flow medium into the chamber in a flow direction, an aerosol injection port adjacent the inlet for introducing a charged aerosol sample into the chamber, a separation section for applying an electric field to the aerosol sample across the flow direction and an outlet opposite the inlet. In the separation section, the aerosol sample becomes entrained in the flow medium and the aerosol particles within the aerosol sample are separated by size into a plurality of aerosol flow streams under the influence of the electric field. The camera is disposed adjacent the housing outlet for optically detecting a relative position of at least one aerosol flow stream exiting the outlet and for optically detecting the number of aerosol particles within the at least one aerosol flow stream.

  13. AdS duals of matrix strings

    NASA Astrophysics Data System (ADS)

    Morales, Jose F.; Samtleben, Henning

    2003-06-01

    We review recent work on the holographic duals of type II and heterotic matrix string theories described by warped AdS3 supergravities. In particular, we compute the spectra of Kaluza-Klein primaries for type I, II supergravities on warped AdS3 × S7 and match them with the primary operators in the dual two-dimensional gauge theories. The presence of non-trivial warp factors and dilaton profiles requires a modification of the familiar dictionary between masses and 'scaling' dimensions of fields and operators. We present these modifications for the general case of domain wall/QFT correspondences between supergravities on warped AdSd+1 × Sq geometries and super Yang-Mills theories with 16 supercharges.

  14. AEROSOL AND GAS MEASUREMENT

    EPA Science Inventory

    Measurements provide fundamental information for evaluating and managing the impact of aerosols on air quality. Specific measurements of aerosol concentration and their physical and chemical properties are required by different users to meet different user-community needs. Befo...

  15. Aerosols and environmental pollution

    NASA Astrophysics Data System (ADS)

    Colbeck, Ian; Lazaridis, Mihalis

    2010-02-01

    The number of publications on atmospheric aerosols has dramatically increased in recent years. This review, predominantly from a European perspective, summarizes the current state of knowledge of the role played by aerosols in environmental pollution and, in addition, highlights gaps in our current knowledge. Aerosol particles are ubiquitous in the Earth’s atmosphere and are central to many environmental issues; ranging from the Earth’s radiative budget to human health. Aerosol size distribution and chemical composition are crucial parameters that determine their dynamics in the atmosphere. Sources of aerosols are both anthropogenic and natural ranging from vehicular emissions to dust resuspension. Ambient concentrations of aerosols are elevated in urban areas with lower values at rural sites. A comprehensive understanding of aerosol ambient characteristics requires a combination of measurements and modeling tools. Legislation for ambient aerosols has been introduced at national and international levels aiming to protect human health and the environment.

  16. Aerosols and environmental pollution.

    PubMed

    Colbeck, Ian; Lazaridis, Mihalis

    2010-02-01

    The number of publications on atmospheric aerosols has dramatically increased in recent years. This review, predominantly from a European perspective, summarizes the current state of knowledge of the role played by aerosols in environmental pollution and, in addition, highlights gaps in our current knowledge. Aerosol particles are ubiquitous in the Earth's atmosphere and are central to many environmental issues; ranging from the Earth's radiative budget to human health. Aerosol size distribution and chemical composition are crucial parameters that determine their dynamics in the atmosphere. Sources of aerosols are both anthropogenic and natural ranging from vehicular emissions to dust resuspension. Ambient concentrations of aerosols are elevated in urban areas with lower values at rural sites. A comprehensive understanding of aerosol ambient characteristics requires a combination of measurements and modeling tools. Legislation for ambient aerosols has been introduced at national and international levels aiming to protect human health and the environment.

  17. Optical measurement of medical aerosol media parameters

    NASA Astrophysics Data System (ADS)

    Sharkany, Josif P.; Zhytov, Nikolay B.; Sichka, Mikhail J.; Lemko, Ivan S.; Pintye, Josif L.; Chonka, Yaroslav V.

    2000-07-01

    The problem of aerosol media parameters measurements are presented in the work and these media are used for the treatment of the patients with bronchial asthma moreover we show the results of the development and the concentration and dispersity of the particles for the long-term monitoring under such conditions when the aggressive surroundings are available. The system for concentration measurements is developed, which consists of two identical photometers permitting to carry out the measurements of the transmission changes and the light dispersion depending on the concentration of the particles. The given system permits to take into account the error, connected with the deposition of the salt particles on the optical windows and the mirrors in the course of the long-term monitoring. For the controlling of the dispersity of the aggressive media aerosols the optical system is developed and used for the non-stop analysis of the Fure-spectra of the aerosols which deposit on the lavsan film. The registration of the information is performed with the help of the rule of the photoreceivers or CCD-chamber which are located in the Fure- plane. With the help of the developed optical system the measurements of the concentration and dispersity of the rock-salt aerosols were made in the medical mines of Solotvino (Ukraine) and in the artificial chambers of the aerosol therapy.

  18. Improving Aerosol Transport to the Arctic in CAM5

    NASA Astrophysics Data System (ADS)

    Wang, H.; Easter, R. C.; Rasch, P.; Wang, M.; Liu, X.; Ghan, S.; Qian, Y.; Yoon, J.; Ma, P.; Vinoj, V.

    2011-12-01

    Of the many factors contributing to the rapid arctic climate change, arctic haze has been identified as a potentially important forcing agent. It has been well established that arctic aerosols largely originate from lower latitudes. Hence, the long-range atmospheric transport of aerosols to the Arctic is of great concern for studying arctic climate change. The treatment of aerosol and cloud processes has been substantially improved in the current version of the Community Atmosphere Model (CAM5) which is widely used in the research of aerosol effects on clouds and climate. However, like many other global models, the CAM5 produces a relatively poor simulation of arctic aerosols and clouds. For example, previous studies have shown that the standard version of CAM5 remarkably underpredicts arctic aerosol concentrations, particularly during the arctic haze season, compared to various measurements. In this study, we focus on improving processes associated with aerosol-cloud interactions, cloud microphysics and macrophysics, and aerosol emission, transformation, removal, and deposition that are key to determining the amount of aerosols reaching the Arctic. Sensitivity experiments are conducted to understand the role of each of the processes and to identify sources of uncertainties, and improvements are made to processes that are not well represented in the CAM5. The evaluation and improvement are guided by aerosol and cloud measurements together with process-oriented model results from the multi-scale aerosol-climate model (PNNL-MMF) that embeds a cloud-resolving model in each CAM5 grid column to explicitly represent convection and aerosol-cloud interactions. Results show that including black carbon (BC) aging process through a more complete 7-mode version of the aerosol module in CAM5 can substantially increase the amount of arctic BC, compared to simulations with the standard 3-mode version, but has minimal effect on other species such as dust and sulfate. Excessive mid

  19. Impact of particle nonsphericity on the development and properties of aerosol models for East Asia

    NASA Astrophysics Data System (ADS)

    Chen, Hao; Cheng, Tianhai; Gu, Xingfa; Wu, Yu

    2015-01-01

    In this paper, the effects of aerosol nonsphericity information on the classification of aerosol models and the associated radiative properties over East Asia are investigated. The radiance measurements and inversions of the Aerosol Robotic Network (AERONET) are used. Four aerosol models over East Asia are obtained by adding the shape information to the clustering analysis. These four aerosols are identified on the basis of their optical properties. Compared to the results without sphericity parameter, adding the sphericity parameter in the clustering process contributes to the extraction of a strongly absorbing aerosol. Furthermore, the effect of the physical and optical properties of the aerosol on the top of atmospheric (TOA) total reflectance and polarized reflectance are investigated. The results indicate that the addition of the sphericity parameter in the clustering process leads to a change in the total reflectance by up to 16% and a change in the polarized reflectance by up to 100%.

  20. Aerosol distribution apparatus

    DOEpatents

    Hanson, W.D.

    An apparatus for uniformly distributing an aerosol to a plurality of filters mounted in a plenum, wherein the aerosol and air are forced through a manifold system by means of a jet pump and released into the plenum through orifices in the manifold. The apparatus allows for the simultaneous aerosol-testing of all the filters in the plenum.

  1. Improved solid aerosol generator

    DOEpatents

    Prescott, D.S.; Schober, R.K.; Beller, J.

    1988-07-19

    An improved solid aerosol generator used to produce a gas borne stream of dry, solid particles of predetermined size and concentration. The improved solid aerosol generator nebulizes a feed solution of known concentration with a flow of preheated gas and dries the resultant wet heated aerosol in a grounded, conical heating chamber, achieving high recovery and flow rates. 2 figs.

  2. Solid aerosol generator

    DOEpatents

    Prescott, Donald S.; Schober, Robert K.; Beller, John

    1992-01-01

    An improved solid aerosol generator used to produce a gas borne stream of dry, solid particles of predetermined size and concentration. The improved solid aerosol generator nebulizes a feed solution of known concentration with a flow of preheated gas and dries the resultant wet heated aerosol in a grounded, conical heating chamber, achieving high recovery and flow rates.

  3. Solid aerosol generator

    DOEpatents

    Prescott, D.S.; Schober, R.K.; Beller, J.

    1992-03-17

    An improved solid aerosol generator used to produce a gas borne stream of dry, solid particles of predetermined size and concentration is disclosed. The improved solid aerosol generator nebulizes a feed solution of known concentration with a flow of preheated gas and dries the resultant wet heated aerosol in a grounded, conical heating chamber, achieving high recovery and flow rates. 2 figs.

  4. Aerosol Correction for Improving OMPS/LP Ozone Retrieval

    NASA Technical Reports Server (NTRS)

    Chen, Zhong; Bhartia, Pawan K.; Loughman, Robert

    2015-01-01

    The Ozone Mapping and Profiler Suite Limb Profiler (OMPS-LP) on board the Suomi National Polar-orbiting Partnership (SNPP) satellite was launched on Oct. 28, 2011. Limb profilers measures the radiance scattered from the Earth's atmospheric in limb viewing mode from 290 to 1000 nm and infer ozone profiles from tropopause to 60 km. The recently released OMPS-LP Version 2 data product contains the first publicly released ozone profiles retrievals, and these are now available for the entire OMPS mission, which extends from April, 2012. The Version 2 data product retrievals incorporate several important improvements to the algorithm. One of the primary changes is to turn off the aerosol retrieval module. The aerosol profiles retrieved inside the ozone code was not helping the ozone retrieval and was adding noise and other artifacts. Aerosols including polar stratospheric cloud (PSC) and polar mesospheric clouds (PMC) have a detectable effect on OMPS-LP data. Our results show that ignoring the aerosol contribution would produce an ozone density bias of up to 10 percent in the region of maximum aerosol extinction. Therefore, aerosol correction is needed to improve the quality of the retrieved ozone concentration profile. We provide Aerosol Scattering Index (ASI) for detecting aerosols-PMC-PSC, defined as ln(Im-Ic) normalized at 45km, where Im is the measured radiance and Ic is the calculated radiance assuming no aerosols. Since ASI varies with wavelengths, latitude and altitude, we can start by assuming no aerosol profiles in calculating the ASIs and then use the aerosol profile to see if it significantly reduces the residuals. We also discuss the effect of aerosol size distribution on the ozone profile retrieval process. Finally, we present an aerosol-PMC-PSC correction scheme.

  5. Evaluation of liquid aerosol transport through porous media.

    PubMed

    Hall, R; Murdoch, L; Falta, R; Looney, B; Riha, B

    2016-07-01

    Application of remediation methods in contaminated vadose zones has been hindered by an inability to effectively distribute liquid- or solid-phase amendments. Injection as aerosols in a carrier gas could be a viable method for achieving useful distributions of amendments in unsaturated materials. The objectives of this work were to characterize radial transport of aerosols in unsaturated porous media, and to develop capabilities for predicting results of aerosol injection scenarios at the field-scale. Transport processes were investigated by conducting lab-scale injection experiments with radial flow geometry, and predictive capabilities were obtained by developing and validating a numerical model for simulating coupled aerosol transport, deposition, and multi-phase flow in porous media. Soybean oil was transported more than 2m through sand by injecting it as micron-scale aerosol droplets. Oil saturation in the sand increased with time to a maximum of 0.25, and decreased with radial distance in the experiments. The numerical analysis predicted the distribution of oil saturation with only minor calibration. The results indicated that evolution of oil saturation was controlled by aerosol deposition and subsequent flow of the liquid oil, and simulation requires including these two coupled processes. The calibrated model was used to evaluate field applications. The results suggest that amendments can be delivered to the vadose zone as aerosols, and that gas injection rate and aerosol particle size will be important controls on the process.

  6. Evaluation of liquid aerosol transport through porous media

    NASA Astrophysics Data System (ADS)

    Hall, R.; Murdoch, L.; Falta, R.; Looney, B.; Riha, B.

    2016-07-01

    Application of remediation methods in contaminated vadose zones has been hindered by an inability to effectively distribute liquid- or solid-phase amendments. Injection as aerosols in a carrier gas could be a viable method for achieving useful distributions of amendments in unsaturated materials. The objectives of this work were to characterize radial transport of aerosols in unsaturated porous media, and to develop capabilities for predicting results of aerosol injection scenarios at the field-scale. Transport processes were investigated by conducting lab-scale injection experiments with radial flow geometry, and predictive capabilities were obtained by developing and validating a numerical model for simulating coupled aerosol transport, deposition, and multi-phase flow in porous media. Soybean oil was transported more than 2 m through sand by injecting it as micron-scale aerosol droplets. Oil saturation in the sand increased with time to a maximum of 0.25, and decreased with radial distance in the experiments. The numerical analysis predicted the distribution of oil saturation with only minor calibration. The results indicated that evolution of oil saturation was controlled by aerosol deposition and subsequent flow of the liquid oil, and simulation requires including these two coupled processes. The calibrated model was used to evaluate field applications. The results suggest that amendments can be delivered to the vadose zone as aerosols, and that gas injection rate and aerosol particle size will be important controls on the process.

  7. Copper aerosols inhibit phytoplankton growth in the Mediterranean Sea

    PubMed Central

    Jordi, Antoni; Basterretxea, Gotzon; Tovar-Sánchez, Antonio; Alastuey, Andrés; Querol, Xavier

    2012-01-01

    Aerosol deposition plays an important role in climate and biogeochemical cycles by supplying nutrients to the open ocean, in turn stimulating ocean productivity and carbon sequestration. Aerosol particles also contain elements such as copper (Cu) that are essential in trace amounts for phytoplankton physiology but that can be toxic at high concentrations. Although the toxicity of Cu associated with aerosols has been demonstrated in bioassay experiments, extrapolation of these laboratory results to natural conditions is not straightforward. This study provides observational evidence of the negative effect of aerosols containing high Cu concentrations on marine phytoplankton over a vast region of the western Mediterranean Sea. Direct aerosol measurements were combined with satellite observations, resulting in the detection of significant declines in phytoplankton biomass after atmospheric aerosol events characterized by high Cu concentrations. The declines were more evident during summer, when nanoflagellates predominate in the phytoplankton population and stratification and oligotrophic conditions prevail in the study region. Together with previous findings concerning atmospheric Cu deposition, these results demonstrate that the toxicity of Cu-rich aerosols can involve large areas of the world’s oceans. Moreover, they highlight the present vulnerability of oceanic ecosystems to Cu-rich aerosols of anthropogenic origins. Because anthropogenic emissions are increasing, large-scale negative effects on marine ecosystems can be anticipated. PMID:23236141

  8. Development of an aerosol module in MOCAGE

    NASA Astrophysics Data System (ADS)

    Nho-Kim, E.-Y.; Josse, B.; Michou, M.; Peuch, V.-H.; Simon, P.

    2003-04-01

    An aerosol module was developed to introduce in MOCAGE, the global chemistry and transport model of Météo-France. This study includes the size specific parameterization of the atmospheric processes of aerosols and comprises the representation of particle size distribution, the emission, the transport, the gravitational sedimentation, the dry deposition and the wet scavenging of aerosols. The particle size distribution is represented by combining one or several modes of lognormal distribution. The distribution is then discretized in classes according to the particles size, and the number density or the mass of each class is introduced in the model as a tracer. The settling velocity of aerosol particles for a given diameter is caculated according to Stokes' Law taking into account thin air condition at higher altitude. Mass transfer by sedimentation was carried out in all model layers except the nearest layer from the surface where the sedimentation is integrated in the dry deposition process. The characterization of dry deposition velocity is based on Slinn and Slinn's (1980) model. The aerodynamic resistance has been estimated as a function of the atmospheric stability, the surface roughness, and the wind speed. The grid surface roughness length has been calculated taking into account the contribution of the land cover and of the subgrid scale orography. The quasi-laminar layer resistance has been parameterized by considering the effects of the Brownian diffusion, the inertial impaction and the contribution of interception by vegetative hairs. In the model, the dry deposition flux is calculated as a product of this velocity by the local concentration of the lowest model level. The aerosol scavenging by the precipitation is parameterized by two different manners, in-cloud scavenging and below-cloud scavenging. The below-cloud scavenging rate is calculated as a function of the collision efficiency between droplets and aerosols and of the vertical flux of the

  9. Influence of Serum and Glucose Additives on Survival of Actinobacillus pleuropneumoniae Aerosolized from the Freeze-Dried State.

    PubMed

    Hensel, A

    1994-06-01

    Serum and/or glucose added to Actinobacillus pleuropneumoniae suspensions before freeze-drying significantly increased survival rates of bacteria in aerosols. Aerosols with predictable numbers of viable bacteria can be made as required in an aerosol infection model. Sucrose supplementation of impinger fluids increased recovery of viable A. pleuropneumoniae.

  10. Aerosol-assisted chemical vapor deposition (AACVD) of binary alloy (Ag{sub x}Pd{sub 1-x}, Cu{sub x}Pd{sub 1-x}, Ag{sub x}Cu{sub 1-x}) films and studies of their compositional variation

    SciTech Connect

    Xu, C.; Hampden-Smith, M.J.; Kodas, T.T.

    1995-08-01

    Atmospheric pressure chemical vapor deposition (CVD) of Ag-Pd,Cu-Pd, and Ag-Cu alloys using aerosol precursor delivery over a range of preheating temperatures, 70-80{degrees}C and substrate temperatures, 250-300{degrees}C is described. The precursors were (hfac)Ag(SEt{sub 2}), (hfac)Cu{sup I}(1,5-COD), Cu(hfac){sub 2}, Pd(hfac){sub 2}, and Pd(hfac){sub 2}(SE5{sub 2}) dissolved in toluene with 10% H{sub 2} in Ar as carrier gas. The films were characterized by scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), and X-ray diffraction. The X-ray diffraction results showed the Ag PD films consisted of AgNO{sub 3} and volatile (hfac)Ag(SEt{sub 2}) as precursors to Ag films were consistent with a chemical vapor deposition (CVD) process. Reactivity studies between precursors and H{sub 2} suggested Pd(hfac){sub 2} is likely to undergo a small amount (<2%) of decomposition during the aerosol-assisted CVD experiments, and Pd(hfac){sub 2}(SEt{sub 2})/Pd(hfac){sub 2{minus}}(SEt{sub 2}) in different ratios in toluene solution. The films were characterized by X-ray diffraction and the results showed the composition of the films was dependent upon the solution stoichiometry. The possible rate-limiting steps are discussed, and it is proposed that the deposition rate is limited by the feed rate of the precursors to the reactor. These predictions were consistent with a study of deposition rate as a function of substrate temperature at constant feed rate in the (hfac)Ag(SEt{sub 2})/Pd(hfac){sub 2}(SEt{sub 2}) system, which showed no variation in the deposition rate over a 75{degrees}C temperature range. It was concluded that conditions of feed-rate or diffusion-rate limited deposition are useful approaches to control film composition. 42 refs., 12 figs., 1 tab.

  11. Organic aerosol formation in citronella candle plumes

    PubMed Central

    Bothe, Melanie

    2010-01-01

    Citronella candles are widely used as insect repellants, especially outdoors in the evening. Because these essential oils are unsaturated, they have a unique potential to form secondary organic aerosol (SOA) via reaction with ozone, which is also commonly elevated on summer evenings when the candles are often in use. We investigated this process, along with primary aerosol emissions, by briefly placing a citronella tealight candle in a smog chamber and then adding ozone to the chamber. In repeated experiments, we observed rapid and substantial SOA formation after ozone addition; this process must therefore be considered when assessing the risks and benefits of using citronella candle to repel insects. PMID:20700379

  12. Evaluation of aerosol properties simulated by the high resolution global coupled chemistry-aerosol-microphysics model C-IFS-GLOMAP

    NASA Astrophysics Data System (ADS)

    Dhomse, Sandip; Mann, Graham; Carslaw, Ken; Flemming, Johannes; Morcrette, Jean-Jacques; Engelen, Richard; Remy, Samuel; Boucher, Olivier; Benduhn, Francois; Hewson, Will; Woodhouse, Matthew

    2016-04-01

    The EU Framework Programme GEMS and MACC consortium projects co-ordinated by the European Centre for Medium-range Weather Forecasts (ECMWF) have developed an operational global forecasting and reanalysis system (Composition-IFS) for atmospheric composition including greenhouse gases, reactive gases and aerosol. The current operational C-IFS system uses a mass-based aerosol model coupled to data assimilation of Aerosol Optical Depth measured by satellite (MODIS) to predict global aerosol properties. During MACC, the GLOMAP-mode aerosol microphysics scheme was added to the system, providing information on aerosol size and number for improved representation of aerosol-radiation and aerosol-cloud interactions, accounting also for simulated global variations in size distribution and internally-mixed particle composition. The IFS-GLOMAP system has recently been upgraded to couple with the sulphur cycle simulated in the online TM5 tropospheric chemistry module for global reactive gases. This C-IFS-GLOMAP system is also being upgraded to use a new "nitrate-extended" version of GLOMAP which realistically treats the size-resolved gas-particle partitioning of semi volatile gases ammonia and nitric acid. In this poster we described C-IFS-GLOMAP and present an evaluation of the global sulphate aerosol distribution simulated in this coupled aerosol-chemistry C-IFS-GLOMAP, comparing to surface observations in Europe, North America and the North Atlantic and contrasting to the fixed timescale sulphate production scheme developed in GEMS. We show that the coupling to the TM5 sulphur chemistry improves the seasonal cycle of sulphate aerosol, for example addressing a persistent wintertime sulphate high bias in northern Europe. The improved skill in simulated sulphate aerosol seasonal cycle is a pre-requisite to realistically characterise nitrate aerosol since biases in sulphate affect the amount of free ammonia available to form ammonium nitrate.

  13. Agricultural Education: Value Adding.

    ERIC Educational Resources Information Center

    Riesenberg, Lou E.; And Others

    1989-01-01

    This issue develops the theme of "Agricultural Education--Value Adding." The concept value adding has been a staple in the world of agricultural business for describing adding value to a commodity that would profit the producer and the local community. Agricultural education should add value to individuals and society to justify agricultural…

  14. Detection of chemical agent aerosols

    NASA Astrophysics Data System (ADS)

    Fox, Jay A.; Ahl, Jeffrey L.; D'Amico, Francis M.; Vanderbeek, Richard G.; Moon, Raphael; Swim, Cynthia R.

    1999-05-01

    One of the major threats presented by a chemical agent attack is that of a munition exploding overhead and 'raining' aerosols which can contaminate surfaces when they impact. Since contact with these surfaces can be fatal, it is imperative to know when such an attack has taken place and the likely threat density and location. We present the results of an experiment designed to show the utility of a CO2 lidar in detecting such an attack. Testing occurred at Dugway Proving Grounds, Utah and involved the simulation of an explosive airburst chemical attack. Explosions occurred at a height of 30 m and liquid droplets from two chemicals, PEG-200 (polyethylene glycol 200) and TEP (triethylphosphate), were expelled and fell to the ground. The munition was the U.S. Army M9 Simulator, Projectile, Airburst, Liquid (SPAL) system that is designed for chemical warfare training exercises. The instrument that was used to detect the presence of the aerosols was the Laser Standoff Chemical Detector (LSCD) which is a light detection and ranging (LIDAR) system that utilizes a rapidly tunable, pulsed CO2 laser. The LIDAR scanned a horizontal path approximately 5 - 8 m above the ground in order to measure the concentration of liquid deposition. The LIDAR data were later correlated with card data to determine how well the system could predict the location and quantity of liquid deposition on the ground.

  15. Does the Madden-Julian Oscillation Influence Aerosol Variability?

    NASA Astrophysics Data System (ADS)

    Tian, B.; Waliser, D. E.; Kahn, R. A.; Li, Q.; Yung, Y. L.; Tyranowski, T.; Geogdzhayev, I. V.; Mishchenko, M. I.; Torres, O.; Smirnov, A.

    2007-12-01

    We investigate the modulation of aerosols by the Madden-Julian Oscillation (MJO) using satellite-based global aerosol products, including aerosol index (AI) from the Total Ozone Mapping Spectrometer (TOMS) on Nimbus-7, and aerosol optical thickness (AOT) from the Moderate Resolution Imaging Spectroradiometer (MODIS) on Terra and Aqua and the Advanced Very High Resolution Radiometer (AVHRR) on NOAA satellites. A composite analysis is performed for boreal winter, and the global pentad rainfall data from the NOAA Climate Prediction Center (CPC) Merged Analysis of Precipitation (CMAP) are used to identify MJO events. The MJO composites exhibit large variations in the TOMS AI and MODIS/AVHRR AOT over the equatorial Indian and western Pacific Oceans where MJO convection is active, as well as the tropical Africa and Atlantic Ocean where MJO convection is relatively weak but the background aerosol level is relatively high. A strong inverse linear relationship between the TOMS AI and rainfall anomalies, but a weaker, less coherent positive correlation between the MODIS/AVHRR AOT and rainfall anomalies, were found. The Aerosol Robotic Network AOT pattern at Kaashidoo (73.5°E, 4.9°N) and Nauru (167°E, 0.5°S) is more consistent with MODIS and AVHRR. These results indicate a connection between the MJO, its associated rainfall and circulation variability, and the observed aerosol variations. Several physical and non-physical factors that may contribute to the observed aerosol-rainfall relationship, such as aerosol humidification effect, wet deposition, surface wind speed, phytoplankton, different sensor sensitivities (absorbing versus non-absorbing aerosols and upper versus lower tropospheric aerosols), sampling issue, and cloud contamination, are discussed. However, a clear causal explanation for the observed patterns remains elusive. Further investigation is needed to unravel this complex aerosol-rainfall relationship.

  16. Retrieval of Aerosol Absorption Properties from Satellite Observations

    NASA Technical Reports Server (NTRS)

    Torres, Omar; Bhartia, Pawan K.; Jethva, H.; Ahn, Chang-Woo

    2012-01-01

    The Angstrom Absorption Exponent (AAE) is a parameter commonly used to characterize the wavelength-dependence of aerosol absorption optical depth (AAOD). It is closely related to aerosol composition. Black carbon (BC) containing aerosols yield AAE values near unity whereas Organic carbon (OC) aerosol particles are associated with values larger than 2. Even larger AAE values have been reported for desert dust aerosol particles. Knowledge of spectral AAOD is necessary for the calculation of direct radiative forcing effect of aerosols and for inferring aerosol composition. We have developed a satellitebased method of determining the spectral AAOD of absorbing aerosols. The technique uses multi-spectral measurements of upwelling radiation from scenes where absorbing aerosols lie above clouds as indicated by the UV Aerosol Index. For those conditions, the satellite measurement can be explained, using an approximations of Beer's Law (BL), as the upwelling reflectance at the cloud top attenuated by the absorption effects of the overlying aerosol layer. The upwelling reflectance at the cloud-top in an aerosol-free atmospheric column is mainly a function of cloud optical depth (COD). In the proposed method of AAE derivation, the first step is determining COD which is retrieved using a previously developed color-ratio based approach. In the second step, corrections for molecular scattering effects are applied to both the observed ad the calculated cloud reflectance terms, and the spectral AAOD is then derived by an inversion of the BL approximation. The proposed technique will be discussed in detail and application results making use of OMI multi-spectral measurements in the UV-Vis. will be presented.

  17. Air pollution and asthma: clinical studies with sulfuric acid aerosols

    SciTech Connect

    Utell, M.J.; Frampton, M.W.; Morrow, P.E. )

    1991-11-01

    Until recently, acid deposition has been widely considered a serious ecological problem but not a threat to human health. The controlled clinical study is an important approach in linking acidic aerosol inhalation with respiratory effects. Asthmatic patients represent a subpopulation most responsive to sulfuric acid aerosols. In a series of studies with asthmatic volunteers, several factors have been identified that may modulate the intensity of the bronchoconstrictor response to inhaled acidic aerosols. We found (1) enhancement of the bronchoconstrictor response during exercise, (2) the more acidic aerosols provoke the greatest changes in lung function, and (3) mitigation of airway responses during sulfuric acid aerosol inhalation caused by high respiratory ammonia concentrations. Additional factors influencing responsiveness await identification.

  18. Aerosol stability of infectious and potentially infectious reovirus particles.

    PubMed Central

    Adams, D J; Spendlove, J C; Spendlove, R S; Barnett, B B

    1982-01-01

    The aerosol stability of two particle forms, infectious and potentially infectious, of reovirus were examined under static conditions for a range of relative humidities at 21 and 24 degrees C. Virus aerosolization efficiency was determined for two methods of dissemination: Collison nebulizer and Chicago atomizer. Suspensions of Bacillus subtilis var. niger spores were added to reovirus preparations that included both particle forms and disseminated into a dynamic aerosol toroid to estimate the physical decay of the aerosols. At 90 to 100% relative humidity, both reovirus particle forms showed less than 10-fold loss of infectivity after 12 h of aging. At lower relative humidities the aerosol decay curve showed rapid initial decay followed by a markedly lower decay rate. Our findings reveal that reovirus particles are relatively stable in the airborne state. PMID:7149719

  19. Atmospheric Residence Times of Continental Aerosols.

    NASA Astrophysics Data System (ADS)

    Balkanski, Yves Jacques

    The global atmospheric distributions of ^{222}Rn and ^{210 }Pb are simulated with a three-dimensional model of atmospheric transport based on the meteorology of the NASA GISS^1>=neral circulation model. The short-lived radioactive gas ^ {222}Rn (half-life = 3.8d) is emitted almost exclusively from land, at a relatively uniform rate; hence it is an excellent tracer of continental influences. Lead -210 is produced by decay of ^{222} Rn and immediately condenses to preexisting aerosol surfaces. It provides an excellent measure of aerosol residence times in the atmosphere because its source is accurately defined by the ^{222} Rn distribution. Results from the three-dimensional model are compared to measurements of ^ {222}Rn and ^{210 }Pb atmospheric concentrations to evaluate model's long-range transport over oceanic regions and to study the deposition mechanisms of atmospheric aerosols. Model results for ^{222} Rn are used to examine the long-range transport of continental air over two selected oceanic regions, the subantartic Indian Ocean and the North Pacific. It is shown that fast transport of air from southern Africa causes substantial continental pollution at southern mid-latitudes, a region usually regarded as pristine. Air over the North Pacific is heavily impacted by continental influences year round, but the altitude at which the transport occurs varies seasonally. Observations of aerosols at island sites, which are commonly used as diagnostics of continental influences, may be misleading because they do not account for influences at high altitude and because aerosols are efficiently scavenged by deposition during transport. The study of ^{210}Pb focuses on defining the residence times of submicron aerosols in the troposphere. Scavenging in wet convective updrafts is found to provide the dominant sink on a global scale. The globally averaged residence time for ^{210 }Pb-containing aerosols in the troposphere is 7 days. The average increase in residence time

  20. Aerosol MTF revisited

    NASA Astrophysics Data System (ADS)

    Kopeika, Norman S.; Zilberman, Arkadi; Yitzhaky, Yitzhak

    2014-05-01

    Different views of the significance of aerosol MTF have been reported. For example, one recent paper [OE, 52(4)/2013, pp. 046201] claims that the aerosol MTF "contrast reduction is approximately independent of spatial frequency, and image blur is practically negligible". On the other hand, another recent paper [JOSA A, 11/2013, pp. 2244-2252] claims that aerosols "can have a non-negligible effect on the atmospheric point spread function". We present clear experimental evidence of common significant aerosol blur and evidence that aerosol contrast reduction can be extremely significant. In the IR, it is more appropriate to refer to such phenomena as aerosol-absorption MTF. The role of imaging system instrumentation on such MTF is addressed too.

  1. Electrostatics of Pharmaceutical Aerosols for Pulmonary Delivery.

    PubMed

    Lip Kwok, Philip Chi

    2015-01-01

    This paper provides a review on key research findings in the rapidly developing area of pharmaceutical aerosol electrostatics. Solids and liquids can become charged without electric fields, the former by contact or friction and the latter by flowing or spraying. Therefore, charged particles and droplets carrying net charges are produced from pharmaceutical inhalers (e.g. dry powder inhalers, metered dose inhalers, and nebulisers) due to the mechanical processes involved in aerosolisation. The charging depends on many physicochemical factors, such as formulation composition, solid state properties, inhaler material and design, and relative humidity. In silico, in vitro, and limited in vivo studies have shown that electrostatic charges may potentially influence particle deposition in the airways. However, the evidence is not yet conclusive. Furthermore, there are currently no regulatory requirements on the characterisation and control of the electrostatic properties of inhaled formulations. Besides the need for further investigations on the relationship between physicochemical factors and charging characteristics of the aerosols, controlled and detailed in vivo studies are also required to confirm whether charges can affect particle deposition in the airways. Since pharmaceutical aerosol electrostatics is a relatively new research area, much remains to be explored. Thus there is certainly potential for development. New findings in the future may contribute to the advancement of pharmaceutical aerosol formulations and respiratory drug delivery.

  2. Electrostatics of Pharmaceutical Aerosols for Pulmonary Delivery.

    PubMed

    Lip Kwok, Philip Chi

    2015-01-01

    This paper provides a review on key research findings in the rapidly developing area of pharmaceutical aerosol electrostatics. Solids and liquids can become charged without electric fields, the former by contact or friction and the latter by flowing or spraying. Therefore, charged particles and droplets carrying net charges are produced from pharmaceutical inhalers (e.g. dry powder inhalers, metered dose inhalers, and nebulisers) due to the mechanical processes involved in aerosolisation. The charging depends on many physicochemical factors, such as formulation composition, solid state properties, inhaler material and design, and relative humidity. In silico, in vitro, and limited in vivo studies have shown that electrostatic charges may potentially influence particle deposition in the airways. However, the evidence is not yet conclusive. Furthermore, there are currently no regulatory requirements on the characterisation and control of the electrostatic properties of inhaled formulations. Besides the need for further investigations on the relationship between physicochemical factors and charging characteristics of the aerosols, controlled and detailed in vivo studies are also required to confirm whether charges can affect particle deposition in the airways. Since pharmaceutical aerosol electrostatics is a relatively new research area, much remains to be explored. Thus there is certainly potential for development. New findings in the future may contribute to the advancement of pharmaceutical aerosol formulations and respiratory drug delivery. PMID:26290198

  3. Adding flavor to AdS4/CFT3

    NASA Astrophysics Data System (ADS)

    Ammon, Martin; Erdmenger, Johanna; Meyer, René; O'Bannon, Andy; Wrase, Timm

    2009-11-01

    Aharony, Bergman, Jafferis, and Maldacena have proposed that the low-energy description of multiple M2-branes at a Bbb C4/Bbb Zk singularity is a (2+1)-dimensional Script N = 6 supersymmetric U(Nc) × U(Nc) Chern-Simons matter theory, the ABJM theory. In the large-Nc limit, its holographic dual is supergravity in AdS4 × S7/Bbb Zk. We study various ways to add fields that transform in the fundamental representation of the gauge groups, i.e. flavor fields, to the ABJM theory. We work in a probe limit and perform analyses in both the supergravity and field theory descriptions. In the supergravity description we find a large class of supersymmetric embeddings of probe flavor branes. In the field theory description, we present a general method to determine the couplings of the flavor fields to the fields of the ABJM theory. We then study four examples in detail: codimension-zero Script N = 3 supersymmetric flavor, described in supergravity by Kaluza-Klein monopoles or D6-branes; codimension-one Script N = (0,6) supersymmetric chiral flavor, described by D8-branes; codimension-one Script N = (3,3) supersymmetric non-chiral flavor, described by M5/D4-branes; codimension-two Script N = 4 supersymmetric flavor, described by M2/D2-branes. Finally we discuss special physical equivalences between brane embeddings in M-theory, and their interpretation in the field theory description.

  4. Generating monodisperse pharmacological aerosols using the spinning-top aerosol generator.

    PubMed

    Biddiscombe, Martyn F; Barnes, Peter J; Usmani, Omar S

    2006-01-01

    Pharmacological aerosols of precisely controlled particle size and narrow dispersity can be generated using the spinning-top aerosol generator (STAG). The ability of the STAG to generate monodisperse aerosols from solutions of raw drug compounds makes it a valuable research instrument. In this paper, the versatility of this instrument has been further demonstrated by aerosolizing a range of commercially available nebulized pulmonary therapy preparations. Nebules of Flixotide (fluticasone propionate), Pulmicort (budesonide), Combivent (salbutamol sulphate and ipratropium bromide), Bricanyl (terbutaline sulphate), Atrovent(ipratropium bromide), and Salamol (salbutamol sulphate) were each mixed with ethanol and delivered to the STAG. Monodisperse drug aerosol distributions were generated with MMADs of 0.95-6.7 microm. To achieve larger particle sizes from the nebulizer drug suspensions, the STAG formed compound particle agglomerates derived from the smaller insoluble drug particles. These compound agglomerates behaved aerodynamically as a single particle, and this was verified using an aerodynamic particle sizer and an Andersen Cascade Impactor. Scanning electron microscope images demonstrated their physical structure. On the other hand using the nebulizer drug solutions, spherical particles proportional to the original droplet diameter were generated. The aerosols generated by the STAG can allow investigators to study the scientific principles of inhaled drug deposition and lung physiology for a range of therapeutic agents. PMID:17034300

  5. 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

  6. A 10-year global gridded Aerosol Optical Thickness Reanalysis for climate and applied applications

    NASA Astrophysics Data System (ADS)

    Lynch, P.; Reid, J. S.; Zhang, J.; Westphal, D. L.; Campbell, J. R.; Curtis, C. A.; Hegg, D.; Hyer, E. J.; Sessions, W.; Shi, Y.; Turk, J.

    2013-12-01

    While standalone satellite and model aerosol products see wide utilization, there is a significant need of a best-available fused product on a regular grid for numerous climate and applied applications. Remote sensing and modeling technologies have now advanced to a point where aerosol data assimilation is an operational reality at numerous centers. It is inevitable that, like meteorological reanalyses, aerosol reanalyses will see heavy use in the near future. A first long term, 2003-2012 global 1x1 degree and 6-hourly aerosol optical thickness (AOT) reanalysis product has been generated. The goal of this effort is not only for climate applications, but to generate a dataset that can be used by the US Navy to understand operationally hindering aerosol events, aerosol impacts on numerical weather prediction, and application of electro-optical technologies. The reanalysis utilizes Navy Aerosol Analysis and Prediction System (NAAPS) at its core and assimilates quality controlled collection 5 Moderate Resolution Imaging Spectroradiometer (MODIS) AOD with minor corrections from Multi-angle Imaging SpectroRaditometer (MISR). A subset of this product includes Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) lidar assimilation since its launch in mid-2006. Surface aerosol sources, including dust and smoke, in the aerosol model have been regionally tuned so that fine and coarse mode AOTs best match those resolve by ground-based Aerosol Robotic Network (AERONET). The AOT difference between the model and satellite AOT is then used to adjust other aerosol processes, eg., sources, dry deposition, etc. Aerosol wet deposition is constrained with satellite-retrieved precipitation. The final AOT reanalysis is shown to exhibit good agreement with AERONET. Here we review the development of the reanalysis and consider issues particular to aerosol reanalyses that make them distinct from standard meteorological reanalyses. Considerations are also made for extending such work

  7. Radiative Effects of Aerosols

    NASA Technical Reports Server (NTRS)

    Valero, Francisco P. J.

    1997-01-01

    During the Atlantic Stratocumulus Transition Experiment (ASTEX) in June 1992, two descents in cloud-free regions allowed comparison of the change in aerosol optical depth as determined by an onboard total-direct-diffuse radiometer (TDDR) to the change calculated from measured size resolved aerosol microphysics and chemistry. Both profiles included pollution haze layer from Europe but the second also included the effect of a Saharan dust layer above the haze. The separate contributions of supermicrometer (coarse) and submicrometer (fine) aerosol were determined and thermal analysis of the pollution haze indicated that the fine aerosol was composed primarily of a sulfate/water mixture with a refractory soot-like core.

  8. Twistor methods for AdS5

    NASA Astrophysics Data System (ADS)

    Adamo, Tim; Skinner, David; Williams, Jack

    2016-08-01

    We consider the application of twistor theory to five-dimensional anti-de Sitter space. The twistor space of AdS5 is the same as the ambitwistor space of the four-dimensional conformal boundary; the geometry of this correspondence is reviewed for both the bulk and boundary. A Penrose transform allows us to describe free bulk fields, with or without mass, in terms of data on twistor space. Explicit representatives for the bulk-to-boundary propagators of scalars and spinors are constructed, along with twistor action functionals for the free theories. Evaluating these twistor actions on bulk-to-boundary propagators is shown to produce the correct two-point functions.

  9. AdS3: the NHEK generation

    NASA Astrophysics Data System (ADS)

    Bena, Iosif; Heurtier, Lucien; Puhm, Andrea

    2016-05-01

    It was argued in [1] that the five-dimensional near-horizon extremal Kerr (NHEK) geometry can be embedded in String Theory as the infrared region of an infinite family of non-supersymmetric geometries that have D1, D5, momentum and KK monopole charges. We show that there exists a method to embed these geometries into asymptotically- {AdS}_3× {S}^3/{{Z}}_N solutions, and hence to obtain infinite families of flows whose infrared is NHEK. This indicates that the CFT dual to the NHEK geometry is the IR fixed point of a Renormalization Group flow from a known local UV CFT and opens the door to its explicit construction.

  10. Shadows, currents, and AdS fields

    SciTech Connect

    Metsaev, R. R.

    2008-11-15

    Conformal totally symmetric arbitrary spin currents and shadow fields in flat space-time of dimension greater than or equal to four are studied. A gauge invariant formulation for such currents and shadow fields is developed. Gauge symmetries are realized by involving the Stueckelberg fields. A realization of global conformal boost symmetries is obtained. Gauge invariant differential constraints for currents and shadow fields are obtained. AdS/CFT correspondence for currents and shadow fields and the respective normalizable and non-normalizable solutions of massless totally symmetric arbitrary spin AdS fields are studied. The bulk fields are considered in a modified de Donder gauge that leads to decoupled equations of motion. We demonstrate that leftover on shell gauge symmetries of bulk fields correspond to gauge symmetries of boundary currents and shadow fields, while the modified de Donder gauge conditions for bulk fields correspond to differential constraints for boundary conformal currents and shadow fields. Breaking conformal symmetries, we find interrelations between the gauge invariant formulation of the currents and shadow fields, and the gauge invariant formulation of massive fields.

  11. Effects of aerosols and relative humidity on cumulus clouds

    NASA Astrophysics Data System (ADS)

    Fan, Jiwen; Zhang, Renyi; Li, Guohui; Tao, Wei-Kuo

    2007-07-01

    The influences of the aerosol type and concentration and relative humidity (RH) on cumulus clouds have been investigated using a two-dimensional spectral-bin cloud model. Three simulations are conducted to represent the polluted continental, clean continental, and marine aerosol types. Under the same initial dynamic and thermodynamic conditions, the maritime aerosol case results in more intensive radar reflectivity in both developing and mature stages than the continental aerosol cases, because of enhanced warm rain by collisions and ice processes by deposition growth due to larger droplet sizes and higher supersaturation, respectively. The considerable delay in convective development due to reduced droplet condensation is responsible for the longer cloud lifetime in the marine aerosol case. For the continental case, the most noticeable effects of increasing aerosol number concentrations (with 15 different initial values) are the increases of the cloud droplet number concentration and cloud water content but a decrease in the effective droplet radius. More latent heat release from increasing condensation results in stronger convection and more melting precipitation at the higher aerosol concentrations. Melting precipitation and secondary clouds primarily contribute to enhanced precipitation with increasing aerosols. The precipitation, however, decreases with increasing aerosol in the extremely high aerosol cases (over 5 × 104 cm-3) due to suppression of convection from depleted water vapor and inefficient coalescence. When the initial aerosol concentration exceeds a critical level, most of the cloud properties become less sensitive to aerosols, implying that the aerosol effect on deep convection is more pronounced in relatively clean air than in heavily polluted air. The aerosol effect on the cloud properties is strongly dependent on RH. As the surface RH increases from 40 to 70%, the cloud changes from shallow warm to deep convective types due to a significant

  12. An experimental method for quantitatively evaluating the elemental processes of indoor radioactive aerosol behavior.

    PubMed

    Yamazawa, H; Yamada, S; Xu, Y; Hirao, S; Moriizumi, J

    2015-11-01

    An experimental method for quantitatively evaluating the elemental processes governing the indoor behaviour of naturally occurring radioactive aerosols was proposed. This method utilises transient response of aerosol concentrations to an artificial change in aerosol removal rate by turning on and off an air purifier. It was shown that the indoor-outdoor exchange rate and the indoor deposition rate could be estimated by a continuous measurement of outdoor and indoor aerosol number concentration measurements and by the method proposed in this study. Although the scatter of the estimated parameters is relatively large, both the methods gave consistent results. It was also found that the size distribution of radioactive aerosol particles and hence activity median aerodynamic diameter remained not largely affected by the operation of the air purifier, implying the predominance of the exchange and deposition processes over other processes causing change in the size distribution such as the size growth by coagulation and the size dependence of deposition.

  13. The impact of atmospheric deposition of cadmium on dominant algal species in the East China Sea

    NASA Astrophysics Data System (ADS)

    Quan, Qiwei; Chen, Ying; Ma, Qingwei; Wang, Fujiang; Meng, Xi; Wang, Bo

    2016-04-01

    Cadmium (Cd) mainly derived from anthropogenic emissions can be transported through atmospheric pathway to marine ecosystem, affecting the phytoplankton community and primary productivity. In this study, we identified the toxicity threshold of Cd for phytoplankton under seawater conditions of the coastal East China Sea (ECS) through both laboratory and in situ mesocosm incubation experiments. The mesocosm experiment showed that Cd in low concentration (0.003 μg per μg chl a) was conducive to the growth of natural community and increased chl a productivity. In high concentration (0.03 μg per μg chl a) Cd acted as an inhibiting factor which decreased the total chl a productivity. The diatom community was found to be more sensitive to Cd toxicity than dinoflagellate, as the low concentration Cd showed toxicity to diatom but enhanced dinoflagellate growth. We noticed that the soluble Cd estimated from atmosphere deposition to the coastal ECS was below the toxicity threshold and the Cd deposition might promote phytoplankton growth in this region. In our laboratory experiments, adding Cd, similar to aerosol deposition, stimulated the growth of both dominant algal species Prorocentrum donghaiense Lu (dinoflagellate) and Skeletonema costatum (diatom). Adding Cd on a higher level inhibited the growth of both the species, but Skeletonema costatum seemed obviously more sensitive to toxicity. This indicates the potential impact of atmospheric deposition Cd on phytoplankton community succession in the ECS.

  14. Direct radiative effect by multicomponent aerosol over China

    SciTech Connect

    Huang, Xin; Song, Yu; Zhao, Chun; Cai, Xuhui; Zhang, Hongsheng; Zhu, Tong

    2015-05-01

    The direct radiative effect (DRE) of multiple aerosol species (sulfate, nitrate, ammonium, black carbon (BC), organic carbon (OC), and mineral aerosol) and their spatiotemporal variations over China were investigated using a fully coupled meteorology–chemistry model (WRF-Chem) for the entire year of 2006. We made modifications to improve model performance, including updating land surface parameters, improving the calculation of transition metal-catalyzed oxidation of SO2, and adding in heterogeneous reactions between mineral aerosol and acid gases. The modified model well reproduced the magnitude, seasonal pattern, and spatial distribution of the measured meteorological conditions, concentrations of PM10 and its components, and aerosol optical depth (AOD). A diagnostic iteration method was used to estimate the overall DRE of aerosols and contributions from different components. At the land surface, all kinds of aerosol species reduced the incident net radiation flux with a total DRE of 10.2 W m-2 over China. Aerosols significantly warm the atmosphere with the national mean DRE of +10.8 W m-2. BC was the leading radiative-heating component (+8.7 W m-2), followed by mineral aerosol (+1.1 W m-2). At the top of the atmosphere (TOA), BC introduced the largest radiative perturbation (+4.5 W m-2), followed by sulfate (-1.4 W m-2). The overall perturbation of aerosols on radiation transfer is quite small over China, demonstrating the counterbalancing effect between scattering and adsorbing aerosols. Aerosol DRE at the TOA had distinct seasonality, generally with a summer maximum and winter minimum, mainly determined by mass loadings, hygroscopic growth, and incident radiation flux.

  15. Numerical simulation of aerosol scavenging by ice-bearing convective clouds

    SciTech Connect

    Bradley, M.M.; Molenkamp, C.R.

    1990-04-01

    Precipitation is the most effective mechanism for cleansing the atmosphere of small aerosol particles. Although there are many process paths by which precipitation can ultimately deposit aerosol on the ground, each path begins with the initial capture, or scavenging, of an aerosol particle. One of the most effective of these processes, at least in the absence of strong electric fields, is condensation nucleation scavenging, in which an aerosol particle serves as a cloud condensation nucleus. Although scavenging is a necessary precursor to aerosol removal by precipitation, scavenging does not guarantee that an aerosol particle will be removed from the atmosphere. For example, the particle will be resuspended if its host cloud droplet evaporates or if the droplet is collected by a raindrop which subsequently evaporates. The removal process becomes further complicated if ice is present in the cloud. The purpose of this research is to study the effects of various ice processes on the net aerosol removal efficiency of convective clouds. 8 refs.

  16. Measurement of the emission rate of an aerosol source--comparison of aerosol and gas transport coefficients.

    PubMed

    Bémer, D; Callé, S; Godinot, S; Régnier, R; Dessagne, J M

    2000-12-01

    A measuring method of the emission rate of an atmospheric pollutant source, based on the use of a tracer gas (helium) and developed in the case of a gaseous source, was tested for an aerosol source. The influence of both particle sedimentation and wall depositions was studied. The transport coefficients of the tracer gas and of alumina particles of various particle sizes (MMAD from 8 to 36 microns) were measured on a vertical axis close to the source, in a 71 m3 room swept by a piston flow. The measurements clearly demonstrated the predominant influence of sedimentation in the case of particles with aerodynamic diameters greater than 10 microns. Particle wall deposition was determined by measuring the gas and particle concentration decay in the ventilated room. To do this, a new tracing method using a fluorescent aerosol was developed. The measured aerosol deposition rates are much higher than those calculated from the formula of Corner for a cubical volume. Aerosol sedimentation and wall deposition are two phenomena limiting the use of a tracer gas to measure the aerosol emission rate. The chemical substances and materials used in work premises are likely to be released into the atmosphere and lead to the formation of pollutants. These emissions stem from either physical or chemical processes (evaporation of a solvent) or from mechanical processes (dispersion of oil droplets at the source of mists).

  17. Aerosol climate time series from ESA Aerosol_cci (Invited)

    NASA Astrophysics Data System (ADS)

    Holzer-Popp, T.

    2013-12-01

    developed further, to evaluate the datasets and their regional and seasonal merits. The validation showed that most datasets have improved significantly and in particular PARASOL (ocean only) provides excellent results. The metrics for AATSR (land and ocean) datasets are similar to those of MODIS and MISR, with AATSR better in some land regions and less good in some others (ocean). However, AATSR coverage is smaller than that of MODIS due to swath width. The MERIS dataset provides better coverage than AATSR but has lower quality (especially over land) than the other datasets. Also the synergetic AATSR/SCIAMACHY dataset has lower quality. The evaluation of the pixel uncertainties shows first good results but also reveals that more work needs to be done to provide comprehensive information for data assimilation. Users (MACC/ECMWF, AEROCOM) confirmed the relevance of this additional information and encouraged Aerosol_cci to release the current uncertainties. The paper will summarize and discuss the results of three year work in Aerosol_cci, extract the lessons learned and conclude with an outlook to the work proposed for the next three years. In this second phase a cyclic effort of algorithm evolution, dataset generation, validation and assessment will be applied to produce and further improve complete time series from all sensors under investigation, new sensors will be added (e.g. IASI), and preparation for the Sentinel missions will be made.

  18. Portable Aerosol Contaminant Extractor

    DOEpatents

    Carlson, Duane C.; DeGange, John J.; Cable-Dunlap, Paula

    2005-11-15

    A compact, portable, aerosol contaminant extractor having ionization and collection sections through which ambient air may be drawn at a nominal rate so that aerosol particles ionized in the ionization section may be collected on charged plate in the collection section, the charged plate being readily removed for analyses of the particles collected thereon.

  19. Global Aerosol Observations

    Atmospheric Science Data Center

    2013-04-19

    ... atmosphere, directly influencing global climate and human health. Ground-based networks that accurately measure column aerosol amount and ... being used to improve Air Quality Models and for regional health studies. To assess the human-health impact of chronic aerosol exposure, ...

  20. 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.

  1. Ganges valley aerosol experiment.

    SciTech Connect

    Kotamarthi, V.R.; Satheesh, S.K.

    2011-08-01

    In June 2011, the Ganges Valley Aerosol Experiment (GVAX) began in the Ganges Valley region of India. The objective of this field campaign is to obtain measurements of clouds, precipitation, and complex aerosols to study their impact on cloud formation and monsoon activity in the region.

  2. Aerosol Characterization and New Instrumentation for Better Understanding Snow Radiative Properties

    NASA Astrophysics Data System (ADS)

    Beres, N. D.

    2015-12-01

    Snow albedo is determined by snowpack thickness and grain size, but also affected by contamination with light-absorbing, microscopic (e.g., mineral dust, combustion aerosols, bio-aerosols) and macroscopic (e.g., microalgae, plant debris, sand, organisms) compounds. Most currently available instruments for measuring snow albedo utilize the natural, downward flux of solar radiation and the reflected upward flux. This reliance on solar radiation (and, thus, large zenith angles and clear-sky conditions) leads to severe constraints, preventing characterization of detailed diurnal snow albedo cycles. Here, we describe instrumentation and methodologies to address these limitations with the development and deployment of new snow radiation sensors for measuring surface spectral and in-snow radiative properties. This novel instrumentation will be tested at the CRREL/UCSB Eastern Sierra (CUES) Snow Study Site at Mammoth Mountain, which is extensively instrumented for characterizing snow properties including snow albedo and surface morphology. However, it has been lacking instrumentation for the characterization of aerosols that can be deposited on the snow surface through dry and wet deposition. Currently, we are installing aerosol instrumentation at the CUES site, which are also described. This includes instruments for the multi-wavelength measurement of aerosol scattering and absorption coefficients and for the characterization of aerosol size distribution. Knowledge of aerosol concentration and physical and optical properties will allow for the study of aerosol deposition and modification of snow albedo and for establishing an aerosol climatology for the CUES site.

  3. Studies of Ambient and Chamber Aerosol Composition using the Aerosol Mass Spectrometer

    NASA Astrophysics Data System (ADS)

    Craven, Jill Suzanne

    This thesis presents composition measurements for atmospherically relevant inorganic and organic aerosol from laboratory and ambient measurements using the Aerodyne aerosol mass spectrometer. Studies include the oxidation of dodecane in the Caltech environmental chambers, and several aircraft- and ground-based field studies, which include the quantification of wildfire emissions off the coast of California, and Los Angeles urban emissions. The oxidation of dodecane by OH under low NO conditions and the formation of secondary organic aerosol (SOA) was explored using a gas-phase chemical model, gas-phase CIMS measurements, and high molecular weight ion traces from particlephase HR-TOF-AMS mass spectra. The combination of these measurements support the hypothesis that particle-phase chemistry leading to peroxyhemiacetal formation is important. Positive matrix factorization (PMF) was applied to the AMS mass spectra which revealed three factors representing a combination of gas-particle partitioning, chemical conversion in the aerosol, and wall deposition. Airborne measurements of biomass burning emissions from a chaparral fire on the central Californian coast were carried out in November 2009. Physical and chemical changes were reported for smoke ages 0--4 h old. CO 2 normalized ammonium, nitrate, and sulfate increased, whereas the normalized OA decreased sharply in the first 1.5--2 h, and then slowly increased for the remaining 2 h (net decrease in normalized OA). Comparison to wildfire samples from the Yucatan revealed that factors such as relative humidity, incident UV radiation, age of smoke, and concentration of emissions are important for wildfire evolution. Ground-based aerosol composition is reported for Pasadena, CA during the sumix mer of 2009. The OA component, which dominated the submicron aerosol mass, was deconvolved into hydrocarbon-like organic aerosol (HOA), semi-volatile oxidized organic aerosol (SVOOA), and low-volatility oxidized organic aerosol

  4. 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.

  5. 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.

  6. Analysis of Atmospheric Aerosols

    NASA Astrophysics Data System (ADS)

    Prather, Kimberly A.; Hatch, Courtney D.; Grassian, Vicki H.

    2008-07-01

    Aerosols represent an important component of the Earth's atmosphere. Because aerosols are composed of solid and liquid particles of varying chemical complexity, size, and phase, large challenges exist in understanding how they impact climate, health, and the chemistry of the atmosphere. Only through the integration of field, laboratory, and modeling analysis can we begin to unravel the roles atmospheric aerosols play in these global processes. In this article, we provide a brief review of the current state of the science in the analysis of atmospheric aerosols and some important challenges that need to be overcome before they can become fully integrated. It is clear that only when these areas are effectively bridged can we fully understand the impact that atmospheric aerosols have on our environment and the Earth's system at the level of scientific certainty necessary to design and implement sound environmental policies.

  7. Size segregated light absorption coefficient of the atmospheric aerosol

    NASA Astrophysics Data System (ADS)

    Horvath, H.

    The light absorption coefficient of atmospheric aerosols in the visible can be determined by depositing the particles on a filter and measuring its "transmission" in a special optical arrangement. With an impactor with rotating impaction plates producing a homogeneous deposit, it is possible to extend this technique to size segregated aerosol samples. A simultaneous determination of the mass size distribution is possible. Test measurements with black carbon aerosol have shown the feasibility of this method. Samples of the atmospheric aerosol have been taken in and near Vienna, in Naples and near Bologna. The light absorption of the aerosol is always highest for particle diameters between 0.1 and 0.2 μm. Only in the humid environment of the Po valley it had a slightly larger peak size, whereas the size of the nonabsorbing particles increased considerably. The light absorption of the atmospheric aerosol is always higher in an urban environment. 'The mass absorption coefficient of the aerosol at all four locations was very similar, and completely different from values which could be. expected using effective refractive indices which are frequently used in models. Using the data measured in this work two alternate models for the effective refractive index and black carbon content of the aerosol are suggested: (a) a size-dependent refractive index, where the imaginary part varies from -0.25 for particles smaller than 30 nm to - 0.003 for particles larger than 2 μm; this could especially be applied if an internal mixing of the aerosol is to be expected, or (2) a size-dependent fraction of elemental carbon in the case of external mixing with 43% of carbon particles for sizes below 30 nm decreasing to 10% for sizes up to 0.4 μm.

  8. Development of an Aerosol Surface Inoculation Method for Bacillus Spores ▿

    PubMed Central

    Lee, Sang Don; Ryan, Shawn P.; Snyder, Emily Gibb

    2011-01-01

    A method was developed to deposit Bacillus subtilis spores via aerosolization onto various surface materials for biological agent decontamination and detection studies. This new method uses an apparatus coupled with a metered dose inhaler to reproducibly deposit spores onto various surfaces. A metered dose inhaler was loaded with Bacillus subtilis spores, a surrogate for Bacillus anthracis. Five different material surfaces (aluminum, galvanized steel, wood, carpet, and painted wallboard paper) were tested using this spore deposition method. This aerosolization method deposited spores at a concentration of more than 107 CFU per coupon (18-mm diameter) with less than a 50% coefficient of variation, showing that the aerosolization method developed in this study can deposit reproducible numbers of spores onto various surface coupons. Scanning electron microscopy was used to probe the spore deposition patterns on test coupons. The deposition patterns observed following aerosol impaction were compared to those of liquid inoculation. A physical difference in the spore deposition patterns was observed to result from the two different methods. The spore deposition method developed in this study will help prepare spore coupons via aerosolization fast and reproducibly for bench top decontamination and detection studies. PMID:21193670

  9. Radiative Effects of Aerosols

    NASA Technical Reports Server (NTRS)

    Valero, Francisco P. J.

    1996-01-01

    During the Atlantic Stratocumulus Transition Experiment (ASTEX) in June 1992, two descents in cloud-free regions allowed comparison of the change in aerosol optical depth as determined by an onboard total-direct-diffuse radiometer (TDDR) to the change calculated from measured size-resolved aerosol microphysics and chemistry. Both profiles included a pollution haze from Europe but the second also included the effect of a Saharan dust layer above the haze. The separate contributions of supermicrometer (coarse) and submicrometer (fine) aerosol were determined and thermal analysis of the pollution haze indicated that the fine aerosol was composed primarily of a sulfate/water mixture with a refractory soot-like core. The soot core increased the calculated extinction by about 10% in the most polluted drier layer relative to a pure sulfate aerosol but had significantly less effect at higher humidities. A 3 km descent through a boundary layer air mass dominated by pollutant aerosol with relative humidities (RH) 10-77% yielded a close agreement between the measured and calculated aerosol optical depths (550 nm) of 0.160 (+/- 0.07) and 0. 157 (+/- 0.034) respectively. During descent the aerosol mass scattering coefficient per unit sulfate mass varied from about 5 to 16 m(exp 2)/g and primarily dependent upon ambient RH. However, the total scattering coefficient per total fine mass was far less variable at about 4+/- 0.7 m(exp 2)/g. A subsequent descent through a Saharan dust layer located above the pollution aerosol layer revealed that both layers contributed similarly to aerosol optical depth. The scattering per unit mass of the coarse aged dust was estimated at 1.1 +/- 0.2 m(exp 2)/g. The large difference (50%) in measured and calculated optical depth for the dust layer exceeded measurements.

  10. IN SILLICO LOBAR MODELS OF HUMAN LUNGS FOR TARGETED DELIVERY OF AEROSOLIZED PHARMACEUTICALS

    EPA Science Inventory

    The identification of factors affecting the deposition patterns of aerosolized pharmaceuticals has important implications to medicine (e.g., inhalation therapy regimens) and toxicology (e.g., drug testing protocols). Airway morphology is a critical element of the process, influen...

  11. ANALYSIS OF RESPIRATORY DESPOSITION DOSE OF INHALED AMBIENT AEROSOLS FOR DIFFERENT SIZE FRACTIONS

    EPA Science Inventory

    ANALYSIS OF RESPIRATORY DEPOSITION DOSE OF INHALED AMBIENT AEROSOLS FOR DIFFERENT SIZE FRACTIONS. Chong S. Kim, SC. Hu**, PA Jaques*, US EPA, National Health and Environmental Effects Research Laboratory, Research Triangle Park, NC 27711; **IIT Research Institute, Chicago, IL; *S...

  12. Aerosol tests conducted at Aberdeen Proving Grounds MD.

    SciTech Connect

    Brockmann, John E.; Lucero, Daniel A.; Servantes, Brandon Lee; Hankins, Matthew Granholm

    2012-06-01

    Test data are reported that demonstrate the deposition from a spray dispersion system (Illinois Tool Works inductively charging rotary atomization nozzle) for application of decontamination solution to various surfaces in the passenger cabin of a Boeing 737 aircraft. The decontamination solution (EnviroTru) was tagged with a known concentration of fluorescein permitting determination of both airborne decontaminant concentration and surface deposited decontaminant solution so that the effective deposition rates and surface coverage could be determined and correlated with the amount of material sprayed. Six aerosol dispersion tests were conducted. In each test, aluminum foil deposition coupons were set out throughout the passenger area and the aerosol was dispersed. The aerosol concentration was measured with filter samplers as well as with optical techniques Average aerosol deposition ranged from 3 to 15 grams of decontamination solution per square meter. Some disagreement was observed between various instruments utilizing different measurement principles. These results demonstrate a potentially effective method to disperse decontaminant to interior surfaces of a passenger aircraft.

  13. A pathway analysis of global aerosol processes

    NASA Astrophysics Data System (ADS)

    Schutgens, N. A. J.; Stier, P.

    2014-06-01

    We present a detailed budget of the changes in atmospheric aerosol mass and numbers due to various processes: emission, nucleation, coagulation, H2SO4 condensation and in-cloud production, ageing and deposition. The budget is created from monthly-averaged tracer tendencies calculated by the global aerosol model ECHAM5.5-HAM2 and allows us to investigate process contributions at various length- and time-scales. As a result, we show in unprecedented detail what processes drive the evolution of aerosol. In particular, we show that the processes that affect aerosol masses are quite different from those affecting aerosol numbers. Condensation of H2SO4 gas onto pre-existing particles is an important process, dominating the growth of small particles in the nucleation mode to the Aitken mode and the ageing of hydrophobic matter. Together with in-cloud production of H2SO4, it significantly contributes to (and often dominates) the mass burden (and hence composition) of the hydrophilic Aitken and accumulation mode particles. Particle growth itself is the leading source of number densities in the hydrophilic Aitken and accumulation modes, with their hydrophobic counterparts contributing (even locally) relatively little. As expected, the coarse mode is dominated by primary emissions and mostly decoupled from the smaller modes. Our analysis also suggests that coagulation serves mainly as a loss process for number densities and that, relative to other processes, it is a rather unimportant contributor to composition changes of aerosol. The analysis is extended with sensitivity studies where the impact of a lower model resolution or pre-industrial emissions is shown to be small. We discuss the use of the current budget for model simplification, prioritisation of model improvements, identification of potential structural model errors and model evaluation against observations.

  14. A pathway analysis of global aerosol processes

    NASA Astrophysics Data System (ADS)

    Schutgens, N. A. J.; Stier, P.

    2014-11-01

    We present a detailed budget of the changes in atmospheric aerosol mass and numbers due to various processes: emission (including instant condensation of soluble biogenic emissions), nucleation, coagulation, H2SO4 condensation and in-cloud production, aging and deposition. The budget is created from monthly averaged tracer tendencies calculated by the global aerosol model ECHAM5.5-HAM2 and allows us to investigate process contributions at various length-scales and timescales. As a result, we show in unprecedented detail what processes drive the evolution of aerosol. In particular, we show that the processes that affect aerosol masses are quite different from those that affect aerosol numbers. Condensation of H2SO4 gas onto pre-existing particles is an important process, dominating the growth of small particles in the nucleation mode to the Aitken mode and the aging of hydrophobic matter. Together with in-cloud production of H2SO4, it significantly contributes to (and often dominates) the mass burden (and hence composition) of the hydrophilic Aitken and accumulation mode particles. Particle growth itself is the leading source of number densities in the hydrophilic Aitken and accumulation modes, with their hydrophobic counterparts contributing (even locally) relatively little. As expected, the coarse mode is dominated by primary emissions and mostly decoupled from the smaller modes. Our analysis also suggests that coagulation serves mainly as a loss process for number densities and that, relative to other processes, it is a rather unimportant contributor to composition changes of aerosol. The analysis is extended with sensitivity studies where the impact of a lower model resolution or pre-industrial emissions is shown to be small. We discuss the use of the current budget for model simplification, prioritization of model improvements, identification of potential structural model errors and model evaluation against observations.

  15. Preparation and characterization of magnetizable aerosols.

    PubMed

    Baumann, Romy; Glöckl, Gunnar; Nagel, Stefan; Weitschies, Werner

    2012-04-11

    Magnetizable aerosols can be used for inhalative magnetic drug targeting in order to enhance the drug concentration at a certain target site within the lung. The aim of the present study was to clarify how a typical ferrofluid can be atomized in a reproducible way. The influence of the atomization principle, the concentration of magnetic nanoparticles within the carrier liquid and the addition of commonly used pharmaceutical excipients on the aerosol droplet size were investigated. Iron oxide (magnetite) nanoparticles were synthesized by alkaline precipitation of mixtures of iron(II)- and iron(III)-chloride and coated with citric acid. The resulting ferrofluid was characterized by photon correlation spectroscopy and vibrating sample magnetometry. Two different nebulizers (Pari Boy and eFlow) with different atomization principles were used to generate ferrofluid aerosols. A range of substances that influence the surface tension, viscosity, density or vapor pressure of the ferrofluid were added to investigate their impact on the generated aerosol droplets. The particle size was determined by laser diffraction. A stable ferrofluid with a magnetic core diameter of 10.7 ± 0.45 nm and a hydrodynamic diameter of 124 nm was nebulized by Pari Boy and eFlow. The aerosol droplet size of Pari Boy was approximately 2.5 μm and remained unaffected by the addition of substances that changed the physical properties of the solvent. The droplet size of aerosols generated by eFlow was approximately 5 μm. It was significantly reduced by the addition of Cremophor RH 40, glycerol, polyvinyl pyrrolidone and ethanol. PMID:22306649

  16. Aqueous aerosol SOA formation: impact on aerosol physical properties.

    PubMed

    Woo, Joseph L; Kim, Derek D; Schwier, Allison N; Li, Ruizhi; McNeill, V Faye

    2013-01-01

    Organic chemistry in aerosol water has recently been recognized as a potentially important source of secondary organic aerosol (SOA) material. This SOA material may be surface-active, therefore potentially affecting aerosol heterogeneous activity, ice nucleation, and CCN activity. Aqueous aerosol chemistry has also been shown to be a potential source of light-absorbing products ("brown carbon"). We present results on the formation of secondary organic aerosol material in aerosol water and the associated changes in aerosol physical properties from GAMMA (Gas-Aerosol Model for Mechanism Analysis), a photochemical box model with coupled gas and detailed aqueous aerosol chemistry. The detailed aerosol composition output from GAMMA was coupled with two recently developed modules for predicting a) aerosol surface tension and b) the UV-Vis absorption spectrum of the aerosol, based on our previous laboratory observations. The simulation results suggest that the formation of oligomers and organic acids in bulk aerosol water is unlikely to perturb aerosol surface tension significantly. Isoprene-derived organosulfates are formed in high concentrations in acidic aerosols under low-NO(x) conditions, but more experimental data are needed before the potential impact of these species on aerosol surface tension may be evaluated. Adsorption of surfactants from the gas phase may further suppress aerosol surface tension. Light absorption by aqueous aerosol SOA material is driven by dark glyoxal chemistry and is highest under high-NO(x) conditions, at high relative humidity, in the early morning hours. The wavelength dependence of the predicted absorption spectra is comparable to field observations and the predicted mass absorption efficiencies suggest that aqueous aerosol chemistry can be a significant source of aerosol brown carbon under urban conditions. PMID:24601011

  17. ADS pilot program Plan

    NASA Technical Reports Server (NTRS)

    Clauson, J.; Heuser, J.

    1981-01-01

    The Applications Data Service (ADS) is a system based on an electronic data communications network which will permit scientists to share the data stored in data bases at universities and at government and private installations. It is designed to allow users to readily locate and access high quality, timely data from multiple sources. The ADS Pilot program objectives and the current plans for accomplishing those objectives are described.

  18. Historical anthropogenic radiative forcing of changes in biogenic secondary aerosol

    NASA Astrophysics Data System (ADS)

    Acosta Navarro, Juan; D'Andrea, Stephen; Pierce, Jeffrey; Ekman, Annica; Struthers, Hamish; Zorita, Eduardo; Guenther, Alex; Arneth, Almut; Smolander, Sampo; Kaplan, Jed; Farina, Salvatore; Scott, Catherine; Rap, Alexandru; Farmer, Delphine; Spracklen, Domink; Riipinen, Ilona

    2016-04-01

    Human activities have lead to changes in the energy balance of the Earth and the global climate. Changes in atmospheric aerosols are the second largest contributor to climate change after greenhouse gases since 1750 A.D. Land-use practices and other environmental drivers have caused changes in the emission of biogenic volatile organic compounds (BVOCs) and secondary organic aerosol (SOA) well before 1750 A.D, possibly causing climate effects through aerosol-radiation and aerosol-cloud interactions. Two numerical emission models LPJ-GUESS and MEGAN were used to quantify the changes in aerosol forming BVOC emissions in the past millennium. A chemical transport model of the atmosphere (GEOS-Chem-TOMAS) was driven with those BVOC emissions to quantify the effects on radiation caused by millennial changes in SOA. We found that global isoprene emissions decreased after 1800 A.D. by about 12% - 15%. This decrease was dominated by losses of natural vegetation, whereas monoterpene and sesquiterpene emissions increased by about 2% - 10%, driven mostly by rising surface air temperatures. From 1000 A.D. to 1800 A.D, isoprene, monoterpene and sesquiterpene emissions decline by 3% - 8% driven by both, natural vegetation losses, and the moderate global cooling between the medieval climate anomaly and the little ice age. The millennial reduction in BVOC emissions lead to a 0.5% to 2% reduction in climatically relevant aerosol particles (> 80 nm) and cause a direct radiative forcing between +0.02 W/m² and +0.07 W/m², and an indirect radiative forcing between -0.02 W/m² and +0.02 W/m².

  19. Dry season aerosol iron solubility in tropical northern Australia

    NASA Astrophysics Data System (ADS)

    Winton, V. Holly L.; Edwards, Ross; Bowie, Andrew R.; Keywood, Melita; Williams, Alistair G.; Chambers, Scott D.; Selleck, Paul W.; Desservettaz, Maximilien; Mallet, Marc D.; Paton-Walsh, Clare

    2016-10-01

    Marine nitrogen fixation is co-limited by the supply of iron (Fe) and phosphorus in large regions of the global ocean. The deposition of soluble aerosol Fe can initiate nitrogen fixation and trigger toxic algal blooms in nitrate-poor tropical waters. We present dry season soluble Fe data from the Savannah Fires in the Early Dry Season (SAFIRED) campaign in northern Australia that reflects coincident dust and biomass burning sources of soluble aerosol Fe. The mean soluble and total aerosol Fe concentrations were 40 and 500 ng m-3 respectively. Our results show that while biomass burning species may not be a direct source of soluble Fe, biomass burning may substantially enhance the solubility of mineral dust. We observed fractional Fe solubility up to 12 % in mixed aerosols. Thus, Fe in dust may be more soluble in the tropics compared to higher latitudes due to higher concentrations of biomass-burning-derived reactive organic species in the atmosphere. In addition, biomass-burning-derived particles can act as a surface for aerosol Fe to bind during atmospheric transport and subsequently be released to the ocean upon deposition. As the aerosol loading is dominated by biomass burning emissions over the tropical waters in the dry season, additions of biomass-burning-derived soluble Fe could have harmful consequences for initiating nitrogen-fixing toxic algal blooms. Future research is required to quantify biomass-burning-derived particle sources of soluble Fe over tropical waters.

  20. Sugars in Antarctic aerosol

    NASA Astrophysics Data System (ADS)

    Barbaro, Elena; Kirchgeorg, Torben; Zangrando, Roberta; Vecchiato, Marco; Piazza, Rossano; Barbante, Carlo; Gambaro, Andrea

    2015-10-01

    The processes and transformations occurring in the Antarctic aerosol during atmospheric transport were described using selected sugars as source tracers. Monosaccharides (arabinose, fructose, galactose, glucose, mannose, ribose, xylose), disaccharides (sucrose, lactose, maltose, lactulose), alcohol-sugars (erythritol, mannitol, ribitol, sorbitol, xylitol, maltitol, galactitol) and anhydrosugars (levoglucosan, mannosan and galactosan) were measured in the Antarctic aerosol collected during four different sampling campaigns. For quantification, a sensitive high-pressure anion exchange chromatography was coupled with a single quadrupole mass spectrometer. The method was validated, showing good accuracy and low method quantification limits. This study describes the first determination of sugars in the Antarctic aerosol. The total mean concentration of sugars in the aerosol collected at the "Mario Zucchelli" coastal station was 140 pg m-3; as for the aerosol collected over the Antarctic plateau during two consecutive sampling campaigns, the concentration amounted to 440 and 438 pg m-3. The study of particle-size distribution allowed us to identify the natural emission from spores or from sea-spray as the main sources of sugars in the coastal area. The enrichment of sugars in the fine fraction of the aerosol collected on the Antarctic plateau is due to the degradation of particles during long-range atmospheric transport. The composition of sugars in the coarse fraction was also investigated in the aerosol collected during the oceanographic cruise.

  1. Eddy covariance measurements with high-resolution time-of-flight aerosol mass spectrometry: a new approach to chemically-resolved aerosol fluxes

    NASA Astrophysics Data System (ADS)

    Farmer, D. K.; Kimmel, J. R.; Phillips, G.; Docherty, K. S.; Worsnop, D. R.; Sueper, D.; Nemitz, E.; Jimenez, J. L.

    2010-12-01

    Although laboratory studies show that biogenic volatile organic compounds (VOCs) yield substantial secondary organic aerosol (SOA), production of biogenic SOA as indicated by upward fluxes has not been conclusively observed over forests. Further, while aerosols are known to deposit to surfaces, few techniques exist to provide chemically-resolved particle deposition fluxes. To better constrain aerosol sources and sinks, we have developed a new technique to directly measure fluxes of chemically-resolved submicron aerosols using the high-resolution time-of-flight aerosol mass spectrometer (HR-AMS) in a new, fast eddy covariance mode. This approach takes advantage of the instrument's ability to quantitatively identify both organic and inorganic components, including ammonium, sulphate and nitrate, at a temporal resolution of several Hz. The new approach has been successfully deployed over a temperate ponderosa pine plantation in California during the BEARPEX-2007 campaign, providing both total and chemically resolved non-refractory (NR) PM1 fluxes. Average deposition velocity for total NR-PM1 aerosol at noon was 2.05 ± 0.04 mm/s. Using a high resolution measurement of the NH2+ and NH3+ fragments, we demonstrate the first eddy covariance flux measurements of particulate ammonium, which show a noon-time deposition velocity of 1.9 ± 0.7 mm/s and are dominated by deposition of ammonium sulphate.

  2. Eddy covariance measurements with high-resolution time-of-flight aerosol mass spectrometry: a new approach to chemically resolved aerosol fluxes

    NASA Astrophysics Data System (ADS)

    Farmer, D. K.; Kimmel, J. R.; Phillips, G.; Docherty, K. S.; Worsnop, D. R.; Sueper, D.; Nemitz, E.; Jimenez, J. L.

    2011-06-01

    Although laboratory studies show that biogenic volatile organic compounds (VOCs) yield substantial secondary organic aerosol (SOA), production of biogenic SOA as indicated by upward fluxes has not been conclusively observed over forests. Further, while aerosols are known to deposit to surfaces, few techniques exist to provide chemically-resolved particle deposition fluxes. To better constrain aerosol sources and sinks, we have developed a new technique to directly measure fluxes of chemically-resolved submicron aerosols using the high-resolution time-of-flight aerosol mass spectrometer (HR-AMS) in a new, fast eddy covariance mode. This approach takes advantage of the instrument's ability to quantitatively identify both organic and inorganic components, including ammonium, sulphate and nitrate, at a temporal resolution of several Hz. The new approach has been successfully deployed over a temperate ponderosa pine plantation in California during the BEARPEX-2007 campaign, providing both total and chemically resolved non-refractory (NR) PM1 fluxes. Average deposition velocities for total NR-PM1 aerosol at noon were 2.05 ± 0.04 mm s-1. Using a high resolution measurement of the NH2+ and NH3+ fragments, we demonstrate the first eddy covariance flux measurements of particulate ammonium, which show a noon-time deposition velocity of 1.9 ± 0.7 mm s-1 and are dominated by deposition of ammonium sulphate.

  3. Acceleration of oxygen decline in the tropical Pacific over the past decades by aerosol pollutants

    NASA Astrophysics Data System (ADS)

    Ito, T.; Nenes, A.; Johnson, M. S.; Meskhidze, N.; Deutsch, C.

    2016-06-01

    Dissolved oxygen in the mid-depth tropical Pacific Ocean has declined in the past several decades. The resulting expansion of the oxygen minimum zone has consequences for the region's ecosystem and biogeochemical cycles, but the causes of the oxygen decline are not yet fully understood. Here we combine models of atmospheric chemistry, ocean circulation and biogeochemical cycling to test the hypothesis that atmospheric pollution over the Pacific Ocean contributed to the redistribution of oxygen in deeper waters. We simulate the pollution-induced enhancement of atmospheric soluble iron and fixed nitrogen deposition, as well as its impacts on ocean productivity and biogeochemical cycling for the late twentieth century. The model reproduces the magnitude and large-scale pattern of the observed oxygen changes from the 1970s to the 1990s, and the sensitivity experiments reveal the reinforcing effects of pollution-enhanced iron deposition and natural climate variability. Despite the aerosol deposition being the largest in mid-latitudes, its effect on oceanic oxygen is most pronounced in the tropics, where ocean circulation transports added iron to the tropics, leading to an increased regional productivity, respiration and subsurface oxygen depletion. These results suggest that anthropogenic pollution can interact and amplify climate-driven impacts on ocean biogeochemistry, even in remote ocean biomes.

  4. Effect of inhaled terbutaline sulphate in relation to its deposition in the lungs.

    PubMed

    Hultquist, C; Wollmer, P; Eklundh, G; Jonson, B

    1992-06-01

    We studied the effects of inhaled terbutaline on FEV1 and gas exchange, and the pattern of deposition within the lungs. To document this and to estimate the dose of terbutaline administered to the lungs, [99mTc]DTPA was added to nebulised terbutaline solution. The aerosol was deposited preferentially in large or small airways by using aerosols with different particle mass median diameters (1.5 and 4.8 microns) and different inhalation flow rates (0.25 and 1.0 l/s). The patients inhaled placebo and then three increasing doses of terbutaline (0.006, 0.02 and 0.08 mg to the lungs). Finally, 2 mg terbutaline was inhaled from a metered dose inhaler via a spacer. After each inhalation FEV1, PaO2 and PaCO2 was measured. The inhalation of small particles at a low flow resulted in a fairly uniform lung deposition, while larger particles at a higher flow resulted in heavy central deposition. Penetration index for small and large particles were 1.3 +/- 0.2 and 0.8 +/- 0.3 (P less than 0.001), respectively. In both groups FEV1 increased similarly with each dose, and at 0.02 and 0.08 mg the increase was significant (P less than 0.01). After eight metered doses of terbutaline sulphate (0.25 mg per dose) inhaled via a spacer, there was a further increase in FEV1 (P less than 0.001). Gas exchange did not differ between the two groups but if they were combined the DA-aO2 was significantly lower after metered doses than control (P less than 0.05). Thus, it appears that the site of deposition is not important for the bronchodilator effect of terbutaline, and gas exchange tended to improve with both modes of administration. PMID:1611230

  5. Simulating Aerosol-cloud-radiation Feedbacks over East Asia Using Wrf-chem

    NASA Astrophysics Data System (ADS)

    Wang, J.; Allen, D. J.; Pickering, K. E.; Li, Z.; Dickerson, R. R.

    2011-12-01

    Aerosols play an important role in climate change through their impact on the radiative balance of the atmosphere. Recently much effort has been put into studying the radiative forcing of aerosols in East Asia. In this study, we apply the regional chemistry and transport model, WRF-Chem, to study aerosol radiative forcing over eastern Asia. Version 3.3 of the model is used with the CBMZ chemical mechanism and the MOSAIC aerosol treatment. The time period of interest is Feb 21, 2005 to April 12, 2005, since there were extensive measurements of radiation, trace gases, and aerosol properties available from EAST-AIRE (East Asian Study of Tropospheric Aerosols: An International Regional Experiment ) campaign during that period. We conduct model simulations with and without aerosol forcing and compare the results to measurements. We investigate the aerosol radiative forcing as well as aerosol direct and indirect effects by analyzing the differences between short wave flux, temperature, and cloud fraction from these two runs. We evaluate our model simulated incoming short wave radiation at the surface with in situ measurements from EAST-AIRE site Xianghe (70 km southeast of Beijing, China). We find that shortwave radiation decreases when aerosols are added lessening the high-bias between model-calculated and observed short wave radiation. We further compare the model simulated cloud fraction from two runs with MODIS Level 2 retrievals, demonstrating aerosol indirect effects in cloud formations.

  6. Code System to Calculate Particle Penetration Through Aerosol Transport Lines.

    1999-07-14

    Version 00 Distribution is restricted to US Government Agencies and Their Contractors Only. DEPOSITION1.03 is an interactive software program which was developed for the design and analysis of aerosol transport lines. Models are presented for calculating aerosol particle penetration through straight tubes of arbitrary orientation, inlets, and elbows. An expression to calculate effective depositional velocities of particles on tube walls is derived. The concept of maximum penetration is introduced, which is the maximum possible penetrationmore » through a sampling line connecting any two points in a three-dimensional space. A procedure to predict optimum tube diameter for an existing transport line is developed. Note that there is a discrepancy in this package which includes the DEPOSITION 1.03 executable and the DEPOSITION 2.0 report. RSICC was unable to obtain other executables or reports.« less

  7. Colorimetric determination of zirconium in antiperspirant aerosols.

    PubMed

    Beavin, P

    1976-07-01

    A rapid direct dilution procedure for the estimation of soluble zirconium and a fusion procedure for the determination of total zirconium (soluble and insoluble forms) in cream base concentrates prepared from antiperspirant aerosols are described. The direct dilution procedure involves extraction of soluble zirconium with HCl (55 + 45). The filtered extract is reacted with alizarin red S to form a stable colored complex which is measured spectrophotometrically. The fusion procedure involves ashing the aerosol concentrate followed by fusion of the ash with potassium pyrosulfate to form an acid-soluble melt. Zirconium is precipitated from solution as the hydroxide and washed to eliminate interfering ions, particularly sulfate. After redissolving in HCl (55 + 45) and reacting with alizarin red S, total zirconium is measured. Zirconyl chloride octahydrate, assayed gravimetrically by hydroxide precipitation and conversion to the oxide, is used as the zirconium reference standard. Concentration range of zirconium measured was 200-500 mug/100 ml. Recoveries of standard zirconium added to commercial aerosols labeled to contain aluminum and zirconyl hydroxychlorides ranged from 97 to 101% by the fusion procedure. Analysis of these aerosols by direct dilution gave generally slightly lower results than by fusion. It is recommended that the procedures be collaboratively studied after further testing of their general applicability to a variety of drugs and cosmetics. PMID:939750

  8. Fire aerosol experiment and comparisons with computer code predictions

    NASA Astrophysics Data System (ADS)

    Gregory, W. S.; Nichols, B. D.; White, B. W.; Smith, P. R.; Leslie, I. H.; Corkran, J. R.

    1988-08-01

    Los Alamos National Laboratory, in cooperation with New Mexico State University, has carried on a series of tests to provide experimental data on fire-generated aerosol transport. These data will be used to verify the aerosol transport capabilities of the FIRAC computer code. FIRAC was developed by Los Alamos for the U.S. Nuclear Regulatory Commission. It is intended to be used by safety analysts to evaluate the effects of hypothetical fires on nuclear plants. One of the most significant aspects of this analysis deals with smoke and radioactive material movement throughout the plant. The tests have been carried out using an industrial furnace that can generate gas temperatures to 300 C. To date, we have used quartz aerosol with a median diameter of about 10 microns as the fire aerosol simulant. We also plan to use fire-generated aerosols of polystyrene and polymethyl methacrylate (PMMA). The test variables include two nominal gas flow rates (150 and 300 cu ft/min) and three nominal gas temperatures (ambient, 150 C, and 300 C). The test results are presented in the form of plots of aerosol deposition vs length of duct. In addition, the mass of aerosol caught in a high-efficiency particulate air (HEPA) filter during the tests is reported. The tests are simulated with the FIRAC code, and the results are compared with the experimental data.

  9. Implementing marine organic aerosols into the GEOS-Chem model

    DOE PAGES

    Gantt, B.; Johnson, M. S.; Crippa, M.; Prévôt, A. S. H.; Meskhidze, N.

    2014-09-09

    Marine organic aerosols (MOA) have been shown to play an important role in tropospheric chemistry by impacting surface mass, cloud condensation nuclei, and ice nuclei concentrations over remote marine and coastal regions. In this work, an online marine primary organic aerosol emission parameterization, designed to be used for both global and regional models, was implemented into the GEOS-Chem model. The implemented emission scheme improved the large underprediction of organic aerosol concentrations in clean marine regions (normalized mean bias decreases from -79% when using the default settings to -12% when marine organic aerosols are added). Model predictions were also in goodmore » agreement (correlation coefficient of 0.62 and normalized mean bias of -36%) with hourly surface concentrations of MOA observed during the summertime at an inland site near Paris, France. Our study shows that MOA have weaker coastal-to-inland concentration gradients than sea-salt aerosols, leading to several inland European cities having > 10% of their surface submicron organic aerosol mass concentration with a marine source. The addition of MOA tracers to GEOS-Chem enabled us to identify the regions with large contributions of freshly-emitted or aged aerosol having distinct physicochemical properties, potentially indicating optimal locations for future field studies.« less

  10. Implementing marine organic aerosols into the GEOS-Chem model

    DOE PAGES

    Gantt, B.; Johnson, M. S.; Crippa, M.; Prévôt, A. S. H.; Meskhidze, N.

    2015-03-17

    Marine-sourced organic aerosols (MOAs) have been shown to play an important role in tropospheric chemistry by impacting surface mass, cloud condensation nuclei, and ice nuclei concentrations over remote marine and coastal regions. In this work, an online marine primary organic aerosol emission parameterization, designed to be used for both global and regional models, was implemented into the GEOS-Chem (Global Earth Observing System Chemistry) model. The implemented emission scheme improved the large underprediction of organic aerosol concentrations in clean marine regions (normalized mean bias decreases from -79% when using the default settings to -12% when marine organic aerosols are added). Modelmore » predictions were also in good agreement (correlation coefficient of 0.62 and normalized mean bias of -36%) with hourly surface concentrations of MOAs observed during the summertime at an inland site near Paris, France. Our study shows that MOAs have weaker coastal-to-inland concentration gradients than sea-salt aerosols, leading to several inland European cities having >10% of their surface submicron organic aerosol mass concentration with a marine source. The addition of MOA tracers to GEOS-Chem enabled us to identify the regions with large contributions of freshly emitted or aged aerosol having distinct physicochemical properties, potentially indicating optimal locations for future field studies.« less

  11. Implementing marine organic aerosols into the GEOS-Chem model

    NASA Astrophysics Data System (ADS)

    Gantt, B.; Johnson, M. S.; Crippa, M.; Prévôt, A. S. H.; Meskhidze, N.

    2015-03-01

    Marine-sourced organic aerosols (MOAs) have been shown to play an important role in tropospheric chemistry by impacting surface mass, cloud condensation nuclei, and ice nuclei concentrations over remote marine and coastal regions. In this work, an online marine primary organic aerosol emission parameterization, designed to be used for both global and regional models, was implemented into the GEOS-Chem (Global Earth Observing System Chemistry) model. The implemented emission scheme improved the large underprediction of organic aerosol concentrations in clean marine regions (normalized mean bias decreases from -79% when using the default settings to -12% when marine organic aerosols are added). Model predictions were also in good agreement (correlation coefficient of 0.62 and normalized mean bias of -36%) with hourly surface concentrations of MOAs observed during the summertime at an inland site near Paris, France. Our study shows that MOAs have weaker coastal-to-inland concentration gradients than sea-salt aerosols, leading to several inland European cities having >10% of their surface submicron organic aerosol mass concentration with a marine source. The addition of MOA tracers to GEOS-Chem enabled us to identify the regions with large contributions of freshly emitted or aged aerosol having distinct physicochemical properties, potentially indicating optimal locations for future field studies.

  12. Implementing marine organic aerosols into the GEOS-Chem model

    NASA Astrophysics Data System (ADS)

    Gantt, B.; Johnson, M. S.; Crippa, M.; Prévôt, A. S. H.; Meskhidze, N.

    2014-09-01

    Marine organic aerosols (MOA) have been shown to play an important role in tropospheric chemistry by impacting surface mass, cloud condensation nuclei, and ice nuclei concentrations over remote marine and coastal regions. In this work, an online marine primary organic aerosol emission parameterization, designed to be used for both global and regional models, was implemented into the GEOS-Chem model. The implemented emission scheme improved the large underprediction of organic aerosol concentrations in clean marine regions (normalized mean bias decreases from -79% when using the default settings to -12% when marine organic aerosols are added). Model predictions were also in good agreement (correlation coefficient of 0.62 and normalized mean bias of -36%) with hourly surface concentrations of MOA observed during the summertime at an inland site near Paris, France. Our study shows that MOA have weaker coastal-to-inland concentration gradients than sea-salt aerosols, leading to several inland European cities having > 10% of their surface submicron organic aerosol mass concentration with a marine source. The addition of MOA tracers to GEOS-Chem enabled us to identify the regions with large contributions of freshly-emitted or aged aerosol having distinct physicochemical properties, potentially indicating optimal locations for future field studies.

  13. ISS Ambient Air Quality: Updated Inventory of Known Aerosol Sources

    NASA Technical Reports Server (NTRS)

    Meyer, Marit

    2014-01-01

    Spacecraft cabin air quality is of fundamental importance to crew health, with concerns encompassing both gaseous contaminants and particulate matter. Little opportunity exists for direct measurement of aerosol concentrations on the International Space Station (ISS), however, an aerosol source model was developed for the purpose of filtration and ventilation systems design. This model has successfully been applied, however, since the initial effort, an increase in the number of crewmembers from 3 to 6 and new processes on board the ISS necessitate an updated aerosol inventory to accurately reflect the current ambient aerosol conditions. Results from recent analyses of dust samples from ISS, combined with a literature review provide new predicted aerosol emission rates in terms of size-segregated mass and number concentration. Some new aerosol sources have been considered and added to the existing array of materials. The goal of this work is to provide updated filtration model inputs which can verify that the current ISS filtration system is adequate and filter lifetime targets are met. This inventory of aerosol sources is applicable to other spacecraft, and becomes more important as NASA considers future long term exploration missions, which will preclude the opportunity for resupply of filtration products.

  14. Particle size distributions of several commonly used seeding aerosols

    NASA Technical Reports Server (NTRS)

    Crosswy, F. L.

    1985-01-01

    During the course of experimentation, no solid particle powder could be found which produced an aerosol with a narrow particle size distribution when fluidization was the only flow process used in producing the aerosol. The complication of adding particle size fractionation processes to the aerosol generation effort appears to be avoidable. In this regard, a simple sonic orifice is found to be effective in reducing the percentage of agglomerates in the several metal oxide powders tested. Marginally beneficial results are obtained for a 0.5/99.5 percent by weight mixture of the flow agent and metal oxide powder. However, agglomeration is observed to be enhanced when the flow agent percentage is increased to 5 percent. Liquid atomization using the Collison nebulizer as well as a version of the Laskin nozzle resulted in polydispersed aerosols with particle size distributions heavily weighted by the small particle end of the size spectrum. The aerosol particle size distributions produced by the vaporization/condensation seeder are closer to the ideal monodispersed aerosol than any of the other aerosols tested. In addition, this seeding approach affords a measure of control over particle size and particle production rate.

  15. Nanoscale welding aerosol sensing based on whispering gallery modes in a cylindrical silica resonator

    PubMed Central

    Lee, Aram; Mills, Thomas; Xu, Yong

    2015-01-01

    We report an experimental technique where one uses a standard silica fiber as a cylindrical whispering gallery mode (WGM) resonator to sense airborne nanoscale aerosols produced by electric arc welding. We find that the accumulation of aerosols on the resonator surface induces a measurable red-shift in resonance frequency, and establish an empirical relation that links the magnitude of resonance shift with the amount of aerosol deposition. The WGM quality factors, by contrast, do not decrease significantly, even for samples with a large percentage of surface area covered by aerosols. Our experimental results are discussed and compared with existing literature on WGM-based nanoparticle sensing. PMID:25837078

  16. Nanoscale welding aerosol sensing based on whispering gallery modes in a cylindrical silica resonator.

    PubMed

    Lee, Aram; Mills, Thomas; Xu, Yong

    2015-03-23

    We report an experimental technique where one uses a standard silica fiber as a cylindrical whispering gallery mode (WGM) resonator to sense airborne nanoscale aerosols produced by electric arc welding. We find that the accumulation of aerosols on the resonator surface induces a measurable red-shift in resonance frequency, and establish an empirical relation that links the magnitude of resonance shift with the amount of aerosol deposition. The WGM quality factors, by contrast, do not decrease significantly, even for samples with a large percentage of surface area covered by aerosols. Our experimental results are discussed and compared with existing literature on WGM-based nanoparticle sensing. PMID:25837078

  17. Stratospheric geoengineering with black carbon aerosols

    NASA Astrophysics Data System (ADS)

    Kravitz, Benjamin S.

    I use a general circulation model of Earth's climate to simulate stratospheric geoengineering with black carbon aerosols, varying the altitude of injection, initial particle size, and whether the deposited black carbon modifies ground albedo. 1 Tg of black carbon aerosols injected into the stratosphere each year will cause significant enough surface cooling to negate anthropogenic warming if the aerosols are small (r=0.03 mum) or if the aerosols are injected into the middle stratosphere, although using small aerosols causes large regional cooling effects that would be catastrophic to agriculture. The aerosols cause significant stratospheric heating, resulting in stratospheric ozone destruction and circulation changes, most notably an increase in the Northern Hemisphere polar jet, which forms an Arctic ozone hole and forces a positive mode of the Arctic Oscillation. The hydrologic cycle is perturbed, specifically the summer monsoon system of India, Africa, and East Asia, resulting in monsoon precipitation collapse. Global primary productivity is decreased by 35.5% for the small particle case. Surface cooling causes some sea ice regrowth, but not at statistically significant levels. All of these climate impacts are exacerbated for small particle geoengineering, with high altitude geoengineering with the default particle size (r=0.08 mum) causing a reasonable amount of cooling, and large particle (r=0.15 mum) geoengineering or particle injection into the lower stratosphere causing few of these effects. The modification of ground albedo by the soot particles slightly perturbs the radiative budget but does not cause any distinguishable climate effects. The cheapest means we investigated for placing 1 Tg of black carbon aerosols into the stratosphere by diesel fuel combustion would cost 1.4 trillion initially and 541 billion annual, or 2.0% and 0.8% of GDP, respectively. The additional carbon dioxide released from combusting diesel to produce these aerosols is about 1

  18. Cloud Condensation Nuclei Profile Value-Added Product

    SciTech Connect

    McFarlane, S; Sivaraman, C; Ghan, S

    2012-10-08

    The cloud condensation nuclei (CCN) concentration at cloud base is the most relevant measure of the aerosol that influences droplet formation in clouds. Since the CCN concentration depends on supersaturation, a more general measure of the CCN concentration is the CCN spectrum (values at multiple supersaturations). The CCN spectrum is now measured at the surface at several fixed ARM sites and by the ARM Mobile Facility (AMF), but is not measured at the cloud base. Rather than rely on expensive aircraft measurements for all studies of aerosol effects on clouds, a way to project CCN measurements at the surface to cloud base is needed. Remote sensing of aerosol extinction provides information about the vertical profile of the aerosol, but cannot be directly related to the CCN concentration because the aerosol extinction is strongly influenced by humidification, particularly near cloud base. Ghan and Collins (2004) and Ghan et al. (2006) propose a method to remove the influence of humidification from the extinction profiles and tie the “dry extinction” retrieval to the surface CCN concentration, thus estimating the CCN profile. This methodology has been implemented as the CCN Profile (CCNPROF) value-added product (VAP).

  19. Volcanic Aerosol Radiative Properties

    NASA Technical Reports Server (NTRS)

    Lacis, Andrew

    2015-01-01

    Large sporadic volcanic eruptions inject large amounts of sulfur bearing gases into the stratosphere which then get photochemically converted to sulfuric acid aerosol droplets that exert a radiative cooling effect on the global climate system lasting for several years.

  20. Palaeoclimate: Aerosols and rainfall

    NASA Astrophysics Data System (ADS)

    Partin, Jud

    2015-03-01

    Instrumental records have hinted that aerosol emissions may be shifting rainfall over Central America southwards. A 450-year-long precipitation reconstruction indicates that this shift began shortly after the Industrial Revolution.

  1. Emergency Protection from Aerosols

    SciTech Connect

    Cristy, G.A.

    2001-11-13

    Expedient methods were developed that could be used by an average person, using only materials readily available, to protect himself and his family from injury by toxic (e.g., radioactive) aerosols. The most effective means of protection was the use of a household vacuum cleaner to maintain a small positive pressure on a closed house during passage of the aerosol cloud. Protection factors of 800 and above were achieved.

  2. Emergency protection from aerosols

    SciTech Connect

    Cristy, G.A.; Chester, C.V.

    1981-07-01

    Expedient methods were developed that could be used by an average person, using only materials readily available, to protect himself and his family from injury by toxic (e.g., radioactive) aerosols. The most effective means of protection was the use of a household vacuum cleaner to maintain a small positive pressure on a closed house during passage of the aerosol cloud. Protection factors of 800 and above were achieved.

  3. Monodisperse aerosol generator

    DOEpatents

    Ortiz, Lawrence W.; Soderholm, Sidney C.

    1990-01-01

    An aerosol generator is described which is capable of producing a monodisperse aerosol within narrow limits utilizing an aqueous solution capable of providing a high population of seed nuclei and an organic solution having a low vapor pressure. The two solutions are cold nebulized, mixed, vaporized, and cooled. During cooling, particles of the organic vapor condense onto the excess seed nuclei, and grow to a uniform particle size.

  4. MISR Aerosol Typing

    NASA Technical Reports Server (NTRS)

    Kahn, Ralph A.

    2014-01-01

    AeroCom is an open international initiative of scientists interested in the advancement of the understanding of global aerosol properties and aerosol impacts on climate. A central goal is to more strongly tie and constrain modeling efforts to observational data. A major element for exchanges between data and modeling groups are annual meetings. The meeting was held September 20 through October 2, 1014 and the organizers would like to post the presentations.

  5. RACORO aerosol data processing

    SciTech Connect

    Elisabeth Andrews

    2011-10-31

    The RACORO aerosol data (cloud condensation nuclei (CCN), condensation nuclei (CN) and aerosol size distributions) need further processing to be useful for model evaluation (e.g., GCM droplet nucleation parameterizations) and other investigations. These tasks include: (1) Identification and flagging of 'splash' contaminated Twin Otter aerosol data. (2) Calculation of actual supersaturation (SS) values in the two CCN columns flown on the Twin Otter. (3) Interpolation of CCN spectra from SGP and Twin Otter to 0.2% SS. (4) Process data for spatial variability studies. (5) Provide calculated light scattering from measured aerosol size distributions. Below we first briefly describe the measurements and then describe the results of several data processing tasks that which have been completed, paving the way for the scientific analyses for which the campaign was designed. The end result of this research will be several aerosol data sets which can be used to achieve some of the goals of the RACORO mission including the enhanced understanding of cloud-aerosol interactions and improved cloud simulations in climate models.

  6. Microphysical properties of transported biomass burning aerosols in coastal regions, and application to improving retrievals of aerosol optical depth from SeaWiFS data

    NASA Astrophysics Data System (ADS)

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

    2013-05-01

    Due to the limited measurement capabilities of heritage and current spaceborne passive imaging radiometers, algorithms for the retrieval of aerosol optical depth (AOD) and related quantities must make assumptions relating to aerosol microphysical properties and surface reflectance. Over the ocean, surface reflectance can be relatively well-modelled, but knowledge of aerosol properties can remain elusive. Several field campaigns and many studies have examined the microphysical properties of biomass burning (smoke) aerosol. However, these largely focus on properties over land and near to the source regions. In coastal and open-ocean regions the properties of transported smoke may differ, due to factors such as aerosol aging, wet/dry deposition, and mixture with other aerosol sources (e.g. influence of maritime, pollution, or mineral dust aerosols). Hence, models based on near-source aerosol observations may be less representative of such transported smoke aerosols, introducing additional uncertainty into satellite retrievals of aerosol properties. This study examines case studies of transported smoke from select globally-distributed coastal and island Aerosol Robotic Network (AERONET) sites. These are used to inform improved models for over-ocean transported smoke aerosol for AOD retrievals from the Sea-viewing Wide Field-of-view Sensor (SeaWiFS). These models are used in an updated version of the SeaWiFS Ocean Aerosol Retrieval (SOAR) algorithm, which has been combined with the Deep Blue algorithm over land to create a 13-year (1997-2010) high-quality record of AOD over land and ocean. Applying these algorithms to other sensors will enable the creation of a long-term global climate data record of spectral AOD.

  7. Modelling of primary aerosols in the chemical transport model MOCAGE: development and evaluation of aerosol physical parameterizations

    NASA Astrophysics Data System (ADS)

    Sič, B.; El Amraoui, L.; Marécal, V.; Josse, B.; Arteta, J.; Guth, J.; Joly, M.; Hamer, P.

    2014-04-01

    This paper deals with recent improvements to the chemical transport model of Météo-France MOCAGE that consists of updates to different aerosol parameterizations. MOCAGE only contains primary aerosol species. We introduced important changes to the aerosol parameterization concerning emissions, wet deposition and sedimentation. For the emissions, size distribution and wind calculations are modified for desert dust aerosols, and a surface sea temperature dependant source function is introduced for sea salt aerosols. Wet deposition is modified toward a more physically realistic representation by introducing re-evaporation of falling rain and snowfall scavenging, and by changing in-cloud scavenging scheme along with calculations of precipitation cloud cover and rain properties. The sedimentation scheme update includes changes regarding the stability and viscosity calculations. Independent data from satellites (MODIS, SEVIRI), the ground (AERONET), and a model inter-comparison project (AeroCom) is compared with MOCAGE simulations and showed that the introduced changes brought a significant improvement on aerosol representation, properties and global distribution. Emitted quantities of desert dust and sea salt, as well their lifetimes, moved closer towards values of AeroCom estimates and the multi-model average. When comparing the model simulations with MODIS aerosol optical depth (AOD) observations over the oceans, the updated model configuration shows a decrease in the bias (from 0.032 to 0.002) and a better correlation (from 0.062 to 0.322) in terms of the geographical distribution and the temporal variability. The updates corrected a strong positive bias in the sea salt representation at high latitudes (from 0.153 to 0.026), and a negative bias in the desert dust representation in the African dust outflow region (from -0.179 to -0.051). The updates in sedimentation produced a modest difference; the bias with MODIS data from 0.002 in the updated configuration went to

  8. What Value "Value Added"?

    ERIC Educational Resources Information Center

    Richards, Andrew

    2015-01-01

    Two quantitative measures of school performance are currently used, the average points score (APS) at Key Stage 2 and value-added (VA), which measures the rate of academic improvement between Key Stage 1 and 2. These figures are used by parents and the Office for Standards in Education to make judgements and comparisons. However, simple…

  9. 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.

  10. Introducing ADS Labs

    NASA Astrophysics Data System (ADS)

    Accomazzi, Alberto; Henneken, E.; Grant, C. S.; Kurtz, M. J.; Di Milia, G.; Luker, J.; Thompson, D. M.; Bohlen, E.; Murray, S. S.

    2011-05-01

    ADS Labs is a platform that ADS is introducing in order to test and receive feedback from the community on new technologies and prototype services. Currently, ADS Labs features a new interface for abstract searches, faceted filtering of results, visualization of co-authorship networks, article-level recommendations, and a full-text search service. The streamlined abstract search interface provides a simple, one-box search with options for ranking results based on a paper relevancy, freshness, number of citations, and downloads. In addition, it provides advanced rankings based on collaborative filtering techniques. The faceted filtering interface allows users to narrow search results based on a particular property or set of properties ("facets"), allowing users to manage large lists and explore the relationship between them. For any set or sub-set of records, the co-authorship network can be visualized in an interactive way, offering a view of the distribution of contributors and their inter-relationships. This provides an immediate way to detect groups and collaborations involved in a particular research field. For a majority of papers in Astronomy, our new interface will provide a list of related articles of potential interest. The recommendations are based on a number of factors, including text similarity, citations, and co-readership information. The new full-text search interface allows users to find all instances of particular words or phrases in the body of the articles in our full-text archive. This includes all of the scanned literature in ADS as well as a select portion of the current astronomical literature, including ApJ, ApJS, AJ, MNRAS, PASP, A&A, and soon additional content from Springer journals. Fulltext search results include a list of the matching papers as well as a list of "snippets" of text highlighting the context in which the search terms were found. ADS Labs is available at http://adslabs.org

  11. Anthropogenic Aerosols and the Dust Bowl

    NASA Astrophysics Data System (ADS)

    Cazavilan, E. J.; Leibensperger, E. M.

    2014-12-01

    We use a general circulation model (GISS GCM ModelE) to study the impact of anthropogenic aerosols on the 1930s Dust Bowl. The Dust Bowl was primarily forced by anomalous sea surface temperatures, but may have been partially shaped by the large amounts of black carbon emitted at that time. A simulation using observed 1932-1938 sea surface temperature and sea ice distributions reveal drier and warmer conditions in the central U.S. Adding the influence of 1930s anthropogenic aerosols exacerbates the drying and warm conditions (0.2 °C increase over mid-west continental US, and a decrease of -0.1 mm/day of precipitation). We find that these changes are concurrent with a weakening and shift of the Bermuda High.

  12. AEROSOL GROWTH IN A STEADY-STATE, CONTINUOUS FLOW CHAMBER: APPLICATION TO STUDIES OF SECONDARY AEROSOL FORMATION

    EPA Science Inventory

    An analytical solution for the steady-state aerosol size distribution achieved in a steady-state, continuous flow chamber is derived, where particle growth is occurring by gas-to-particle conversion and particle loss is occurring by deposition to the walls of the chamber. The s...

  13. Internal mixture of sea salt, silicates, and excess sulfate in marine aerosols.

    PubMed

    Andreae, M O; Charlson, R J; Bruynseels, F; Storms, H; VAN Grieken, R; Maenhaut, W

    1986-06-27

    Individual aerosol particles from the remote marine atmosphere were investigated by scanning electron microscopy and electron microprobe analysis. A large fraction of the silicate mineral component of the aerosol was found to be internally mixed with sea-salt aerosol particles. This observation explains the unexpected similarity in the size distributions of silicates and sea salt that has been observed in remote marine aerosols. Reentrainment of dust particles previously deposited onto the sea surface and collision between aerosol particles can be excluded as possible source mechanisms for these internally mixed aerosols. The internal mixing could be produced by processes within clouds, including droplet coalescence. Cloud processes may also be responsible for the observed enrichment of excess (nonsea-salt) sulfate on sea-salt particles.

  14. Improving satellite-retrieved aerosol microphysical properties using GOCART data

    NASA Astrophysics Data System (ADS)

    Li, S.; Kahn, R.; Chin, M.; Garay, M. J.; Liu, Y.

    2015-03-01

    The Multi-angle Imaging SpectroRadiometer (MISR) aboard the NASA Earth Observing System's Terra satellite can provide more reliable aerosol optical depth (AOD) and better constraints on particle size (Ångström exponent, or ANG), sphericity, and single-scattering albedo (SSA) than many other satellite instruments. However, many aerosol mixtures pass the algorithm acceptance criteria, yielding a poor constraint, when the particle-type information in the MISR radiances is low, typically at low AOD. We investigate adding value to the MISR aerosol product under these conditions by filtering the list of MISR-retrieved mixtures based on agreement between the mixture ANG and absorbing AOD (AAOD) values, and simulated aerosol properties from the Goddard Chemistry Aerosol Radiation and Transport (GOCART) model. MISR-GOCART ANG difference and AAOD ratio thresholds for applying GOCART constraints were determined based on coincident AOD, ANG, and AAOD measurements from the AErosol RObotic NETwork (AERONET). The results were validated by comparing the adjusted MISR aerosol optical properties over the contiguous USA between 2006 and 2009 with additional AERONET data. The correlation coefficient (r) between the adjusted MISR ANG derived from this study and AERONET improves to 0.45, compared to 0.29 for the MISR Version 22 standard product. The ratio of the adjusted MISR AAOD to AERONET increases to 0.74, compared to 0.5 for the MISR operational retrieval. These improvements occur primarily when AOD < 0.2 for ANG and AOD < 0.5 for AAOD. Spatial and temporal differences among the aerosol optical properties of MISR V22, GOCART, and the adjusted MISR are traced to (1) GOCART underestimation of AOD and ANG in polluted regions; (2) aerosol mixtures lacking in the MISR Version 22 algorithm climatology; (3) low MISR sensitivity to particle type under some conditions; and (4) parameters and thresholds used in our method.

  15. Background Southeast United States Aerosol Optical Properties and Their Dependence Upon Meteorology

    NASA Astrophysics Data System (ADS)

    Pawlyszyn, C.; West, M.; Sherman, J. P.; Link, M.; Zhou, Y.

    2015-12-01

    Aerosol effects on SE U.S. radiation budget are highly-seasonal. Aerosol loading is much higher in summer, due largely to high levels of biogenic secondary organic aerosol and sulfates. Aerosol loading is lowest in winter. Aerosol optical properties relevant to radiative forcing have been measured continuously at the Appalachian Atmospheric Interdisciplinary Research facility (AppalAIR) since the summer of 2009. AppalAIR is the only site in the eastern US to house co-located NOAA ESRL and NASA AeroNET instrumentation and is located in the mountains of Boone, NC. Lower tropospheric sub-micron (PM1) light scattering and absorption coefficients measured over seven summers and six winters are presented here, in addition to PM1 organic and sulfate aerosol mass concentrations measured during summers 2012-2013 as well as winter 2013. The objective is to determine the influence of aerosol sources and meteorology along the air mass back-trajectories on aerosol loading and composition. PM1 aerosol mass was dominated by organic aerosol and sulfate during the periods measured. Aerosol light scattering and organic aerosol concentrations were positively correlated during summer with temperature and solar flux along the parcel back-trajectory and negatively-correlated with rainfall along the back-trajectory. Wet deposition was a major factor in the difference between the upper and lower scattering coefficient quartiles for both summer and winter. Summer PM1 light scattering coefficient declined by approximately 30-40% since 2009, with smaller decreases during winter months. Long-term studies of aerosol optical properties from the regionally-representative AppalAIR site are necessary to determine the relationships between changing SE U.S. air quality and aerosol effects on regional climate and weather.

  16. Deposition of Asian Dust in the Tahoe Basin and the Impact of Climate Patterns on Deposition

    NASA Astrophysics Data System (ADS)

    Snyder, Jason

    Routine monitoring of fine aerosols in the Lake Tahoe basin began with the Tahoe Regional Planning Association (TRPA) in 1988 (Molenar et. al., 1994). During this time two sites of aerosol impact analysis were chosen based on prior work done by the ARB (Cahill et. al., 1997). These sites included Bliss SP, which is located near Emerald Bay at 200 m Lake Tahoe. Aerosols deposited at the Bliss SP site during each spring from 1988 to 2004, were predominately from sources outside of the Lake Tahoe basin and contained signatures from an "unknown north Sacramento Valley source" (Cahill and Cliff, 2002). The aerosols amounted to about ½ of all fine soil seen at South Lake Tahoe. With a better knowledge regarding the efficiency of the transport of fine aerosol plumes across the Pacific Ocean to North American combined with the presence of Asian dust signatures at other sites including Crater Lake and the Yukon, it was now determined that the source of fine particles to the Lake Tahoe basin was possibly Asian in origin. For this study, aerosols were collected during spring 2006, which coincides with the annual peak of Asian dust transport toward North America. Aerosols were collected at the TERC Tahoe Fish Hatchery, a relatively pollution free site northeast of Tahoe City. Aerosol collections at this site were done on an offshore pier, which reduced the amount of contamination for shore sources of aerosols and pollution such as road dust. The result was the identification of Asian dust signatures in aerosol deposition data for the period of April 28 to May 15, 2006. Such dust plumes were identified using HYSPLIT trajectories. Chemical signatures were also used including the Fe/Ca ratio, which is unique in Asian dust plumes. The particulate matter in these dust plumes produce a regional haze across the Lake Tahoe basin, which could impact incoming solar radiation. Furthermore, deposition of particles from the aerosol plume into the lake not only contributed to suspended

  17. Optimal Delivery of Aerosols to Infants During Mechanical Ventilation

    PubMed Central

    Azimi, Mandana; Hindle, Michael

    2014-01-01

    Abstract Purpose: The objective of this study was to determine optimal aerosol delivery conditions for a full-term (3.6 kg) infant receiving invasive mechanical ventilation by evaluating the effects of aerosol particle size, a new wye connector, and timing of aerosol delivery. Methods: In vitro experiments used a vibrating mesh nebulizer and evaluated drug deposition fraction and emitted dose through ventilation circuits containing either a commercial (CM) or new streamlined (SL) wye connector and 3-mm endotracheal tube (ETT) for aerosols with mass median aerodynamic diameters of 880 nm, 1.78 μm, and 4.9 μm. The aerosol was released into the circuit either over the full inhalation cycle (T1 delivery) or over the first half of inhalation (T2 delivery). Validated computational fluid dynamics (CFD) simulations and whole-lung model predictions were used to assess lung deposition and exhaled dose during cyclic ventilation. Results: In vitro experiments at a steady-state tracheal flow rate of 5 L/min resulted in 80–90% transmission of the 880-nm and 1.78-μm aerosols from the ETT. Based on CFD simulations with cyclic ventilation, the SL wye design reduced depositional losses in the wye by a factor of approximately 2–4 and improved lung delivery efficiencies by a factor of approximately 2 compared with the CM device. Delivery of the aerosol over the first half of the inspiratory cycle (T2) reduced exhaled dose from the ventilation circuit by a factor of 4 compared with T1 delivery. Optimal lung deposition was achieved with the SL wye connector and T2 delivery, resulting in 45% and 60% lung deposition for optimal polydisperse (∼1.78 μm) and monodisperse (∼2.5 μm) particle sizes, respectively. Conclusions: Optimization of selected factors and use of a new SL wye connector can substantially increase the lung delivery efficiency of medical aerosols to infants from current values of <1–10% to a range of 45–60%. PMID:24299500

  18. Aerosol processing in stratiform clouds in ECHAM6-HAM

    NASA Astrophysics Data System (ADS)

    Neubauer, David; Lohmann, Ulrike; Hoose, Corinna

    2013-04-01

    chemical components as well as 5 tracers for aerosol particles in ice crystals. This allows simulations of aerosol processing in warm, mixed-phase (e.g. through the Bergeron-Findeisen process) and ice clouds. The fixed scavenging ratios used for wet deposition in clouds in standard HAM are replaced by an explicit treatment of collision of cloud droplets/ice crystals with interstitial aerosol particles. Nucleation scavenging of aerosol particles by acting as cloud condensation nuclei or ice nuclei, freezing and evaporation of cloud droplets and melting and sublimation of ice crystals are treated explicitly. In extension to previous studies, aerosol particles from evaporating precipitation are released to modes which correspond to their size. Cloud processing of aerosol particles changes their size distribution and hence influences cloud droplet and ice crystal number concentrations as well as precipitation rate, which in turn affects aerosol concentrations. Results will be presented at the conference. Hoose et al., JGR, 2008a, doi: 10.1029/2007JD009251 Hoose et al., ACP, 2008b, doi: 10.5194/acp-8-6939-2008 Stevens et al., 2013, submitted Stier et al., ACP, 2005, doi: 10.5194/acp-5-1125-2005

  19. Aerosol properties over south india during different seasons

    NASA Astrophysics Data System (ADS)

    Sivaprasad, P.; Babu, C. A.; Jayakrishnan, P. R.

    Aerosols play an important role in the radiation balance and cloud properties, thereby affect the entire climatology of the earth-atmosphere system. Besides natural sources like dust, seasalt and natural sulphates, anthropogenic activities also inject aerosols like soot and industrial sulphates. Of these sea-salt and sulphates scatter the solar radiation. Soot is an absorbing aerosol while soil dust and organic matters are partly absorbing aerosols. Wind and rainfall are major factors affecting the transportation and deposition of the aerosols. India is a country blessed with plenty of monsoon rains. Winter (December to February), summer (March to May), monsoon (June to September) and post monsoon (October to November) are the four seasons over the region. Aerosol properties vary according to the season. Natural aerosols blown from the deserts have a major role in the aerosol optical depth over India. Of this, dust from Arabian desert that is carried by the winds are most important. The aerosol optical depth of south India is entirely different from that of north India. Maximum aerosol concentration is found over Gangetic plane in most of the seasons, whereas entire south India shows less aerosol optical depth. In the present study the aerosol properties of south India is analysed in general. Particular analysis is carried out for the four regions in the east and west coasts around Chennai, Kolkotha, Mumbai and Cochin. Chennai and Kolkotha are situated in the east coast whereas Cochin and Mumbai are in the west coast. These are industrial cities in India. Chennai region does not get monsoon rainfall since it is situated in the leeward side of Western ghats. But in the post monsoon season Chennai gets good amount of rainfall. Other three regions get good amount of rainfall during monsoon season. The study uses Terra MODIS, TOMS, NCEP/NCAR and TRMM data. Aerosol properties are analysed using Terra MODIS and Nimbus TOMS data. The variations of the aerosol optical

  20. Biological aerosol background characterization

    NASA Astrophysics Data System (ADS)

    Blatny, Janet; Fountain, Augustus W., III

    2011-05-01

    To provide useful information during military operations, or as part of other security situations, a biological aerosol detector has to respond within seconds or minutes to an attack by virulent biological agents, and with low false alarms. Within this time frame, measuring virulence of a known microorganism is extremely difficult, especially if the microorganism is of unknown antigenic or nucleic acid properties. Measuring "live" characteristics of an organism directly is not generally an option, yet only viable organisms are potentially infectious. Fluorescence based instruments have been designed to optically determine if aerosol particles have viability characteristics. Still, such commercially available biological aerosol detection equipment needs to be improved for their use in military and civil applications. Air has an endogenous population of microorganisms that may interfere with alarm software technologies. To design robust algorithms, a comprehensive knowledge of the airborne biological background content is essential. For this reason, there is a need to study ambient live bacterial populations in as many locations as possible. Doing so will permit collection of data to define diverse biological characteristics that in turn can be used to fine tune alarm algorithms. To avoid false alarms, improving software technologies for biological detectors is a crucial feature requiring considerations of various parameters that can be applied to suppress alarm triggers. This NATO Task Group will aim for developing reference methods for monitoring biological aerosol characteristics to improve alarm algorithms for biological detection. Additionally, they will focus on developing reference standard methodology for monitoring biological aerosol characteristics to reduce false alarm rates.

  1. MISR UAE2 Aerosol Versioning

    Atmospheric Science Data Center

    2013-03-21

    ... the MISR aerosol microphysical properties are "Beta." Uncertainty envelopes for the aerosol optical depths are given in  Kahn et ... particle microphysical property validation is in progress, uncertainty envelopes on particle size distribution, shape, and ...

  2. Atmospheric Chemistry: Nature's plasticized aerosols

    NASA Astrophysics Data System (ADS)

    Ziemann, Paul J.

    2016-01-01

    The structure of atmospheric aerosol particles affects their reactivity and growth rates. Measurements of aerosol properties over the Amazon rainforest indicate that organic particles above tropical rainforests are simple liquid drops.

  3. Characterization of aerosols containing Legionella generated upon nebulization

    NASA Astrophysics Data System (ADS)

    Allegra, Séverine; Leclerc, Lara; Massard, Pierre André; Girardot, Françoise; Riffard, Serge; Pourchez, Jérémie

    2016-09-01

    Legionella pneumophila is, by far, the species most frequently associated with Legionnaires’ disease (LD). Human infection occurs almost exclusively by aerosol inhalation which places the bacteria in juxtaposition with alveolar macrophages. LD risk management is based on controlling water quality by applying standardized procedures. However, to gain a better understanding of the real risk of exposure, there is a need (i) to investigate under which conditions Legionella may be aerosolized and (ii) to quantify bacterial deposition into the respiratory tract upon nebulization. In this study, we used an original experimental set-up that enables the generation of aerosol particles containing L. pneumophila under various conditions. Using flow cytometry in combination with qPCR and culture, we determined (i) the size of the aerosols and (ii) the concentration of viable Legionella forms that may reach the thoracic region. We determined that the 0.26–2.5 μm aerosol size range represents 7% of initial bacterial suspension. Among the viable forms, 0.7% of initial viable bacterial suspension may reach the pulmonary alveoli. In conclusion, these deposition profiles can be used to standardize the size of inoculum injected in any type of respiratory tract model to obtain new insights into the dose response for LD.

  4. Anthropogenic influence on the distribution of tropospheric sulphate aerosol

    NASA Astrophysics Data System (ADS)

    Langner, J.; Rodhe, H.; Crutzen, P. J.; Zimmermann, P.

    1992-10-01

    HUMAN activities have increased global emissions of sulphur gases by about a factor of three during the past century, leading to increased sulphate aerosol concentrations, mainly in the Northern Hemisphere. Sulphate aerosols can affect the climate directly, by increasing the backscattering of solar radiation in cloud-free air, and indirectly, by providing additional cloud condensation nuclei1-4. Here we use a global transport-chemistry model to estimate the changes in the distribution of tropospheric sulphate aerosol and deposition of non-seasalt sulphur that have occurred since pre-industrial times. The increase in sulphate aerosol concentration is small over the Southern Hemisphere oceans, but reaches a factor of 100 over northern Europe in winter. Our calculations indicate, however, that at most 6% of the anthropogenic sulphur emissions is available for the formation of new aerosol particles. This is because about one-half of the sulphur dioxide is deposited on the Earth's surface, and most of the remainder is oxidized in cloud droplets so that the sulphate becomes associated with pre-existing particles. Even so, the rate of formation of new sulphate particles may have doubled since pre-industrial times.

  5. Characterization of aerosols containing Legionella generated upon nebulization

    PubMed Central

    Allegra, Séverine; Leclerc, Lara; Massard, Pierre André; Girardot, Françoise; Riffard, Serge; Pourchez, Jérémie

    2016-01-01

    Legionella pneumophila is, by far, the species most frequently associated with Legionnaires’ disease (LD). Human infection occurs almost exclusively by aerosol inhalation which places the bacteria in juxtaposition with alveolar macrophages. LD risk management is based on controlling water quality by applying standardized procedures. However, to gain a better understanding of the real risk of exposure, there is a need (i) to investigate under which conditions Legionella may be aerosolized and (ii) to quantify bacterial deposition into the respiratory tract upon nebulization. In this study, we used an original experimental set-up that enables the generation of aerosol particles containing L. pneumophila under various conditions. Using flow cytometry in combination with qPCR and culture, we determined (i) the size of the aerosols and (ii) the concentration of viable Legionella forms that may reach the thoracic region. We determined that the 0.26–2.5 μm aerosol size range represents 7% of initial bacterial suspension. Among the viable forms, 0.7% of initial viable bacterial suspension may reach the pulmonary alveoli. In conclusion, these deposition profiles can be used to standardize the size of inoculum injected in any type of respiratory tract model to obtain new insights into the dose response for LD. PMID:27671446

  6. Two Virasoro symmetries in stringy warped AdS3

    NASA Astrophysics Data System (ADS)

    Compère, Geoffrey; Guica, Monica; Rodriguez, Maria J.

    2014-12-01

    We study three-dimensional consistent truncations of type IIB supergravity which admit warped AdS3 solutions. These theories contain subsectors that have no bulk dynamics. We show that the symplectic form for these theories, when restricted to the non-dynamical subsectors, equals the symplectic form for pure Einstein gravity in AdS3. Consequently, for each consistent choice of boundary conditions in AdS3, we can define a consistent phase space in warped AdS3 with identical conserved charges. This way, we easily obtain a Virasoro × Virasoro asymptotic symmetry algebra in warped AdS3; two different types of Virasoro × Kač-Moody symmetries are also consistent alternatives.

  7. Aerosol characterization with lidar methods

    NASA Astrophysics Data System (ADS)

    Sugimoto, Nobuo; Nishizawa, Tomoaki; Shimizu, Atsushi; Matsui, Ichiro

    2014-08-01

    Aerosol component analysis methods for characterizing aerosols were developed for various types of lidars including polarization-sensitive Mie scattering lidars, multi-wavelength Raman scattering lidars, and multi-wavelength highspectral- resolution lidars. From the multi-parameter lidar data, the extinction coefficients for four aerosol components can be derived. The microphysical parameters such as single scattering albedo and effective radius can be also estimated from the derived aerosol component distributions.

  8. Alveolar targeting of aerosol pentamidine. Toward a rational delivery system

    SciTech Connect

    Simonds, A.K.; Newman, S.P.; Johnson, M.A.; Talaee, N.; Lee, C.A.; Clarke, S.W. )

    1990-04-01

    Nebulizer systems that deposit a high proportion of aerosolized pentamidine on large airways are likely to be associated with marked adverse side effects, which may lead to premature cessation of treatment. We have measured alveolar deposition and large airway-related side effects (e.g., cough, breathlessness, and effect on pulmonary function) after aerosolization of 150 mg pentamidine isethionate labeled with {sup 99m}Tc-Sn-colloid. Nine patients with AIDS were studied using three nebulizer systems producing different droplet size profiles: the Acorn System 22, Respirgard II, and Respirgard II with the inspiratory baffle removed. Alveolar deposition was greatest and side effects least with the nebulizer producing the smallest droplet size profile (Respirgard II), whereas large airway-related side effects were prominent and alveolar deposition lowest with the nebulizer producing the largest droplet size (Acorn System 22). Values for alveolar deposition and adverse airway effects were intermediate using the Respirgard with inspiratory baffle removed, thus indicating the importance of the baffle valve in determining droplet size. Addition of a similar baffle valve to the Acorn System 22 produced a marked improvement in droplet size profile. Selection of a nebulizer that produces an optimal droplet size range offers the advantage of enhancing alveolar targeting of aerosolized pentamidine while reducing large airway-related side effects.

  9. Does chronic nitrogen deposition during biomass growth affect atmospheric emissions from biomass burning?

    NASA Astrophysics Data System (ADS)

    Giordano, Michael R.; Chong, Joey; Weise, David R.; Asa-Awuku, Akua A.

    2016-03-01

    Chronic nitrogen deposition has measureable impacts on soil and plant health. We investigate burning emissions from biomass grown in areas of high and low NO x deposition. Gas and aerosol-phase emissions were measured as a function of photochemical aging in an environmental chamber at UC-Riverside. Though aerosol chemical speciation was not available, results indicate a systemic compositional difference between biomass grown in high and low deposition areas. Aerosol emissions from biomass grown in areas of high NO x deposition exhibit a lower volatility than biomass grown in a low deposition area. Furthermore, fuel elemental analysis, NO x emission rates, and aerosol particle number distributions differed significantly between the two sites. Despite the limited scale of fuels explored, there is strong evidence that the atmospheric emissions community must pay attention to the regional air quality of biomass fuels growth areas.

  10. Compound Specific Stable Isotope Analysis of Southern African Aerosols

    NASA Astrophysics Data System (ADS)

    Billmark, K. A.; Swap, R. J.; Macko, S. A.

    2001-12-01

    Southern Africa has recently been the focus of intensive subcontinental level study, particularly with regard to atmospheric aerosols and regional atmospheric transport. Results from these analyses have shown that emissions from extensive, often anthropogenic, biomass burning in southern Africa affects biogeochemical cycling in the region, and that emitted trace gases and aerosols as well as industrial emissions, marine aerosols and mineral dust tend to accumulate and recirculate in the well defined anticyclonic atmospheric gyre that persists for long time periods over southern Africa. The long-range transport of these materials is an important component of biogeochemical dynamics in this nutrient limited region. A recent field campaign, the Southern African Regional Science Initiative (SAFARI 2000), was conducted in part to investigate the impacts of this large-scale transport and deposition of aerosols on southern African biogeochemical cycling. As a part of the SAFARI 2000 initiative, we present data illustrating that compound specific stable isotope analysis of individual molecular components is a useful tool for the evaluation of the origins of aerosols and their generating processes. This study specifically examines fatty acids extracted from aerosols to more precisely characterize emissions produced in the high intensity biomass burning region of western Zambia, the slightly less intense biomass burning region of northeastern South Africa and a site downwind of these two regions within the gyre circulation at Sua Pan, Botswana. This discrete characterization of fatty acids contained within the organic fraction of collected aerosols establishes a means to trace biomass burning products as they are transported within the gyre and subsequently deposited on the subcontinent.

  11. Cantera Aerosol Dynamics Simulator

    SciTech Connect

    Moffat, Harry

    2004-09-01

    The Cantera Aerosol Dynamics Simulator (CADS) package is a general library for aerosol modeling to address aerosol general dynamics, including formation from gas phase reactions, surface chemistry (growth and oxidation), bulk particle chemistry, transport by Brownian diffusion, thermophoresis, and diffusiophoresis with linkage to DSMC studies, and thermal radiative transport. The library is based upon Cantera, a C++ Cal Tech code that handles gas phase species transport, reaction, and thermodynamics. The method uses a discontinuous galerkin formulation for the condensation and coagulation operator that conserves particles, elements, and enthalpy up to round-off error. Both O-D and 1-D time dependent applications have been developed with the library. Multiple species in the solid phase are handled as well. The O-D application, called Tdcads (Time Dependent CADS) is distributed with the library. Tdcads can address both constant volume and constant pressure adiabatic homogeneous problems. An extensive set of sample problems for Tdcads is also provided.

  12. FTIR Analysis of Functional Groups in Aerosol Particles

    NASA Astrophysics Data System (ADS)

    Shokri, S. M.; McKenzie, G.; Dransfield, T. J.

    2012-12-01

    Secondary organic aerosols (SOA) are suspensions of particulate matter composed of compounds formed from chemical reactions of organic species in the atmosphere. Atmospheric particulate matter can have impacts on climate, the environment and human health. Standardized techniques to analyze the characteristics and composition of complex secondary organic aerosols are necessary to further investigate the formation of SOA and provide a better understanding of the reaction pathways of organic species in the atmosphere. While Aerosol Mass Spectrometry (AMS) can provide detailed information about the elemental composition of a sample, it reveals little about the chemical moieties which make up the particles. This work probes aerosol particles deposited on Teflon filters using FTIR, based on the protocols of Russell, et al. (Journal of Geophysical Research - Atmospheres, 114, 2009) and the spectral fitting algorithm of Takahama, et al (submitted, 2012). To validate the necessary calibration curves for the analysis of complex samples, primary aerosols of key compounds (e.g., citric acid, ammonium sulfate, sodium benzoate) were generated, and the accumulated masses of the aerosol samples were related to their IR absorption intensity. These validated calibration curves were then used to classify and quantify functional groups in SOA samples generated in chamber studies by MIT's Kroll group. The fitting algorithm currently quantifies the following functionalities: alcohols, alkanes, alkenes, amines, aromatics, carbonyls and carboxylic acids.

  13. Postdeposition dispersion of aerosol medications using surfactant carriers.

    PubMed

    Marcinkowski, Amy L; Garoff, Stephen; Tilton, Robert D; Pilewski, Joseph M; Corcoran, Timothy E

    2008-12-01

    Inhaled aerosol drugs provide a means of directly treating the lungs; however, aerosol deposition and drug distribution can be nonuniform, especially in obstructive lung disease. We hypothesize that surfactant-based aerosol carriers will disperse medications over airway surfaces after deposition through surface tension driven flows, increasing dose uniformity and improving drug distribution into underventilated regions. We considered saline and surfactant aerosol delivery via cannula onto several model airway surfaces including porcine gastric mucus (PGM) and both cystic fibrosis (CF) and non-CF human bronchial epithelial cells (HBEs). Fluorescent dye and microspheres (d = 100 nm, 1 mum) were used to qualitatively and quantitatively assess postdeposition dispersion. Aerosol volume median diameters were in the 1-4 mum range. The tested surfactants included sodium dodecyl sulfate (SDS), cetyl trimethyl ammonium bromide (CTAB), tyloxapol, and calfactant. All surfactants tested on PGM (tyloxapol, calfactant, SDS, and CTAB) significantly increased dispersion area versus saline with all markers (2-20-fold increases; all p < 0.04). Both surfactants tested on CF HBEs (tyloxapol and calfactant) significantly increased dispersion area versus saline with all markers (1.6-4.1-fold increases; all p aerosol deposition onto model airway surfaces, and may improve the efficacy of inhaled preparations such as inhaled antibiotics for cystic fibrosis.

  14. Indian aerosols: present status.

    PubMed

    Mitra, A P; Sharma, C

    2002-12-01

    This article presents the status of aerosols in India based on the research activities undertaken during last few decades in this region. Programs, like International Geophysical Year (IGY), Monsoon Experiment (MONEX), Indian Middle Atmospheric Program (IMAP) and recently conducted Indian Ocean Experiment (INDOEX), have thrown new lights on the role of aerosols in global change. INDOEX has proved that the effects of aerosols are no longer confined to the local levels but extend at regional as well as global scales due to occurrence of long range transportation of aerosols from source regions along with wind trajectories. The loading of aerosols in the atmosphere is on rising due to energy intensive activities for developmental processes and other anthropogenic activities. One of the significant observation of INDOEX is the presence of high concentrations of carbonaceous aerosols in the near persistent winter time haze layer over tropical Indian Ocean which have probably been emitted from the burning of fossil-fuels and biofuels in the source region. These have significant bearing on the radiative forcing in the region and, therefore, have potential to alter monsoon and hydrological cycles. In general, the SPM concentrations have been found to be on higher sides in ambient atmosphere in many Indian cities but the NOx concentrations have been found to be on lower side. Even in the haze layer over Indian Ocean and surrounding areas, the NOx concentrations have been reported to be low which is not conducive of O3 formation in the haze/smog layer. The acid rain problem does not seem to exist at the moment in India because of the presence of neutralizing soil dust in the atmosphere. But the high particulate concentrations in most of the cities' atmosphere in India are of concern as it can cause deteriorated health conditions. PMID:12492171

  15. Indian aerosols: present status.

    PubMed

    Mitra, A P; Sharma, C

    2002-12-01

    This article presents the status of aerosols in India based on the research activities undertaken during last few decades in this region. Programs, like International Geophysical Year (IGY), Monsoon Experiment (MONEX), Indian Middle Atmospheric Program (IMAP) and recently conducted Indian Ocean Experiment (INDOEX), have thrown new lights on the role of aerosols in global change. INDOEX has proved that the effects of aerosols are no longer confined to the local levels but extend at regional as well as global scales due to occurrence of long range transportation of aerosols from source regions along with wind trajectories. The loading of aerosols in the atmosphere is on rising due to energy intensive activities for developmental processes and other anthropogenic activities. One of the significant observation of INDOEX is the presence of high concentrations of carbonaceous aerosols in the near persistent winter time haze layer over tropical Indian Ocean which have probably been emitted from the burning of fossil-fuels and biofuels in the source region. These have significant bearing on the radiative forcing in the region and, therefore, have potential to alter monsoon and hydrological cycles. In general, the SPM concentrations have been found to be on higher sides in ambient atmosphere in many Indian cities but the NOx concentrations have been found to be on lower side. Even in the haze layer over Indian Ocean and surrounding areas, the NOx concentrations have been reported to be low which is not conducive of O3 formation in the haze/smog layer. The acid rain problem does not seem to exist at the moment in India because of the presence of neutralizing soil dust in the atmosphere. But the high particulate concentrations in most of the cities' atmosphere in India are of concern as it can cause deteriorated health conditions.

  16. Easy Volcanic Aerosol

    NASA Astrophysics Data System (ADS)

    Toohey, Matthew; Stevens, Bjorn; Schmidt, Hauke; Timmreck, Claudia

    2016-04-01

    Radiative forcing by stratospheric sulfate aerosol of volcanic origin is one of the strongest drivers of natural climate variability. Transient model simulations attempting to match observed climate variability, such as the CMIP historical simulations, rely on volcanic forcing reconstructions based on observations of a small sample of recent eruptions and coarse proxy data for eruptions before the satellite era. Volcanic forcing data sets used in CMIP5 were provided either in terms of optical properties, or in terms of sulfate aerosol mass, leading to significant inter-model spread in the actual volcanic radiative forcing produced by models and in their resulting climate responses. It remains therefore unclear to what degree inter-model spread in response to volcanic forcing represents model differences or variations in the forcing. In order to isolate model differences, Easy Volcanic Aerosol (EVA) provides an analytic representation of volcanic stratospheric aerosol forcing, based on available observations and aerosol model results, prescribing the aerosol's radiative properties and primary modes of spatial and temporal variability. In contrast to regriddings of observational data, EVA allows for the production of physically consistent forcing for historic and hypothetical eruptions of varying magnitude, source latitude, and season. Within CMIP6, EVA will be used to reconstruct volcanic forcing over the past 2000 years for use in the Paleo-Modeling Intercomparison Project (PMIP), and will provide forcing sets for VolMIP experiments aiming to quantify model uncertainty in the response to volcanic forcing. Here, the functional form of EVA will be introduced, along with illustrative examples including the EVA-based reconstruction of volcanic forcing over the historical period, and that of the 1815 Tambora eruption.

  17. ANALYSIS OF FLOW THROUGH A HUMAN ORAL MODEL FOR USE IN INHALATION TOXICOLOGY AND AEROSOL THERAPY PROTOCOLS

    EPA Science Inventory


    RATIONALE
    Understanding the transport and deposition of inhaled aerosols is of fundamental importance to inhalation toxicology and aerosol therapy. Herein, we focus on the development of a computer based oral morphology and related computational fluid dynamics (CFD) studi...

  18. simplified aerosol representations in global modeling

    NASA Astrophysics Data System (ADS)

    Kinne, Stefan; Peters, Karsten; Stevens, Bjorn; Rast, Sebastian; Schutgens, Nick; Stier, Philip

    2015-04-01

    The detailed treatment of aerosol in global modeling is complex and time-consuming. Thus simplified approaches are investigated, which prescribe 4D (space and time) distributions of aerosol optical properties and of aerosol microphysical properties. Aerosol optical properties are required to assess aerosol direct radiative effects and aerosol microphysical properties (in terms of their ability as aerosol nuclei to modify cloud droplet concentrations) are needed to address the indirect aerosol impact on cloud properties. Following the simplifying concept of the monthly gridded (1x1 lat/lon) aerosol climatology (MAC), new approaches are presented and evaluated against more detailed methods, including comparisons to detailed simulations with complex aerosol component modules.

  19. Short inhalation exposures of the isolated and perfused rat lung to respirable dry particle aerosols; the detailed pharmacokinetics of budesonide, formoterol, and terbutaline.

    PubMed

    Ewing, Per; Eirefelt, Stefan J; Andersson, Paul; Blomgren, Anders; Ryrfeldt, Ake; Gerde, Per

    2008-06-01

    There is an increasing interest in using the lung as a route of entry for both local and systemic administration of drugs. However, because adequate technologies have been missing in the preclinical setting, few investigators have addressed the detailed disposition of drugs in the lung following short inhalation exposures to highly concentrated dry powder aerosols. New methods are needed to explore the disposition of drugs after short inhalation exposures, thus mimicking a future clinical use. Our aim was to study the pulmonary disposition of budesonide, formoterol, and terbutaline, which are clinically used for the treatment of bronchial asthma. Using the recently developed DustGun aerosol technology, we exposed by inhalation for approximately 1 min the isolated and perfused rat lung (IPL) to respirable dry particle aerosols of the three drugs at high concentrations. The typical aerosol concentration was 1 mug/mL, and the particle size distribution of the tested substances varied with a MMAD ranging from 2.3 to 5.3 mum. The IPL was perfused in single pass mode and repeated samples of the perfusate were taken for up to 80 min postexposure. The concentration of drug in perfusate and in lung extracts was measured using LC-MS/MS. The deposited dose was determined by adding the amounts of drug collected in perfusate to the amount extracted from the tissues at 80 min. Deposited amounts of budesonide, formoterol fumarate, and terbutaline sulphate were 23 +/- 17, 36 +/- 8, and 60 +/- 3.2 mug (mean +/- SD, n = 3), respectively. Retention in lung tissues at the end of the perfusion period expressed as fraction of deposited dose was 0.19 +/- 0.05, 0.19 +/- 0.06, and 0.04 +/- 0.01 (mean +/- SD, n = 3) for budesonide, formoterol, and terbutaline, respectively. Each short inhalation exposure to the highly concentrated aerosols consumed 1-3 mg powder. Hence, this system can be particularly useful for obtaining a detailed pharmacokinetic characterization of inhaled compounds in

  20. Lung deposition and respirable mass during wet nebulization.

    PubMed

    Sangwan, Sanjay; Condos, Rany; Smaldone, Gerald C

    2003-01-01

    For metered dose inhalers (MDIs), high-flow cascade impaction with a United States Pharmacopia (USP) throat provides a useful prediction of in vivo lung and oropharyngeal aerosol deposition. Particles expected to deposit in the lung are included in the "fine particle fraction" measured on the bench. Comparable in vitro standards are not available for nebulizers. The present study compared aerosol deposition in an in vitro model using low-flow cascade impaction with deposition in vivo in human subjects. A low-flow (1 Lmin), 10-stage cascade impactor measured aerodynamic distributions of aerosolized interferon-gamma (IFN-gamma) from two nebulizers (Misty-Neb and AeroEclipse). (99m)Technetium diethylene triaminepenta-acetic acid ((99m)Tc-DTPA) was used as the radiolabel. Two bench conditions were specified: no breathing (standing cloud) and simulated ventilation with a piston pump (tidal volume 750 mL frequency 25 per minute and duty cycle 0.5). Mass median aerodynamic diameter (MMAD) for both nebulizers was affected by ventilation (Misty-Neb vs. AeroEclipse: 5.2 vs. 4.6 microm for standing cloud and 3.1 vs. 2.2 microm during ventilation). In three subjects, measured values of oropharyngeal deposition averaged 68.1 +/- 0.08% for Misty-Neb and 30.9 +/- 0.03% for AeroEclipse. In vivo deposition patterns compared to aerosol distributions from both nebulizers indicated that, for wet nebulization, penetration of aerosol beyond the upper airways (fine particle fraction) will occur only for aerosol particles below 2.5 microm. This assessment requires that the bench aerosol distribution be measured under conditions of clinical use (i.e., during tidal breathing). PMID:14977428

  1. Leading Change, Adding Value.

    PubMed

    Evans, Nick

    2016-09-12

    Essential facts Leading Change, Adding Value is NHS England's new nursing and midwifery framework. It is designed to build on Compassion in Practice (CiP), which was published 3 years ago and set out the 6Cs: compassion, care, commitment, courage, competence and communication. CiP established the values at the heart of nursing and midwifery, while the new framework sets out how staff can help transform the health and care sectors to meet the aims of the NHS England's Five Year Forward View. PMID:27615573

  2. Comparison of aerosol code predictions with experimental observations on the behavior of aerosols in steam

    SciTech Connect

    Tobias, M.L.

    1983-01-01

    Several computer codes have been developed to predict the behavior of aerosols in steam, a situation which is expected to occur in a light-water reactor accident. Among the codes with capabilities in this respect are MAEROS (Sandia) AEROMECH (University of Missouri) and NAUA-Mod4 (Karlsruhe). NAUA was specifically developed to model steam-aerosol behavior in hypothetical accidents in pressurized water reactors. It is based upon a series of experiments, in which aerosols of uranium oxide, platinum oxide, and sodium nitrate were generated in a steam atmosphere. Several series of experiments have been conducted in the NSPP vessel using aerosols generated by plasma torch in a steam-air atmosphere. From these experiments we have selected those performed with iron oxide or uranium oxide for comparison with various computer codes, principally NAUA-Mod4. Comparisons of particle size are displayed also. Results of parameter studies to determine the sensitivity of the calculated results to the steam input level, initial particle size, deposition parameters, and assumed particle density are presented.

  3. Highly stable aerosol generator

    SciTech Connect

    DeFord, Henry S.; Clark, Mark L.

    1981-01-01

    An improved compressed air nebulizer has been developed such that a uniform aerosol particle size and concentration may be produced over long time periods. This result is achieved by applying a vacuum pressure to the makeup assembly and by use of a vent tube between the atmosphere and the makeup solution. By applying appropriate vacuum pressures to the makeup solution container and by proper positioning of the vent tube, a constant level of aspirating solution may be maintained within the aspirating assembly with aspirating solution continuously replaced from the makeup solution supply. This device may also be adapted to have a plurality of aerosol generators and only one central makeup assembly.

  4. Highly stable aerosol generator

    DOEpatents

    DeFord, H.S.; Clark, M.L.

    1981-11-03

    An improved compressed air nebulizer has been developed such that a uniform aerosol particle size and concentration may be produced over long time periods. This result is achieved by applying a vacuum pressure to the makeup assembly and by use of a vent tube between the atmosphere and the makeup solution. By applying appropriate vacuum pressures to the makeup solution container and by proper positioning of the vent tube, a constant level of aspirating solution may be maintained within the aspirating assembly with aspirating solution continuously replaced from the makeup solution supply. This device may also be adapted to have a plurality of aerosol generators and only one central makeup assembly. 2 figs.

  5. Stratospheric Aerosol Measurements

    NASA Technical Reports Server (NTRS)

    Pueschel, Rudolf, F.; Gore, Warren J. (Technical Monitor)

    1998-01-01

    Stratospheric aerosols affect the atmospheric energy balance by scattering and absorbing solar and terrestrial radiation. They also can alter stratospheric chemical cycles by catalyzing heterogeneous reactions which markedly perturb odd nitrogen, chlorine and ozone levels. Aerosol measurements by satellites began in NASA in 1975 with the Stratospheric Aerosol Measurement (SAM) program, to be followed by the Stratospheric Aerosol and Gas Experiment (SAGE) starting in 1979. Both programs employ the solar occultation, or Earth limb extinction, techniques. Major results of these activities include the discovery of polar stratospheric clouds (PSCs) in both hemispheres in winter, illustrations of the impacts of major (El Chichon 1982 and Pinatubo 1991) eruptions, and detection of a negative global trend in lower stratospheric/upper tropospheric aerosol extinction. This latter result can be considered a triumph of successful worldwide sulfur emission controls. The SAGE record will be continued and improved by SAGE III, currently scheduled for multiple launches beginning in 2000 as part of the Earth Observing System (EOS). The satellite program has been supplemented by in situ measurements aboard the ER-2 (20 km ceiling) since 1974, and from the DC-8 (13 km ceiling) aircraft beginning in 1989. Collection by wire impactors and subsequent electron microscopic and X-ray energy-dispersive analyses, and optical particle spectrometry have been the principle techniques. Major findings are: (1) The stratospheric background aerosol consists of dilute sulfuric acid droplets of around 0.1 micrometer modal diameter at concentration of tens to hundreds of monograms per cubic meter; (2) Soot from aircraft amounts to a fraction of one percent of the background total aerosol; (3) Volcanic eruptions perturb the sulfuric acid, but not the soot, aerosol abundance by several orders of magnitude; (4) PSCs contain nitric acid at temperatures below 195K, supporting chemical hypotheses

  6. Comparison of Aerosol Formulations of Formoterol Fumarate and Budesonide

    PubMed Central

    Nirale, N. M.; Nagarsenker, M. S.; Mendon, S. B.; Chanagare, R.; Katkurwar, A.; Lugade, V.

    2011-01-01

    The aerodynamic diameter of pharmaceutical aerosols is the main factor governing their deposition in the human respiratory tract. Particle size of the pharmaceutical aerosols is characterized by liquid impingers and Andersen Cascade Impactors. The present study was aimed at comparing two metered dose inhaler formulation containing formoterol fumarate (6 μg) and budesonide (200 μg). These two formulations were evaluated by using Twin Stage Impinger and Andersen Cascade Impactor. Study revealed that developed metered dose inhaler I formulation of the formoterol fumarate and budesonide had lower mass median aerodynamic diameter and higher fine particle fraction than marketed formulation. PMID:22457551

  7. Satellite observations and EMAC model calculations of sulfate aerosols from Kilauea: a study of aerosol formation, processing, and loss

    NASA Astrophysics Data System (ADS)

    Penning de Vries, Marloes; Beirle, Steffen; Brühl, Christoph; Dörner, Steffen; Pozzer, Andrea; Wagner, Thomas

    2016-04-01

    The currently most active volcano on Earth is Mount Kilauea on Hawaii, as it has been in a state of continuous eruption since 1983. The opening of a new vent in March 2008 caused half a year of strongly increased SO2 emissions, which in turn led to the formation of a sulfate plume with an extent of at least two thousand kilometers. The plume could be clearly identified from satellite measurements from March to November, 2008. The steady trade winds in the region and the lack of interfering sources allowed us to determine the life time of SO2 from Kilauea using only satellite-based measurements (no a priori or model information). The current investigation focuses on sulfate aerosols: their formation, processing and subsequent loss. Using space-based aerosol measurements by MODIS, we study the evolution of aerosol optical depth, which first increases as a function of distance from the volcano due to aerosol formation from SO2 oxidation, and subsequently decreases as aerosols are deposited to the surface. The outcome is compared to results from calculations using the EMAC (ECHAM/MESSy Atmospheric Chemistry) model to test the state of understanding of the sulfate aerosol life cycle. For this comparison, a particular focus is on the role of clouds and wet removal processes.

  8. Multiangle Imaging Spectroradiometer (MISR) Global Aerosol Optical Depth Validation Based on 2 Years of Coincident Aerosol Robotic Network (AERONET) Observations

    NASA Technical Reports Server (NTRS)

    Kahn, Ralph A.; Gaitley, Barbara J.; Martonchik, John V.; Diner, David J.; Crean, Kathleen A.; Holben, Brent

    2005-01-01

    Performance of the Multiangle Imaging Spectroradiometer (MISR) early postlaunch aerosol optical thickness (AOT) retrieval algorithm is assessed quantitatively over land and ocean by comparison with a 2-year measurement record of globally distributed AERONET Sun photometers. There are sufficient coincident observations to stratify the data set by season and expected aerosol type. In addition to reporting uncertainty envelopes, we identify trends and outliers, and investigate their likely causes, with the aim of refining algorithm performance. Overall, about 2/3 of the MISR-retrieved AOT values fall within [0.05 or 20% x AOT] of Aerosol Robotic Network (AERONET). More than a third are within [0.03 or 10% x AOT]. Correlation coefficients are highest for maritime stations (approx.0.9), and lowest for dusty sites (more than approx.0.7). Retrieved spectral slopes closely match Sun photometer values for Biomass burning and continental aerosol types. Detailed comparisons suggest that adding to the algorithm climatology more absorbing spherical particles, more realistic dust analogs, and a richer selection of multimodal aerosol mixtures would reduce the remaining discrepancies for MISR retrievals over land; in addition, refining instrument low-light-level calibration could reduce or eliminate a small but systematic offset in maritime AOT values. On the basis of cases for which current particle models are representative, a second-generation MISR aerosol retrieval algorithm incorporating these improvements could provide AOT accuracy unprecedented for a spaceborne technique.

  9. Organics Substantially Reduce HO2 Uptake onto Aerosols Containing Transition Metal ions.

    PubMed

    Lakey, Pascale S J; George, Ingrid J; Baeza-Romero, Maria T; Whalley, Lisa K; Heard, Dwayne E

    2016-03-10

    A HO2 mass accommodation coefficient of α = 0.23 ± 0.07 was measured onto submicron copper(II)-doped ammonium sulfate aerosols at a relative humidity of 60 ± 3%, at 293 ± 2 K and at an initial HO2 concentration of ∼ 1 × 10(9) molecules cm(-3) by using an aerosol flow tube coupled to a sensitive fluorescence assay by gas expansion (FAGE) HO2 detection system. The effect upon the HO2 uptake coefficient γ of adding different organic species (malonic acid, citric acid, 1,2-diaminoethane, tartronic acid, ethylenediaminetetraacetic acid (EDTA), and oxalic acid) into the copper(II)-doped aerosols was investigated. The HO2 uptake coefficient decreased steadily from the mass accommodation value to γ = 0.008 ± 0.009 when EDTA was added in a one-to-one molar ratio with the copper(II) ions, and to γ = 0.003 ± 0.004 when oxalic acid was added into the aerosol in a ten-to-one molar ratio with the copper(II). EDTA binds strongly to copper(II) ions, potentially making them unavailable for catalytic destruction of HO2, and could also be acting as a surfactant or changing the viscosity of the aerosol. The addition of oxalic acid to the aerosol potentially forms low-volatility copper-oxalate complexes that reduce the uptake of HO2 either by changing the viscosity of the aerosol or by causing precipitation out of the aerosol forming a coating. It is likely that there is a high enough oxalate to copper(II) ion ratio in many types of atmospheric aerosols to decrease the HO2 uptake coefficient. No observable change in the HO2 uptake coefficient was measured when the other organic species (malonic acid, citric acid, 1,2-diaminoethane, and tartronic acid) were added in a ten-to-one molar ratio with the copper(II) ions.

  10. The Adaptive Aerosol Delivery (AAD) technology: Past, present, and future.

    PubMed

    Denyer, John; Dyche, Tony

    2010-04-01

    Conventional aerosol delivery systems and the availability of new technologies have led to the development of "intelligent" nebulizers such as the I-neb Adaptive Aerosol Delivery (AAD) System. Based on the AAD technology, the I-neb AAD System has been designed to continuously adapt to changes in the patient's breathing pattern, and to pulse aerosol only during the inspiratory part of the breathing cycle. This eliminates waste of aerosol during exhalation, and creates a foundation for precise aerosol (dose) delivery. To facilitate the delivery of precise metered doses of aerosol to the patient, a unique metering chamber design has been developed. Through the vibrating mesh technology, the metering chamber design, and the AAD Disc function, the aerosol output rate and metered (delivered) dose can be tailored to the demands of the specific drug to be delivered. In the I-neb AAD System, aerosol delivery is guided through two algorithms, one for the Tidal Breathing Mode (TBM), and one for slow and deep inhalations, the Target Inhalation Mode (TIM). The aim of TIM is to reduce the treatment time by increasing the total inhalation time per minute, and to increase lung deposition by reducing impaction in the upper airways through slow and deep inhalations. A key feature of the AAD technology is the patient feedback mechanisms that are provided to guide the patient on delivery performance. These feedback signals, which include visual, audible, and tactile forms, are configured in a feedback cascade that leads to a high level of compliance with the use of the I-neb AAD System. The I-neb Insight and the Patient Logging System facilitate a further degree of sophistication to the feedback mechanisms, by providing information on long term adherence and compliance data. These can be assessed by patients and clinicians via a Web-based delivery of information in the form of customized graphical analyses.

  11. The thermal infrared radiance properties of dust aerosol over ocean

    NASA Astrophysics Data System (ADS)

    Hao, Zengzhou; Pan, Delu; Tu, Qianguang; Gong, Fang; Chen, Jianyu

    2015-10-01

    Asian dust storms, which can long-range transport to ocean, often occur on spring. The present of Asian dust aerosols over ocean makes some difficult for other studies, such as cloud detection, and also take some advantage for ocean, such as take nutrition into the ocean by dry or wet deposition. Therefore, it is important to study the dust aerosol and retrieve the properties of dust from satellite observations that is mainly from the thermal infrared radiance. In this paper, the thermal infrared radiance properties of dust aerosol over ocean are analyzed from MODIS and MTSAT2 observations and Streamer model simulations. By analyzing some line samples and a series of dust aerosol region, it shows that the dust aerosol brightness temperature at 12μm (BT12) is always greater than BT11 and BT8.5, and BT8.5 is general greater than BT11. The brightness temperature different between 11μm and 12μm (BTD11-12) increases with the dust intensity. And the BTD11-12 will become positive when the atmospheric relative humidity is greater than 70%. The BTD11-12 increases gradually with the surface temperature while the effect on BTD11-12 of dust layer temperature is not evident. Those are caused by the transmission of the dust aerosol is different at the two thermal infrared channels. During daytime, dust infrared brightness temperature at mid-infrared bands should reduce the visual radiance, which takes about 25K or less. In general, BT3.7 is greater than BT11 for dust aerosol. Those results are helpful to monitor or retrieve dust aerosol physical properties over ocean from satellite.

  12. The Adaptive Aerosol Delivery (AAD) Technology: Past, Present, and Future

    PubMed Central

    Dyche, Tony

    2010-01-01

    Abstract Conventional aerosol delivery systems and the availability of new technologies have led to the development of “intelligent” nebulizers such as the I-neb Adaptive Aerosol Delivery (AAD) System. Based on the AAD technology, the I-neb AAD System has been designed to continuously adapt to changes in the patient's breathing pattern, and to pulse aerosol only during the inspiratory part of the breathing cycle. This eliminates waste of aerosol during exhalation, and creates a foundation for precise aerosol (dose) delivery. To facilitate the delivery of precise metered doses of aerosol to the patient, a unique metering chamber design has been developed. Through the vibrating mesh technology, the metering chamber design, and the AAD Disc function, the aerosol output rate and metered (delivered) dose can be tailored to the demands of the specific drug to be delivered. In the I-neb AAD System, aerosol delivery is guided through two algorithms, one for the Tidal Breathing Mode (TBM), and one for slow and deep inhalations, the Target Inhalation Mode (TIM). The aim of TIM is to reduce the treatment time by increasing the total inhalation time per minute, and to increase lung deposition by reducing impaction in the upper airways through slow and deep inhalations. A key feature of the AAD technology is the patient feedback mechanisms that are provided to guide the patient on delivery performance. These feedback signals, which include visual, audible, and tactile forms, are configured in a feedback cascade that leads to a high level of compliance with the use of the I-neb AAD System. The I-neb Insight and the Patient Logging System facilitate a further degree of sophistication to the feedback mechanisms, by providing information on long term adherence and compliance data. These can be assessed by patients and clinicians via a Web-based delivery of information in the form of customized graphical analyses. PMID:20373904

  13. Development