NASA Technical Reports Server (Ntrs) 20000021368: Cloud and Aerosol Retrieval for the 2001 Glas Satellite Lidar Mission by NASA Technical Reports Server (Ntrs); published by
NASA Technical Reports Server (Ntrs) 20000021368: Cloud and Aerosol Retrieval for the 2001 Glas Satellite Lidar Mission by NASA Technical Reports Server (Ntrs); published by
NASA Technical Reports Server (Ntrs) 20010081594: a Nanometer Aerosol Size Analyzer (NASA) for Rapid Measurement of High-Concentration Size Distributions by NASA Technical Reports Server (Ntrs); published by
NASA Technical Reports Server (Ntrs) 20010081594: a Nanometer Aerosol Size Analyzer (NASA) for Rapid Measurement of High-Concentration Size Distributions by NASA Technical Reports Server (Ntrs); published by
NASA Technical Reports Server (Ntrs) 19910012172: Comparison of Unl Laser Imaging and Sizing System and a Phase Doppler System for Analyzing Sprays from a NASA Nozzle by NASA Technical Reports Server (Ntrs); published by
NASA Technical Reports Server (Ntrs) 19910012172: Comparison of Unl Laser Imaging and Sizing System and a Phase Doppler System for Analyzing Sprays from a NASA Nozzle by NASA Technical Reports Server (Ntrs); published by
NASA Technical Reports Server (Ntrs) 20000114831: Tropical Tropospheric Ozone: a Multi-Satellite View from Toms and Other Instruments by NASA Technical Reports Server (Ntrs); published by
NASA Technical Reports Server (Ntrs) 20000114831: Tropical Tropospheric Ozone: a Multi-Satellite View from Toms and Other Instruments by NASA Technical Reports Server (Ntrs); published by
NASA Technical Reports Server (Ntrs) 20060013184: Improvement of Raman Lidar Algorithm for Quantifying Aerosol Extinction by NASA Technical Reports Server (Ntrs); published by
NASA Technical Reports Server (Ntrs) 20060013184: Improvement of Raman Lidar Algorithm for Quantifying Aerosol Extinction by NASA Technical Reports Server (Ntrs); published by
Like and oppositely charged particles or dust grains in linear shear flows are often driven to collide with one another by fluid and/or electrostatic forces, which can strongly influence particle-size distribution evo...
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Like and oppositely charged particles or dust grains in linear shear flows are often driven to collide with one another by fluid and/or electrostatic forces, which can strongly influence particle-size distribution evolution. In gaseous media, collisions in shear are further complicated because particle inertia can influence differential motion. Expressions for the collision rate coefficient have not been developed previously which simultaneously account for the influences of linear shear, particle inertia, and electrostatic interactions. Here, we determine the collision rate coefficient accounting for the aforementioned effects by determining the collision area, i.e., the area of the plane perpendicular to the shear flow defining the relative initial locations of particles which will collide with one another. Integration of the particle flux over this area yields the collision rate. Collision rate calculations are parametrized as an enhancement factor, i.e., the ratio of the collision rate considering potential interactions and inertia to the traditional collision rate considering laminar shear only. For particles of constant surface charge density, the enhancement factor is found dependent only on the Stokes number (quantifying particle inertia), the electrostatic energy to shear energy ratio, and the ratio of colliding particle radii. Enhancement factors are determined for Stokes numbers in the 0–10 range and energy ratios up to 5. Calculations show that the influences of both electrostatic interactions and inertia are significant; for inertialess (St=0) equal-sized and oppositely charged particles, we find that even at energy ratios as low as 0.2, enhancement factors are in excess of 2. For the same situation but like-charged particles, enhancement factors fall below 0.5. Increasing the Stokes number acts to mitigate the influence of electrostatic potentials for both like and oppositely charged particles; i.e., inertia reduces the enhancement factor for oppositel
Ultrafine particles (UFP) have been postulated to significantly contribute to the adverse health effects associated with exposure to particulate matter (PM). Due to their extremely small size (aerodynamic diameter <...
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Ultrafine particles (UFP) have been postulated to significantly contribute to the adverse health effects associated with exposure to particulate matter (PM). Due to their extremely small size (aerodynamic diameter <100 nm), UFP are able to deposit deep within the lung after inhalation and evade many mechanisms responsible for the clearance of larger particles. There is a lack of biologically relevant personal exposure metrics for exposure to occupational-and environmental-related micro-and nano-sized PM. The aim of the present study is to assess UFP in induced sputum (IS) and exhaled breath condensate (EBC) as possible biomarkers for assessing lung function impairment. Sputum induction and EBC testing were performed by conventional methods. UFP particles were assessed with the NanoSight LM20 (NanoSight Ltd, London, UK). The subjects included 35 exposed and 25 non-exposed workers. There were no group differences in pulmonary function test results and differential cell counts, but 63.6% of the exposed subjects had a higher percentage of neutrophils (OR3.28 p = 0.03) compared to the nonexposed subjects. The exposed subjects had higher percentages of UFP between 10 and 50 nm (69.45 +/- 18.70 vs 60.11 +/- 17.52 for the non-exposed group, p = 0.004). No differences were found in the IS samples. Years of exposure correlated positively to UFP content (r = 0.342 p = 0.01) and macrophage content (r = -0.327 p = 0.03). The percentage of small fraction of UFP in EBC, but not IS, is higher in exposed workers, and EBC may be a sensitive biomarker to assess exposure to nanoparticles.
NASA Technical Reports Server (Ntrs) 20040105575: Geoscience Laser Altimeter System (Glas) Loop Heat Pipes: an Eventual First Year on-Orbit by NASA Technical Reports Server (Ntrs); published by
NASA Technical Reports Server (Ntrs) 20040105575: Geoscience Laser Altimeter System (Glas) Loop Heat Pipes: an Eventual First Year on-Orbit by NASA Technical Reports Server (Ntrs); published by
NASA Technical Reports Server (Ntrs) 20050070882: Impact of Urban Surfaces on Precipitation Processes by NASA Technical Reports Server (Ntrs); published by
NASA Technical Reports Server (Ntrs) 20050070882: Impact of Urban Surfaces on Precipitation Processes by NASA Technical Reports Server (Ntrs); published by
NASA Technical Reports Server (Ntrs) 19860002233: Sage Aerosol Measurements. Volume 1: February 21, 1979 to December 31, 1979 by NASA Technical Reports Server (Ntrs); published by
NASA Technical Reports Server (Ntrs) 19860002233: Sage Aerosol Measurements. Volume 1: February 21, 1979 to December 31, 1979 by NASA Technical Reports Server (Ntrs); published by
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