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Aerosol penetration of leak pathways : an examination of the available data and models.

Description: Data and models of aerosol particle deposition in leak pathways are described. Pathways considered include capillaries, orifices, slots and cracks in concrete. The Morewitz-Vaughan criterion for aerosol plugging of leak pathways is shown to be applicable only to a limited range of particle settling velocities and Stokes numbers. More useful are sampling efficiency criteria defined by Davies and by Liu and Agarwal. Deposition of particles can be limited by bounce from surfaces defining leak path… more
Date: April 1, 2009
Creator: Powers, Dana Auburn
Partner: UNT Libraries Government Documents Department
open access

Investigation of the Impact of Aerosols on Clouds During May 2003 Intensive Operational Period at the Southern Great Plains

Description: The effect of aerosols on the clouds, or the so-called aerosol indirect effect (AIE), is highly uncertain (Penner et al. 2001). The estimation of the AIE can vary from 0.0 to -4.8 W/m2 in Global Climate Models (GCM). Therefore, it is very important to investigate these interactions and cloud-related physical processes further. The Aerosol Intensive Operation Period (AIOP) at the Southern Great Plains (SGP) site in May 2003 dedicated some effort towards the measurement of the Cloud Condensation … more
Date: March 18, 2005
Creator: Guo, H.; Penner, J.E. & Herzog, M.
Partner: UNT Libraries Government Documents Department
open access

Scanning Transmission X-ray Microscopy: Applications in Atmospheric Aerosol Research

Description: Scanning transmission x-ray microscopy (STXM) combines x-ray microscopy and near edge x-ray absorption fine structure spectroscopy (NEXAFS). This combination provides spatially resolved bonding and oxidation state information. While there are reviews relevant to STXM/NEXAFS applications in other environmental fields (and magnetic materials) this chapter focuses on atmospheric aerosols. It provides an introduction to this technique in a manner approachable to non-experts. It begins with relevant… more
Date: January 20, 2011
Creator: Moffet, Ryan C.; Tivanski, Alexei V. & Gilles, Mary K.
Partner: UNT Libraries Government Documents Department
open access

Real time in situ detection of organic nitrates in atmospheric aerosols

Description: A new field instrument is described that quantifies total particle phase organic nitrates. The instrument is based on the thermal dissociation laser induced fluorescence (TD-LIF) method that thermally converts nitrates to NO2 which is then detected by LIF. This instrument is unique in its ability to provide fast sensitive measurements of particle phase organic nitrates, without interference from inorganic nitrate. Here we use it to quantify organic nitrates in SOA generated from high-NOx photoo… more
Date: June 11, 2010
Creator: Rollins, Andrew W.; Smith, Jared D.; Wilson, Kevin R. & Cohen, Ronald C.
Partner: UNT Libraries Government Documents Department
open access

Final report for "Characterization of Fine Particulate Matter (PM) and secondary PM Precursor Gases in the Mexico City Metropolitan Area"

Description: The objectives of this funded project were (a) to further analyze the data collected by our group and collaborators in Mexico City during the MCMA-2003 field campaign, with the goal of further our understanding of aerosol sources and processes; and (b) to deploy several advanced instruments, including the newly developed high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS) and thermal-denuder (TD), during the MILAGRO/MAX-Mex/MCMA-2006 field campaign, and to analyze those data (… more
Date: May 18, 2009
Creator: Jimenez, Jose-Luis
Partner: UNT Libraries Government Documents Department
open access

CADS:Cantera Aerosol Dynamics Simulator.

Description: This manual describes a library for aerosol kinetics and transport, called CADS (Cantera Aerosol Dynamics Simulator), which employs a section-based approach for describing the particle size distributions. CADS is based upon Cantera, a set of C++ libraries and applications that handles gas phase species transport and reactions. The method uses a discontinuous Galerkin formulation to represent the particle distributions within each section and to solve for changes to the aerosol particle distribu… more
Date: July 1, 2007
Creator: Moffat, Harry K.
Partner: UNT Libraries Government Documents Department
open access

Modeling the wind-fields of accidental releases with an operational regional forecast model

Description: The Atmospheric Release Advisory Capability (ARAC) is an operational emergency preparedness and response organization supported primarily by the Departments of Energy and Defense. ARAC can provide real-time assessments of atmospheric releases of radioactive materials at any location in the world. ARAC uses robust three-dimensional atmospheric transport and dispersion models, extensive geophysical and dose-factor databases, meteorological data-acquisition systems, and an experienced staff. Altho… more
Date: September 11, 1995
Creator: Albritton, J.R.; Lee, R.L. & Sugiyama, G.
Partner: UNT Libraries Government Documents Department
open access

Emergency Protection from Aerosols

Description: 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.
Date: November 13, 2001
Creator: Cristy, G. A. & Chester, C. V.
Partner: UNT Libraries Government Documents Department
open access

Final Report: " Growth Rates of Freshly Nucleated Particles"

Description: This report lists of archival journal articles that were written with support from this grant. Research objectives from the original proposal are given, along with papers that were written to meet each of those objectives. The papers are all available in the archival literature.
Date: March 12, 2013
Creator: McMurry, Peter H. & Smith, James N.
Partner: UNT Libraries Government Documents Department
open access

Stratospheric Monitoring Program

Description: "Design work was completed and construction initiated on a prototype field altimeter based on the gas density dependence of Townsend discharge current in an electrical discharge. The design of an ion tracer air velocity meter for laboratory applications, and construction of three units were successfully completed. Theoretical and experimental support is presented, showing the applicability of the ion tracer system to the accurate measurement of linear gas velocity. The operating range of the la… more
Date: January 13, 1963
Creator: Cravitt, S.; Lilienfeld, P. & Foldes, A.
Partner: UNT Libraries Government Documents Department
open access

Deposition of Submicron-Size Particles in Ventilation Ducts

Description: The purpose of this study was to investigate mathematically the concentration decrease due to particle deposition phenomena in highly concentrated monodispersed aerosols (mean particle size less than 1.0 mu) flowing through ventilation ducts. It was found that, from the standpoint of removal, the decrease in concentration due to deposition on duct walls was insignificant; but, when considering contamination on duct walls, the amount deposited, even though small when compared with the amount in … more
Date: August 1964
Creator: Davis, L. P.
Partner: UNT Libraries Government Documents Department
open access

Standard instrument calibration aerosol test system

Description: >A system for testing personal respirable'' samplers in a well characterized coal dust environment is described. Components of the system, contained in one cabinet, include a Wright Dust Feed mechanism, tritide charge neutralizer, aerosol chamber, electrostatic precipitator sampler, and a GCA Respirable Dust Monitor. in addition to air flow plumbing and controls. Employment of this test system to evaluate the performance of personal respirable'' particulate air sampling instruments required var… more
Date: September 1, 1973
Creator: Fairchild, C. I.; Ettinger, H. J.; Carson, G. A.; Gettemy, D. J.; Tillery, M. I. & Almich, B.
Partner: UNT Libraries Government Documents Department
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