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Electrostatic Classification of Submicron Airborne Particles : Progress report, April 1 to June 1, 1962

Description: The following report focuses on the study of electrostatic classification of submicron aerosols, with emphasis on particles below 0.1 micron. During the period this work was concerned with detailed studies of the ARF charger, the Whitby ionizer used as a charger or neutralizer, and the high-volume classifier.
Date: 1962
Creator: Langer, G.
Partner: UNT Libraries Government Documents Department

Electrostatic Classification of Submicron Airborne Particles : Progress Report, August 1 to October 1, 1962

Description: Introduction: "This study is concerned with the classification of submicron aerosols by electrostatic means. The controlled charging of the particles without undue aerosol losses is of principal interest. We are investigating means of eliminating the interference due to the deposition of small and large particles in the same area. The sampler is to be developed to classify atmospheric dust particles at a rate approaching 1 cfm. During the period covered by this report, work was concerned with the charger and with bringing the high-volume classifier into routing operation. Further tests were made on the classification of atmospheric dust."
Date: 1962
Creator: Langer, G.
Partner: UNT Libraries Government Documents Department

Electrostatic Classification of Submicron Airborne Particles : Progress Report, December 15, 1960 to February 15, 1961

Description: Introduction: "This program is a study of the basic variables that affects electrostatic classification of heterogeneous aerosols of submicron size, especially below 0.1 micron. The variables of concern are particle size, concentration, composition, shape, and initial charge. During this period optimum charger design was studied. The results will serve as a basis for a systematic study of particle charging. A number of improvements were incorporated into the classifier flow system and electrical circuits. The technique for photographing deposits in the electron microscope was also improved, and sample photographs are included."
Date: 1961
Creator: Langer, G.
Partner: UNT Libraries Government Documents Department

Electrostatic Classification of Submicron Airborne Particles : Progress Report, February 1 to March 31, 1962

Description: Introduction: "This project is a study of eletrostatic classification of submicron aerosols with emphasis on particles below 0.1[mu]. Previous work has shown that classification of particles between 0.1 to 1.0[mu] is feasible by this process. Further improvements along this line include the elimination of interference from initial aerosol charge and increase in sampling rate. The effect of heavy deposits on collection have to be established. More information is desired on the charging regime below 0.1[mu]. Also the overlap of the smallest particles with the larger ones has to be eliminated. It is also of interest to study the possibility of measuring the current due to the precipitating particles. This would make it possible to automate the device. During this period project work was initiated again. There was some delay in finalizing the contract and the laboratory work was not started until early in March."
Date: 1962
Creator: Langer, G.
Partner: UNT Libraries Government Documents Department

Electrostatic Classification of Submicron Airborne Particles : Progress Report, February 15 to April 15, 1961

Description: Introduction: "This program is a study of the basic variables that affect electrostatic classifications of heterogeneous aerosols of submicron size, especially below 0.1 micron. The variables of interest are particle size, concentration, composition, shape, an initial charge. During this period emphasis was placed on studying and controlling initial charge. A new technique was developed for collecting light and electron microscope samples. Further improvements of the charging device were studied."
Date: 1961
Creator: Langer, G.
Partner: UNT Libraries Government Documents Department

Electrostatic Classification of Submicron Airborne Particles : Progress Report, April 15 to June 15, 1961

Description: Abstract: "This program is a study of the basic variables that affect electrostatic classification of heterogeneous aerosols of submicron size,especially below 0.1[mu]. The variables of interest are particle size, concentration, composition, shape, and initial charge. During this period research was concerned with classifying particles as small as 0.01[mu]. This research included work on an aerosol generator for monodispersed 0.015-[mu] gold particles. The performance of the charger was further improved by studying its basic electrical characteristics. Tests with the electrostatic classifier showed very clearly the interference due to the stabilizer material associated with polystyrene latex suspensions. These suspensions are used to produce monodispersed aerosols for calibration."
Date: 1961
Creator: Langer, G.
Partner: UNT Libraries Government Documents Department

Electrostatic Classification of Submicron Airborne Particles : Progress Report, October 15 to December 15, 1960

Description: From introduction: "This study is concerned with the basic variables that affect the electrostatic classification of heterogeneous aerosols in the submicron range, especially below 0.1 micron. The variables of interest are particle size, concentration, composition, dielectric constant, shape, and initial charge as they relate to rate of charging and therefore to the point of deposition in the classifier."
Date: 1960
Creator: Langer, G.
Partner: UNT Libraries Government Documents Department

Electrostatic Classification of Submicron Airborne Particles : Progress Report, October 1 to December 1, 1962

Description: Introduction: "One of the major objectives of this study is to develop a routine charger that has no aerosol losses. Also, the interference due to deposition of small and large particles in the same area must be overcome. During this period efforts were concentrated on the former problem, which is the key to practical application of this device."
Date: 1962
Creator: Langer, G.
Partner: UNT Libraries Government Documents Department

Electrostatic Classification of Submicron Airborne Particles : Progress Report, June 1 to August 1, 1962

Description: Introduction: "This project is a study of electrostatic classification of submicron aerosols, with emphasis on particles smaller than 0.1 micron. The overlap of the smallest particles with the larger ones is of principal concern. Also, a faster sampling rate is desired, i.e., heavier deposits in a shorter time are necessary. During the period covered by this report, work was concerned with studies of charging by corona and diffusion, neutralization of initial charge, and classification of various types if aerosols."
Date: 1962
Creator: Langer, G.
Partner: UNT Libraries Government Documents Department

Electrostatic Classification of Submicron Airborne Particles : Final Report, August 16, 1961 to January 31, 1963

Description: From abstract: "This project was a study of electrostatic classification of submicron aerosols. Classification of particles as small as 0.006-[mu]-diameter was shown to be feasible, and good classification of atmospheric dust was achieved. However, a practical solution to the problem of overlapping between particles larger and smaller than 0.1 [mu], the point of minimum electric mobility, was not found."
Date: January 31, 1963
Creator: Langer, G.
Partner: UNT Libraries Government Documents Department

Preliminary Report on Existing Active Particle Hazard-200 Areas

Description: "Recent surveys by the Health Instrument Section have disclosed the presence of many small radioactive spots on ground surfaces in the T and B plant areas. Investigation has shown that representative samples of the spots when mechanically separated invariably end in a single radioactive particle."
Date: October 22, 1947
Creator: Mickelson, M. L.
Partner: UNT Libraries Government Documents Department

Measurement and Control of Radioactive Particulate Contamination: Summary Report

Description: The following report is meant to review the characteristics of airborne particulate contamination matter, which sets it apart from other phases of the radiation control program and make it necessary to apply to it different concepts, analytical procedures, and control measures.
Date: 1956
Creator: Match, Theodore F.
Partner: UNT Libraries Government Documents Department

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 Nucleus concentration (CCN) as a function of super-saturation and in relating CCN concentration to aerosol composition and size distribution. Furthermore, airborn measurement for the cloud droplet concentration was also available. Therefore this AIOP provides a good opportunity to examine the AIE. In this study, we use a Cloud Resolving Model (CRM), i.e., Active Tracer High-resolution Atmospheric Model (ATHAM), to discuss the effect of aerosol loadings on cloud droplet effective radius (Re) and concentration. The case we examine is a stratiform cloud that occurred on May 17, 2003.
Date: March 18, 2005
Creator: Guo, H.; Penner, J.E. & Herzog, M.
Partner: UNT Libraries Government Documents Department

Short-term Variability of Extinction by Broadband Stellar Photometry

Description: Aerosol optical depth variation over short-term time intervals is determined from broadband observations of stars with a whole sky imager. The main difficulty in such measurements consists of accurately separating the star flux value from the non-stellar diffuse skylight. Using correction method to overcome this difficulty, the monochromatic extinction at the ground due to aerosols is extracted from heterochromatic measurements. A form of closure is achieved by comparison with simultaneous or temporally close measurements with other instruments, and the total error of the method, as a combination of random error of measurements and systematic error of calibration and model, is assessed as being between 2.6 and 3% rms.
Date: March 18, 2005
Creator: Musat, I.C. & Ellingson, R.G.
Partner: UNT Libraries Government Documents Department

Representing Cloud Processing of Aerosol in Numerical Models

Description: The satellite imagery in Figure 1 provides dramatic examples of how aerosol influences the cloud field. Aerosol from ship exhaust can serve as nucleation centers in otherwise cloud-free regions, forming ship tracks (top image), or can enhance the reflectance/albedo in already cloudy regions. This image is a demonstration of the first indirect effect, in which changes in aerosol modulate cloud droplet radius and concentration, which influences albedo. It is thought that, through the effects it has on precipitation (drizzle), aerosol can also affect the structure and persistence of planetary boundary layer (PBL) clouds. Regions of cellular convection, or open pockets of cloudiness (bottom image) are thought to be remnants of strongly drizzling PBL clouds. Pockets of Open Cloudiness (POCs) (Stevens et al. 2005) or Albrecht's ''rifts'' are low cloud fraction regions characterized by anomalously low aerosol concentrations, implying they result from precipitation. These features may in fact be a demonstration of the second indirect effect. To accurately represent these clouds in numerical models, we have to treat the coupled cloud-aerosol system. We present the following series of mesoscale and large eddy simulation (LES) experiments to evaluate the important aspects of treating the coupled cloud-aerosol problem. 1. Drizzling and nondrizzling simulations demonstrate the effect of drizzle on a mesoscale forecast off the California coast. 2. LES experiments with explicit (bin) microphysics gauge the relative importance of the shape of the aerosol spectrum on the 3D dynamics and cloud structure. 3. Idealized mesoscale model simulations evaluate the relative roles of various processes, sources, and sinks.
Date: March 18, 2005
Creator: Mechem, D.B. & Kogan, Y.L.
Partner: UNT Libraries Government Documents Department

AN INTERCOMPARISON CF THE INTEGRATING PLATE AND THE LASER TRANSMISSION METHODS FOR DETERMINATION OF AEROSOL ABSORPTION COEFFICIENTS

Description: The absorption coefficients determined by the integrating plate method and the laser transmission method are found to be comparable and highly correlated. Furthermore, a high correlation is found between these absorption coefficients and the carbon content of the aerosol in urbanized regions.
Date: July 1, 1980
Creator: Sadler, M.; Charlson, R.J.; Rosen, H. & Novakov, T.
Partner: UNT Libraries Government Documents Department

Data Quality Assessment and Control for the ARM Climate Research Facility

Description: The mission of the Atmospheric Radiation Measurement (ARM) Climate Research Facility is to provide observations of the earth climate system to the climate research community for the purpose of improving the understanding and representation, in climate and earth system models, of clouds and aerosols as well as their coupling with the Earth's surface. In order for ARM measurements to be useful toward this goal, it is important that the measurements are of a known and reasonable quality. The ARM data quality program includes several components designed to identify quality issues in near-real-time, track problems to solutions, assess more subtle long-term issues, and communicate problems to the user community.
Date: June 26, 2012
Creator: Peppler, R.
Partner: UNT Libraries Government Documents Department

Response of California temperature to regional anthropogenic aerosol changes

Description: In this paper, we compare constructed records of concentrations of black carbon (BC)--an indicator of anthropogenic aerosols--with observed surface temperature trends in California. Annual average BC concentrations in major air basins in California significantly decreased after about 1990, coincident with an observed statewide surface temperature increase. Seasonal aerosol concentration trends are consistent with observed seasonal temperature trends. These data suggest that the reduction in anthropogenic aerosol concentrations contributed to the observed surface temperature increase. Conversely, high aerosol concentrations may lower surface temperature and partially offset the temperature increase of greenhouse gases.
Date: May 12, 2008
Creator: Kirchstetter, Thomas; Novakov, T.; Kirchstetter, T.W.; Menon, S. & Aguiar, J.
Partner: UNT Libraries Government Documents Department

Applying EMSL Capabilities to Biogeochemistry and Environmental Research

Description: The Environmental Molecular Sciences laboratory (EMSL) is a national scientific user facility operated by the Pacific Northwest National Laboratory (PNNL) for the U.S. Department of Energy's Office of Biological and Environmental Research. Located in Richland, Washington, EMSL offers researchers a comprehensive array of cutting-edge capabilities unmatched anywhere else in the world and access to the expertise of over 300 resident users--all at one location. EMSL's resources are available on a peer-reviewed proposal basis and are offered at no cost if research results are shared in the open literature. Researchers are encouraged to submit a proposal centered around one of EMSL's four Science Themes, which represent growing areas of research: (1) Geochemistry/Biogeochemistry and Subsurface Science; (2) Atmospheric Aerosol Chemistry; (3) Biological Interactions and Dynamics; and (4) Science of Interfacial Phenomena. To learn more about EMSL, visit www.emsl.pnl.gov.
Date: April 19, 2007
Creator: Felmy, Andy
Partner: UNT Libraries Government Documents Department