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Modeling downwind hazards after an accidental release of chlorine trifluoride

Description: A module simulating ClF{sub 3} chemical reactions with water vapor and thermodynamic processes in the atmosphere after an accidental release has been developed. This module was liked to the HGSYSTEM. Initial model runs simulate the rapid formation of HF and ClO{sub 2} after an atmospheric release of ClF{sub 3}. At distances beyond the first several meters from the release point, HF and ClO{sub 2} concentrations pose a greater threat to human health than do ClF{sub 3} concentrations. For most of the simulations, ClF{sub 3} concentrations rapidly fall below the IDLH. Fro releases occurring in ambient conditions with low relative humidity and/or ambient temperature, ClF{sub 3} concentrations exceed the IDLH up to almost 500 m. The performance of this model needs to be determined for potential release scenarios that will be considered. These release scenarios are currently being developed.
Date: May 1, 1996
Creator: Lombardi, D.A. & Cheng, Meng-Dawn
Partner: UNT Libraries Government Documents Department

PHYSICO-CHEMICAL DYNAMICS OF NANOPARTICLE FORMATION DURING LASER DECONTAMINATION AND CHARACTERIZATION

Description: Improvement of understanding on nanoparticle production during simultaneous laser-based decontamination and characterization is imperative to the acceleration of decommission and deactivation (D&D) missions of US Department of Energy (DOE). Many researchers, mostly in material research, have explored issues related to aerosol particle formation by laser ablation, but there are little data relevant to D&D. Nanoparticles are harmful to D&D workers and the environment. The formation, properties, growth and transport mechanisms of radionuclides and toxic metals--laden nanoparticles are little known. The focus of this research is to investigate the effects of the laser parameters and the chemistry of target samples (contaminated and uncontaminated) on the dynamics and properties of produced particles. Data will facilitate better design of pollution control strategies. There are three goals associated with achieving the required understanding of nanoparticle dynamics. (1) To develop baseline property data of laser-produced nanoparticles from samples of different bulk chemical composition and surface morphology. The data would include properties of particles such as the size, shape, distribution, and chemical composition. (2) To develop advanced particle instrumentation (for sizing and chemistry measurement) so that reliable data can be obtained in higher resolution and shorter interval to delineate the dynamics, and (3) To employ an advanced computer simulation model to analyze and/or predict the dynamics of particles produced.
Date: June 1, 2002
Creator: Cheng, Meng-Dawn
Partner: UNT Libraries Government Documents Department

PHYSICO-CHEMICAL DYNAMICS OF NANOPARTICLE FORMATION DURING LASER DECONTAMINATION AND CHARACTERIZATION

Description: Acceleration of decommission and deactivation (D&D) activities of US Department of Energy (DOE) requires improved understandings of nanoparticle production and transformation during laser decontamination. Many material researchers have explored particle formation during laser energy-material interaction, but there are little data relevant to D&D work while laser energy is used to remove materials from contaminated surfaces. Fine particles are harmful to D&D workers and the environment. The focus of this research is to investigate the effects of the laser parameters and the chemistry of target samples on the dynamics and properties of produced particles. Data will facilitate better design of decontamination and deactivation strategies. There are three goals associated with achieving the required understanding of nanoparticle dynamics. (1) To develop baseline property data of laser-produced nanoparticles from samples of different bulk chemical composition and surface morphology. The data would include properties of particles such as the size from a few nanometers to a few micrometers, shape, distribution, and chemical composition. (2) To develop advanced particle instrumentation (for sizing and chemistry measurement) enabling higher resolution and shorter interval measurement, and (3) To develop computer simulation model to analyze and predict the dynamics of particles produced.
Date: June 1, 2003
Creator: Cheng, Meng-Dawn
Partner: UNT Libraries Government Documents Department