Research Interests: Engineering, Earth Sciences, Environmental Science, Chemistry, Mass Transfer, and 13 moreMedicine, Diffusion, Temperature, Partition Coefficient, Relative Humidity, Indoor air pollution, Theoretical Models, Humidity, NIST, Toluene, Volatile organic compound, Indoor air, and Medical and Health Sciences
Research Interests: Engineering, Environmental Science, Chemistry, Architecture, Diffusion, and 10 moreBuilding, Building Environment, NIST, Certified Reference Material, National Institute of Standards and Technology, Predictive value of tests, Volatile organic compound, ENVIRONMENTAL SCIENCE AND MANAGEMENT, Emission rate, and Relative Standard Deviation
Nanoscale cerium oxide is used as a diesel fuel additive to reduce particulate matter emissions and increase fuel economy, but its fate in the environment has not been established. Cerium oxide released as a result of the combustion of... more
Nanoscale cerium oxide is used as a diesel fuel additive to reduce particulate matter emissions and increase fuel economy, but its fate in the environment has not been established. Cerium oxide released as a result of the combustion of diesel fuel containing the additive Envirox, which utilizes suspended nanoscale cerium oxide to reduce particulate matter emissions and increase fuel economy, was captured from the exhaust stream of a diesel engine and was characterized using a combination of bulk analytical techniques and high resolution transmission electron microscopy. The combustion process induced significant changes in the size and morphology of the particles; ∼15 nm aggregates consisting of 5-7 nm faceted crystals in the fuel additive became 50-300 nm, near-spherical, single crystals in the exhaust. Electron diffraction identified the original cerium oxide particles as cerium(IV) oxide (CeO2, standard FCC structure) with no detectable quantities of Ce(III), whereas in the exhau...
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Assessing human exposure to semivolatile organic compounds (SVOCs) emitted from materials and products is difficult because methods are not available to easily measure the key emission parameters. A simple method based on passive sampling... more
Assessing human exposure to semivolatile organic compounds (SVOCs) emitted from materials and products is difficult because methods are not available to easily measure the key emission parameters. A simple method based on passive sampling technique was thus developed to measure the gas-phase SVOC concentration (y0 ) immediately adjacent to the material surface in a consumer product. The method employs standard stainless-steel thermal desorption tubes, with values of y0 and an additional unknown parameter, K, the tube surface/air partition coefficient inside the desorption tube, obtained by fitting a diffusion model to the sampling data. Phthalates in two types of polyvinyl chloride flooring were selected to test the method. The values of y0 and K agree well with those measured in independent chamber tests. The y0 measurement method is shown to be applicable to chemicals with a wide range of vapor pressures. This novel method should be useful for assessing potential exposure to SVOCs...
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Research Interests: Engineering, Mass Transfer, Mass Spectrometry, Energy Conservation, Environmental Monitoring, and 17 moreAir pollution, Environmental Sciences, Humans, Solvent Extraction, High Temperature, Fluidized Bed, Indoor air pollution, Phase measurement, Room Temperature, Free volume, Indoor Environment, Elevated Temperature, Organic Chemicals, Volatile organic compound, Indoor air, Volatilization, and Thermal desorption
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... Transport properties in polyurethane/clay nanocomposites as barrier materials: Effect of processing conditions. ... View Within Article. 3.3.2. Effect of clay type. The CH 4 permeability data for the various nanocomposite clays are... more
... Transport properties in polyurethane/clay nanocomposites as barrier materials: Effect of processing conditions. ... View Within Article. 3.3.2. Effect of clay type. The CH 4 permeability data for the various nanocomposite clays are compared in Fig. 8A as a function of clay content. ...