Mark Stolzenburg - Academia.edu (original) (raw)
Papers by Mark Stolzenburg
Journal of Aerosol Science, Nov 1, 2021
Abstract The measurement of airborne particles with sizes below 3 nm is critical, as it helps the... more Abstract The measurement of airborne particles with sizes below 3 nm is critical, as it helps the understanding of atmospheric nucleation and elucidates important particle synthesis mechanisms in the gas phase. Condensation particle counters (CPCs) have been widely used to measure the concentration of aerosols. However, it is challenging for the CPCs to measure particles below 3 nm due to the insufficient activation of these particles via vapor condensation. Methods have been proposed to increase the saturation ratio of the condensing vapor to promote the detection efficiency of sub-3 nm particles in the CPCs. Different working fluids also make a considerable impact on particle detection. Given the various types of parameters and the wide range of values these parameters can take, modeling studies are needed in searching for the optimal operating conditions of a CPC. In this work, we simulated the sub-3 nm particle activation and growth in a laminar flow CPC using COMSOL Multiphysics®, which has the advantages of simulating complex flow conditions and interfacing with post-processing software such as MATLAB. Our simulation incorporates the influence of temperature-dependent air and working fluid properties on particle activation and the impact of latent heat and non-continuum effects on droplet growth. Following the method introduced by Iida, Stolzenburg and McMurry (2009), particle activation is optimized for a given working fluid and condenser temperature by adjusting the saturator temperature to achieve a homogeneous nucleation rate of 1 s−1. The results, characterized by Dkel,0 (largest particle size that cannot be activated) and Dkel,50 (particle size activated with 50% efficiency), were compared against the analytical Graetz model used in Stolzenburg (1988). Our COMSOL simulations show that glycerine, diethylene glycol, ethylene glycol, 2-aminoethanol, and dimethyl phthalate are the best five working fluids achieving the smallest Dkel,50 among 45 commonly used solvents. The Dkel,50 values simulated by COMSOL under a condenser temperature of 10 °C for the five working fluids are 1.56, 1.88, 1.92, 1.98, and 2.10 nm, respectively, while the values simulated by the analytical Graetz solution differ slightly from 0.4% to 0.7%. The results demonstrate excellent agreement between these two simulation methods. For the five best working fluids activating the same 2.1 nm particles, the droplets can grow to sizes detectable by a second-stage CPC. The sensitivity of the COMSOL solution to the inlet condition and the form of convective diffusion equations is investigated. We also discussed the effect of CPC operating conditions, such as the condenser geometry and flow conditions, on particle activation for optimizing the performance of the CPC in detecting sub-3 nm particles.
Aerosol Science and Technology, Apr 19, 2018
Atmospheric Environment, Apr 1, 2002
Aerosol Science and Technology, Aug 28, 2008
Journal of Aerosol Science, Jun 1, 1998
Aerosol Science and Technology, 1998
... 6 Temperature 6 Valve O-Probe \ ... One critical orifice fixes the com-bined flow of the OPC ... more ... 6 Temperature 6 Valve O-Probe \ ... One critical orifice fixes the com-bined flow of the OPC and CNC. The flow split between the counters is adjusted by a manual regulating valve in the exit flow leg from the OPC. The HF-DMA sheath air exit flow is set by a second critical orifice. ...
Lawrence Berkeley National Laboratory, Sep 1, 2001
Aerosol Science and Technology, Sep 1, 2012
ABSTRACT Conventional Differential Mobility Analyzers (DMAs) for classification of aerosol partic... more ABSTRACT Conventional Differential Mobility Analyzers (DMAs) for classification of aerosol particles have one polydisperse-particle inlet and one monodisperse-particle outlet. As a result, when they are used as particle classifiers in aerosol-mobility spectrometers it is needed to scan through different operating conditions, thereby requiring a significant amount of time (i.e., of the order of a minute) for a single mobility distribution measurement. DMAs with multiple outlets can significantly reduce this scanning time because particles of different mobility can be classified and detected simultaneously. In addition, depending on the relative location of the first and the last outlet from the inlet, one can increase the dynamic mobility range of the selected particles in a single particle mobility distribution measurement. In this paper we derive analytical expressions for estimating the transfer function and the resolution of DMAs with multiple monodisperse outlets. Starting with the simple consideration of non-diffusing particles, we extend our analysis for diffusing particles and provide expressions of different complexity and accuracy. The theoretical framework provided in this paper can be employed to optimize the design of DMAs with more than one monodisperse-particle outlet, and to analyze the measurements when such DMAs are used in aerosol mobility spectrometers.
Journal of Aerosol Science, Feb 1, 2012
Aerosol Science and Technology, 1995
Air & waste, Feb 1, 1994
ABSTRACT Contributions of the major fine particle species to light scattering were evaluated usin... more ABSTRACT Contributions of the major fine particle species to light scattering were evaluated using Mie theory from measurements of sizeresolved chemistry and particle hygroscopicity obtained during the 1990 NGS Visibility Study at Hopi Point, Grand Canyon, from January 9, 1990 through March 31, 1990. It was found that scattering efficiencies of participate carbon mass ranged from 1.5 to 8 m per gram of carbon particle mass (assumed equal to 1.4 times carbon mass), with an average value of 5.4 ± 1.5 m/g. Sulfur size distributions, which are available for the entire 80-day study, show that sulfate scattering efficiencies depend on both relative humidity and on median particle size, and that “dry” (RH 0.3 μm were only found during periods of high relative humidity, but not all high humidity periods had large sulfur mass median diameters. Sulfate scattering efficiencies for >60 percent RH were smaller for instances of direct transport of
Journal of Geophysical Research, Dec 2, 2006
Aerosol Science and Technology, May 1, 2005
Journal of Aerosol Science, 1988
A unique ultrafine aerosol condensation nucleus counter (UFACNC) was used to test the performance... more A unique ultrafine aerosol condensation nucleus counter (UFACNC) was used to test the performance of two commercially available membrane filters. Details of this instrument have been discussed in previous publications (Stolzenburg and McMurry, 1986). Simultaneous ...
Atmospheric environment, 1987
Journal of Geophysical Research, 2005
Aerosol Science and Technology, 1991
... An Ultrafine Aerosol Condensation Nucleus Counter Mark R. Stolzenburg a & Peter H... more ... An Ultrafine Aerosol Condensation Nucleus Counter Mark R. Stolzenburg a & Peter H. McMurry a a Particle Technology Laboratory, Department of Mechanical Engineering, University of Minnesota, 111 Church Street SE, Minneapolis, MN, 55455 ... Counter ...
![Research paper thumbnail of Corrigendum to “On-road measurement of fine particle and nitrogen oxide emissions from light- and heavy-duty motor vehicles” [Atmospheric Environment 33 (18) (1999) 2955–2968]](https://attachments.academia-assets.com/119291594/thumbnails/1.jpg)
](Atmospheric Environment, Dec 1, 2002
Nanotechnology, Jun 26, 2006
Carbon nanofibres aerosolized by the agitation of as-produced commercial powder have been charact... more Carbon nanofibres aerosolized by the agitation of as-produced commercial powder have been characterized in situ by using the differential mobility analyser-aerosol particle mass analyser (DMA-APM) method to determine their structural properties such as the effective density and fractal dimension for toxicology study. The effective density of the aerosolized carbon nanofibres decreased from 1.2 to 0.4 g cm(-3) as the mobility diameters increased from 100 to 700 nm, indicating that the carbon nanofibres had open structures with an overall void that increased with increasing diameter, due to increased agglomeration of the nanofibres. This was confirmed by transmission electron microscopy (TEM) observation, showing that 100 nm mobility diameter nanofibres were predominantly single fibres, while doubly or triply attached fibres were seen at mobility diameters of 200 and 400 nm. Effective densities calculated using Cox's theory were in reasonable agreement with experimental values. The mass fractal dimension of the carbon nanofibres was found to be 2.38 over the size range measured and higher than that of single-walled carbon nanotubes (SWCNTs), suggesting that the carbon nanofibres have more compact structure than SWCNTs.
Journal of Aerosol Science, Nov 1, 2021
Abstract The measurement of airborne particles with sizes below 3 nm is critical, as it helps the... more Abstract The measurement of airborne particles with sizes below 3 nm is critical, as it helps the understanding of atmospheric nucleation and elucidates important particle synthesis mechanisms in the gas phase. Condensation particle counters (CPCs) have been widely used to measure the concentration of aerosols. However, it is challenging for the CPCs to measure particles below 3 nm due to the insufficient activation of these particles via vapor condensation. Methods have been proposed to increase the saturation ratio of the condensing vapor to promote the detection efficiency of sub-3 nm particles in the CPCs. Different working fluids also make a considerable impact on particle detection. Given the various types of parameters and the wide range of values these parameters can take, modeling studies are needed in searching for the optimal operating conditions of a CPC. In this work, we simulated the sub-3 nm particle activation and growth in a laminar flow CPC using COMSOL Multiphysics®, which has the advantages of simulating complex flow conditions and interfacing with post-processing software such as MATLAB. Our simulation incorporates the influence of temperature-dependent air and working fluid properties on particle activation and the impact of latent heat and non-continuum effects on droplet growth. Following the method introduced by Iida, Stolzenburg and McMurry (2009), particle activation is optimized for a given working fluid and condenser temperature by adjusting the saturator temperature to achieve a homogeneous nucleation rate of 1 s−1. The results, characterized by Dkel,0 (largest particle size that cannot be activated) and Dkel,50 (particle size activated with 50% efficiency), were compared against the analytical Graetz model used in Stolzenburg (1988). Our COMSOL simulations show that glycerine, diethylene glycol, ethylene glycol, 2-aminoethanol, and dimethyl phthalate are the best five working fluids achieving the smallest Dkel,50 among 45 commonly used solvents. The Dkel,50 values simulated by COMSOL under a condenser temperature of 10 °C for the five working fluids are 1.56, 1.88, 1.92, 1.98, and 2.10 nm, respectively, while the values simulated by the analytical Graetz solution differ slightly from 0.4% to 0.7%. The results demonstrate excellent agreement between these two simulation methods. For the five best working fluids activating the same 2.1 nm particles, the droplets can grow to sizes detectable by a second-stage CPC. The sensitivity of the COMSOL solution to the inlet condition and the form of convective diffusion equations is investigated. We also discussed the effect of CPC operating conditions, such as the condenser geometry and flow conditions, on particle activation for optimizing the performance of the CPC in detecting sub-3 nm particles.
Aerosol Science and Technology, Apr 19, 2018
Atmospheric Environment, Apr 1, 2002
Aerosol Science and Technology, Aug 28, 2008
Journal of Aerosol Science, Jun 1, 1998
Aerosol Science and Technology, 1998
... 6 Temperature 6 Valve O-Probe \ ... One critical orifice fixes the com-bined flow of the OPC ... more ... 6 Temperature 6 Valve O-Probe \ ... One critical orifice fixes the com-bined flow of the OPC and CNC. The flow split between the counters is adjusted by a manual regulating valve in the exit flow leg from the OPC. The HF-DMA sheath air exit flow is set by a second critical orifice. ...
Lawrence Berkeley National Laboratory, Sep 1, 2001
Aerosol Science and Technology, Sep 1, 2012
ABSTRACT Conventional Differential Mobility Analyzers (DMAs) for classification of aerosol partic... more ABSTRACT Conventional Differential Mobility Analyzers (DMAs) for classification of aerosol particles have one polydisperse-particle inlet and one monodisperse-particle outlet. As a result, when they are used as particle classifiers in aerosol-mobility spectrometers it is needed to scan through different operating conditions, thereby requiring a significant amount of time (i.e., of the order of a minute) for a single mobility distribution measurement. DMAs with multiple outlets can significantly reduce this scanning time because particles of different mobility can be classified and detected simultaneously. In addition, depending on the relative location of the first and the last outlet from the inlet, one can increase the dynamic mobility range of the selected particles in a single particle mobility distribution measurement. In this paper we derive analytical expressions for estimating the transfer function and the resolution of DMAs with multiple monodisperse outlets. Starting with the simple consideration of non-diffusing particles, we extend our analysis for diffusing particles and provide expressions of different complexity and accuracy. The theoretical framework provided in this paper can be employed to optimize the design of DMAs with more than one monodisperse-particle outlet, and to analyze the measurements when such DMAs are used in aerosol mobility spectrometers.
Journal of Aerosol Science, Feb 1, 2012
Aerosol Science and Technology, 1995
Air & waste, Feb 1, 1994
ABSTRACT Contributions of the major fine particle species to light scattering were evaluated usin... more ABSTRACT Contributions of the major fine particle species to light scattering were evaluated using Mie theory from measurements of sizeresolved chemistry and particle hygroscopicity obtained during the 1990 NGS Visibility Study at Hopi Point, Grand Canyon, from January 9, 1990 through March 31, 1990. It was found that scattering efficiencies of participate carbon mass ranged from 1.5 to 8 m per gram of carbon particle mass (assumed equal to 1.4 times carbon mass), with an average value of 5.4 ± 1.5 m/g. Sulfur size distributions, which are available for the entire 80-day study, show that sulfate scattering efficiencies depend on both relative humidity and on median particle size, and that “dry” (RH 0.3 μm were only found during periods of high relative humidity, but not all high humidity periods had large sulfur mass median diameters. Sulfate scattering efficiencies for >60 percent RH were smaller for instances of direct transport of
Journal of Geophysical Research, Dec 2, 2006
Aerosol Science and Technology, May 1, 2005
Journal of Aerosol Science, 1988
A unique ultrafine aerosol condensation nucleus counter (UFACNC) was used to test the performance... more A unique ultrafine aerosol condensation nucleus counter (UFACNC) was used to test the performance of two commercially available membrane filters. Details of this instrument have been discussed in previous publications (Stolzenburg and McMurry, 1986). Simultaneous ...
Atmospheric environment, 1987
Journal of Geophysical Research, 2005
Aerosol Science and Technology, 1991
... An Ultrafine Aerosol Condensation Nucleus Counter Mark R. Stolzenburg a & Peter H... more ... An Ultrafine Aerosol Condensation Nucleus Counter Mark R. Stolzenburg a & Peter H. McMurry a a Particle Technology Laboratory, Department of Mechanical Engineering, University of Minnesota, 111 Church Street SE, Minneapolis, MN, 55455 ... Counter ...
Atmospheric Environment, Dec 1, 2002
Nanotechnology, Jun 26, 2006
Carbon nanofibres aerosolized by the agitation of as-produced commercial powder have been charact... more Carbon nanofibres aerosolized by the agitation of as-produced commercial powder have been characterized in situ by using the differential mobility analyser-aerosol particle mass analyser (DMA-APM) method to determine their structural properties such as the effective density and fractal dimension for toxicology study. The effective density of the aerosolized carbon nanofibres decreased from 1.2 to 0.4 g cm(-3) as the mobility diameters increased from 100 to 700 nm, indicating that the carbon nanofibres had open structures with an overall void that increased with increasing diameter, due to increased agglomeration of the nanofibres. This was confirmed by transmission electron microscopy (TEM) observation, showing that 100 nm mobility diameter nanofibres were predominantly single fibres, while doubly or triply attached fibres were seen at mobility diameters of 200 and 400 nm. Effective densities calculated using Cox's theory were in reasonable agreement with experimental values. The mass fractal dimension of the carbon nanofibres was found to be 2.38 over the size range measured and higher than that of single-walled carbon nanotubes (SWCNTs), suggesting that the carbon nanofibres have more compact structure than SWCNTs.