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Search Publications by: Joseph M Conny (Assoc)

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Displaying 1 - 25 of 28

Rapid chemical screening of microplastics and nanoplastics by thermal desorption and pyrolysis mass spectrometry with unsupervised fuzzy clustering

August 11, 2023
Author(s)
Thomas P. Forbes, John Pettibone, Eric S. Windsor, Joseph M. Conny, Robert A. Fletcher
The transport and chemical identification of microplastics and nanoplastics (MNPs) are critical to the concerns over plastic accumulation in the environment. Chemically and physically transient MNP species present unique challenges for isolation and

Evaluation of Thermal Optical Analysis (TOA) Using an Aqueous Binary Mixture

June 30, 2020
Author(s)
Courtney D. Grimes, Joseph Conny, Russell Dickerson
Thermal Optical Analysis (TOA), a commonly implemented technique used to measure the amount of particulate carbon in the atmosphere or deposited on a filter substrate, distinguishes organic carbon (OC) from elemental carbon (EC) through the monitoring of

Chemical Compound Classification by Elemental Signatures in Castle Dust Using SEM Automated X-ray Particle Analysis

August 1, 2018
Author(s)
Diana Ortiz-Montalvo, Edward P. Vicenzi, Nicholas W. Ritchie, Carol A. Grissom, Richard A. Livingston, Zoe Weldon-Yochim, Joseph M. Conny, Scott A. Wight
Discoloration on the Smithsonian Institution Building and Enid A. Haupt Garden gateposts was recently revealed to be related to a Mn enriched rock varnish. Mn does not appear to be derived locally from the building stone; therefore, its source is likely

Dependence of Soot Optical Properties on Particle Morphology: Measurements and Model Comparisons

February 18, 2014
Author(s)
James Radney, Rian You, Xiaofei Ma, Joseph Conny, Michael R. Zachariah, Joseph T. Hodges, Christopher D. Zangmeister
We measure the mass-specific absorption and extinction cross sections for laboratory-generated soot aerosols. Two soot morphologies are investigated, both comprising fractal aggregates of nearly spherical monomers. The first type consists of monomer chains

Filter Material Effects on Particle Absorption Characteristics

February 10, 2014
Author(s)
Cary Presser, Joseph M. Conny, Ashot Nazarian
The absorption coefficient and mass specific absorption cross section were determined for nigrosin-laden quartz, Teflon, and polycarbonate filters in inert surroundings at different steady-state temperatures and particle mass loadings. The objective was to

XRD Rietveld Simulations Y 2 O 3 - ZrO 2 Phases

October 16, 2008
Author(s)
Jennifer R. Verkouteren, Joseph M. Conny
X-ray diffraction patterns of tetragonal and cubic yttria-stabilized were simulated to test the capability of Rietveld refinement to accurately seperate the phases. The effects of peak broadening and different c/a ratios on the refinement results were

Measurement of the Optical Extinction Coefficient of Combustion-Generated Aerosol

February 1, 2005
Author(s)
J F. Widmann, J X. Duchez, Joseph M. Conny, George W. Mulholland
This note describes mesurements of the optical extinction coefficient of carbonaceous aerosol produced during hydrocarbon combustion. Measurements of the mass specific extinction coefficient were obtained by laser extinction at 632 nm wavelength. The

Soot Inception in a Well Stirred Reactor

March 19, 2003
Author(s)
L G. Blevins, K A. Jensen, R A. Ristau, N Y. Yang, C W. Frayne, R C. Striebich, M J. DeWitt, S D. Stouffer, E J. Lee, Robert A. Fletcher, J M. Oran, Joseph M. Conny, George W. Mulholland
Soot samples collected from a well stirred reactor operating with ethylene/air equivalence ratios of 1.9, 2.0, and 2.1 were examined to determine yield, size distribution, morphology, and composition. For F = 1.9, particles are absent. For F = 2.0 and 2.1

Analysis of Kaolinite/Chrysotile Mixtures by Ashing and X-Ray Diffraction

September 1, 2002
Author(s)
Jennifer R. Verkouteren, Eric S. Windsor, Joseph M. Conny, R L. Perkins, J T. Ennis
A simple ashing procedure is described that converts kaolinite to amorphous metakaolinite while retaining the diffraction intensity of chrysotile. This ashing procedure removes the XRD pattern overlap between kaolinite and chrysotile that can interfere