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There are two predominant methods for understanding and studying bioaerosol aging: capture on microfibers, and Goldberg rotating drums. There are advantages and disadvantages to each approach depending on the experimental needs, cost, and timeline, but they have rarely been compared in parallel to determine the similarity of results. Experiments that use Goldberg drums have the advantage of studying aerosol particles in suspension, but due time resolution of aging processes is limited by chamber volume, sample volumes, and aerosol loss mechanisms. For microfiber experiments, particles are adhered to the fiber, and so only simulate natural aerosols, but there are significant advantages since particles are not lost during aging and the time resolution is not limited by sampling. In this study, we compared outdoor UV-transmitting Goldberg rotating drums with polymethyl methacrylate (PMMA) synthetic spider web material in a complex real-world environment during a summer near Houston, Texas. Bacillus thuringiensis al hakam spores were aerosolized into UV-transmitting, gas-permeable chambers that allowed relevant exposure to real-world atmospheric conditions while isolating particles of interest. Aging was compared for up to 4 h in both sunlight exposed and protected environments to compare and quantify relative degradation rates. The two disparate methodologies yielded similar results, with no statistical difference found in three out of four combinations of carbon-filtered air vs. ambient air, and protection from sunlight vs. exposure to sunlight, but this could vary for other particle sizes or organisms. Copyright © 2023 American Association for Aerosol Research [ABSTRACT FROM AUTHOR]

Thermotropic liquid crystalline polymers (TLCPs) exhibit a number of mechanical and physical properties such as excellent chemical resistance, low permeability, low coefficient of thermal expansion, high tensile strength and modulus, and good impact resistance, which make them desirable as a rotationally molded storage vessel. However, there are no reports in the technical literature of the successful rotational molding of TLCPs. In this article, conditions are identified that lead to the successful rotational molding of a TLCP, Vectra B 950. First, a technique was developed to produce particles suitable for rotational molding because TLCPs cannot be ground into a free-flowing powder. Second, because the viscosity at low shear rates can be detrimental to the sintering process, coalescence experiments with isolated particles were carried out to determine the thermal and environmental conditions at which sintering should occur. These conditions were then applied to static sintering experiments to determine whether coalescence and densification of the bulk powder would occur. Finally, the powders were successfully rotationally molded into tubular structures in a single axis, lab-scale device. The density of the molded structure was essentially equivalent to the material density and the tensile strength and modulus were approximately 18 MPa and 2 GPa, respectively. POLYM. ENG. SCI., 45:410-423, 2005. [c] Society of Plastics Engineers, INTRODUCTION Thermotropic liquid crystalline polymers (TLCPs) exhibit a number of mechanical and physical properties that make them desirable for use in storage vessels for cryogenic or corrosive fluids. TLCPs have [...]