@article{kumar_gautam_atri_tafreshi_pourdeyhimi_2023, title={Importance of Dipole Orientation in Electrostatic Aerosol Filtration}, volume={39}, ISSN={["1520-5827"]}, url={https://doi.org/10.1021/acs.langmuir.3c02016}, DOI={10.1021/acs.langmuir.3c02016}, abstractNote={Electrostatic charge is a major part of modern-day aerosol filtration media (e.g., N95 respirators and surgical facemasks) that has remained poorly understood due to its complicated physics. As such, charging a fibrous material has relied on empiricism in dire need of a mathematical foundation to further advance product design and optimization. In this concern, we have conducted a series of numerical simulations to improve our understanding of how an electrostatically charged fiber captures airborne particles and to quantify how the fiber's dipole orientation impacts its capture efficiency. Special attention was paid to the role of Coulomb and dielectrophoretic forces in the capture of particles of different charge polarities (e.g., particles having a Boltzmann charge distribution). Simulation results were compared with the predictions of the popular empirical correlations from the literature and discussed in detail. Predictions of the empirical correlations better agreed with the simulation results obtained for fibers with a dipole perpendicular to the flow direction rather than for fibers with a dipole parallel to the flow. This indicates that such empirical correlations are more suitable for filters charged via contact electrification (friction charging), where the dipoles are mostly perpendicular to the flow direction, and less suitable for corona-charged media, where the fiber dipoles are generally parallel to the flow direction.}, number={49}, journal={LANGMUIR}, author={Kumar, A. and Gautam, S. and Atri, S. and Tafreshi, H. V. and Pourdeyhimi, B.}, year={2023}, month={Nov}, pages={17653–17663} }
 @article{jamali_atri_gautam_saleh_tafreshi_pourdeyhimi_2023, title={Macroscale modeling of electrostatically charged facemasks}, volume={4}, ISSN={["1521-7388"]}, url={https://publons.com/wos-op/publon/65200080/}, DOI={10.1080/02786826.2023.2203188}, abstractNote={Abstract In this study, the instantaneous collection efficiency and pressure drop of an N95 facemask is numerically simulated in a setting similar (but not identical) to that used by NIOSH to certify N95 respirators. More specifically, a CPU-friendly macroscale model is developed, for the first time, to simulate the performance of an electrostatically-charged facemask when the mask is clean and when it is loaded with neutral or neutralized nanoparticles. The simulations were performed using ANSYS software enhanced with in-house subroutines, and they were calibrated using the experimental data reported in the literature for the initial efficiency of N95 masks. In addition, a correction factor was developed for the Kozeny-Carman permeability equation to expand its application to the case of nanoparticle-deposits, where the dendrites porosity is very high and the aerodynamic slip is expected to occur. Copyright © 2023 American Association for Aerosol Research}, journal={AEROSOL SCIENCE AND TECHNOLOGY}, author={Jamali, M. and Atri, S. and Gautam, S. and Saleh, A. M. and Tafreshi, H. V. and Pourdeyhimi, B.}, year={2023}, month={Apr} }