The Experts below are selected from a list of 804 Experts worldwide ranked by ideXlab platform
David Y.h. Pui - One of the best experts on this subject based on the ideXlab platform.
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Carbon Nanotube Penetration Through Fiberglass and Electret Respirator Filter and Nuclepore Filter Media: Experiments and Models
Aerosol Science and Technology, 2014Co-Authors: Sheng Chieh Chen, Jing Wang, Yeon Kyoung Bahk, Heinz Fissan, David Y.h. PuiAbstract:Three different respirator Filter media (two electrets and one Fiberglass) were challenged with monodisperse multi-walled carbon nanotubes (MWCNTs) of mobility diameters 20–500 nm at 5.3 and 10.6 cm s−1 face velocities. The penetration data were compared with that of sphere-like NaCl particles. The MWCNT penetrations were generally lower than those of NaCl at both face velocities in all three Filters. However, the MWCNTs had a slightly higher penetration than the NaCl in the Fiberglass Filter at 10.6 cm s−1 face velocity when their mobility diameters were lower than 50 nm and the alignment effect was expected to occur. Results from the scanning electron microscopic (SEM) analysis supported the hypothesis of the alignment effect, which showed that the MWCNTs tend to be straighter or with higher aspect-ratios at the mobility sizes less than 100 nm, leading them more readily to align with the flow. Therefore, caution should be exercised when respirators are used against the MWCNTs with the mobility diameters...
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Carbon Nanotube Penetration Through Fiberglass and Electret Respirator Filter and Nuclepore Filter Media: Experiments and Models
2014Co-Authors: Sheng Chieh Chen, Jing Wang, Yeon Kyoung Bahk, Heinz Fissan, David Y.h. PuiAbstract:Three different respirator Filter media (two electrets and one Fiberglass) were challenged with monodisperse multi-walled carbon nanotubes (MWCNTs) of mobility diameters 20–500 nm at 5.3 and 10.6 cm s−1 face velocities. The penetration data were compared with that of sphere-like NaCl particles. The MWCNT penetrations were generally lower than those of NaCl at both face velocities in all three Filters. However, the MWCNTs had a slightly higher penetration than the NaCl in the Fiberglass Filter at 10.6 cm s−1 face velocity when their mobility diameters were lower than 50 nm and the alignment effect was expected to occur. Results from the scanning electron microscopic (SEM) analysis supported the hypothesis of the alignment effect, which showed that the MWCNTs tend to be straighter or with higher aspect-ratios at the mobility sizes less than 100 nm, leading them more readily to align with the flow. Therefore, caution should be exercised when respirators are used against the MWCNTs with the mobility diameters less than 100 nm. The single fiber theory predicted the penetration of both particles in the Fiberglass Filters well for the particles with below 100 nm mobility diameters but discrepancies occurred beyond 100 nm. The theory still predicted the NaCl penetration through the electret Filters well for the sizes below 100 nm but only predicted the MWCNT penetration well for ∼20–30 nm. The Nuclepore Filter and the corresponding capillary tube model were adopted to study the mechanical deposition mechanisms of MWCNTs. The model was found to predict MWCNT penetration very well when the effective length of the MWCNT was taken into account.Copyright 2014 American Association for Aerosol Research
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Structural Properties and Filter Loading Characteristics of Soot Agglomerates
Aerosol Science and Technology, 2009Co-Authors: Seong Chan Kim, Jing Wang, Weon Gyu Shin, Jacob H. Scheckman, David Y.h. PuiAbstract:Nanoparticle agglomerates are pervasive in atmospheric sciences, air pollution, and manufacturing of powdered materials, yet studies for filtration of nanoparticle agglomerates are still scarce compared to those for spherical particles. We investigated loading of soot nanoparticle agglomerates on fibrous air Filter media. The soot agglomerates were generated from a diffusion burner with propane gas as fuel and compressed air as oxidant/sheath. The mode of the number distribution was determined to be 120 nm. A Differential Mobility Analyzer (DMA)—Aerosol Particle Mass Analyzer (APM) system was used to measure the mass of agglomerates as a function of the mobility size, which gave a mass-mobility exponent of 1.9 ± 0.1. Using transmission electron microscopy (TEM), we found that the primary particles in the agglomerates had a mean diameter of 28 nm with a geometric standard deviation of 1.26. Loading experiments were carried out with the face velocity of 10 cm/s on a Fiberglass Filter media. The pressure dro...
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A comparison of two nano-sized particle air filtration tests in the diameter range of 10 to 400 nanometers
Journal of Nanoparticle Research, 2006Co-Authors: Daniel A. Japuntich, Seong Chan Kim, David Y.h. Pui, Luke M. Franklin, Thomas H. Kuehn, Andrew S. VinerAbstract:Two different air Filter test methodologies are discussed and compared for challenges in the nano-sized particle range of 10–400 nm. Included in the discussion are test procedure development, factors affecting variability and comparisons between results from the tests. One test system which gives a discrete penetration for a given particle size is the TSI 8160 Automated Filter tester (updated and commercially available now as the TSI 3160) manufactured by the TSI, Inc., Shoreview, MN. Another Filter test system was developed utilizing a Scanning Mobility Particle Sizer (SMPS) to sample the particle size distributions downstream and upstream of an air Filter to obtain a continuous percent Filter penetration versus particle size curve. Filtration test results are shown for Fiberglass Filter paper of intermediate filtration efficiency. Test variables affecting the results of the TSI 8160 for NaCl and dioctyl phthalate (DOP) particles are discussed, including condensation particle counter stability and the sizing of the selected particle challenges. Filter testing using a TSI 3936 SMPS sampling upstream and downstream of a Filter is also shown with a discussion of test variables and the need for proper SMPS volume purging and Filter penetration correction procedure. For both tests, the penetration versus particle size curves for the Filter media studied follow the theoretical Brownian capture model of decreasing penetration with decreasing particle diameter down to 10 nm with no deviation. From these findings, the authors can say with reasonable confidence that there is no evidence of particle thermal rebound in the size range.
Andrew S. Viner - One of the best experts on this subject based on the ideXlab platform.
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A comparison of two nano-sized particle air filtration tests in the diameter range of 10 to 400 nanometers
Journal of Nanoparticle Research, 2007Co-Authors: Daniel A. Japuntich, Luke M. Franklin, Thomas H. Kuehn, Andrew S. VinerAbstract:Two different air Filter test methodologies are discussed and compared for challenges in the nano-sized particle range of 10–400 nm. Included in the discussion are test procedure development, factors affecting variability and comparisons between results from the tests. One test system which gives a discrete penetration for a given particle size is the TSI 8160 Automated Filter tester (updated and commercially available now as the TSI 3160) manufactured by the TSI, Inc., Shoreview, MN. Another Filter test system was developed utilizing a Scanning Mobility Particle Sizer (SMPS) to sample the particle size distributions downstream and upstream of an air Filter to obtain a continuous percent Filter penetration versus particle size curve. Filtration test results are shown for Fiberglass Filter paper of intermediate filtration efficiency. Test variables affecting the results of the TSI 8160 for NaCl and dioctyl phthalate (DOP) particles are discussed, including condensation particle counter stability and the sizing of the selected particle challenges. Filter testing using a TSI 3936 SMPS sampling upstream and downstream of a Filter is also shown with a discussion of test variables and the need for proper SMPS volume purging and Filter penetration correction procedure. For both tests, the penetration versus particle size curves for the Filter media studied follow the theoretical Brownian capture model of decreasing penetration with decreasing particle diameter down to 10 nm with no deviation. From these findings, the authors can say with reasonable confidence that there is no evidence of particle thermal rebound in the size range.
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A comparison of two nano-sized particle air filtration tests in the diameter range of 10 to 400 nanometers
Journal of Nanoparticle Research, 2006Co-Authors: Daniel A. Japuntich, Seong Chan Kim, David Y.h. Pui, Luke M. Franklin, Thomas H. Kuehn, Andrew S. VinerAbstract:Two different air Filter test methodologies are discussed and compared for challenges in the nano-sized particle range of 10–400 nm. Included in the discussion are test procedure development, factors affecting variability and comparisons between results from the tests. One test system which gives a discrete penetration for a given particle size is the TSI 8160 Automated Filter tester (updated and commercially available now as the TSI 3160) manufactured by the TSI, Inc., Shoreview, MN. Another Filter test system was developed utilizing a Scanning Mobility Particle Sizer (SMPS) to sample the particle size distributions downstream and upstream of an air Filter to obtain a continuous percent Filter penetration versus particle size curve. Filtration test results are shown for Fiberglass Filter paper of intermediate filtration efficiency. Test variables affecting the results of the TSI 8160 for NaCl and dioctyl phthalate (DOP) particles are discussed, including condensation particle counter stability and the sizing of the selected particle challenges. Filter testing using a TSI 3936 SMPS sampling upstream and downstream of a Filter is also shown with a discussion of test variables and the need for proper SMPS volume purging and Filter penetration correction procedure. For both tests, the penetration versus particle size curves for the Filter media studied follow the theoretical Brownian capture model of decreasing penetration with decreasing particle diameter down to 10 nm with no deviation. From these findings, the authors can say with reasonable confidence that there is no evidence of particle thermal rebound in the size range.
Yves Andres - One of the best experts on this subject based on the ideXlab platform.
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Adenovirus behavior in air handling unit Fiberglass Filters
Aerobiologia, 2019Co-Authors: Victor Bandaly, Yves Andres, Aurélie Joubert, Pierre Le CannAbstract:Viral aerosols can lead to respiratory viral infections with high infectivity. About 90% of people’s time is spent in closed environments. A few studies have pointed out that the ventilation systems in air handling units (AHUs) that treat and transmit a new synthetic clean and conditioned environment can also spread and transport viral particles in buildings. The aim of this work is to study the characterization of adenovirus, a DNA non-enveloped respiratory virus, on the F7 Fiberglass Filter used in AHUs. In this study, an experimental setup simulating an AHU was used. The SYBR^® QPCR, Electrical Low-Pressure Impactor (ELPI™) and Scanning Mobility Particle Sizer (SMPS™) were used to detect, measure and characterize the aerosolized adenovirus solution. The characterization results showed that the nebulized adenovirus could be aerosolized in different forms associated or not with cell debris and proteins. The quantification and level of infectivity of adenovirus demonstrated that viruses passed through Filters and remained infectious up- and downstream of the system during the 25 min of aerosolization. This study showed that AHUs should be considered an indoor source of viral contamination.
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Adenovirus behavior in air handling unit Fiberglass Filters
Aerobiologia, 2019Co-Authors: Victor Bandaly, Yves Andres, Aurélie Joubert, Pierre Le CannAbstract:Viral aerosols can lead to respiratory viral infections with high infectivity. About 90% of people’s time is spent in closed environments. A few studies have pointed out that the ventilation systems in air handling units (AHUs) that treat and transmit a new synthetic clean and conditioned environment can also spread and transport viral particles in buildings. The aim of this work is to study the characterization of adenovirus, a DNA non-enveloped respiratory virus, on the F7 Fiberglass Filter used in AHUs. In this study, an experimental setup simulating an AHU was used. The SYBR® QPCR, Electrical Low-Pressure Impactor (ELPI™) and Scanning Mobility Particle Sizer (SMPS™) were used to detect, measure and characterize the aerosolized adenovirus solution. The characterization results showed that the nebulized adenovirus could be aerosolized in different forms associated or not with cell debris and proteins. The quantification and level of infectivity of adenovirus demonstrated that viruses passed through Filters and remained infectious up- and downstream of the system during the 25 min of aerosolization. This study showed that AHUs should be considered an indoor source of viral contamination. © 2019, Springer Nature B.V.
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The Fate of Mengovirus on Fiberglass Filter of Air Handling Units
Food and Environmental Virology, 2017Co-Authors: Victor Bandaly, Pierre Le Cann, Aurélie Joubert, Yves AndresAbstract:One of the most important topics that occupy public health problems is the air quality. That is the reason why mechanical ventilation and air handling units (AHU) were imposed by the different governments in the collective or individual buildings. Many buildings create an artificial climate using heating, ventilation, and air-conditioning systems. Among the existing aerosols in the indoor air, we can distinguish the bioaerosol with biological nature such as bacteria, viruses, and fungi. Respiratory viral infections are a major public health issue because they are usually highly infective. We spend about 90% of our time in closed environments such as homes, workplaces, or transport. Some studies have shown that AHU contribute to the spread and transport of viral particles within buildings. The aim of this work is to study the characterization of viral bioaerosols in indoor environments and to understand the fate of mengovirus eukaryote RNA virus on glass fiber Filter F7 used in AHU. In this study, a set-up close to reality of AHU system was used. The mengovirus aerosolized was characterized and measured with the electrical low pressure impact and the scanner mobility particle size and detected with RT-qPCR. The results about quantification and the level of infectivity of mengovirus on the Filter and in the biosampler showed that mengovirus can pass through the Filter and remain infectious upstream and downstream the system. Regarding the virus infectivity on the Filter under a constant air flow, mengovirus was remained infectious during 10 h after aerosolization.
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The fate of mengovirus on Fiberglass Filter of air handling units
Food and Environmental Virology, 2017Co-Authors: Victor Bandaly, Pierre Le Cann, Aurélie Joubert, Yves AndresAbstract:One of the most important topics that occupy public health problems is the air quality. That is the reason why mechanical ventilation and air handling units (AHU) were imposed by the different governments in the collective or individual buildings. Many buildings create an artificial climate using heating, ventilation and airconditioning (HVAC) systems. Among the existing aerosols in the indoor air, we can distinguish the bioaerosol with biological nature such as bacteria, viruses, fungi. Respiratory viral infections are a major public health issue because they are usually highly infective. We spend about 90% of our time in closed environments such as homes, workplaces or transport. Some studies have shown that AHU contribute to the spread and transport of viral particles within buildings. The aim of this work is to study the characterization of viral bioaerosols in indoor environments and to understand the fate of mengovirus eukaryote RNA virus on glass fiber Filter F7 used in AHU. In this study, a setup close to reality of AHU system was used. The mengovirus aerosolized was characterized and measured with the Electrical Low Pressure Impact (ELPI) and the Scanner Mobility Particle Size (SMPS) and detected with RT-qPCR. The results about quantification and the level of infectivity of mengovirus on the Filter and in the biosampler showed that mengovirus can pass through the Filter and remain infectious upstream and downstream the system. Regarding the virus effectiveness on the Filter under a constant air flow, and mengovirus was remained infectious during 10 hours after aerosolization.
Pablo Richter - One of the best experts on this subject based on the ideXlab platform.
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A new rotating-disk sorptive extraction mode, with a copolymer of divinylbenzene and N-vinylpyrrolidone trapped in the cavity of the disk, used for determination of florfenicol residues in porcine plasma
Analytical and bioanalytical chemistry, 2014Co-Authors: Alejandro Cañas, Samuel Valdebenito, Pablo RichterAbstract:A novel extraction approach was developed based on rotating-disk sorptive extraction (RDSE). In this approach the rotating-disk extraction device consists of a Teflon disk, with a cavity that is loaded with a commercial sorbent phase selected according to the polarity of the analyte. To avoid leakage of the sorbent, the cavity is covered with a Fiberglass Filter and sealed with a Teflon ring. The proposed novel analytical RDSE technique was used in this study to determine florfenicol levels in plasma as a model analyte, or sample system, to describe the pharmacokinetics of a veterinary formulation. The sorbent used for this application was the copolymer of divinylbenzene and N-vinylpyrrolidone (Oasis HLB), which was selected because the florfenicol molecule contains both hydrophilic and lipophilic moieties. After the extraction, final determination of the analyte was performed by HPLC–DAD. Calibration plots and other analytical features were obtained after 90 min of extraction. The calibration plot was linear over the interval 0.4–16 μg mL−1 (n = 6), with R 2 = 0.9999. Recovery and repeatability were determined using a blank plasma sample spiked with 4.8 μg mL−1 florfenicol. A recovery of 91.5 %, with a relative standard deviation (RSD) of 8.8 %, was obtained when the extraction was evaluated using six different rotating-disk devices. Precision was also assessed, using the same disk (containing the same sorbent phase) for eight aliquots of the same sample. The RSD under these conditions was 10.2 %, clearly indicating that the sorptive phase could possibly be re-used. Accordingly, RDSE is a suitable sample preparation alternative to liquid–liquid extraction (LLE), solid-phase extraction (SPE), and stir-bar sorptive extraction (SBSE).
Daniel A. Japuntich - One of the best experts on this subject based on the ideXlab platform.
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A comparison of two nano-sized particle air filtration tests in the diameter range of 10 to 400 nanometers
Journal of Nanoparticle Research, 2007Co-Authors: Daniel A. Japuntich, Luke M. Franklin, Thomas H. Kuehn, Andrew S. VinerAbstract:Two different air Filter test methodologies are discussed and compared for challenges in the nano-sized particle range of 10–400 nm. Included in the discussion are test procedure development, factors affecting variability and comparisons between results from the tests. One test system which gives a discrete penetration for a given particle size is the TSI 8160 Automated Filter tester (updated and commercially available now as the TSI 3160) manufactured by the TSI, Inc., Shoreview, MN. Another Filter test system was developed utilizing a Scanning Mobility Particle Sizer (SMPS) to sample the particle size distributions downstream and upstream of an air Filter to obtain a continuous percent Filter penetration versus particle size curve. Filtration test results are shown for Fiberglass Filter paper of intermediate filtration efficiency. Test variables affecting the results of the TSI 8160 for NaCl and dioctyl phthalate (DOP) particles are discussed, including condensation particle counter stability and the sizing of the selected particle challenges. Filter testing using a TSI 3936 SMPS sampling upstream and downstream of a Filter is also shown with a discussion of test variables and the need for proper SMPS volume purging and Filter penetration correction procedure. For both tests, the penetration versus particle size curves for the Filter media studied follow the theoretical Brownian capture model of decreasing penetration with decreasing particle diameter down to 10 nm with no deviation. From these findings, the authors can say with reasonable confidence that there is no evidence of particle thermal rebound in the size range.
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A comparison of two nano-sized particle air filtration tests in the diameter range of 10 to 400 nanometers
Journal of Nanoparticle Research, 2006Co-Authors: Daniel A. Japuntich, Seong Chan Kim, David Y.h. Pui, Luke M. Franklin, Thomas H. Kuehn, Andrew S. VinerAbstract:Two different air Filter test methodologies are discussed and compared for challenges in the nano-sized particle range of 10–400 nm. Included in the discussion are test procedure development, factors affecting variability and comparisons between results from the tests. One test system which gives a discrete penetration for a given particle size is the TSI 8160 Automated Filter tester (updated and commercially available now as the TSI 3160) manufactured by the TSI, Inc., Shoreview, MN. Another Filter test system was developed utilizing a Scanning Mobility Particle Sizer (SMPS) to sample the particle size distributions downstream and upstream of an air Filter to obtain a continuous percent Filter penetration versus particle size curve. Filtration test results are shown for Fiberglass Filter paper of intermediate filtration efficiency. Test variables affecting the results of the TSI 8160 for NaCl and dioctyl phthalate (DOP) particles are discussed, including condensation particle counter stability and the sizing of the selected particle challenges. Filter testing using a TSI 3936 SMPS sampling upstream and downstream of a Filter is also shown with a discussion of test variables and the need for proper SMPS volume purging and Filter penetration correction procedure. For both tests, the penetration versus particle size curves for the Filter media studied follow the theoretical Brownian capture model of decreasing penetration with decreasing particle diameter down to 10 nm with no deviation. From these findings, the authors can say with reasonable confidence that there is no evidence of particle thermal rebound in the size range.