Design and evaluation of an aerodynamic focusing micro-well aerosol collector

He, Jiayang; Novosselov, Igor

doi:10.1080/02786826.2017.1329515

Cited by 23 publications

(23 citation statements)

References 27 publications

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“…The pressure drop in the cartridge was mostly due to the losses in the nozzle and the abrupt change of the flow direction at the impaction plate. The experimental pressure drop of the low-cost cartridge was compared to the results of the computational fluid dynamics study performed during the design stage [ 37 ]. The results show excellent agreement between the computational and experimental pressure drop measurements.…”

Section: Resultsmentioning

confidence: 99%

“…The results are consistent with the inertial mechanism of particle capture. The particle with the lower Stokes number, associated with the low velocities in the focusing inlet, can not reach the μ-well wall [ 37 ]. Higher sampling rates are desired to improve the capture efficiency of single-organism bioaerosols.…”

Section: Resultsmentioning

confidence: 99%

“…Miniaturization and integration of components for personal exposure monitors require the development and validation of novel aerosol collectors; it also presents an opportunity to improve analysis methods and enable rapid in-situ sample characterization. Recently, we presented a design methodology for a combined an aerodynamic focusing (AF) inlet and a μ-well trap compatible with a small sample elution volume and in-situ optical analysis [ 37 ]. Fluorescence techniques such as UV laser-induced fluorescence (UV-LIF) and Raman spectroscopy have been used for classification and quantitative determination of the aerosol particles [ 38 – 42 ].…”

Section: Introductionmentioning

confidence: 99%

“…The design of the low-cost μ-well collection cartridge is based on the methodology outlined in our previous work [ 37 ]. The low-cost collection cartridge presented here consists of two injection-molded parts (see Fig 1 ).…”

Section: Introductionmentioning

confidence: 99%

“…In contrast, if the Stokes number is near the optimum value, the particle is focused by the AF inlet and projected into the μ-well. The optimum Stokes number Stk* was selected to be 1, based on the previous studies [ 43 , 44 ] and our own work based on the CFD simulations of a number of focusing inlet geometries and flow rates [ 37 ]. Stk ~ 0.55–0.85 have been reported for aerodynamic focusing using parallel slit geometries [ 35 , 45 ].…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Evaluation of micro-well collector for capture and analysis of aerosolized Bacillus subtilis spores

He¹,

Beck²,

Kossik³

et al. 2018

PLoS ONE

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Bioaerosol sampling and identification are vital for the assessment and control of airborne pathogens, allergens, and toxins. In-situ analysis of chemical and biological particulate matter can significantly reduce the costs associated with sample preservation, transport, and analysis. The analysis of conventional filters is challenging, due to dilute samples in large collection regions. A low-cost cartridge for collection and analysis of aerosols is developed for use in epidemiological studies and personal exposure assessments. The cartridge collects aerosol samples in a micro-well which reduces particles losses due to the bounce and does not require any coating. The confined particle collection area (dwell~1.4 mm) allows reducing the elution volume for subsequent analysis. The performance of the cartridge is validated in laboratory studies using aerosolized bacterial spores (Bacillus subtilis). Colony forming unit analysis is used for bacterial spore enumeration. Cartridge collection efficiency is evaluated by comparison with the reference filters and found to be consistent with tested flow rates. Sample recovery for the pipette elution is ~80%. Due to the high density of the collected sample, the cartridge is compatible with in-situ spectroscopic analysis and sample elution into the 10–20 μl liquid volume providing a significant increase in sample concentration for subsequent analysis.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Evaluation of micro-well collector for capture and analysis of aerosolized Bacillus subtilis spores

He¹,

Beck²,

Kossik³

et al. 2018

PLoS ONE

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Design and optimization of a compact low-cost optical particle sizer

Njalsson

Novosselov

2018

Journal of Aerosol Science

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Direct measurements of time- and size-resolved particulate matter (PM) concentrations are of major importance in air quality studies and pollution monitoring. Low-cost, compact optical particle counters (OPCs), which provide accurate PM measurements independent of the particle complex index of refraction (CRI), can be useful in personal exposure monitoring and distributed sensor network studies applications. A methodology is presented for the optimization of the sensor design and operation parameter space aimed at reducing the effect of the CRI on particle sizing errors. The Monte Carlo numerical simulation, which utilizes Mie scattering calculations, is used to determine the optimal detector angle for the specific set of constraints described by the weighting coefficients. The optimized detector position (θ = 48°) has the lowest dependency on CRI over the entire particle size range of 0.5–10 microns. The near-forward, optimized, and perpendicular detector angles are compared experimentally using monodisperse 2 μm and 4 μm particles of silica, PSL, and alumina; the light collection cone angle is set at α = 20° in all experiments. The data agree well with the numerical results for all tested scenarios. Overall, the perpendicular detector location has the best precision and worst accuracy related to the CRI variations. The optimized detector position has the best accuracy for both silica and alumina particles. The use of low-cost components, such as laser diodes, photodiodes, miniaturized integrated electronics, and simple component layouts allows for the development of compact OPCs capable of accurately sizing PM. The number of sizing bins, sizing accuracy and precision, and other parameters of interest can be used as an input to an optimization algorithm.

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Behavior of ultrafine particles in electro-hydrodynamic flow induced by corona discharge

Vaddi

Guan

Novosselov

2020

Journal of Aerosol Science

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Ultrafine particle behavior in electro-hydrodynamic (EHD) flow induced by corona discharge is studied experimentally and numerically. The EHD flow serves as a primary particle aspiration/ sampling mechanism, the collector does not require any additional flow generation. Multiphysics numerical model couples the ion transport equation and the Navier-Stokes equations (NSE) to solve for the spatiotemporal distribution of electric field, charge density, and flow field, the results are compared with experimental velocity profiles at the exit. The computed velocity and flow rate data are in good agreement with the experimental data; the maximum velocity is located at the axis and ranges from 1 m/s to 4 m/s as a function of corona voltage. Experimentally evaluated particle transmission trends for ambient and NaCl nanoparticles particles in the 20 nm -150 nm range are in good agreement with the theoretical models. However, for particles in the 10 nm -20 nm size range, the transmission is lower due to the increased particle charging resulted from their exposure to the high-intensity electric field and high charge density in the EHD driven flow. These conditions yield a high probability of particles below 20 nm to acquire and hold a unit charge. The transmission is lower for smaller particle (10 nm) due to their high charge to mass ratio, and it increases as the single-charged particles grow in mass up to 20 nm, resulting in their lower electrical mobility. For particles larger than 20 nm, the electrical mobility increases again as they can acquire multiple charges. The results shed insight into interaction of nanoparticle and ions in high electrical field environment, that occur in primary EHD driven flows and in the secondary flows generated by corona discharge.

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Design and evaluation of an aerodynamic focusing micro-well aerosol collector

Cited by 23 publications

References 27 publications

Evaluation of micro-well collector for capture and analysis of aerosolized Bacillus subtilis spores

Evaluation of micro-well collector for capture and analysis of aerosolized Bacillus subtilis spores

Design and optimization of a compact low-cost optical particle sizer

Behavior of ultrafine particles in electro-hydrodynamic flow induced by corona discharge

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