A Circumferential Slot In-Line Virtual Impactor

Seshadri, S.K.; Hari, Sridhar; Hu, Shishan; McFarland, Andrew R.

doi:10.1080/02786820701787928

Cited by 6 publications

(5 citation statements)

References 18 publications

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“…Also, a more dense mesh could be added to the separation zone by choosing a 2-D model. Checking the results of 2-D using 3-D simulation might add insight to this difference in future work Seshadri et al 2008). In addition, the outlet for the vapor flow had the shape of circumferential slit in the 2-D axisymmetric model.…”

Section: Discussionmentioning

confidence: 97%

Optimization of the Design of a Semivolatile Aerosol Dichotomous Sampler

Kim

Raynor

2010

Aerosol Science and Technology

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This article reports the results of an optimization procedure for a semivolatile aerosol dichotomous sampler (SADS) and experimental confirmation of the instrument's performance with an optimized sampler. Using numerical model results, the relationships between four major design and operating parameters significantly affecting the performance of the SADS and four performance parameters were expressed in log polynomial equations. Utilizing an optimization procedure, values for the major parameters giving the best performance were determined and used as the base model for optimizing minor parameters. Five minor parameters were then investigated for their possible contribution to better performance of the SADS. The optimal dimensions found were as follows: the diameter ratio between the nozzle and the collection probe was 1.30 and the length ratio of the distance between the nozzle and the collection probe divided by the nozzle diameter was 0.6. Among the minor parameters, only the entrance angle of the nozzle made noticeable improvement at 45 • . Experimental tests confirmed that the performance of the new sampler was improved although not as much as expected from the numerical simulation.

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Section: Discussionmentioning

confidence: 97%

Optimization of the Design of a Semivolatile Aerosol Dichotomous Sampler

Kim

Raynor

2010

Aerosol Science and Technology

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“…Particle losses in the acceleration region may be reduced by aerosol focusing techniques. 34 In the case of solid particles, some of the deposited particles were bounced from the impaction zone, leading to distortion of the collection efficiency curve. 35 To prevent this phenomenon, some researchers have coated the impaction zone with highly viscous liquids (e.g., silicon oil, grease).…”

Section: Resultsmentioning

confidence: 99%

Real-time detection of an airborne microorganism using inertial impaction and mini-fluorescent microscopy

et al. 2014

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To achieve successful real-time detection of airborne pathogenic microorganisms, the problem must be considered in terms of their physical size and biological characteristics. We developed an airborne microorganism detection chip to realize the detection of microorganisms, ensuring compactness, sensitivity, cost-efficiency, and portability, using three key components: an inertial impaction system, a cartridgetype impaction plate, and a mini-fluorescent microscope. The inertial impaction system was used to separate microorganisms in terms of their aerodynamic particle size, and was fabricated with three impaction stages. Numerical analysis was performed to design the system; the calculated cutoff diameter at each impaction stage was 2.02 (first stage), 0.88 (second stage), and 0.54 μm (third stage). The measured cutoff diameters were 2.24, 0.91, and 0.49 μm, respectively. A cartridge-type impaction plate was used, composed of molded polydimethylsiloxane (PDMS) and an actual impaction region made of a SYBR green I dye-stained agar plate. A mini-fluorescent microscope was used to distinguish microbes from non-biological particles. Images of the microorganisms deposited at the impaction zone were obtained via mini-fluorescent microscopy, and fluorescent intensities of the images were calculated using in-house image-processing software. The results showed that the developed system successfully identified aerosolized biological particles from non-biological particles in real time.

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“…The oil surface should be best suited for use in the IRI where modest dust loadings are anticipated. If anticipated dust loadings were to be high, an inlet fitted with an in-line virtual impactor (Seshadri et al 2008) should be considered.…”

Section: Retention Of Dry Dusts On Different Collection Surfacesmentioning

confidence: 99%

“…(US National Research Council 2005). Cyclones and real impactors have an advantage in simplicity of design, but in dusty environments, there can be solid particle carryover (Dzubay et al 1976;Markowski 1984), whereas virtual impactors (Romay et al 2002;Seshadri et al 2008) allow a much greater mass of dust to be sampled without solid particle carryover. However, virtual impactors are more complex in design, and they require additional flow components to transport the large particles from the fractionation zone.…”

Section: Introductionmentioning

confidence: 99%

In-Line Impactor Inlet for Bioaerosol Sampling

McFarland

Baehl

et al. 2011

Aerosol Science and Technology

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The proof of concept of a novel in-line real impactor (IRI) for preseparation of large particles in ambient inlets was demonstrated with a 1,250 L/min design. Numerical simulations predicted a cutpoint Stokes number 0.3 for a ratio of jet-to-plate spacing to jet width (S/W) of 2.0 and 0.5 for a ratio of 4.0. This variation in cutpoint Stokes number allows minor adjustments in cutpoint for a given device size. Experimental benchmark tests support the prediction of a shift in cutpoint with S/W. Inlet systems with flow rates of 100 and 400 L/min were designed by Stokes scaling of the 1,250 L/min IRI and integrating the lower flow devices with an existing inlet aspiration section and an insect screen. Experiments with the inlet system were conducted in a wind tunnel with particles from 3 to 20 µm aerodynamic diameter (AD) and wind speeds of 2, 8, and 24 km/h. A nominal cutpoint of approximately 11 µm AD was selected to accommodate bioaerosol sampling needs, and the wind tunnel results showed the average cutpoints of the 100 and 400 L/min inlet systems at the three wind speeds were 11.2 and 11.6 µm AD, respectively. Stand-alone tests with the 100 and 400 L/min IRIs were conducted where dry dusts (Arizona road dust/fine and coarse) were impacted on three types of collection surfaces (dry, grease-coated, and oil-soaked porous surfaces) to characterize solid particle carryover. The oil-soaked porous media allowed the least carryover of large solid particles.

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A Circumferential Slot In-Line Virtual Impactor

Cited by 6 publications

References 18 publications

Optimization of the Design of a Semivolatile Aerosol Dichotomous Sampler

Optimization of the Design of a Semivolatile Aerosol Dichotomous Sampler

Real-time detection of an airborne microorganism using inertial impaction and mini-fluorescent microscopy

In-Line Impactor Inlet for Bioaerosol Sampling

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