Field Comparison of TSI DustTrak versus TEOM in Two Poultry Houses

2018 ◽  
Vol 61 (2) ◽  
pp. 653-660
Author(s):  
Xufei Yang ◽  
Chen Zhang ◽  
Hong Li
Keyword(s):  
Light Scattering ◽  
Correction Factor ◽  
Mass Concentration ◽  
Field Performance ◽  
Mie Scattering ◽  
Correction Factors ◽  
Poultry Houses ◽  
Equivalent Method ◽  
Tapered Element Oscillating Microbalance ◽  
Broiler House

Abstract. The TSI DustTrak monitor has been used for particulate matter (PM) monitoring at various animal facilities. The instrument determines PM concentrations based on the principle of light scattering. Several assumptions (e.g., particle size, refractive index, and density) are imposed during the calibration process; however, they may not apply to PM emanating from agricultural settings. In this study, PM10 monitoring was conducted at a broiler house and a layer breeding house with four collocated instruments: three DustTrak monitors and one tapered element oscillating microbalance (TEOM). Being a federal equivalent method (FEM) for PM10 monitoring, TEOM was selected here as a transfer standard for assessing the field performance of DustTrak. Results revealed a good linearity between DustTrak and TEOM PM10 readings (R2 =0.92 and 0.85 in the broiler and layer breeding houses, respectively). However, DustTrak significantly underestimated PM10 concentrations in both houses. To correct for the monitoring bias by DustTrak, an average correction factor was derived from correlation analysis that characterized the ratio of DustTrak’s PM10 response to TEOM’s. The factor was calculated as 0.267 for the broiler house and 0.244 for the layer breeding house. Mie scattering simulation was performed to further verify the derived correction factors. A factor of 0.204 was estimated from the simulation, and it accorded well with experimental results. A dependence of the correction factor on PM10 concentration was noted in both poultry houses, indicating the feasibility of developing a concentration-dependent correction factor for future monitoring efforts. Such a relationship could also be explained by Mie scattering. This study is expected to facilitate a better understanding of the limitations and perspectives of the TSI DustTrak and other light scattering PM monitors for agricultural air quality research. Keywords: DustTrak, Mass concentration, Mie scattering, PM10, Poultry, TEOM.

scholarly journals Predicted Light Scattering from Particles Observed in Human Age-Related Nuclear Cataracts Using Mie Scattering Theory

2007 ◽  
Vol 48 (1) ◽  
pp. 303 ◽  
Author(s):  
M. Joseph Costello ◽  
So¨nke Johnsen ◽  
Kurt O. Gilliland ◽  
Christopher D. Freel ◽  
W. Craig Fowler
Keyword(s):  
Light Scattering ◽  
Scattering Theory ◽  
Mie Scattering ◽  
Age Related ◽  
Mie Scattering Theory

scholarly journals Effect of aerosol composition on the performance of low-cost optical particle counter correction factors

2019 ◽  
Author(s):  
Leigh R. Crilley ◽  
Ajit Singh ◽  
Louisa J. Kramer ◽  
Marvin D. Shaw ◽  
Mohammed S. Alam ◽  
...  
Keyword(s):  
Correction Factor ◽  
Low Cost ◽  
Particle Mass ◽  
Ambient Atmosphere ◽  
Correction Factors ◽  
Aerosol Composition ◽  
Kohler Theory ◽  
Suitable Reference ◽  
Aerosol Hygroscopicity ◽  
Mass Concentrations

Abstract. There is considerable interest in using low-cost optical particle counters (OPC) to supplement existing routine air quality networks that monitor particle mass concentrations. In order to do this, low-cost OPC data needs to be cross-comparable with particle mass reference instrumentation, and as yet, there is no widely agreed methodology. Aerosol hygroscopicity is known to be a key parameter to consider when correcting particle mass concentrations derived from a low-cost OPC, particularly at high ambient Relative Humidity (RH). Correction factors have been developed that apply κ-Köhler theory to correct for the influence of water uptake by hygroscopic aerosols. We have used datasets of co-located reference particle measurements and a low-cost OPC (OPC-N2, Alphasense), collected in four cities in three continents, to explore the performance of this correction factor. We report evidence that the elevated particle mass concentrations, reported by the low-cost OPC relative to reference instrumentation, is due to bulk aerosol hygroscopicity under different RH conditions, which is determined by aerosol composition and in particular the levels of hygroscopic aerosols (sulphate and nitrate). We exploit measurements made in volcanic plumes in Nicaragua, that are predominantly composed of sulphate aerosol, as a natural experiment to demonstrate this behaviour in the ambient atmosphere, with the observed humidogram closely resembling the calculated pure sulphuric acid humidogram. The results indicate that the particle mass concentrations derived from low-cost OPCs during periods of high RH (> 60 %) need to be corrected for aerosol hygroscopic growth. We employed a correction factor based on κ-Köhler theory and observed corrected OPC-N2 PM2.5 mass concentrations to be within 33 % of reference measurements at all sites. The results indicated that an in situ derived κ (using suitable reference instrumentation) would lead to the most accurate correction relative to co-located reference instruments. Applying literature κ in the correction factor also resulted in improved performance of OPC-N2, to be within 50 % of reference. Therefore, for areas where suitable reference instrumentation for developing a local correction factor is lacking, using a literature κ value can result in a reasonable correction. For locations with low levels of hygroscopic aerosols and RH, a simple calibration against gravimetric measurements (using suitable reference instrumentation) would likely be sufficient. Whilst this study generated correction factors specific for the Alphasense OPC-N2 sensor, the calibration methodology developed is likely amenable to other low cost PM sensors.

Comparison Between Light Scattering and Gravimetric Devices for Sampling PM10 Mass Concentration in Livestock Houses

2012 ◽  
Author(s):  
María Cambra-López ◽  
Albert Winkel ◽  
Julio Mosquera ◽  
Nico W. M Ogink ◽  
André J. A Aarnink
Keyword(s):  
Light Scattering ◽  
Mass Concentration ◽  
Pm10 Mass

Uncertainty of Dust Mass Concentration Measurement

2014 ◽  
Vol 611 ◽  
pp. 511-518
Author(s):  
Miroslav Dovica ◽  
Vladislav Maxim ◽  
Michal Kelemen ◽  
Tatiana Kelemenová ◽  
Ivan Virgala ◽  
...  
Keyword(s):  
Light Scattering ◽  
Mass Concentration ◽  
Concentration Measurement ◽  
Working Environment ◽  
Respirable Dust ◽  
Respirable Fraction ◽  
Dust Mass ◽  
Dust Fraction

Paper deals with dust mass concentration measurement in working environment. The measurement is focused to respirable dust fraction, which is dangerous for people. Light scattering principle of dust mass concentration measurement is used for this purpose. Also cyclone as mechanical way of separation of respirable fraction can be used for this purpose. Next problem is determination of uncertainty of this measurement.

Strain Control Correction for Fatigue Testing in LWR Environments

2020 ◽  
Author(s):  
Marc Vankeerberghen ◽  
Alec Mclennan ◽  
Igor Simonovski ◽  
German Barrera ◽  
Sergio Arrieta Gomez ◽  
...  
Keyword(s):  
Correction Factor ◽  
Fatigue Testing ◽  
Crack Nucleation ◽  
Gauge Length ◽  
Correction Factors ◽  
Element Analysis ◽  
Cross Sectional ◽  
Strain Control ◽  
Specimen Diameter ◽  
Contact Points

Abstract During strain-controlled fatigue testing of solid bar specimens in a LWR environment within an autoclave, it is common practice to avoid the use of a gauge length extensometer to remove the risk of preferential corrosion and early crack nucleation from the extensometer contact points. Instead, displacement- or strain-control is applied at the specimen shoulders, where the cross-sectional area of the specimen is higher and so surface stress levels are lower. A correction factor is applied to the control waveform at the shoulder in order to achieve approximately the target waveform within the specimen gauge length. The correction factor is generally derived from trials conducted in air by cycling samples with extensometers attached to both the shoulders and the gauge length; typically, the average ratio between the strains or the ratio at half-life in these locations is taken to be the correction factor used in testing. These calibration trials may be supplemented by Finite Element Analysis modelling of the specimens, or by other analysis of results from the calibration trials. Within the INCEFA+ collaborative fatigue research project, a total of six organizations are performing fatigue testing in LWR environments within an autoclave. Of these, one organization is performing tests in an autoclave using extensometers attached to both the specimen shoulders and the specimen gauge length. Therefore the INCEFA+ project provides a unique opportunity to compile and compare methods of shoulder control correction used by different organizations when fatigue testing in LWR environments. This paper presents the different methods of correcting shoulder control waveforms used by partners within the INCEFA+ project, compares the correction factors used, and assesses sensitivities of the correction factor to parameters such as specimen diameter. In addition, correction factors for air and PWR environments are compared. Conclusions are drawn and recommendations made for future fatigue testing in LWR environments within autoclaves.

scholarly journals Experimental Study of the Effect of Dense Spray on Drop Size Measurement by Light Scattering Technology

1990 ◽  
Author(s):  
Ju Shan Chin ◽  
Wei Ming Li ◽  
Yan Zhang
Keyword(s):  
Experimental Data ◽  
Light Scattering ◽  
Correction Factor ◽  
Drop Size ◽  
Empirical Equation ◽  
Size Measurement ◽  
Sauter Mean Diameter ◽  
Internal Mixing ◽  
Mean Diameter ◽  
Factor Data

The effect of dense spray on drop size measurement by light scattering technology was studied by using Malvern instrument with five duplicated internal mixing airblast atomizers aligned in line with laser beam. The correction factor data for multiple scattering were obtained. By regression analysis, an empirical equation was obtained which correlated the correction factor as a function of obscuration (OBS), Sauter mean diameter under dilute spray condition SMD0. and drop size distribution parameter for Rosin–Rammler distribution under dilute spray conditions N0. The experimental data showed definitely that the correction factor is not only a function of OBS, SMD0, as proposed by Dodge, but also is a function of N0. The correlation fits the experimental data very well, and can be used for practical purposes to correct the data from Malvern drop sizer at high obscuration conditions.

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