The Size Distribution of Particles Released by Garments During Helmke Drum Tests

The Helmke Drum test method to measure particles shed from garments was developed twenty years ago. It consists of a tumbling drum containing the garment under test. A probe connected to an optical particle counter is used to transport the sample from the drum. Dilution air is drawn into the drum from the surrounding cleanroom. The optical particle counters at the time of development were limited in resolution to 0.5 μm diameter. This particle size requirement is still in the current version of IEST-RP-CC003.2, Garment Systems Considerations for Cleanrooms and Other Controlled Environments. A question was raised in the current IEST Contamination Control Working Group 003, "Garment System Considerations for Cleanrooms and Other Controlled Environments," as to whether the method could be extended to smaller particle diameters. The method would benefit by including measurements of smaller particle diameters for two reasons: the higher particle counts expected for sub-0.5 μm particles might improve the statistics of the method; and there is a growing need to consider contamination by ultra-fine particles during the manufacture of high performance products. We hypothesized that the size distribution of particles released by garments follows a power law similar to that for cleanroom classes. The form of the power law distribution is N(d) = Ad(-B), where N(d) is the cumulative concentration greater to or equal to d, d is the particle diameter, and A and B are statistically determined coefficients. The size distributions from a number of Helmke Drum tests were analyzed and were found to be highly correlated to the power law equation. However, the slopes appeared to vary depending on the type of garment tested. These results support including guidance with respect to particle size in the Helmke Drum test section in the upcoming revision of IEST-RP-CC003.2.

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The effects of particle size distribution on the settleability of CSOs pollutants

Water Science & Technology ◽

10.2166/wst.2001.0261 ◽

2001 ◽

Vol 43 (5) ◽

pp. 103-110 ◽

Cited By ~ 3

Author(s):

E. B. Shin ◽

H. S. Yoon ◽

Y. D. Lee ◽

Y. S. Pae ◽

S. W. Hong ◽

...

Keyword(s):

Particle Size ◽

Particle Size Distribution ◽

Size Distribution ◽

Power Law ◽

Particle Diameter ◽

Size Spectrum ◽

Average Particle ◽

Factors Affecting ◽

Major Factors ◽

Power Law Distributions

Over the past decades, flocculation and/or sedimentation processes have been adopted to remove pollutants from CSOs. It has been learned that major factors affecting settlement of pollutants are the particle size distribution, their settling velocities and their specific gravity. It is, therefore, a good idea to analyze the particle size distribution and settleability of CSOs pollutants in order to develop details in designing a process. Discussed in this study are pollutant characteristics of CSOs such as particle size distribution and settleability of pollutants. The power law function is applied and is found to be an effective and reliable index for expressing the particle size distribution of pollutants in CSOs. Based on the particle size spectrum analysis, the tendency toward settling and simultaneous flocculation-settling phenomenon of CSOs pollutants is described. Based on the regression analysis it is observed that the derived constants of curves representing settling velocity profile are proportional to the initial concentration of particles and to the β-values of power law distributions. It is also revealed that the simultaneous flocculation-settling processes are effectively described by the changes of the average particle diameter and of the β-values of power law distributions.

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Fine Dust Creation during Hardwood Machine Sanding

Applied Sciences ◽

10.3390/app11146602 ◽

2021 ◽

Vol 11 (14) ◽

pp. 6602

Author(s):

Marta Pędzik ◽

Tomasz Rogoziński ◽

Jerzy Majka ◽

Kinga Stuper-Szablewska ◽

Petar Antov ◽

...

Keyword(s):

Particle Size ◽

Particle Size Distribution ◽

Size Distribution ◽

Fine Particles ◽

Health And Safety ◽

Particle Diameter ◽

Wood Dust ◽

Sieve Analysis ◽

Pedunculate Oak ◽

Hardwood Species

Wood dust generated during woodworking—particularly from hardwood species during sanding—poses a health and safety hazard to workers in the wood industry. This study aimed to determine the particle-size distribution of selected hardwood species and the content of fine particles in dust created during machine sanding, which pose the highest health and safety hazards in the woodworking industry. Six hardwood species were studied: black alder, European ash, common walnut, pedunculate oak, hornbeam, and European beech. The sieve analysis method was used to determine the particle-size distribution and article mean arithmetic particle diameter, and laser diffraction analysis was used to determine the finest particle content. Two size ranges were assumed: <2.5 μm and <10 μm. Beech dust had the smallest mean particle diameter. Dust from wood species used in the test had similar contents of fine fractions of particles. The average content of particles smaller than 2.5 µm in wood dust from the tested hardwood species did not exceed 1.9%. In terms of occupational exposure to wood dust, machine sanding conditions of hardwoods should be properly adjusted to limit the formation of large amounts of dust.

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Global variability of phytoplankton functional types from space: assessment via the particle size distribution

Biogeosciences Discussions ◽

10.5194/bgd-7-4295-2010 ◽

2010 ◽

Vol 7 (3) ◽

pp. 4295-4340 ◽

Cited By ~ 10

Author(s):

T. S. Kostadinov ◽

D. A. Siegel ◽

S. Maritorena

Keyword(s):

Particle Size ◽

Particle Size Distribution ◽

Size Distribution ◽

Power Law ◽

Seasonal Succession ◽

Remote Sensing Data ◽

Good Correspondence ◽

Size Classes ◽

Functional Types ◽

Phytoplankton Size

Abstract. A new method of retrieving the parameters of a power-law particle size distribution (PSD) from ocean color remote sensing data was used to assess the global distribution and dynamics of phytoplankton functional types (PFT's). The method retrieves the power-law slope, ξ, and the abundance at a reference diameter, N0, based upon the shape and magnitude of the particulate backscattering coefficient spectrum. Relating the PSD to PFT's on global scales assumes that the open ocean particulate assemblage is biogenic. The retrieved PSD's can be integrated to define three size-based PFT's by the percent volume concentration contribution of three phytoplankton size classes – picoplankton (0.5–2 μm in equivalent spherical diameter), nanoplankton (2–20 μm) and microplankton (20–50 μm). Validation with in-situ HPLC diagnostic pigments results in satisfactory match-ups for the pico- and micro-phytoplankton size classes. Global climatologies derived from SeaWiFS monthly data reveal PFT and particle abundance spatial patterns that are consistent with current understanding. Oligotrophic gyres are characterized by lower particle abundance and higher contribution by picoplankton-sized particles than transitional or eutrophic regions. Seasonal succession patterns for size-based PFT's reveal good correspondence between increasing chl and percent contribution by microplankton, as well as increasing particle abundance. Long-term trends in particle abundances are generally inconclusive yet are well correlated with the MEI index indicating increased oligotrophy (i.e. lower particle abundance and increased contribution of picoplankton-sized particles) during the warm phase of an El Niño event. This work demonstrates the utility and future potential of assessing phytoplankton functional types using remote characterization of the particle size distribution.

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Digital microscopic image application (DMIA), an automatic method for particle size distribution analysis in waste activated sludge

Water Science & Technology ◽

10.2166/wst.2021.102 ◽

2021 ◽

Author(s):

S. Cazares ◽

J. A. Barrios ◽

C. Maya ◽

G. Velásquez ◽

M. Pérez ◽

...

Keyword(s):

Particle Size ◽

Particle Size Distribution ◽

Activated Sludge ◽

Size Distribution ◽

Particle Diameter ◽

Diffraction Method ◽

Laser Diffraction ◽

Waste Activated Sludge ◽

Equivalent Diameter ◽

Distribution Analysis

Abstract An important physical property in environmental samples is particle size distribution. Several processes exist to measure particle diameter, including change in electrical resistance, blocking of light, the fractionation of field flow and laser diffraction (these being the most commonly used). However, their use requires expensive and complex equipment. Therefore, a Digital Microscopic Imaging Application (DMIA) method was developed adapting the algorithms used in the Helminth Egg Automatic Detector (HEAD) software coupled with a Neural Network (NN) and Bayesian algorithms. This allowed the determination of particle size distribution in samples of waste activated sludge (WAS), recirculated sludge (RCS), and pretreated sludge (PTS). The recirculation and electro-oxidation pre-treatment processes showed an effect in increasing the degree of solubilization (DS), decreasing particle size and breakage factor with ranges between 44.29%, and 31.89%. Together with a final NN calibration process, it was possible to compare results. For example, the 90th percentile of Equivalent Diameter (ED) value obtained by the DMIA with the corresponding result for the laser diffraction method. DMIA values: 228.76 μm (WAS), 111.18 μm (RCS), and 84.45 μm (PTS). DMIA processing has advantages in terms of reducing complexity, cost and time, and offers an alternative to the laser diffraction method.

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Calibration of the passive cavity aerosol spectrometer probe for airborne determination of the size distribution

Atmospheric Measurement Techniques Discussions ◽

10.5194/amtd-6-4123-2013 ◽

2013 ◽

Vol 6 (3) ◽

pp. 4123-4152 ◽

Cited By ~ 3

Author(s):

Y. Cai ◽

J. R. Snider ◽

P. Wechsler

Keyword(s):

Particle Size ◽

Size Distribution ◽

Scattered Light ◽

Particle Diameter ◽

Polystyrene Latex ◽

Calibration Methods ◽

Research Aircraft ◽

Amplifier Gain ◽

Gain Stage

Abstract. This work describes calibration methods for the particle sizing and particle concentration systems of the passive cavity aerosol spectrometer probe (PCASP). Laboratory calibrations conducted over six years, in support of the deployment of a PCASP on a cloud physics research aircraft, are analyzed. Instead of using the many calibration sizes recommended by the PCASP manufacturer, a relationship between particle diameter and scattered light intensity is established using three sizes of mobility-selected polystyrene latex particles, one for each amplifier gain stage. In addition, studies of two factors influencing the PCASP's determination of the particle size distribution – amplifier baseline and particle shape – are conducted. It is shown that the PCASP-derived size distribution is sensitive to adjustments of the sizing system's baseline voltage, and that for aggregate spheres, a PCASP-derived particle size and a sphere-equivalent particle size agree within uncertainty dictated by the PCASP's sizing resolution. Robust determination of aerosol concentration, and size distribution, also require calibration of the PCASP's aerosol flowrate sensor. Sensor calibrations, calibration drift, and the sensor's non-linear response are documented.

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The Role of Particle Size Distribution in the Performance and Modelling of Filtration

Water Science & Technology ◽

10.2166/wst.1993.0199 ◽

1993 ◽

Vol 27 (10) ◽

pp. 19-34 ◽

Cited By ~ 9

Author(s):

R. I. Mackie ◽

R. Bai

Keyword(s):

Particle Size ◽

Particle Size Distribution ◽

Size Distribution ◽

Fine Particles ◽

Coarse Particles ◽

Large Particles

The paper examines the importance of size distribution of the influent suspension on the performance of deep bed filters and its significance with regard to modelling. Experiments were carried out under a variety of conditions using suspensions which were identical in every respect apart from their size distribution. The results indicate that the presence of coarse particles does increase the removal of fine particles. Deposition of fine particles leads to a greater headloss than deposition of large particles. Changes in size distribution with time and depth play an important role in determining the behaviour of a filter, and models of both removal and headloss development must take account of this.

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Dietary and Genetic Effects on LDL Size Measures in Baboons

Arteriosclerosis Thrombosis and Vascular Biology ◽

10.1161/01.atv.16.12.1448 ◽

1996 ◽

Vol 16 (12) ◽

pp. 1448-1453 ◽

Cited By ~ 14

Author(s):

Amareshwar T.K. Singh ◽

David L. Rainwater ◽

Candace M. Kammerer ◽

R. Mark Sharp ◽

Mahmood Poushesh ◽

...

Keyword(s):

Particle Size ◽

Size Distribution ◽

Dietary Fat ◽

Group Membership ◽

Particle Diameter ◽

Hdl Cholesterol ◽

Genetic Effects ◽

Ldl Size ◽

Sire Group ◽

Two Measures

Genetic and dietary effects on LDL phenotypes, including predominant LDL particle diameter, LDL size distribution, and non–HDL cholesterol and apoB concentrations, were investigated in 150 pedigreed baboons that are members of 19 sire groups. Baboons were fed a sequence of three defined diets differing in levels of fat and cholesterol. Increasing dietary fat had relatively little effect on two measures of LDL particle size. However, increasing the level of cholesterol in the diet resulted in larger increases of the predominant LDL particle diameters and in the proportion of stain on LDLs >28 nm. As expected, apoB and non–HDL cholesterol concentrations significantly increased when levels of dietary fat and cholesterol were increased. Correlations among the LDL phenotypes suggested that several different aspects of the LDL phenotype were captured by the four LDL measures across the three diets. Genetic effects indicated by sire group membership were significant both for expression of the LDL phenotypes and for response to changes in diet.

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Performance Characteristics of Centrifugal Slurry Pumps

Journal of Fluids Engineering ◽

10.1115/1.1366322 ◽

2001 ◽

Vol 123 (2) ◽

pp. 271-280 ◽

Cited By ~ 37

Author(s):

B. K. Gandhi ◽

S. N. Singh ◽

V. Seshadri

Keyword(s):

Particle Size ◽

Particle Size Distribution ◽

Size Distribution ◽

Fine Particles ◽

Performance Characteristics ◽

Solid Concentration ◽

Solid Materials ◽

Power Characteristics ◽

Additional Losses

The performance of two centrifugal slurry pumps has been reported for three solid materials having different particle size distribution (PSD) in terms of head, capacity, and power characteristics. The results have shown that the values of head and efficiency ratios are not only dependent on solid concentration but are also affected by PSD of the solids and properties of the slurry. The addition of fine particles in the slurry of coarser material leads to reduction in the additional losses that occur in the pumps due to the presence of solids. It is also observed that with the increase in the pump size, the additional losses due to presence of solids reduce.

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