scholarly journals Size Spectra of Snow Particles Measured in Wintertime Precipitation in the Pacific Northwest

2008 ◽  
Vol 65 (1) ◽  
pp. 189-205 ◽  
Author(s):  
Christopher P. Woods ◽  
Mark T. Stoelinga ◽  
John D. Locatelli
Keyword(s):  
Particle Size ◽  
Size Distribution ◽  
Pacific Northwest ◽  
Particle Diameter ◽  
Size Spectrum ◽  
Size Spectra ◽  
The Pacific ◽  
Single Moment ◽  
Research Aircraft ◽  
The University

Abstract Particle size spectra collected by the University of Washington’s Convair-580 research aircraft at a variety of altitudes and temperatures in winter frontal and orographic precipitation systems during the Improvement of Microphysical Parameterization through Observational Verification Experiment (IMPROVE) are analyzed in this study. The particle size spectra generally appeared to conform to an exponential size distribution, with well-correlated linear fits between the log of the number concentration and particle diameter. When the particle size spectra were grouped according to the habit composition as determined from airborne imagery, significantly improved correlations between the size spectrum parameters and temperature were obtained. This result could potentially be exploited for specifying the size distribution in a single-moment bulk microphysical scheme, if particle habit is predicted by the scheme. Analyses of “spectral trajectories” suggest that the rime-splintering process was likely responsible for the presence of needle and column habit types and the positive shift in both N0s and λs at temperatures warmer than −10°C.

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

2013 ◽  
Vol 6 (3) ◽  
pp. 4123-4152 ◽  
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.

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

2013 ◽  
Vol 6 (9) ◽  
pp. 2349-2358 ◽  
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 aggregates of spheres, a PCASP-derived particle size and a sphere-equivalent particle size agree within uncertainty dictated by the PCASP's sizing resolution. Robust determinations 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.

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

2001 ◽  
Vol 43 (5) ◽  
pp. 103-110 ◽  
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.

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

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.

scholarly journals Dietary and Genetic Effects on LDL Size Measures in Baboons

1996 ◽  
Vol 16 (12) ◽  
pp. 1448-1453 ◽  
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.

Species body size distribution patterns of marine benthic macrofauna assemblages from contrasting sediment types

1999 ◽  
Vol 79 (5) ◽  
pp. 793-801 ◽  
Author(s):  
David M. Parry ◽  
Michael A. Kendall ◽  
Ashley A. Rowden ◽  
Stephen Widdicombe
Keyword(s):  
Body Size ◽  
Size Distribution ◽  
Species Turnover ◽  
Distribution Patterns ◽  
Benthic Macrofauna ◽  
Size Spectrum ◽  
Size Spectra ◽  
Β Diversity ◽  
Sediment Types ◽  
Geometric Size

Species body size spectra have been constructed for macrofauna assemblages from four sites with contrasting sediment granulometry and heterogeneity in and around Plymouth Sound. The number of species and species turnover (β diversity) were higher on coarse sediment. While the fauna were distinct between sites, the median geometric size-class was conservative (class 14; 0.153–0.305 mg dry blotted weight). Only one site had significantly lower heterogeneity within the species size spectrum, yet this was the most heterogeneous sediment. As such, we were unable to reject the null hypothesis that species body size distribution patterns are conservative despite differences in sediment granulometry and heterogeneity.

scholarly journals Keeping the World in Balance - Music Therapy in a Ritual Context

2002 ◽  
Vol 2 (2) ◽  
Author(s):  
Carolyn Kenny
Keyword(s):  
Native American ◽  
Pacific Northwest ◽  
Field Studies ◽  
Northwest Coast ◽  
University Of British Columbia ◽  
Pacific Northwest Coast ◽  
The Arts ◽  
The People ◽  
The Pacific ◽  
The University

I asked Walker why the Spirit Dances were held in the Winter. He told me that in the Winter the Earth's reserves are low, so the people must dance to create energy for the Earth during the Winter months. At the time I was a graduate student in anthropology at the University of British Columbia doing my field studies in the Salish Guardian Spirit Dance Ceremonials of the Pacific Northwest Coast (Kenny, 1982). Walker didn't seem to care as much about the academics as he cared about the fact that I was Native American myself. And he wanted to support my learning about healing and the arts. The Winter Dances, as the Salish people call them, are known for healing young adults in Pacific Northwest Coast Native societies who are not able to be cured by standard medical and psychological treatments (Kenny, 1982; Jilek, 1972).

Effect Analysis of Various Gradient Particle Size Distribution on Electrical Performance of Anode-Supported SOFCs With Gradient Anode

2020 ◽  
Vol 142 (7) ◽  
Author(s):  
Pei Fu ◽  
Yuansheng Song ◽  
Jian Yang ◽  
Qiuwang Wang
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Current Density ◽  
Molar Fraction ◽  
Particle Diameter ◽  
Electrical Performance ◽  
Diameter Distribution ◽  
Functional Layer ◽  
Layer 2

Abstract Gradient particle size anode has shown great potential in improving the electrical performance of anode-supported solid oxide fuel cells (SOFCs). In this study, a 3D comprehensive model is established to study the effect of various gradient particle size distribution on the cell electrical performance for the anode microstructure optimization. The effect of homogeneous particle size on the cell performance is studied first. The maximum current density of homogeneous anode SOFC is obtained for the comparison with the electrical performance of gradient anode SOFC. Then the effect of various gradient particle size distribution on the cell molar fraction, polarization losses, and electronic current density distribution is analyzed and discussed in detail. Results show that increasing the particle diameter gradient can effectively reduce the anodic concentration overpotential. Decreasing the particle diameter of anode functional layer 2 is beneficial for reducing the activation and ohmic overpotentials. On these bases, the comprehensive electrical performance of SOFCs with gradient particle size anode and homogeneous anode is compared to highlight the optimal gradient particle diameter distribution. In the studied cases of this work, the gradient particle diameter of 0.7 μm, 0.4 μm, and 0.1 μm at anode support layer (ASL), anode functional layer 1, and anode functional layer 2 (case 3) is the optimal particle size distribution.

A Personal Journey toward Teaching Success

1994 ◽  
Vol 44 (2) ◽  
pp. 69-72
Author(s):  
Margaret Pressley ◽  
Rebecca Henry
Keyword(s):  
Music Education ◽  
Pacific Northwest ◽  
Music Teachers ◽  
Washington State ◽  
Indiana University ◽  
Violin Pedagogy ◽  
Music Festival ◽  
The Pacific ◽  
The University ◽  
Washington University

Margaret Pressley is well known in the Pacific Northwest as a teacher of gifted pre-college violinists and as an enabler of conservatory-level music education in Seattle. Attending the University of Washington, with a major in violin performance, she chose a career in violin pedagogy, which has spanned 30 years. Pressley has built a highly successful class of continuously prize-winning students, who are eagerly sought by conservatories. She is the founder and director of the Pressley Conservatory of Music in Seattle. Pressley is a lecturer at Western Washington University and is also on the faculty of the Indiana University Summer String Academy, a member of the advisory board of the Seattle Young Artist Music Festival and the National Music Teachers Association Competition String Repertoire Committee, and string chair for the Washington State Music Teachers Association. She was named ASTA's 1994 Washington State Studio Teacher of the Year.

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