scholarly journals Normalized Hail Particle Size Distributions from the T-28 Storm-Penetrating Aircraft

2019 ◽  
Vol 58 (2) ◽  
pp. 231-245 ◽  
Author(s):  
Paul R. Field ◽  
Andrew J. Heymsfield ◽  
Andrew G. Detwiler ◽  
Jonathan M. Wilkinson
Keyword(s):  
Particle Size ◽  
Water Content ◽  
Size Distribution ◽  
Optical Probe ◽  
Particle Size Distributions ◽  
South Dakota School ◽  
Significant Damage ◽  
In Situ Observations ◽  
Cloud Evolution

AbstractHail and graupel are linked to lightning production and are important components of cloud evolution. Hail can also cause significant damage when it precipitates to the surface. The accurate prediction of the amount and location of hail and graupel and the effects on the other hydrometeor species depends upon the size distribution assumed. Here, we use ~310 km of in situ observations from flights of the South Dakota School of Mines and Technology T-28 storm-penetrating aircraft to constrain the representation of the particle size distribution (PSD) of hail. The maximum ~1-km hail water content encountered was 9 g m−3. Optical probe PSD measurements are normalized using two-moment normalization relations to obtain an underlying exponential shape. By linking the two normalizing moments through a power law, a parameterization of the hail PSD is provided based on the hail water content only. Preliminary numerical weather simulations indicate that the new parameterization produces increased radar reflectivity relative to commonly used PSD representations.

The Impact of Facies Variability within the Harwich Formation on Ground Engineering in the London Area, UK.

2021 ◽  
pp. qjegh2020-136
Author(s):  
Justyna Edgar ◽  
Richard C. Ghail ◽  
James Lawrence ◽  
Jacqueline Skipper ◽  
Philippa J. Mason
Keyword(s):  
Particle Size ◽  
Fault Zones ◽  
Size Distributions ◽  
Infrastructure Projects ◽  
Particle Size Distributions ◽  
Facies Model ◽  
In Situ Observations ◽  
The Impact

The Eocene Harwich Formation, underlying the Greater London (UK) area, presents many construction problems for design and location of tunnels, pipelines, and other engineering infrastructure projects. Variable deposits make up the sequence of the Harwich Formation. These include cemented fault zones, hard grounds, loose gravel and sand that, when unexpectedly encountered, can cause construction delays and increase costs. Here, we interpret borehole cores and logs, in-situ observations coupled with borehole derived samples, and calculate particle-size distributions to develop a general facies model that accounts for the lithological distribution within the Harwich Formation. This provides an improved geological framework for proposed subsurface construction that can reduce inherent engineering uncertainties, not only in the London region, but potentially in other similar geological environments.

scholarly journals A Study of Cirrus Ice Particle Size Distribution Using TC4 Observations

2010 ◽  
Vol 67 (1) ◽  
pp. 195-216 ◽  
Author(s):  
Lin Tian ◽  
Gerald M. Heymsfield ◽  
Lihua Li ◽  
Andrew J. Heymsfield ◽  
Aaron Bansemer ◽  
...  
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Size Spectra ◽  
Lognormal Distributions ◽  
Characteristic Particle ◽  
In Situ Observations

Abstract An analysis of two days of in situ observations of ice particle size spectra, in convectively generated cirrus, obtained during NASA’s Tropical Composition, Cloud, and Climate Coupling (TC4) mission is presented. The observed spectra are examined for their fit to the exponential, gamma, and lognormal function distributions. Characteristic particle size and concentration density scales are determined using two (for the exponential) or three (for the gamma and lognormal functions) moments of the spectra. It is shown that transformed exponential, gamma, and lognormal distributions should collapse onto standard curves. An examination of the transformed spectra, and of deviations of the transformed spectra from the standard curves, shows that the lognormal function provides a better fit to the observed spectra.

In situ quasi-elastic scattering characterization of particle size effects on the hydration of tricalcium silicate

2004 ◽  
Vol 19 (11) ◽  
pp. 3242-3254 ◽  
Author(s):  
A.J. Allen ◽  
J.C. McLaughlin ◽  
D.A. Neumann ◽  
R.A. Livingston
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Tricalcium Silicate ◽  
Size Distributions ◽  
Particle Size Distributions ◽  
Hydration Time ◽  
Initial Particle ◽  
Initial Particle Size

The effects of different particle size distributions on the real-time hydration of tricalcium silicate cement paste were studied in situ by quasi-elastic neutron scattering. The changing state of water in the cement system was followed as a function both of cement hydration time and of temperature for different initial particle size distributions. It was found that the length of the initial, dormant, induction period, together with the kinetics of hydration product nucleation and growth, depends on the hydration temperature but not on the particle size distribution. However, initial particle size does affect the total amount of cement hydrated, with finer particle size producing more hydrated cement. Furthermore, the diffusion-limited rate of hydration at later hydration time is largely determined by the initial tricalcium silicate particle size distribution.

scholarly journals Technical Note: Evaporation of polar stratospheric cloud particles, in situ, in a heated inlet

2005 ◽  
Vol 5 (1) ◽  
pp. 97-106 ◽  
Author(s):  
T. Eidhammer ◽  
T. Deshler
Keyword(s):  
Particle Size ◽  
Nitric Acid ◽  
Size Distribution ◽  
Technical Note ◽  
Ternary Solution ◽  
Slow Evaporation ◽  
Partial Pressures ◽  
Polar Stratospheric Cloud ◽  
Stratospheric Clouds

Abstract. In December 2001 and 2002 in situ aerosol measurements were made from balloon-borne platforms within polar stratospheric clouds (PSC) which contained particles of supercooled ternary solution (STS), nitric acid trihydrate (NAT) and ice. Particle size and number concentrations were measured with two optical particle counters. One of these included an ~80cm inlet heated to K to evaporate the PSC particles and thus to obtain measurements, within PSCs, of the size distribution of the particles upon which the PSCs condensed. These measurements are compared to models, described here, that calculate the evaporation of PSC particles at and for an inlet transition time of about 0.1s. The modeled evaporation for STS agrees well with the measurements. For NAT the modeled evaporation is less than the evaporation measured. The primary uncertainty concerns the phase and morphology of NAT particles as they are brought to temperatures >50K above equilibrium temperatures for NAT at stratospheric partial pressures. The slow evaporation of NAT in heated inlets could be used to identify a small NAT component within a mixed phase PSC dominated by STS.

Particle Size Distribution and Morphology of in Situ Suspension Polymerized Toner

2003 ◽  
Vol 42 (22) ◽  
pp. 5568-5575 ◽  
Author(s):  
Jun Yang ◽  
Ting-Jie Wang ◽  
Hong He ◽  
Fei Wei ◽  
Yong Jin
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution

The moment ratios of particle size distributions in some simple growth models

1980 ◽  
Vol 17 (4) ◽  
pp. 956-967 ◽  
Author(s):  
H. L. MacGillivray
Keyword(s):  
Particle Size ◽  
Size Distribution ◽  
Growth Model ◽  
Hazard Rate ◽  
Growth Models ◽  
Size Distributions ◽  
Particle Size Distributions ◽  
Initial Size ◽  
The Moment ◽  
Simple Growth

Important parameters of particle size distributions in dispersed systems in engineering and related fields are ratios of moments and inverse powers of these ratios, known as mean sizes. The variation in these parameters is examined for the simplest growth model in which the size distribution is translated, and the results for this process considered in relation to the problems of models of other growth processes. For initial size distributions with monotone hazard rate, the results are particularly significant, and the properties of the normalised moments of other distributions are also considered.

scholarly journals X-Ray Tomography Study on Porosity and Particle Size Distribution in In Situ Al-4.5Cu-5TiB2 Semisolid Rolled Composites

JOM ◽  
2019 ◽  
Vol 71 (11) ◽  
pp. 4050-4058 ◽  
Author(s):  
Swapnil Morankar ◽  
Monalisa Mandal ◽  
Nadia Kourra ◽  
Mark A. Williams ◽  
Rahul Mitra ◽  
...  
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
X Ray
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