Synthesis of Immiscible Alloys by the Mixalloying Process

1989 ◽  
Vol 111 (1) ◽  
pp. 70-78 ◽  
Author(s):  
S. Tu¨rker Oktay ◽  
Chong N. Chu ◽  
Nannaji Saka ◽  
Nam P. Suh
Keyword(s):  
Particle Size ◽  
Computational Simulation ◽  
Particle Diameter ◽  
Al Alloys ◽  
Size Distributions ◽  
Simulation Studies ◽  
Particle Size Distributions ◽  
The Mean ◽  
Log Normal ◽  
Mean Particle Diameter

Dispersed-phase microstructures of the immiscible Pb-Zn, Pb-Zn-Sn and Pb-Al alloys were produced by the Mixalloying Process [1]. The particle size was found to follow the log-normal statistical distribution and the mean particle diameter correlated well with the –3/5th power of the Weber number. Furthermore, computational simulation studies showed that the particle-size distributions became significantly broader due to Stokes coalescence during solidification.

Experimental investigation of the effects of turbulence intensity on frazil ice characteristics

2008 ◽  
Vol 35 (1) ◽  
pp. 67-79 ◽  
Author(s):  
Shawn Clark ◽  
John Doering
Keyword(s):  
Particle Size ◽  
Standard Deviation ◽  
Turbulence Intensity ◽  
Particle Diameter ◽  
Size Distributions ◽  
Particle Size Distributions ◽  
Frazil Ice ◽  
Rotating Flume ◽  
The Mean ◽  
Hot Film

The counter-rotating flume at the University of Manitoba was used to conduct a series of 21 laboratory experiments to investigate the effects of turbulence intensity on frazil ice formation and evolution. A detailed study of the velocity and turbulence intensity distributions within the counter-rotating flume was initially conducted using a constant-temperature anemometer equipped with a one-dimensional conical hot-film probe. Five levels of turbulence intensity were generated by five different sets of bed plates and flume wall rotation rates in order to study how turbulence affected the frazil particle size distributions and the statistics related to clear disk-shaped particles. It was found that a lognormal distribution could not be rejected when describing the frazil particle size distributions, regardless of the turbulence intensity of the water. The variation of the mean and standard deviation of particle diameter with turbulence intensity are well described by a parabolic shape. A preliminary equation to describe the variation of the mean and standard deviation of particle diameter as a function of turbulence intensity and time is presented.

The ATAL and its aerosol microphysical properties in the Asian Monsoon Anticyclone

2020 ◽  
Author(s):  
Christoph Mahnke ◽  
Stephan Borrmann ◽  
Ralf Weigel ◽  
Francesco Cairo ◽  
Armin Afchine ◽  
...  
Keyword(s):  
Particle Size ◽  
Asian Monsoon ◽  
Extreme Values ◽  
Monsoon Season ◽  
Measurement Techniques ◽  
Potential Temperature ◽  
Particle Diameter ◽  
Size Distributions ◽  
Particle Size Distributions ◽  
Microphysical Properties

<p>During the StratoClim 2017 measurement campaign in Nepal, within the Asian Monsoon Anticyclone (AMA), measurements of the aerosols’ microphysical properties up to UT/LS altitudes were successfully completed with a modified version of the commercially available (Droplet Measurement Technologies Inc.) aerosol spectrometer UHSAS-A. Technical rearrangements of parts of the UHSAS-A were developed and implemented, which improve the instrument’s measuring performance and extend its airborne application range from around 12 km altitude to the extreme ambient conditions in the stratosphere at heights of 20 km. The measurement techniques used for this purpose were characterized by laboratory experiments.</p><p>Within the AMA region, extreme values of the particle mixing ratio (PMR) ranging between 6 mg<sup>-1</sup> and about 10000 mg<sup>-1</sup> were found with the UHSAS-A (particle diameter range: 65 nm to 1000 nm). The median of the PMR for all research flights was about 1300 mg<sup>-1</sup> close to the ground. Within tropospheric altitudes, the PMR was highly variable and median values between 70 mg<sup>-1</sup> and 400 mg<sup>-1</sup> were observed.  At levels of 370 K potential temperature, the median PMR maximally reaches about 700 mg<sup>-1 </sup>while the 1 Hz resolved measurements show values up to about 10000 mg<sup>-1</sup>. Between 450 K and 475 K, median PMR between 40 mg<sup>-1</sup> and 50 mg<sup>-1</sup> were observed. The aerosol size distributions (measured by the UHSAS-A) were extended by an additional diameter size bin obtained from the 4-channel Condensation Particle counting System (COPAS), i.e. for aerosol diameter between 10 nm and 65 nm.</p><p>The UHSAS-A measured aerosol particle size distributions were compared with balloon-borne measurements (by T. Deshler et al., Dep. of Atmospheric Science, University of Wyoming, USA) at altitudes of up to 20 km. These show that the size distributions measured during the StratoClim 2017 campaign fit well within the range of the balloon-borne measurements during the Asian Monsoon season over India (Hyderabad) in 2015 and the USA (Laramie) in 2013. Further analyses of measured particle size distributions by means of backscatter ratio show remarkable consistency with CALIOP satellite observations of the ATAL during the StratoClim mission period.</p>

Gas-phase particle size distributions and lead loss during spray pyrolysis of (Bi,Pb)–Sr–Ca–Cu–O

1995 ◽  
Vol 10 (7) ◽  
pp. 1644-1652 ◽  
Author(s):  
Abhijit S. Gurav ◽  
Toivo T. Kodas ◽  
Jorma Joutsensaari ◽  
Esko I. Kauppincn ◽  
Riitta Zilliacus
Keyword(s):  
Particle Size ◽  
Spray Pyrolysis ◽  
Gas Phase ◽  
Phase Particle ◽  
Average Particle Size ◽  
Particle Diameter ◽  
Processing Temperature ◽  
Average Particle ◽  
Size Distributions ◽  
Particle Size Distributions

Gas-phase particle size distributions and lead loss were measured during formation of (Bi,Pb)-Sr-Ca-Cu-O and pure PbO particles by spray pyrolysis at different temperatures. A differential mobility analyzer (DMA) in conjunction with a condensation particle counter (CPC) was used to monitor the gas-phase particle size distributions, and a Berner-type low-pressure impactor was used to obtain mass size distributions and size-classified samples for chemical analysis. For (Bi,Pb)-Sr-Ca-Cu-O, as the processing temperature was raised from 200 to 700 °C, the number average particle size decreased due to metal nitrate decomposition, intraparticle reactions forming mixed-metal oxides and particle densification. The geometric number mean particle diameter was 0.12 μm at 200 °C and reduced to 0.08 and 0.07 μm, respectively, at 700 and 900 °C. When the reactor temperature was raised from 700 and 800 °C to 900 °C, a large number (∼107 no./cm3) of new ultrafine particles were formed from PbO vapor released from the particles and the reactor walls. Particles made at temperatures up to 700 °C maintained their initial stoichiometry over the whole range of particle sizes monitorcd; however, those made at 800 °C and above were heavily depleted in lead in the size range 0.5–5.0 μm. The evaporative losses of lead oxide from (Bi,Pb)-Sr-Ca-Cu-O particles were compared with the losses from PbO particles to gain insight into the pathways involved in lead loss and the role of intraparticle processes in controlling it.

Textural properties of regoliths on vegetated steep slopes in upland regions, Scotland

1986 ◽  
Vol 77 (3) ◽  
pp. 241-250 ◽  
Author(s):  
J. L. Innes
Keyword(s):  
Particle Size ◽  
Early Stage ◽  
Probability Distributions ◽  
Textural Properties ◽  
Size Distributions ◽  
Particle Size Distributions ◽  
Normal Probability ◽  
Log Normal ◽  
Steep Slopes

ABSTRACTThe textural properties of many sediments provide a good indication of their provenance, but surprisingly little information is available on the transitional stages between the breakdown of a rock and the incorporation of the material into a fluvial sediment. These transitional stages are important as certain fractions (particularly the finer ones) may be selectively removed. Regoliths developed on steep slopes represent an early stage in the debris cascade and they are here examined in detail to assess the role of parent lithology on the textural properties of the regolith. There are substantial variations between lithologies, although the majority of regoliths are dominated by coarser fractions and are poorly sorted. Most particle size distributions show some degree of fit to both log-normal probability distributions and Rosin distributions. Differences from these can be ascribed to the processes operating on steep slopes, particularly the influx of sand- and silt-sized material by colluvial processes and the removal of clay-sized material by leaching. The regoliths form a distinct facies type which may be recognisable in the geological record.

scholarly journals The Influence of Wildfires on Aerosol Size Distributions in Rural Areas

2012 ◽  
Vol 2012 ◽  
pp. 1-13 ◽  
Author(s):  
E. Alonso-Blanco ◽  
A. I. Calvo ◽  
R. Fraile ◽  
A. Castro
Keyword(s):  
Particle Size ◽  
Rural Areas ◽  
Size Distributions ◽  
Average Increase ◽  
Particle Size Distributions ◽  
Before And After ◽  
Fine Mode ◽  
The Mean ◽  
The One ◽  
Number Of Particles

The number of particles and their size distributions were measured in a rural area, during the summer, using a PCASP-X. The aim was to study the influence of wildfires on particle size distributions. The comparative studies carried out reveal an average increase of around ten times in the number of particles in the fine mode, especially in sizes between 0.10 and 0.14 μm, where the increase is of nearly 20 times. An analysis carried out at three different points in time—before, during, and after the passing of the smoke plume from the wildfires—shows that the mean geometric diameter of the fine mode in the measurements affected by the fire is smaller than the one obtained in the measurements carried out immediately before and after (0.14 μm) and presents average values of 0.11 μm.

DETERMINATION OF ELEMENT CONCENTRATION AND PARTICLE SIZE DISTRIBUTION IN BEIJING URBAN ATMOSPHERIC AEROSOL

1992 ◽  
Vol 02 (04) ◽  
pp. 637-644 ◽  
Author(s):  
GUANGHUA ZHU ◽  
XINFU WANG ◽  
XINYIN SHEN
Keyword(s):  
Particle Size ◽  
Atmospheric Aerosol ◽  
Element Concentration ◽  
Size Distributions ◽  
Particle Size Distributions ◽  
Retention Models ◽  
Elemental Concentrations ◽  
Log Normal ◽  
Least Squares Minimization

The atmospheric aerosol samples are collected in Beijing using a ten-stage cascade impactor sampler, and the elemental concentrations are analyzed by the PIXE analytical method. The parameters of particle size distributions are determined by the use of log-normal plots and the least-squares minimization. From these parameters the total amount of deposit in a day at the naso-pharyngeal, tracheo-bronchial and pulmonary are evaluated based on the deposition and retention models.

CFD Simulation of Spouted Bed Working with a Size Distribution of Sand Particles: Segregation Aspects

2017 ◽  
Vol 899 ◽  
pp. 95-100
Author(s):  
Kássia Graciele dos Santos ◽  
L.V. Ferreira ◽  
Ricardo Correa Santana ◽  
Marcos Antonio de Souza Barrozo
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Cfd Simulation ◽  
Computational Simulation ◽  
Particle Diameter ◽  
Spouted Bed ◽  
Particle Segregation ◽  
Cfd Method ◽  
Mean Particle Diameter

Spouted bed simulations are usually performed using only one granular phase with a mean particle diameter representing the entire particle mixture, instead of a particle size distribution. In this study, the effect of the particle size distribution is accounted through the simulation of a mixture with five granular phases. The results showed that the particle segregation occurs. Larger particles are more concentrated in the upper region, while the smaller particles are preferably positioned in the lower region of the bed. Computational simulation using CFD method reproduced well the segregation experiments with different participle sizes of sand.

Effect of Synthesis Parameter on Properties of Heat-Sensitive Nanocapsules

2013 ◽  
Vol 675 ◽  
pp. 302-305
Author(s):  
Pu Ying An ◽  
Zhao Yun Yu ◽  
Hai Song Zhang ◽  
Xin Wu Ba
Keyword(s):  
Particle Size ◽  
Glass Transition ◽  
Size Distributions ◽  
Particle Size Distributions ◽  
Glass Transition Temperatures ◽  
Hyperbranched Poly ◽  
Crosslinker Content ◽  
Mean Size ◽  
The Mean ◽  
Triton X

The crosslinked poly(methylmethacrylate) (PMMA) heat-sensitive nanocapsules were prepared by emulsion polymerization, in which Triton X-100 was used as an emulsifier and unsaturated hyperbranched poly(amide-ester) (UHBP) as a crosslinker. The effects of three determinative process parameters on the particle size distributions, glass transition temperatures(Tgs) and heat sensitive color-developing properties of nanocapsules were investigated in detail. As a result, the mean size of nanocapsules became smaller and their particle size distribution became narrower with the increase in emulsifying rate. The Tg of nanocapsules was 123.8°C with the emulsifier content being 0.6%. The color-developing absorbency was the highest with the crosslinker content being 6.0 %.

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