Ultrafine particle size distribution during high velocity impact of high density metals

2012 ◽  
Author(s):  
Giorgio Buonanno ◽  
Luca Stabile ◽  
Andrew Ruggiero ◽  
Gianluca Iannitti ◽  
Nicola Bonora
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
High Velocity ◽  
Ultrafine Particle ◽  
High Density ◽  
High Velocity Impact ◽  
Velocity Impact

scholarly journals Reaction Mechanism and Process Control of Hydrogen Reduction of Ammonium Perrhenate

Metals ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 640
Author(s):  
Junjie Tang ◽  
Yuan Sun ◽  
Chunwei Zhang ◽  
Long Wang ◽  
Yizhou Zhou ◽  
...  
Keyword(s):  
Particle Size ◽  
High Temperature ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Hydrogen Reduction ◽  
Reduction Rate ◽  
Reduction Reaction ◽  
High Density ◽  
Reduction Temperature ◽  
Ammonium Perrhenate

The preparation of rhenium powder by a hydrogen reduction of ammonium perrhenate is the only industrial production method. However, due to the uneven particle size distribution and large particle size of rhenium powder, it is difficult to prepare high-density rhenium ingot. Moreover, the existing process requires a secondary high-temperature reduction and the deoxidization process is complex and requires a high-temperature resistance of the equipment. Attempting to tackle the difficulties, this paper described a novel process to improve the particle size distribution uniformity and reduce the particle size of rhenium powder, aiming to produce a high-density rhenium ingot, and ammonium perrhenate is completely reduced by hydrogen at a low temperature. When the particle size of the rhenium powder was 19.74 µm, the density of the pressed rhenium ingot was 20.106 g/cm3, which was close to the theoretical density of rhenium. In addition, the hydrogen reduction mechanism of ammonium perrhenate was investigated in this paper. The results showed that the disproportionation of ReO3 decreased the rate of the reduction reaction, and the XRD and XPS patterns showed that the increase in the reduction temperature was conducive to increasing the reduction reaction rate and reducing the influence of disproportionation on the reduction process. At the same reduction temperature, reducing the particle sizes of ammonium perrhenate was conducive to increasing the hydrogen reduction rate and reducing the influence of the disproportionation.

Synthesis of hypoxia-high density TZM alloy based on mechanochemistry and particle size distribution theories

2017 ◽  
Vol 698 ◽  
pp. 994-1001 ◽  
Author(s):  
Ping Hu ◽  
Tian Chang ◽  
Zhi-tao Yu ◽  
Fan Yang ◽  
Bo-liang Hu ◽  
...  
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
High Density

scholarly journals Evidence of an elevated source of nucleation based on model simulations and data from the NIFTy experiment

2012 ◽  
Vol 12 (17) ◽  
pp. 8021-8036 ◽  
Author(s):  
P. Crippa ◽  
T. Petäjä ◽  
H. Korhonen ◽  
G. S. El Afandi ◽  
S. C. Pryor
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Ultrafine Particle ◽  
Ground Level ◽  
Particle Formation ◽  
Atmospheric Conditions ◽  
New Particle Formation ◽  
Near Surface ◽  
Nocturnal Inversion

Abstract. New particle formation has been observed at a number of ground-based measurement sites. Prior research has provided evidence that this new particle formation, while observed in the near-surface layer, is actually occurring in atmospheric layers above the surface and appears to be focused in or close to the residual layer formed by the nocturnal inversion. Here, we present both observations and modeling for southern Indiana which support this postulate. Based on simulations with a detailed aerosol dynamics model and the Weather Research and Forecasting model, along with data from ground-based remote sensing instruments and detailed gas and particle phase measurements, we show evidence that (i) the maximum rate change of ultrafine particle concentrations as observed close to the surface is always preceded by breakdown of the nocturnal inversion and enhancement of vertical mixing and (ii) simulated particle size distributions exhibit greatest accord with surface observations during and subsequent to nucleation only when initialized with a particle size distribution representative of clear atmospheric conditions, rather than the in situ (ground-level) particle size distribution.

scholarly journals Ultrafine particle generation by high-velocity impact of metal projectiles

2014 ◽  
Vol 500 (18) ◽  
pp. 182018 ◽  
Author(s):  
L Stabile ◽  
G Iannitti ◽  
P Vigo ◽  
A Ruggiero ◽  
A Russi ◽  
...  
Keyword(s):  
High Velocity ◽  
Ultrafine Particle ◽  
High Velocity Impact ◽  
Velocity Impact ◽  
Particle Generation

Measurements of ultrafine particle size distribution near Rome

2010 ◽  
Vol 98 (1) ◽  
pp. 69-77 ◽  
Author(s):  
Fenjuan Wang ◽  
Francesca Costabileb ◽  
Hong Li ◽  
Dong Fang ◽  
Ivo Alligrini
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Ultrafine Particle
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