Periodic precipitation patterns in the presence of concentration gradients. 1. Dependence on ion product and concentration difference

1982 ◽  
Vol 86 (20) ◽  
pp. 4078-4087 ◽  
Author(s):  
Stefan C. Mueller ◽  
Shoichi Kai ◽  
John Ross
Keyword(s):  
Concentration Gradients ◽  
Concentration Difference ◽  
Periodic Precipitation ◽  
Precipitation Patterns

Gravity Effect on the Formation of Periodic Precipitation Patterns

2000 ◽  
Vol 65 (9) ◽  
pp. 1438-1442 ◽  
Author(s):  
Vladislav Holba ◽  
Frederik Fusek
Keyword(s):  
Gravitational Field ◽  
Spatial Arrangement ◽  
Experimental Results ◽  
Single Sample ◽  
Gravity Effect ◽  
Periodic Precipitation ◽  
Precipitation Patterns ◽  
Liesegang Bands

The effect of gravity on the formation of Liesegang patterns of Ag2Cr2O7in gelatin and that of PbI2in agar was investigated. Spatial arrangement of Liesegang bands was measured in the parallel and antiparallel orientation to the gravitational field in a single sample with all other parameters kept fixed. The experimental results are discussed in terms of the prenucleation theory of periodic precipitation.

Independence of Primary and Secondary Structures in Periodic Precipitation Patterns

2011 ◽  
Vol 2 (4) ◽  
pp. 345-349 ◽  
Author(s):  
Stoyan K. Smoukov ◽  
István Lagzi ◽  
Bartosz A. Grzybowski
Keyword(s):  
Secondary Structures ◽  
Periodic Precipitation ◽  
Precipitation Patterns

Gravity dependence of phases III, IV, and V in single-breath washout curves

1983 ◽  
Vol 54 (4) ◽  
pp. 887-895 ◽  
Author(s):  
M. Verhamme ◽  
J. Roelandts ◽  
M. De Roo ◽  
M. Demedts
Keyword(s):  
Vertical Gradient ◽  
Residual Volume ◽  
Concentration Gradients ◽  
Concentration Difference ◽  
Single Breath ◽  
N2 Method ◽  
Phase Iiib ◽  
Lateral Decubitus ◽  
The Difference ◽  
Washout Curves

The gravity dependence of phases III (IIIa and IIIb), IV, and V of simultaneously performed He-bolus and N2-resident gas single-breath washout curves was studied in different body positions by the technique of 180 degrees body inversion between inspiration and expiration. Phase IIIa was mainly determined by nongravitational factors. Phase IIIb was influenced by gravitational, as well as nongravitational, factors. The former were more important with the bolus method in both lateral decubitus positions and the latter with the N2 method in the prone and supine positions. Phases IV and V were mainly gravity dependent. The difference in gravity dependence between the He and N2 methods appeared to be correlated with the vertical interregional concentration gradients of both gases; indeed the vertical gradient was larger for the 133Xe bolus inhaled at residual volume (which is comparable to the He-bolus distribution) than for the 133Xe residual volume-to-total lung capacity ratio (which is comparable to the N2-resident gas distribution). The greater gravity dependence in the lateral decubitus positions than in the supine or prone postures was related to the larger vertical interregional concentration difference as well as to the more pronounced sequential ventilation in the former positions. Finally the negligible effect of gravity on phase IIIa, its moderate effect on phase IIIb, and its predominant effect on phases IV and V were in agreement with the increased sequential filling and emptying due to gravity near residual volume.

Wet Stamping of Microscale Periodic Precipitation Patterns

2005 ◽  
Vol 109 (7) ◽  
pp. 2774-2778 ◽  
Author(s):  
I. T. Bensemann ◽  
M. Fialkowski ◽  
B. A. Grzybowski
Keyword(s):  
Periodic Precipitation ◽  
Precipitation Patterns

Curiosities in Periodic Precipitation Patterns

Science ◽  
1982 ◽  
Vol 216 (4546) ◽  
pp. 635-637 ◽  
Author(s):  
S. C. MULLER ◽  
S. KAI ◽  
J. ROSS
Keyword(s):  
Periodic Precipitation ◽  
Precipitation Patterns

scholarly journals Impact of the oasis effect on wind tunnel measurements of ammonia volatilization from urea

2016 ◽  
Vol 96 (4) ◽  
pp. 485-495 ◽  
Author(s):  
Devon Watt ◽  
Philippe Rochette ◽  
Andrew VanderZaag ◽  
Ian B. Strachan ◽  
Normand Bertrand
Keyword(s):  
Wind Tunnel ◽  
Ammonia Volatilization ◽  
Wind Tunnels ◽  
Small Scale ◽  
Nonlinear Relationship ◽  
Concentration Gradients ◽  
Concentration Difference ◽  
Wind Tunnel Measurements ◽  
Flux Difference ◽  
Oasis Effect

The validity of emission factors derived from small-scale measurements of ammonia (NH3) volatilization has been questioned in the literature because gaseous NH3 concentration gradients differ at the edge of the measurement plot and may result in higher emissions than at field scale. We studied this “oasis effect” using two very long (22 m) wind tunnels constructed indoors over soil plots fertilized with surface-applied urea (20 g N m−2). We hypothesized that NH3 flux would be highest at the start of the tunnel and decrease with distance. Air NH3 concentration was measured every 2 m along each tunnel for 2 wk after urea application; NH3 flux did not decrease along the length of the tunnels. Of the 60 measurement periods, when there was significant NH3 volatilization, only two had a significant nonlinear relationship (P ≤ 0.05) between NH3 concentration and distance. For the other periods, the NH3 concentration increased linearly with distance (P ≤ 0.05). The background NH3 concentration difference between halves of the tunnels was not significantly related to NH3 flux difference (P > 0.1). Our results indicate that wind tunnel measurements of NH3 volatilization fertilized using urea are not impacted by a measurable oasis effect.

Periodic Precipitation Patterns during Coalescence of Reacting Sessile Droplets

Langmuir ◽  
2015 ◽  
Vol 31 (42) ◽  
pp. 11484-11490 ◽  
Author(s):  
Marie Jehannin ◽  
Sophie Charton ◽  
Stefan Karpitschka ◽  
Thomas Zemb ◽  
Helmuth Möhwald ◽  
...  
Keyword(s):  
Periodic Precipitation ◽  
Precipitation Patterns
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