Femtosecond filamentation in air at low pressures. Part II: Laboratory experiments

2006 ◽  
Vol 261 (2) ◽  
pp. 322-326 ◽  
Author(s):  
G. Méchain ◽  
T. Olivier ◽  
M. Franco ◽  
A. Couairon ◽  
B. Prade ◽  
...  
Keyword(s):  
Laboratory Experiments ◽  
Femtosecond Filamentation ◽  
Low Pressures

Femtosecond filamentation in air at low pressures: Part I: Theory and numerical simulations

2006 ◽  
Vol 259 (1) ◽  
pp. 265-273 ◽  
Author(s):  
A. Couairon ◽  
M. Franco ◽  
G. Méchain ◽  
T. Olivier ◽  
B. Prade ◽  
...  
Keyword(s):  
Numerical Simulations ◽  
Femtosecond Filamentation ◽  
Low Pressures

Femtosecond filamentation in air at low pressures

2005 ◽  
Author(s):  
G. Mechain ◽  
M. Franco ◽  
A. Couairon ◽  
T. Olivier ◽  
B. Prade ◽  
...  
Keyword(s):  
Femtosecond Filamentation ◽  
Low Pressures

scholarly journals A lower-than-expected saltation threshold at Martian pressure and below

2021 ◽  
Vol 118 (5) ◽  
pp. e2012386118 ◽  
Author(s):  
Bruno Andreotti ◽  
Philippe Claudin ◽  
Jens Jacob Iversen ◽  
Jonathan P. Merrison ◽  
Keld R. Rasmussen
Keyword(s):  
Sediment Transport ◽  
Laboratory Experiments ◽  
Vacuum Chamber ◽  
Density Ratio ◽  
Collective Effects ◽  
Simulation Experiments ◽  
Characteristic Wavelength ◽  
Density Ratios ◽  
Aeolian Sediment ◽  
Low Pressures

Aeolian sediment transport is observed to occur on Mars as well as other extraterrestrial environments, generating ripples and dunes as on Earth. The search for terrestrial analogs of planetary bedforms, as well as environmental simulation experiments able to reproduce their formation in planetary conditions, are powerful ways to question our understanding of geomorphological processes toward unusual environmental conditions. Here, we perform sediment transport laboratory experiments in a closed-circuit wind tunnel placed in a vacuum chamber and operated at extremely low pressures to show that Martian conditions belong to a previously unexplored saltation regime. The threshold wind speed required to initiate saltation is only quantitatively predicted by state-of-the art models up to a density ratio between grain and air of 4×105 but unexpectedly falls to much lower values for higher density ratios. In contrast, impact ripples, whose emergence is continuously observed on the granular bed over the whole pressure range investigated, display a characteristic wavelength and propagation velocity essentially independent of pressure. A comparison of these findings with existing models suggests that sediment transport at low Reynolds number but high grain-to-fluid density ratio may be dominated by collective effects associated with grain inertia in the granular collisional layer.

Covering of cometary nucleus by refractory crust and its evolution into asteroid-like body

1999 ◽  
Vol 173 ◽  
pp. 365-370
Author(s):  
Kh.I. Ibadinov
Keyword(s):  
Laboratory Experiments ◽  
Cometary Nucleus ◽  
Sublimation Rate ◽  
Cometary Nuclei ◽  
Short Period Comet ◽  
Short Period ◽  
Brightness Decrease ◽  
Crust Thickness ◽  
Ice Sublimation ◽  
Period Comet

AbstractFrom the established dependence of the brightness decrease of a short-period comet dependence on the perihelion distance of its orbit it follows that part of the surface of these cometary nuclei gradually covers by a refractory crust. The results of cometary nucleus simulation show that at constant insolation energy the crust thickness is proportional to the square root of the insolation time and the ice sublimation rate is inversely proportional to the crust thickness. From laboratory experiments resulted the thermal regime, the gas productivity of the nucleus, covering of the nucleus by the crust, and the tempo of evolution of a short-period comet into the asteroid-like body studied.

When Does Voice Have to be More Than Only Listening? Procedural Justice Effects as a Function of Confident Leadership

2010 ◽  
Vol 9 (2) ◽  
pp. 69-78 ◽  
Author(s):  
David De Cremer ◽  
Maarten Wubben
Keyword(s):  
Procedural Justice ◽  
Interaction Effect ◽  
Laboratory Experiments ◽  
Negative Emotions

The present research examined how voice procedures and leader confidence affect participants’ negative emotions and willingness to withdraw. It was predicted that receiving voice would be valued out of instrumental concerns, but only when the enacting leader was high in confidence. Two laboratory experiments indeed showed an interaction between type of voice (pre-decisional vs. post-decisional) and leader’s confidence (low vs. high) on participants’ negative emotions and willingness to withdraw. In particular, post-decision voice only led to more negative responses than did pre-decision voice when the enacting leader was high in confidence. Negative emotions mediated this interaction effect of type of voice on willingness to withdraw. Implications for integrating the leadership and procedural justice literatures are discussed.

Review of Laboratory Experiments in Psychology.

1968 ◽  
Vol 13 (10) ◽  
pp. 536-536
Author(s):  
Peter G. Polson
Keyword(s):  
Laboratory Experiments
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