Surface slope effects for ripple orientation on sand dunes in López crater, Terra Tyrrhena region of Mars

2017 ◽  
Vol 26 ◽  
pp. 57-62 ◽  
Author(s):  
James R. Zimbelman ◽  
Molly B. Johnson
Keyword(s):  
Sand Dunes ◽  
Surface Slope ◽  
Ripple Orientation

The Nature of Mining-Induced Horizontal Displacement of Surface on the Example of Several Coal Mines

2014 ◽  
Vol 59 (4) ◽  
pp. 971-986 ◽  
Author(s):  
Krzysztof Tajduś
Keyword(s):  
Underground Mining ◽  
Mining Industry ◽  
Horizontal Displacement ◽  
Surface Slope ◽  
Proportionality Coefficient ◽  
Model Studies ◽  
Displacement Vectors ◽  
Mining Conditions ◽  
Design Projects ◽  
Academy Of Sciences

Abstract The paper presents the analysis of the phenomenon of horizontal displacement of surface induced by underground mining exploitation. In the initial part, the basic theories describing horizontal displacement are discussed, followed by three illustrative examples of underground exploitation in varied mining conditions. It is argued that center of gravity (COG) method presented in the paper, hypothesis of Awierszyn and model studies carried out in Strata Mechanics Research Institute of the Polish Academy of Sciences indicate the proportionality between vectors of horizontal displacement and the vector of surface slope. The differences practically relate to the value of proportionality coefficient B, whose estimated values in currently realized design projects for mining industry range between 0.23r to 0.42r for deep exploitations, whereas in the present article the values of 0.33r and 0.47r were obtained for two instances of shallow exploitation. Furthermore, observations on changes of horizontal displacement vectors with face advancement indicated the possibility of existence of COG zones above the mined-out field, which proved the conclusions of hitherto carried out research studies (Tajduś 2013).

Discussion on wind factor influencing the distribution of biological soil crusts on surface of sand dunes

2013 ◽  
Vol 5 (6) ◽  
pp. 739
Author(s):  
Wu YongSheng ◽  
Erdun Hasi ◽  
Yin RuiPing ◽  
Zhang Xin ◽  
Ren Jie ◽  
...  
Keyword(s):  
Sand Dunes ◽  
Biological Soil Crusts ◽  
Soil Crusts

The early stages of spontaneous forest regeneration on poor soils and continental sand dunes in northern Belgium

1983 ◽  
Vol 49 ◽  
Author(s):  
M. Van Miegroet
Keyword(s):  
Scots Pine ◽  
Age Differences ◽  
Forest Regeneration ◽  
Sand Dunes ◽  
Mixed Forest ◽  
Pedunculate Oak ◽  
White Poplar ◽  
Technical Problems ◽  
Homogeneous Groups ◽  
Invading Species

Spontaneous  natural regeneration under variable conditions on sandy soils and continental  sand dunes were analysed in 5 locations in N.E. Belgium.     The number of seedlings varies between 14.000 and 522.000/ha. The most  prominent invading species are red oak, pedunculate oak and Scots pine.    Two principal types of regeneration are recognized : homogeneous groups of  oak or pine and mixtures, predominantly composed by the same species.  Pioneers such as birch, willow, white poplar and wild black cherry do not  play an important role.    Social differentiation sets in quite early and is mainly provoked by age  differences. Therefore early silvicultural intervention is advisable. The  growth relationships between the species indicate that Scots pine is not in  danger of spontaneous elemination by other species. Because of the density  and variability of spontaneous forest regeneration, the conversion of pure  pine stands into mixed forest, using group regeneration to this end, poses no  real technical problems.

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