Application of capacitively-coupled and DC electrical resistivity imaging for mountain permafrost studies
In this paper, the AA. address the frequency dependence of resistivity and its sensitivity to surveys on frozen ground by comparing data from several resistivity surveys along the same profile in the eastern Swiss Alps. The applicability
of OhmMapper, a capacitively-coupled resistivity system, which overcomes the problem of direct (galvanic) electrode contact in highly resistive environments and has been successfully applied on arctic permafrost, was compared to standard multi-channel
Preliminary study of the interference of surface objects and rainfall in overland flow resistance
This study examines the validity of linear superposition approach when rainfall and surface roughness are considered in overland flow resistance. To examine a possible interference in flow resistance, a set of flume experiments using surface objects
and rainfall as roughness elements were conducted. Since the flow resistance due to each element cannot be measured directly, the linear superposition equation had to be rewritten using friction factor increment as variable. The result shows
that the interference between rainfall and surface roughness is significant and the composite resistance does not statistically equal to the sum of individual resistance. The linear superposition approach is hence invalid in the case of rainfall and surface elements
An hypothesis from which a general principle covering deformation of alluvial boundaries may be developed is proposed, namely flow of fluid past a deformable boundary will deform the boundary so as to increase the resistance to flow. Upon attainment
of a local maximum of resistance to flow the boundary shape will cease to change.
Mechanical and hydraulic resistance relations in crust-topped soils
In this study, changes and relationships of both resistances under sprinkle irrigation (or rainfall) and sprinkle followed by flooding, were examined. Two typical agricultural soils in the Egyptian Delta were used for the experiment : a silt-loam
soil from the central Nile Delta, and a clay soil from the western region of the Nile Delta. Pertinent physical and chemical soil properties of the two soils were determined. Discussion of the results (mechanical resistance, hydraulic resistance, change
The influence of rock resistance on coastal morphology around Lord Howe Island, Southwest Pacific
The geology of the island is varied, with hard and resistant basalt lavas, breccias and tuffs of intermediate resistance, and highly erodible eolianites. This variability provides an excellent opportunity to examine the influence of rock resistance
on the development of the spectacular rock coast landforms that occur around the island. Relative rock resistance was assessed through a combination of Schmidt hammer data, and statistical analysis was undertaken to remove outlying values. The paper considers
the possibility of landform inheritance and examines the distribution of resistant plunging cliffs and erosional shore platform.
The effect of bed mobility on resistance to overland flow
The data for this study come from 54 flume experiments with fixed beds and 38 with mobile beds. The results imply that mobile beds offer greater resistance to flow than do fixed beds. Grain collisions with mobile beds are less elastic than those
Resistance to rill erosion : observations on the efficiency of rill erosion on a tilled clay soil under simulated rain and run-on water in Rill erosion. Processes and significance.
This paper reports a study of rill development under simulated rain and run-on water on a bare, tilled soil on the eastern Darling Downs, Queensland. The development of rills on this soil relatively resistant to rilling is compared with that on two
soils shown to have virtually no resistance to rilling.
Macroscale surface roughness and frictional resistance in overland flow
by a brief review of the physical variables which may contribute to flow resistance and some of the possible dimensionless groupings arising from those variables. Previously published field and laboratory data are re-evaluated in terms of the frictional
resistance as a function of an estimated inundation ratio for each flow, and the results are compared with the trends predicted by the model.
Effect of saltating sediment on flow resistance and bred roughness in overland flow
This study has evaluated the effect of saltating sediment on flow resistance and bed roughness in overland flow on a fixed sand-covered bed. It is concluded that saltating sediment has a considerable impact on overland flow hydraulics, at least
on fixed granular beds. Saltation is likely to have a relatively smaller effect on overland flow on natural hillslopes and agricultural fields where form and wave resistance dominate.
The imagineering of resistance : Pollock Free State and the practice of postmodern politics
The conflict over the construction of the M77 motorway in Glasgow, is an example of a subculture of resistance which has emerged within Britain over the past fifteen years. The paper focuses upon the actions of Glasgow Earth First!, and the role
of an ecological encampment located in the projected path of the motorway. Such resistance is characteristic of a postmodern political practice. It is symbolic and extensively mediated.
Resistivity structures in Alas areas in Central Yakutia, Siberia, and the interpretation of permafrost history
This paper discusses the relationship between resistivity structure and permafrost, followed by an overview of the permafrost conditions and geology at the study sites. Based on the obtained resistivity structure, numerical analyses were conducted
On the use of resistance envelopes to identify the controls on slope stability in the tropics
In tropical and sub-tropical slopes, soil suction may in certain circumstances play a role in maintaining slope stability. Resistance envelope methods are outlined that provide a means of assessing the threshold soil water conditions for stability
. Application to slopes in St.-Lucia, show the accordance of resistance envelope predictions with stability analysis results. A methodology for the geomorphological investigation of stability processes in tropical slopes is proposed.
Short communication. Suction-controlled triaxial testing : laboratory procedures in relation to resistance envelope methods
predicted by resistance envelope methods. It is shown that for two sites examined in St. Lucia, the results from such a test confirm results obtained by use of resistance envelopes.
The AA. present hydraulic measurements and calculations from 6 step-pool reaches of natural streams and from flume experiments dynamically similar to the prototypes. They aim to determine how rapidly flow resistance decreases, and velocity increases
, with discharge in step-pool channels; to compare these findings with standard predictive equations using a roughness height; and to see how the parameter values which optimise the fit of appropriate resistance equations relate to measured bed properties.