Penetration experiments will find several applications in exploration missions in the near future. Penetrators are common tools for the investigation of physical surface properties. The techniques and theories are widely applied under 1g condition on Earth and the results are used by engineers and scientists. The main contribution to the bearing resistance of a soil is combined of shaft and bas...

The interdependency of biological and physical components of the arctic tundra system can yield strongly nonlinear processes with potential thresholds for ecosystem shifts. Hydrology critically infl uences the ecosystem dynamics in the Arctic, even though the tundra appears to have a relatively simple hydrologic system, often consisting of only a saturated active layer underlain by permafrost. ...

Freezing and thawing of soils may affect the turnover of soil organic matter and thus the losses of C and N from soils. Here we review the literature with special focus on: (i) the mechanisms involved, (ii) the effects of freezing temperature and frequency, (iii) the differences between arable soils and soils under natural vegetation, and (iv) the hypothesis that freeze-thaw events lead to sign...

Laboratory studies were conducted to evaluate effect of microwave irradiation of sandy loam soil on thermal energy absorption and control of plant-parasitic nematodes when air dry soil layers were placed on top of less moist, moist, and wet soil layers. The soil was packed in 12 cm high and 10 cm dia columns to a bulk density of 1.4 g/cm3. Moisture contents of air dry, less moist, moist, and we...

We quantify mechanical processes common to soil penetration by earthworms and growing plant roots, including the energetic requirements for soil plastic displacement. The basic mechanical model considers cavity expansion into a plastic wet soil involving wedging by root tips or earthworms via cone-like penetration followed by cavity expansion due to pressurized earthworm hydroskeleton or root r...

Offshore pipelines used for oil and gas transportation are often buried to avoid damage from fishing activities and to provide thermal insulation. Thermal expansion and contraction of the pipeline during operation can lead to lateral or upheaval buckling. A safe buried pipeline design must take into account a reliable evaluation of soil uplift resistance and pipe embedment depth. While the cost...

offshore pipelines used for oil and gas transportation are often buried to avoid damage from fishing activities and to provide thermal insulation. thermal expansion and contraction of the pipeline during operation can lead to lateral or upheaval buckling. a safe buried pipeline design must take into account a reliable evaluation of soil uplift resistance and pipe embedment depth. while the cost...