Natural substrates like sand, soil, leaf litter and snow vary widely in penetration resistance. To search for principles of appendage design in robots and animals that permit high performance on such flowable ground, we developed a ground control technique by which the penetration resistance of a dry granular substrate could be widely and rapidly varied. The approach was embodied in a device co...

Abstract. A horizontal, on-line penetrometer has been used on several fields in Sweden to measure penetration resistance. The yield on these fields have been mapped and compared to the penetration resistance. In some of the fields, deep loosening has been done on parts of the field in order to be able to study the effects on the yield. Some correlation of higher penetration resistance and lower...

The chloride penetration resistance of phosphoaluminate cement (PAC) concrete was investigated in this study. The effects of mixture proportioning parameters, including cement content, water–cement ratio (w/c), and superplasticizer content on chloride ion penetration resistance of PAC concrete were investigated by the rapid chloride migration test (RCM). The result shows that the increase of ce...

Penetration resistance represents the first level of plant defense against phytopathogenic fungi. Here, we report that the starch-deficient Arabidopsis thaliana phosphoglucomutase (pgm) mutant has impaired penetration resistance against the hemibiotrophic fungus Colletotrichum higginsianum. We could not determine any changes in leaf cutin and epicuticular wax composition or indolic glucosinolat...

assessment and management of the environmental impacts of forest harvesting operations have become increasingly critical factors in practicing commercial forestry. this study investigated soil disturbance from a forest logging system operation on an 8-hectare mixed broadleaved stand in compartment no. 309 in gorazbon district in kheyrud educational and research forest. the objective of this stu...

Frameworks for estimating soil properties from CPT penetration resistances must account for the effects of overburden stress on both the penetration resistance and the soil property of interest, including how such effects vary with soil type. For example, common procedures for estimating the liquefaction resistance of sands include functional terms that account for the effect of overburden stre...

wind is an important erosive force in deserts, where limited cover of vascular plant material offers little soil-surface protection. erosion and sediment from soil surfaces occurs when wind forces exceed soil threshold friction velocities. soils with physical or biological crusts usually resist wind erosion. this study was conducted by the aim of investigation the effect of trichoderma harzianu...

field study was conducted at five villages of botswana namely, tsabong, tshane, mathathane, motlhabaneng and tsetsejwe during the periods of june to august 1999 and june to august 2000. the objective of the study was to assess and compare the soil physicochemical properties of soils at the five villages and to study the effect of cultivation on some soil physical properties. parameters measured...