نتایج جستجو برای: unconsolidated sandstone
تعداد نتایج: 5533 فیلتر نتایج به سال:
In many arid and semiarid regions, saline playas represent a significant source of unconsolidated sediments available for aeolian transport, and severe saline dust storms occur frequently due to human disturbance. In this study, saline dust storms are reviewed systematically from the aspects of concept, general characteristics, conditions of occurrence, distribution and ecological impact. Our r...
Planetary rovers are increasingly challenged to negotiate extreme terrain. Early destinations have been benign to preclude risk, but canyons, funnels, and newly discovered holes present steep slopes that defy tractive descent. Steep craters and holes with unconsolidated material pose a particularly treacherous danger to modern rovers. This research explores robotic braking by plowing, a novel m...
Introduction: The recognition of low-pressure shock-metamorphic effects in quartz is of increasing importance in studies attempting to verify an impact origin for highly eroded structures [1], recognize sedi-mentary-target impacts characterized by a wide range of shock-pressure regimes, and identify distal impact-ejecta layers or impact-tsunamiites where high-pressure indicators may be rare or ...
Within the framework of responsible mining, a SOLSA project (www.solsa-mining.eu) to develop an in-situ tool allowing a quick mineralogical identification of site drill cores has been recently launched. Its objective is to develop new or improved highly-efficient and cost-effective, sustainable exploration technologies. It combines and integrates nondestructive sensors: X-ray fluorescence, X-ra...
The paper presents some results of the characterization of microstuctural differences inside and outside compaction bands in natural sandstone. Specimens of Aztec sandstone were scanned at the synchrotron APS, at Argonne National Laboratory (USA). Porosity measurements obtained by image analysis show a sharp transition inside/outside the compaction band. Finally, preliminary permeability measur...
Temperature, relative humidity and overhygroscopic moisture fields in a sandstone wall provided with interior thermal insulation were calculated in order to assess the hygric performance of the retrofitted wall. Computational simulations showed that during the time period of 10 years which was subject of investigation no overhygroscopic moisture appeared in the analyzed building envelope so tha...
Pore-Cor can be used to obtain enhanced information from the mercury intrusion porosimetry of oil-reservoir sandstone core plugs. Although the geometry of the PoreCor network is simplistic, it is nevertheless flexible enough to closely simulate the percolations properties of actual sandstone samples. Also, crucially, it makes an allowance for the shielding of large pores by small throats, which...
The depositional environment and sequence stratigraphy of the Samana Suk Formation (of CollovianBathonian age) based on field and petrographic data is presented. The formation is mainly composed of limestone with subordinate sandstone and marl. The limestone is medium to thick bedded and nodular at places with inter beds of sandstone and thin conglomerate intervals. The sandstone is reddish bro...
Measurements of Middle Jurassic tridactyl dinosaur tracks from the Bathonian, Lealt Shale, Valtos Sandstone, Duntulm and Kilmaluag formations of the Isle of Skye, UK, are compared to the same measurements taken for dinosaur footprints from the Bajocian, Gypsum Spring and the Bathonian, Sundance Formation of the Bighorn Basin, Wyoming, USA. Principal component analysis of the data suggests that ...
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