نتایج جستجو برای: hard rocks
تعداد نتایج: 168880 فیلتر نتایج به سال:
In this paper, we present a tiling method for generating piles of rocks without any computationally demanding physically-based simulation. Previous techniques rely on a periodic tiling of rocks and generate unrealistic repetitive patterns. In contrast, our approach relies on a modified corner cube algorithm to generate a set of aperiodic tiles. We generalize the construction method so that the ...
Archean rocks may provide a record of early Earth environments. However, such rocks have often been metamorphosed by high pressure and temperature, which can overprint the signatures of their original formation. Here, we show that the early Archean banded rocks from Isua, Akilia, and Innersuartuut, Greenland, are enriched in heavy iron isotopes by 0.1 to 0.5 per mil per atomic mass unit relativ...
The development of hydrogeology with respect to hard-rock and fractured-rock aquifers is described. differences between porous karst are explained, as well the groundwater flow regimes in different fractured rocks. A position taken on numerical modeling, from beginning modeling present day, focus particular challenges. Because importance aquifers, tools for exploration future resource managemen...
Siliceous sedimentary rocks of Tertiary age were recovered at three of the nine sites drilled during Leg 31 (Table 1). Only relatively small amounts of lithified material were retrieved, but these rocks are particularly interesting because they include three distinct types of siliceous rock and because each type occurs with a distinct sediment lithology. The kinds of rocks sampled are (with lit...
In this paper we classify the range of feldspathic igneous rocks using five geochemical variables: the FeO/(FeOþMgO) ratio or Fe-index, the modified alkali^lime index, the aluminum-saturation index, the alkalinity index, and the feldspathoid silica-saturation index.The Fe-index distinguishes between melts that have undergone extensive iron enrichment during differentiation from those that have ...
Abstract Alexandria is one of the Mediterranean UNESCO World Heritage sites at risk from coastal flooding and erosion due to sea-level rise. The city’s position on coast means it especially vulnerable rising sea levels. in Egypt flooding. All archaeological northern are also said be erosion. flood expected reach a tipping point by 2050. This research presents numerical analysis geotechnical str...
Characterization of Excavation Damaged Zone (EDZ) around an underground excavation is a major research topic for deep geological disposal of medium to high level radioactive waste. Rock fracturing due to excavation and thermal loading and its resultant rock mass permeability change in the EDZ are important aspects in the EDZ characterisation. A new function to predict rock mass permeability cha...
Same level falls continue to contribute to an alarming number of slip/trip/fall injuries in the mining workforce. The objective of this study was to investigate how walking on different surface types and transverse slopes influences gait parameters that may be associated with a trip event. Gait analysis was performed for ten subjects on two orientations (level and sloped) on smooth, hard surfac...
First we need to define what “FOD” is and how serious is the threat. In the aviation industry, there are two generally accepted meanings for the acronym FOD. One definition is “Foreign Object Debris”, which includes substances, debris or any articles that could potentially cause damage to a vehicle or engine (Figures 1 and 2). It is anything – large or small – inside or around aircraft and flig...
Capuchins living in Boa Vista (Piauì, Brazil) crack open hard palm nuts on hard, level surfaces (anvils) using stones (hammers) as percussive tools. This activity leaves diagnostic physical remains: distinctive shallow depressions (pits) on the surface of the anvil, cracked shells, and stone hammers on the anvil. To initiate comparison of percussive stone tool use and interpretation of the arti...
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