نتایج جستجو برای: rock material
تعداد نتایج: 400441 فیلتر نتایج به سال:
Coal dust explosions in underground coal mines are pre vented by a generous application of rock dust (usually lime stone). If an explosion should occur, the rock dust disperses, mixes with the coal dust and prevents fl ame propagation by acting as a thermal inhibitor or heat sink. To investigate this process in more detail, a number of ex plosion experiments using various coal dust and limes...
water has an important role in creating pollution problems in the mining regimes influencing the surrounding surface environment. the purpose of this study is to make an assessment of groundwater quality in an underground mine site in portugal with a view of determining the pollution potential of groundwater. in the corresponding surface area of this underground mine, intersections of fou...
The teeth of limpets exploit distinctive composite nanostructures consisting of high volume fractions of reinforcing goethite nanofibres within a softer protein phase to provide mechanical integrity when rasping over rock surfaces during feeding. The tensile strength of discrete volumes of limpet tooth material measured using in situ atomic force microscopy was found to range from 3.0 to 6.5 GP...
—We provide the first description of the nest, eggs, and breeding behavior of the Mérida Tapaculo (Scytalopus meridanus). Data are from one pair in the moist cloud forest of Yacambu National Park, Venezuela during April–May 2004. Two nests, constructed by the same pair, were globular in structure and consisted of mossy material placed in a rock crevice of a muddy rock wall. The eggs were cream ...
Pedogenesis and clay mineralogy of soils and rock samples were studied in a transect of calcareous, gypsiferous, saline soils and sediments of Bakhtegan lake bank in southern Iran. The main objectives of study were to determine the occurrence of clay minerals and factors controlling their distribution pattern and relative abundance in soils and parent materials. The soil parent material is high...
Source determination of fecal contamination is imperative to efficiently reduce the fecal material load to environmental waters. This study developed primer pairs targeting three F+ RNA bacteriophages and a simple filtration sampling method to enumerate and identify coliphages in environmental waters. Water samples were collected seasonally for one year from the watershed of Table Rock Lake on ...
Compaction of porous rocks can occur in two modes: uniform and localized. Recent experimental work has demonstrated that compaction can occur in tabular zones that expand with increasing applied deformation. The appearance of compaction bands and their growth has a strong influence on the measured permeability of the host rock. The rock behind the moving compaction front can be either uniformly...
In this paper, we explore the fundamental physics behind the application of electrical resistivity and induced polarization during tunnel boring machine (TBM) mining. Using finite element (FE) analysis, we model the electric field created when current is injected into the surrounding ground via electrodes in the TBM cutterhead. The FE analysis simulates a variety of materials and conditions inc...
Cracks in a rock mass subjected to a uniaxial stress will be preferentially closed depending on the angle between the fracture normal and the direction of the applied stress. If the prestress fracture distribution is isotropic, the effective elastic properties of such a material are then transversely isotropic due to the preferred alignment of the cracks. Velocity measurements in multiple direc...
Current studies investigating the role of biophysical cues on cell migration focus on the use of culture platforms with static material parameters. However, migrating cells in vivo often encounter spatial variations in extracellular matrix stiffness. To better understand the effects of stiffness gradients on cell migration, we developed a 2.5D cell culture platform where cells are sandwiched be...
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