نتایج جستجو برای: hard rocks

تعداد نتایج: 168880  

Journal: :Geosciences 2022

We experimentally determined the hydraulic properties of fractures within various rock types, focusing on a variety Variscan rocks. Flow-through experiments were performed slate, graywacke, quartzite, granite, natural fault gouge, and claystone samples containing an artificial fracture with given roughness. For slate samples, transmissivity was measured at confining pressures, pc, up to 50 MPa,...

2008
Andrea Hamilton Christopher Hall

It is well known that sodium sulfate causes salt crystallization damage in building materials and rocks. However since the early 1900s the existence of the metastable heptahydrate has been largely forgotten and almost entirely overlooked in scientific publications on salt damage mechanics and on terrestrial and planetary geochemistry. We use hard synchrotron x-rays to detect the formation of th...

2006
Hans-Rudolf Wenk Georg Dresen Gabriela Gonzalez

Mechanical Dauphiné twinning in quartz has been of long-standing interest, both in single crystals and polycrystalline aggregates. This study investigates texture development in fine-grained quartz rock novaculite with no initial texture using compression experiments conducted in the Paterson gas apparatus to explore the influence of stress and temperature. Texture patterns are measured with ti...

2015
P. Kaminski

Nowadays, one of the main tasks of Ukrainian coal industry is increasing labour productivity by means of complex mechanization and automatization of mining operations with usage of modern equipment. The best example is implementation of modern plow complexes on Western Donbas mines, PJSC “DTEK Pavlogradvugillia”. Currently, plowing is one of perspective directions of coal extraction development...

2009
Rainer Krenn Andreas Gibbesch Gerd Hirzinger

Software simulations of the locomotion play an important role in the chassis design and dimensioning phase of planetary rovers. In this paper two key modeling techniques for simulating the physical contact between rover wheels and planetary surface will be presented. The first one is PCM (Polygonal Contact Model). Generally, PCM provides the contact dynamics between two bodies, which are specif...

2001
Takashi Kubota Shujiro Sawai Tatsuaki Hashimoto Jun'ichiro Kawaguchi Akira Fujiwara

The MUSES-C mission is the world’s first sample and return attempt to/from the near Earth asteroid. In deep space, it is hard to navigate, guide, and control a spacecraft on a real-time basis remotely from the earth mainly due to the communication delay. So autonomy is required for final approach and landing to an unknown body. It is important to navigate and guide a spacecraft to the landing p...

Journal: :زمین شناسی اقتصادی 0
ملیحه قورچی روکی سعید سعادت علیرضا عاشوری

study area is located in district of bajestan and ferdows cities, ne of iran. structurally, this area is part of lut block. the oldest exposed rocks, to the north of intrusive rocks and in eastern bajestan, are meta-chert, slate, quartzite, thin-bedded crystalline limestone and meta-argillite. the sedimentary units are: sardar formation (carboniferous), jamal formation (permian), sorkh shale an...

2014
Richard D. Norris James M. Norris Ralph D. Lorenz Jib Ray Brian Jackson

The engraved trails of rocks on the nearly flat, dry mud surface of Racetrack Playa, Death Valley National Park, have excited speculation about the movement mechanism since the 1940s. Rock movement has been variously attributed to high winds, liquid water, ice, or ice flotation, but has not been previously observed in action. We recorded the first direct scientific observation of rock movements...

Journal: :geopersia 0
vahid rastegarian postgraduate student in engineering geology, bu-ali sina university, geology department, hamadan mojtaba heidari assisstant prof. in engineering geology, bu-ali sina university, geology department, hamadan behrouz rafiei associate prof. in sedimentary petrology, bu-ali sina university, geology department, hamadan yazdan mohebi phd student in engineering geology, bu-ali sina university, geology department, hamadan

a research program was conducted on different clay-bearing rocks selected from the ilam, sarpol-e zahab and tajarak regions (iran) to predict their slaking characteristics. the new durability apparatus (nested mesh drums) separates disintegrated particles varying from > 25.4 to < 2 mm as the drums were rotated. on the basis of the particle size distribution, the disintegration ratio (dr) was us...

Journal: :iranian journal of earth science 0
habib allah torshizian department of geology, islamic azad university, mashhad branch, mashhad, iran

the study area is located in the northeast of iran. miankuhi formation is 500m thick and comprises homogeneous shales, brown granular sandstone and siltstone. in this study, 45 samples were taken from miankuhi shales and sandstones in order to determine their tectonic origin by using a polarizing microscope. samples were analysed by x-ray fluorescence (xrf) method to determine their chemical co...

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