نتایج جستجو برای: micro structure of intact rocks
تعداد نتایج: 21239398 فیلتر نتایج به سال:
The purpose of this study is developing of a model for estimation of elastic modulus of intact rocks. Mechanical rock excavation projects require static modulus of elasticity (E) of the intact rock material. High-quality core specimens of proper geometry are nedded for the direct determination of this parameter. However, it is not always possible to obtain suitable specimens from highly fractur...
The geotechnical importance of studying fluid flow through porous media and soils in particular, becomes evident when dealing with groundwater movement in surficial geomaterials that can be initiated by hydraulic gradients that develop during construction activity, groundwater extraction, impounding of reservoirs and groundwater recharge during adverse climatic events. In a geotechnical context...
In this work, the mechanism for fracture of brittle substances such as rocks under a uniform normal tension is considered. The oriented straight micro-cracks are mostly created in all the polycrystalline materials resulting from the stress concentrations. The present work focuses on the interactions of the pre-existing micro-cracks, which can grow and propagate within a rock-like specimen. The ...
Background: The concentrations of radionuclides like 226Ra, 232Th and 40K and the dose rate are measured in igneous and metamorphic rock formations in and around Chickmagalur. A total of 236 samples from 13 different locations around study area were analyzed. Materials and Methods: The activity concentrations of the three radioactive elements were determined for mean period of 25000 s using HPG...
abstract the main purpose of this study was to investigate whether there was any significant difference between the speaking achievement of learners who were trained by means of consciousness raising of sociolinguistic skills and that of learners who were trained without the above mentioned task. the participants of this study consist of 60 intermediate level students participating languag...
Reservoir rocks, regardless of what kind (oil-, gasor water-bearing), are classified by their specific properties. Most rock properties, such as storage, permeability, electric conductivity, heat capacity and so on are determined by laboratory experiments and field tests under different external conditions. Besides temperature, pressure and chemical reactions, also the geometry of the pore spac...
peace and national security protection and ironic solving of international conflicts become the preliminary foundation of the united nations charter and had been considered as the main responsibilities of the security council, after world war ii and the establishment of united nations organization. therefore, the security council enables to analyze every kind of conflicts and challenges which ...
chapter one is devoted to a moderate discussion on preliminaries, according to our requirements. chapter two which is based on our work in (24) is devoted introducting weighted semigroups (s, w), and studying some famous function spaces on them, especially the relations between go (s, w) and other function speces are invesigated. in fact this chapter is a complement to (32). one of the main fea...
The study area is located at 130 km northwest of Nehbandan in South of Khorasan and is a part of the rectangular Chahvak (Dehsalm). Dacite, rhiodacite, andesite, rhyolite, tuff and lithic tuff with Eocene age are recognized in the study area. According to mineralogy, mentioned rocks include plagioclase, quartz, pyroxene, amphibole, biotite and alkaline feldspar. Plagioclase consists of zonal st...
background ecstasy or 3-4, methylenedioxymethamphetamine (mdma), as an amphetamine derivate, could lead to learning and memory impairment. objectives as the hippocampus is responsible for learning and memory, herein we evaluated acute and chronic effects of mdma on the structure of the hippocampus. materials and methods male wistar rats (200-250 g) received single or multiple injections of mdma...
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