Himalayan transverse faults and folds and their parallelism with subsurface structures of north indian plains—discussion     

K.S. Misra 《Tectonophysics》1979,56(3-4)

  相似文献   

Analytical solution for micropile design under tension and compression     

Anil Misra  C.-H. Chen 《Geotechnical and Geological Engineering》2004,22(2):199-225

Micropiles are being increasingly utilized in foundation rehabilitation and seismic retrofitting projects. The function of the micropiles in these projects is to enhance the foundation ultimate capacity as well as reduce foundation deflection. This paper focuses on an analytical model for micropile load-displacement behavior subjected to compressive as well as tensile loading. The soil-micropile interaction is considered explicitly in the model development. Furthermore, to keep the model simple and accessible to designers, the micropile-soil interface is assumed to be linearly elastic-perfectly plastic and homogeneous with depth. Closed form expressions of micropile deformation as a function of applied load are presented. These expressions are used to study the effect of model parameters on micropile yield behavior. Micropile strain distribution and the load transfer behavior calculated by the model are discussed. The model calculations are compared with the field measured load-displacement curves. The measured micropile load-displacement data available in the literature are analyzed to evaluate the model parameters. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

Nature of diamonds in Yakutian eclogites: views from eclogite tomography and mineral inclusions in diamonds   总被引：1，自引：0，他引：1  

Mahesh Anand  Lawrence A. Taylor  Kula C. Misra  William D. Carlson  Nikolai V. Sobolev 《Lithos》2004,77(1-4):333-348

We have performed dissections of two diamondiferous eclogites (UX-1 and U33/1) from the Udachnaya kimberlite, Yakutia in order to understand the nature of diamond formation and the relationship between the diamonds, their mineral inclusions, and host eclogite minerals. Diamonds were carefully recovered from each xenolith, based upon high-resolution X-ray tomography images and three-dimensional models. The nature and physical properties of minerals, in direct contact with diamonds, were investigated at the time of diamond extraction. Polished sections of the eclogites were made, containing the mould areas of the diamonds, to further investigate the chemical compositions of the host minerals and the phases that were in contact with diamonds. Major- and minor-element compositions of silicate and sulfide mineral inclusions in diamonds show variations among each other, and from those in the host eclogites. Oxygen isotope compositions of one garnet and five clinopyroxene inclusions in diamonds from another Udachnaya eclogite (U51) span the entire range recorded for eclogite xenoliths from Udachnaya. In addition, the reported compositions of almost all clinopyroxene inclusions in U51 diamonds exhibit positive Eu anomaly. This feature, together with the oxygen isotopic characteristics, is consistent with the well-established hypothesis of subduction origin for Udachnaya eclogite xenoliths. It is intuitive to expect that all eclogite xenoliths in a particular kimberlite should have common heritage, at least with respect to their included diamonds. However, the variation in the composition of multiple inclusions within diamonds, and among diamonds, from the same eclogite indicates the involvement of complex processes in diamond genesis, at least in the eclogite xenoliths from Yakutia that we have studied.  相似文献   

Measured kinematic fields in the biaxial shear of granular materials   总被引：1，自引：0，他引：1  

A. Misra  H. Jiang 《Computers and Geotechnics》1997,20(3-4):267-285

Biaxial experiments are performed with rod assemblies to study the micro-mechanical deformation behavior of granular materials. The focus of these experiments is upon the micromechanical behavior under mixed boundary conditions, with stress-controlled lateral boundaries and displacement-controlled axial boundaries. Particle motions, i.e. displacements and rotations, are measured during the test. The particle motions are analyzed to study deformation patterns, including shear localization. Deformation patterns in a number of rod assemblies with random packing structures are investigated.  相似文献   

The Lower Permian coal seams from Singrauli coalfield (M.P.), India: petrochemical nature, rank, age and sedimentation     

B.K. Misra  B.D. Singh 《International Journal of Coal Geology》1990,14(4)

Biopetrographic and chemical investigations carried out on the Lower Permian (Barakar Formation) coal seams encountered in two bore-holes (NCSM-3 and CMSA-111) from the Singrauli coalfield, Son Valley, reveal that they are, in general, rich in inertinite and mineral matter towards the eastern part. Whereas, towards the western part they are rich in vitrinite with subordinate amounts of inertinite and mineral matter. The Turra and Purewa Top seams, in the eastern part, consist chiefly of mixed and fusic coal types and the Turra and Purewa Merged seams, in the western part of the basin, are characterized dominantly by vitric and mixed coal types. The basin of deposition was shallower in its major part but deepened towards west. Consequently frequent oxic fluctuations are most common in the coal seams of the eastern part.The rank of these coal seams ranges between subbituminous-A to high-volatile bituminous-C stages. They show normal increase in rank with depth. The coal seams in the western part of the area are higher in rank than their counterparts in the east. The Purewa Bottom seam (NCSM-3) is petro-palynologically correlatable with the Turra seam (CMSA-111) of the western part.It has been presumed that Glossopteridophyta (a complex group of gymnospermous plants), arthrophytes and ferns were the vegetal source for the formation of Barakar coal seams. These plants during the Early Permian grew as thick forests along river valleys and as upland and subaquatic vegetation, and experienced a warm, humid and windy temperate climate. The coal seams were presumably deposited in backwater and lacustrine swamps in fluvial environment from hypoauchthonous source material.An attempt has been made to explain reasons for the high incidence of mineral matter and its apparent relationship with inertinite content in the coal seams while also discussing the depositional history.  相似文献   

Downwind non-uniform mixing in shoreline fumigation processes   总被引：1，自引：0，他引：1  

M. Stunder  S. Sethuraman  P. K. Misra  H. Sahota 《Boundary-Layer Meteorology》1986,34(1-2):177-184

The assumption of vertical uniform mixing in shoreline fumigation models is tested using two types of modifications to a base statistical model that takes into account non-uniform mixing. One of the modifications involves the use of a downdraft velocity scheme developed for a convective boundary layer. The other modification is based on an empirical adjustment factor derived from water tank experiments. Results from all three models are compared with field observations. Comparisons indicate that the modifications do not improve the results of the base dispersion model.  相似文献   

The effects of mesoscale turbulence on plume rise in a land/lake environment     

G. C. Edwards  P. K. Misra 《Boundary-Layer Meteorology》1984,29(2):155-165

An extensive data base of LIDAR and photographically measured plumes from the Nanticoke thermal generating station (located on the north shore of Lake Erie) has been accumulated over several years of full-scale atmospheric experiments. Analysis of the data shows that the empirical entrainment constant used in the Briggs simple plume rise formulation has a value of 0.8, which is significantly larger than 0.6 found by Briggs (1975). A hypothesis is proposed that mesoscale eddies present in the land/lake environment are responsible for vertical plume meander leading to the observed enhanced vertical plume spread and lower mean plume rise at this site. This is substantiated through theoretical considerations and experimental data. The results are significant in the computation of ground-level concentrations at such complex terrain sites.  相似文献   

Depositional environment of the Krol Group of the Nainital area and its impact on the stromatolites     

S. B. Misra 《Journal of Earth System Science》1984,93(4):447-464

Depositional environment of the Krol group varied temporally from subtidal in the Manora to intertidal in the Sleepy Hollow times. The conditions that succeeded were peritidal in the Ayarpatta and supratidal in the Narainnagar times. These conditions were the main controlling factors in the growth and development of the algal stromatolites. The Manora formation, due to subtidal conditions, and the Sleepy Hollow formation, due to detrital influx, are almost devoid of stromatolites. The carbonates of the Ayarpatta formation representing a peritidal complex possess columnar and oncolitic stromatolites, while the sediments of the Narainnagar formation characterized by supratidal features contain blistered, domal and crinkled-laminar forms. The types and sizes of stromatolites therefore are governed by the depositional conditions prevailing in the sedimentary basin.  相似文献   

Stable (δ13C and δ15N) isotopes and magnetic susceptibility record of late Holocene climate change from a lake profile of the northeast Himalaya     

Shailesh Agrawal  Pradeep Srivastava  Sonam  N. K. Meena  Santosh K. Rai  R. Bhushan  D. K. Misra  A. K. Gupta 《Journal of the Geological Society of India》2015,86(6):696-705

  相似文献   

Effect of the finite size of an asteroid on its deflection using a tether–ballast system     

Mohammad J. Mashayekhi  Arun K. Misra 《Celestial Mechanics and Dynamical Astronomy》2016,125(3):363-380

Potentially hazardous near-Earth objects which can impose a significant threat on life on the planet have generated a lot of interest in the study of various asteroid deflection strategies. There are numerous asteroid deflection techniques suggested and discussed in the literature. This paper is focused on one of the non-destructive asteroid deflection strategies by attaching a long tether–ballast system to the asteroid. In the existing literature on this technique, very simplified models of the asteroid-tether–ballast system including a point mass model of the asteroid have been used. In this paper, the dynamical effect of using a finite size asteroid model on the asteroid deflection achieved is analyzed in detail. It has been shown that considering the finite size of the asteroid, instead of the point mass approximation, can have significant influence on the deflection predicted. Furthermore the effect of the tether-deployment stage, which is an essential part of any realistic asteroid deflection mission, on the predicted deflection is studied in this paper. Finally the effect of cutting the tether on the deflection achieved is analyzed and it has been shown that depending on the orbital properties of the asteroid as well as its size and rotational rate, cutting the tether at an appropriate time can increase the deflection achieved. Several numerical examples have been used in this paper to elaborate on the proposed technique and to quantitatively analyze the effect of different parameters on the asteroid deflection.  相似文献