Interactions Between Soils and Laboratory Simulated Electrolyte Solution     

Sitaram Nayak  B. M. Sunil  S. Shrihari  P. V. Sivapullaiah 《Geotechnical and Geological Engineering》2010,28(6):899-906

To study the impact of salt water intrusion on two types of soils from west coast region of India were investigated in the laboratory. The key characteristics evaluated included Atterberg limits, compaction characteristics, hydraulic conductivity and chemical characteristics of selected soils. The sea at this coast receives effluent from different points and hence the characteristics change with time and locality. Therefore, to maintain uniform composition, 0.5 N sodium chloride solution (NaCl) was prepared in the laboratory and batch tests were used to determine the immediate effect on soils. Soil specimens were prepared by mixing the soils with 0.5 N NaCl in the increments of 0, 5, 10 and 20% by weight to vary the degree of contamination. Experimental results of soils mixed with 0.5 N NaCl showed that the maximum dry density increases and the optimum moisture content (OMC) decreases with increasing sodium chloride concentration. The study also revealed that the hydraulic conductivity of the soils tested increases with increase in sodium chloride concentration. The Atterberg limits of contaminated specimens show a remarkable change when compared with uncontaminated specimens.  相似文献   

Postseismic relaxation due to Bhuj earthquake on January 26, 2001: possible mechanisms and processes     

C. D. Reddy  P. S. Sunil  Roland B��rgmann  D. V. Chandrasekhar  Teruyuki Kato 《Natural Hazards》2013,65(2):1119-1134

Earthquakes cause static stress perturbations in the nearby crust and mantle. Obeying rheological laws, this stress relaxes in a time frame of months to years with the spatial extent of few km to hundreds of km. While postseismic relaxation associated with major inter-plate earthquakes is well established, there have been few opportunities to explore its occurrence following intraplate earthquakes. The M _w 7.6 Bhuj earthquake on January 26, 2001 in western India is considered to be an intraplate event and provided a unique opportunity to examine post-earthquake relaxation processes sufficiently away from plate boundaries. To study the characteristics of transient postseismic deformation, six Global Positioning System campaigns were made at 14 sites. The postseismic transients were delineated after removing plate motions from the position time series. Postseismic deformation has been observed at all the sites in the study area. During 2001?C2007, the site closest to the epicenter exhibited postseismic deformation of about 30 and 25?mm in the north and east components, respectively. Time series of the NS and EW components of the postseismic transients can be fitted to both logarithmic and exponential functions. Close to the epicenter, the logarithmic function fits well to the initial transient, and an exponential function fits well to the later phases. The remaining sites (located east and west of the epicentral region) exhibited significantly diminished north?Csouth relaxation. Rapidly decaying afterslip and poroelastic mechanisms seem to be responsible for postseismic relaxation in the vicinity of epicenter during the initial period subsequent to the Bhuj earthquake. Postseismic relaxation by viscoelastic flow below the seismogenic zone seems to affect displacements across the entire Bhuj region. This paper presents the characteristics of postseismic transients and deformation processes in the scenario of the highly heterogeneous crust in the Bhuj region.  相似文献   

An analysis of debris-flow events in the Sardinia Island (Thyrrenian Sea, Italy)   总被引：1，自引：1，他引：0  

Laura Turconi  Sunil Kumar De  Francesca Demurtas  Luca Demurtas  Bruna Pendugiu  Domenico Tropeano  Gabriele Savio 《Environmental Earth Sciences》2013,69(5):1509-1521

On 6 December 2004, the Villagrande Strisaili area (middle-east Sardinia), was struck by debris flows; 330 mm of rainfall took place within 3 h with an hourly intensity of 120 mm, which is far more above than normal for the study area. In the urban center stony and driftwood deposits accounted for a total volume estimated as 10,000 m³. The event claimed huge amount of infrastructural loss and two human lives. According to the chronicle reports, the area experienced two debris-flow events in the last century. The present paper is the outcome of an intensive study of such debris-flow events including their physical processes and geomorphological effects through both field survey and laboratory analysis.  相似文献   

A GIS-based Spatial Pattern Analysis Model for eco-region mapping and characterization     

Yingchun Zhou  Sunil Narumalani  William J. Waltman  Sharon W. Waltman  Michael A. Palecki 《International journal of geographical information science》2013,27(5):445-462

Growing concerns about global climate change, biodiversity maintenance, natural resources conservation, and long-term ecosystem sustainability have been responsible for the transformation of traditional single resource management approaches into integrated ecosystem management models. Eco-regions are large ecosystems of regional extent that contain smaller ecosystems of similar response potential and resource production capabilities. They can be used as a geographical framework for organizing and reporting resource information, setting bioecological recovery criteria, extrapolating site-level management, and monitoring global change. The objective of this research is to develop a quantitative, multivariate regionalization model that is capable of delineating eco-regions at multiple levels from remotely sensed information and other environmental and natural resources spatial data. The Spatial Pattern Analysis Model developed in this study uses a region-growing algorithm to generate spatially contiguous regions from primitive polygonal land units. The algorithm merges the most similar pair of neighbouring units at each iteration, based on satisfying certain similarity criteria until all units are grouped into one. This model was utilized to develop an eco-region map of Nebraska with three hierarchical levels. In the mapping process, the STATSGO data set was used to build the primitive map units. Environmental parameters included in the model were multi-temporal AVHRR data, soil rooting depth, organic matter content, available water capacity, and long-term annual averages of water balance and growing degree day totals. Development of the model provides a new and useful approach to eco-region mapping for resource managers and researchers. The method is automated and efficient, reduces the judgement biases and uncertainty of manual analyses, and can be replicated for other regions or for the regionalization of other themes.  相似文献   

IAG/AIG NEWSLETTER NO. 28 (2/2012)     

Sunil Kumar De 《地球表面变化过程与地形》2013,38(5):547-550

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IAG/AIG Newsletter No. 27 (3 ‐4/2011)     

Sunil Kumar De 《地球表面变化过程与地形》2012,37(10):1126-1132

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Bulk viscous barotropic magnetised string cosmological models     

Sunil K. Tripathy  Subodha K. Nayak  Subrat K. Sahu  Tushar R. Routray 《Astrophysics and Space Science》2009,323(3):281-287

Spatially homogeneous and anisotropic LRSBianchi type-I string cosmological models are studied in the frame work of general relativity when the source for the energy momentum tensor is a bulk viscous fluid containing one dimensional strings embedded in a magnetic field. A barotropic equation of state for the pressure and density is assumed to get determinate solutions of the field equations. The bulk viscous pressure is assumed to be proportional to the energy density. The effects of viscosity and electromagnetic field on the properties of the model are investigated. The role of bulk viscosity and electromagnetic field in getting an inflationary phase and in establishing a string phase in the universe is studied.  相似文献   

Bianchi type-VI_h string cloud cosmological models with bulk viscosity     

Sunil K. Tripathy  Dipanjali Behera 《Astrophysics and Space Science》2010,330(1):191-201

String cloud cosmological models are studied using spatially homogeneous and anisotropic Bianchi type VI_h metric in the frame work of general relativity. The field equations are solved for massive string cloud in presence of bulk viscosity. A general linear equation of state of the cosmic string tension density with the proper energy density of the universe is considered. The physical and kinematical properties of the models have been discussed in detail and the limits of the anisotropic parameter responsible for different phases of the universe are explored.  相似文献   

Underground opening damage from earthquakes   总被引：18，自引：0，他引：18  

Sunil Sharma  William R. Judd 《Engineering Geology》1991,30(3-4):263-276

A summary of worldwide qualitative data regarding the behavior of underground openings during earthquakes is presented. This information has been collected for 192 reports of underground behavior from 85 earthquakes throughout the world. The data have been assembled into a data base to determine some of the significant factors that may affect underground stability. The parameters of interest are: (1) extent of damage; (2) overburden cover; (3) predominant rock type; (4) form of support (i.e. type of internal liner or opening support); (5) geographic location; and (6) magnitude and epicentral distance of the affecting earthquake. A significant contribution to this study is the development of a correlation between peak ground acceleration at the surface, overburden depth and damage. This relationship will allow for preliminary assessment of stability of new underground structures prior to extensive dynamic analyses. Also, the vulnerability of existing underground facilities may be assessed rapidly on the basis of the qualitative data presented herein.  相似文献   

Development of Information Evaluation System for Smart City Planning Using Geoinformatics Techniques     

Prashant Persai  Sunil Kumar Katiyar 《Journal of the Indian Society of Remote Sensing》2018,46(11):1881-1891

Urbanization is a continuous process, which transforms the traditional setup into the modern era. Uneven population growth over the next 3 decades is expected in cities. In this context, the new technology-based solutions are desirable, which can provide more efficient and robust approaches for urban infrastructure planning. Keeping these visions, the smart city concept is evolving in the developing countries like India, which appears a new paradigm of systematic intelligent urban infrastructure planning in the city. This research work comprises of grids-based, eight different land use and infrastructure-related information evaluation systems namely urban settlements information evaluation system, water resource information evaluation system, urban green space information evaluation system, intelligent transportation information evaluation system, basic infrastructure information evaluation system, power distribution information evaluation system, telecommunication mast information evaluation system and city surveillance information evaluation system for the development of smart city priority zones in the Bhopal city, capital of Madhya Pradesh, India. The LISS IV and Cartosat 1 sensor digital Image data along with ancillary data were used. The GPS survey was carried out to confirm ground realities, and digital intelligent map was prepared for various utilities after integration of thematic layers. The geostatistical analysis and weights-based methods were used for the creation of information evaluation system for city planning. The investigation of results have shown that various parameters related to smart city planning can be analyzed in a more efficient manner by dividing the area into an appropriate size grid. The spatial integration of information evaluation systems were carried out and areas were divided into low-, medium- and high-priority zones. These prominent categories such as high-priority zones covered the 14% of the study area, similarly medium-priority zones covered the 34% of the study area and low-priority zones covered the 52% of the study area. This research work investigations are very useful for the formulation of new strategic plans, in order to achieve better land use and infrastructure features utilization for the smart city planning.  相似文献