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101.
A procedure for cyclonic microzonation of coastal regions with the help of the cyclone track records is outlined using a sound
method of statistical forecast and finding wind speed at a site with the help of standard wind field model. The procedure
can be adopted for regions where directly measured wind speeds are scarce like, coastal regions of the developing and under
developed countries. For the purpose of microzonation, the regions along with the available cyclone tracks are mapped using
GIS. The area is then divided into a number of grids. The centre of the grid (site) is taken as the centre of the circle of
influence. The cyclonic wind speeds at the site are estimated from the tracks falling within the influence circle. Distribution
of the cyclonic wind speed at the site is then obtained from the estimated cyclonic wind speeds. Assuming the arrival of cyclone
to be a Poisson process, a cyclone hazard curve, denoting the annual probability of exceedance versus cyclonic wind speed
is determined. From the hazard curves drawn for different sites of the region, cyclonic microzonation map is prepared for
different return periods of the cyclonic wind speed. The procedure is illustrated by applying it to microzone a very crucial
coastal region of Andhra Pradesh in India, for which cyclone track records are available. 相似文献
102.
Hydrogeochemical investigations are carried out in the different blocks of Burdwan district, West Bengal, India in order to
assess its suitability for drinking as well as irrigation water purpose. Altogether 49 representative groundwater samples
are collected from bore wells and the water chemistry of various ions viz. Ca2+, Mg2+, Na+, K+, CO32−, HCO3−, Cl−, SO42− and NO3− are carried out. The chemical relationships in Piper and Gibbs diagram suggest that the groundwater mainly belongs to alkali
type and Cl− group and are controlled by rock dominance. A comparison of groundwater quality in relation to drinking water quality standards
proves that most of the water samples are suitable for drinking water purpose whereas groundwater in some areas of the district
has high salinity and high sodium adsorption ratio (SAR), indicating unsuitability for irrigation water and needs adequate
drainage. 相似文献
103.
104.
105.
Shear Behaviour of Loose and Compacted Pond Ash 总被引:1,自引:0,他引:1
Massive utilization of pond ash in earth works requires thorough understanding of its geotechnical characteristics, especially
strength characteristics. Here in this paper, a detailed experimental study carried on the strength and other geotechnical
characteristics of pond ash samples, collected from inflow and outflow points of two ash ponds in India, are presented. Strength
characteristics were investigated using consolidated drained (CD) and undrained (
[`(\textCU)] \overline{\text{CU}} ) triaxial tests with pore water pressure measurements, conducted on loose and compacted specimens of pond ash samples under
different confining pressures. Ash samples from inflow point exhibited behaviour similar to sandy soils in many respects.
They exhibited higher strengths than reference material (Yamuna sand), though their specific gravity and compacted maximum
dry densities are significantly lower than sands. Ash samples from outflow point exhibited significant differences in their
properties and values, compared to samples from inflow point. Shear strength of the ash samples from outflow point are observed
to be low, particularly in loose state where static liquefaction is observed. 相似文献
106.
Manoj Datta G. Venkatappa Rao Shashi K. Gulhati 《Marine Georesources & Geotechnology》2013,31(4):307-341
Abstract This paper presents the results of a laboratory investigation undertaken to study the nature of two submarine carbonate soils from Bombay High off the west coast of India, as well as to study the shear and plasticity behavior of their sand and silt‐clay fractions, respectively. Scanning electron micrographs reveal that the carbonate content in both soils is comprised primarily of nonskeletal particles of various types. X‐ray diffraction and infrared absorption analyses indicate that in one soil the carbonate fraction consists of calcite and aragonite minerals, whereas in the other soil dolomite is also present. The non‐carbonate fraction of both soils is comprised primarily of quartz and feldspar, and also some clay minerals. The nature of the carbonate fraction of the two soils indicates that they were formed by different depositional processes. During drained triaxial shear the nonskeletal sand grains of both soils exhibit a lower degree of crushing when compared with that of the skeletal carbonate sands, and thus appear to be stronger foundation material. Although the carbonate contents of the silt‐clay fractions of the two soils are similar, they exhibit markedly different plasticity characteristics . This is probably because of the microlevel cementation produced by carbonate material in one soil. This study leads one to the conclusion that carbonate content alone should not be treated as a parameter which controls the engineering behavior of submarine soils; the nature and form of carbonate material must also be identified. 相似文献
107.
After reviewing the outer and central regions of a neutron star, we discuss the central region and the possibility that the core has a solid structure. We present the work of different groups on the solidification problem, suggesting that the neutron star-cores are indeed solid. 相似文献
108.
Biomarker responses in Macoma nasuta (Bivalvia) exposed to sediments from northern San Francisco Bay
Our study investigates biomarker responses and survival of Macoma nasuta exposed to sediments collected from six locations in northern San Francisco Bay. Biomarkers analyzed were stress proteins (hsp70) in gill, mantle and digestive gland, lysosomal membrane damage and histopathologic lesions. Sediments and clam tissues were analyzed for a comprehensive suite of heavy metals and trace organic pollutants. Sediment grain size and organic carbon content were determined. Clams accumulated metals, polyaromatic hydrocarbons (PAHs) and organochlorine pesticides (aldrin and p,p(')-DDT and its metabolites p,p(')-DDD and p,p(')-DDE). Pearson and Spearman correlation analysis revealed that mortality, hsp70 in gill and histopathologic lesion scores in gonads, and lysosomal membrane damage were significantly correlated with tissue concentrations of DDT and/or its metabolites. Tissue concentrations of metals, in particular nickel, chromium, and copper, were associated with macrophage aggregates in digestive gland and germ cell necrosis. Cadmium was linked to mortality and lysosomal membrane damage. 相似文献
109.
Seasonal variations in the antioxidant enzymes (catalase, superoxide dismutase [SOD], NADH-DT diaphorase), biotransformation enzyme, glutathione-S-transferase (GST) and microsomal lipid peroxidation in digestive tissue of barnacle, Balanus balanoides, from polluted and non-polluted populations have been evaluated. Relationships with accumulated polyaromatic hydrocarbon (PAH) concentration in barnacle tissues and environmental parameters (water temperature, salinity, dissolved oxygen concentration, water pH) were determined. As a general trend, maximum antioxidant enzyme and GST activities were detected in the pre-monsoon period or summer (March-June) followed by a gradual decrease during the monsoon (July October) with a minimum in the post-monsoon period or winter (November February). This pattern was similar to tissue concentrations of PAHs, resulting in a significant positive correlation with antioxidant enzymes, mainly catalase and SOD. Microsomal lipid peroxidation exhibited an almost reverse trend of seasonal variation to that of antioxidant enzyme activities indicating an enhanced susceptibility of barnacle tissues to oxidative stress. Among the environmental parameters, only water temperature seemed to have a significant effect on observed variations of antioxidant enzymes and GST activities. The barnacles from polluted and non-polluted populations exhibited seasonal differences in the activities of all the enzymes studied, particularly catalase, SOD and GST, suggesting the possibility of some biochemical adaptation in organisms from a chronically polluted environment. The results indicated that antioxidant defense components, catalase and SOD, are sensitive parameters that could be useful biomarkers for the evaluation of contaminated aquatic ecosystems. The results also suggested the potentiality of barnacle, B. balanoides, as a bioindicator organism against organic pollution. 相似文献
110.
Summary Compressional wave velocity has been measured in the laboratory by the ultrasonic pulse technique in a number of rock specimens of different geological formations collected from different parts of India. The effect of water saturation on the velocity in some of the porous samples has been investigated. The velocity in some polycrystalline aggregate crystals and in some ores has also been determined. The accuracy of measurements varies from 1 to 2 per cent. The results of measurements with geological details are presented in tabulated form.This paper is published by the kind permission of the Director General, Geological Survey of India. 相似文献