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Hydrochemical characteristics and groundwater quality assessment in Tirupur Region, Coimbatore District, Tamil Nadu, India 总被引：3，自引：0，他引：3
Groundwater samples from 62 locations have been collected from Tirupur region viz. Avinashi, Tirupur and Palladam taluks of
Coimbatore District. The extensive agricultural industrial activities and urbanization resulted in the contamination of the
aquifer. To study the contamination of groundwater, water samples were collected in an area of 180 km2 and analysed for major cations and anions. Most of the locations are contaminated by higher concentration of EC, TDS, K and
NO3. Major hydro chemical facies were identified using Piper trilinear diagram. Based on US salinity diagram, most of the samples
fall in the field of C3S1, indicating high salinity and low sodium water, which can be used for almost all types of soil with
little danger of exchangeable sodium. Majority of the samples are not suitable for domestic purposes and far from drinking
water standards. However, PI values indicates that groundwater is suitable for irrigation. 相似文献
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Arumugam Sakunthalai Ramadhas Chandrasekaran Muraleedharan Simon Jayaraj 《洁净——土壤、空气、水》2008,36(12):978-983
Biodiesel is a renewable alternative fuel that can be used as substitute for mineral diesel. The use of biodiesel in diesel engines reduces all of the exhaust emissions expect NOx. The higher temperature in the combustion chamber increases the NOx emissions. The recirculation of a small percentage of cooled exhaust gases into the combustion chamber through the intake manifold reduces the in‐cylinder temperature. Moreover, the cooling of exhaust gases before mixing with fresh air introduced to the engine does not affect its volumetric efficiency but it absorbs the heat of combustion. This leads to a reduction in NOx emissions and improves the engine brake thermal efficiency. This paper describes the investigation of the performance and emission characteristics of a biodiesel‐fueled, naturally aspirated, single cylinder diesel engine with cooled exhaust gas recirculation. 相似文献
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In 1986, the Malaysian Highway Authority constructed a series of trial embankments on the Muar Plain (soft marine clay) with the aim of evaluating the effectiveness of various ground improvement techniques. This study investigates the effect of two such ground improvement schemes: (a) preloading of foundation with surface geogrids and synthetic vertical drains and (b) sand compaction piles. The paper is focused on the finite element analysis of settlements and lateral displacements of the soft foundation. In scheme (a), the numerical predictions are compared with the field measurements. In scheme (b), only the numerical analysis is presented and discussed in the absence of reliable measurements due to the malfunctioning of the electronic extensometer and inclinometer system during embankment construction. The current analysis employs critical state soil mechanics, and the deformations are predicted on the basis of the fully coupled (Biot) consolidation model. The vertical drain pattern is converted to equivalent drain walls to enable plane strain modelling, and the geogrids are simulated by linear interface slip elements. The effect of sand compaction piles is investigated considering both ideal drains and non-ideal drains, as well as varying the pile stiffness. © 1997 by John Wiley & Sons, Ltd. 相似文献
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The observations of Stokes line profiles require an accurate knowledge of the instrumental polarisation caused by optical components in the path of the light beam. In this context we present a theoretical approach to the instrumental polarisation caused by the 3-mirror coelostat system of the Kodaikanal Solar Tower.Collaborative Program in Astronomy and Astrophysics, Department of Physics, Indian Institute of Science, Bangalore 560 012 India. 相似文献
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Lauren A. MacDonald Kevin W. Turner Ann M. Balasubramaniam Brent B. Wolfe Roland I. Hall Jon N. Sweetman 《水文研究》2012,26(1):117-129
Recent studies using remote sensing analysis of lake‐rich thermokarst landscapes have documented evidence of declining lake surface area in response to recent warming. However, images alone cannot identify whether these declines are due to increasing frequency of lake drainage events associated with accelerated thermokarst activity or to increasing evaporation in response to longer ice‐free season duration. Here, we explore the potential of combining aerial photograph time series with paleolimnological analyses to track changes in hydrological conditions of a thermokarst lake in the Old Crow Flats (OCF), Canada, and to identify their causes. Images show that the water level in lake OCF 48 declined markedly sometime between 1972 and 2001. In a sediment core from OCF 48, complacent stratigraphic profiles of several physical, geochemical, and biological parameters from ～1874–1967 indicate hydro‐limnological conditions were relatively stable. From ～1967–1989, declines in organic matter content, organic carbon isotope values, and pigment concentrations are interpreted to reflect an increase in supply of minerogenic sediment, and subsequent decline in aquatic productivity, caused by increased thermo‐erosion of shoreline soils. Lake expansion was likely caused by increased summer rainfall, as recorded by increased cellulose‐inferred lake‐water oxygen isotope compositions. Stratigraphic trends defining the lake expansion phase terminated at ～1989, which likely marks the year when the lake drained. Above‐average precipitation during the previous year probably raised the lake level and promoted further thermo‐erosion of the shoreline soils that caused the lake to drain. These are meteorological conditions that have led to other recent lake‐drainage events in the OCF. Thus, the decline in lake level, evident in the aerial photograph from 2001, is unlikely to have been caused by evaporation, but rather is a remnant of a drainage event that took place more than a decade earlier. After drainage, the lake began to refill, and most paleolimnological parameters approach levels that are similar to those during the stable phase. These findings indicate that combined use of aerial images and paleolimnological methods offers much promise for identifying the hydrological consequences of recent climatic variations on thermokarst lakes. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
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K.S. Balasubramaniam 《Chemical Geology》1987,60(1-4):121-130
Bauxite deposits of Kutch occur in two different environments, viz. continental and marine, and hence it is of considerable interest from the points of view of genetic aspects, exploration and exploitation. Based on detailed exploration data some new softwares are developed to synthesise the geological and geochemical data. After studying the geostatistics, trend surface analysis has been carried out. With the aid of computer analysis and graphics, a geomodelling study has been attempted for the bauxite deposits that are derived from basalt (continental environment) and another one is presented which is associated with the marine environment. The significance of geomodelling study is substantially brought out. 相似文献
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An attempt is made to reveal a geochemical compatibility with paleoenvironment to understand the genesis of bauxite deposits that are derived from two different parent rocks. For this purpose two in situ bauxite profiles, one developed over basalt and another over sandstone, have been taken. Gibbsite is the major mineral in all these bauxites with minor occurrences of goethite, hematite, anatase, kaolinite, etc. From the study it is evident that the paleoenvironment and geochemical processes are vital factors that could lead to the formation of bauxites. The significance of this is fully discussed. 相似文献
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R. M. Samudraiah Desu Ashutosh Kumar Jha Senthil Kumar Arumugam V. N. Krishna Murthy Yelisetty Ujjwal Kumar Kusum Arunachalam 《Journal of the Indian Society of Remote Sensing》2018,46(6):895-902
Ocean colour sensors traditionally are of fixed spectral channel systems with specified bandwidth of about 20 nm in the visible region and about 40 nm in Near Infrared region. In these systems, it is known that a radiometric error of 1% in the measurement of top of the atmosphere signal may lead to an error of 10% in the retrieved ocean upwelling radiance. In this paper we investigated the range of wavelengths participating in signal collection (effective spectral pass band, ESPB) using relative spectral response data of various sensors flown earlier. ESPB values were computed for each spectral channel for various percentages of signal and the results showed that they are quite high compared to bandwidths specified. These values were found to vary with sensor and channel. ESPB shall be small for accurate computation of spectral radiance. As the knowledge of spectral profile of the signal in the range of ESPB helps in better estimation of spectral radiance at the intended wavelengths, a miniature high performance linear variable filter based hyperspectral sensor is proposed as an alternative. We present here the design concept and report the estimated performance of such sensor that can be realized even with commercial off the shelf components for operational implementation. 相似文献