The Use Of Environmental Isotopes And Chloride As Natural Tracers To Investigate The Effects Of Depressurisation Of A Coastal Aquifer For Lignite Mining,India     

B.S. Sukhija  D.V. Reddy  P. Nagabhushanam  Syed Hussain  V.Y. Giri 《Hydrogeology Journal》1996,4(2):70-88

In order to mine lignite from the Neyveli opencast mines, about 200 km south of Madras, India, the Neyveli aquifer has been undergoing depressurisation continuously for almost three decades. To gain insight into the aquifer hydrodynamics, environmental-isotope and chloride measurements on selected groundwater samples were initiated two decades ago, and detailed studies were undertaken during 1985–91. This article demonstrates the effect of large-scale groundwater withdrawals on the hydrologic regime and the effects on environmental chloride and isotopic distributions. A feature common to both the radiocarbon and chloride data of 1991 is their marked variation in a small area between the recharge zone and the mine area where pumping is concentrated. Furthermore, an excellent correlation exists between the temporal increase in the apparent radiocarbon ages of groundwater sampled in 1991 and 1985 and the corresponding lowering of potentiometric levels. Isochlors based on 1991 and 1985 data also indicate a changed hydrologic regime. In certain areas, heavy withdrawals have resulted in increased groundwater salinity.  相似文献   

Rn solution by the circulating fluids in a “hot dry rock” geothermal reservoir     

J.N. Andrews  N. Hussain  A.S. Batchelor  K. Kwakwa   《Applied Geochemistry》1986,1(6)

The mechanism of²²²Rn release into fracture fluids by direct alpha-recoil, lattice and grain boundary/micro-crack diffusion is discussed. Experimental measurements of²²²Rn release into surrounding air and water phases have been made for crystalline rock specimens with well defined surface areas. The²²²Rn flux from an infinite plane surface and hence the effective diffusion length of²²²Rn in the rock matrix has been estimated.The²²²Rn flux from plane crystalline rock surfaces has been used in conjunction with a simple hydrological model of the reservoir to calculate the²²²Rn content of the return fluids of a geothermal doublet circulation system. For given production rate and piezometric difference between the injection and production wells, the²²²Rn content of the return fluid is dependent upon the distribution of flow path lengths and fracture apertures in the reservoir. Matching of the calculated and experimental²²²Rn contents of the return fluids has been used to select appropriate parameters for the reservoir model and hence to estimate the extent of the heat-transfer surface. The model estimates the fracture width of the flow paths, total swept surface area and fracture volume within the reservoir.  相似文献   

Geodynamic evolution and crustal growth of the central Indian Shield: Evidence from geochemistry of gneisses and granitoids     

M. Faruque Hussain  M. E. A. Mondal  T. Ahmad 《Journal of Earth System Science》2004,113(4):699-714

The rare earth element patterns of the gneisses of Bastar and Bundelkhand are marked by LREE enrichment and HREE depletion with or without Eu anomaly. The spidergram patterns for the gneisses are characterized by marked enrichment in LILE with negative anomalies for Ba, P and Ti. The geochemical characteristics exhibited by the gneisses are generally interpreted as melts generated by partial melting of a subducting slab. The style of subduction was flat subduction, which was most common in the Archean. The rare earth patterns and the multi-element diagrams with marked enrichment in LILE and negative anomalies for Ba, P and Ti of the granitoids of both the cratons indicate interaction between slab derived melts and the mantle wedge. The subduction angle was high in the Proterozoic. Considering the age of emplacement of the gneisses and granitoids that differs by ∼ 1 Ga, it can be assumed that these are linked to two independent subduction events: one during Archaean (flat subduction) that generated the precursor melts for the gneisses and the other during the Proterozoic (high angle subduction) that produced the melts for the granitoids. The high values of Mg #, Ni, Cr, Sr and low values of SiO₂ in the granitoids of Bastar and Bundelkhand cratons compared to the gneisses of both the cratons indicate melt-mantle interaction in the generation of the granitoids. The low values of Mg#, Ni, Cr, Sr and high values of SiO₂ in the gneisses in turn overrules such melt-mantle interaction.  相似文献   

Recharge processes: piston flow vs preferential flow in semi-arid aquifers of India   总被引：3，自引：4，他引：3  

B. S. Sukhija  D. V. Reddy  P. Nagabhushanam  Syed Hussain 《Hydrogeology Journal》2003,11(3):387-395

Study of groundwater recharge processes is vital for quantification of total natural recharge to the aquifers. One of the recharge processes demonstrated earlier by tracer experiments in the unsaturated zone is that of piston flow movement of soil moisture. Based on this recharge process, environmental tritium, chloride and injected tritium studies have been carried out extensively in various geological environs of India. The purpose of this paper is to evaluate the validity of the piston flow concept in different geological environs viz. consolidated fractured and weathered granites, semi-consolidated sandstones and unconsolidated alluvial tracts, and quantify the contribution from this process as well as that from the preferential flow mechanism using different tracers. Analysis of tracer data demonstrates that the preferential flow recharge process contributes very significantly (an average of 75% of total recharge) in the case of fractured granites and is important (an average of 33% of total recharge) for semi-consolidated sandstones, whereas the preferential flow recharge component is minimal in unconsolidated alluvial tracts (piston flow model is applicable). These findings necessitate re-evaluation of the total natural recharge potential of the above mentioned geological environs in view of the significant preferential flow recharge that is evidenced and estimated. Electronic Publication  相似文献   

Comparisons of images derived from independent Zeeman Doppler imaging codes     

G. A. J. Hussain  J.-F. Donati  A. Collier Cameron  J. R. Barnes 《Monthly notices of the Royal Astronomical Society》2000,318(4):961-973

We compare surface brightness and magnetic field surface maps for the K0 dwarf AB Doradus, obtained using two independently developed Zeeman Doppler imaging codes. We find that even the fine structure in the two sets of images shows excellent agreement. Magnetic field maps appear to be less sensitive to line-modelling effects than brightness maps. We argue that these results point to the consistency and reliability of Doppler imaging techniques even when using poorly sampled data sets, provided that the spectra used are of sufficiently high signal-to-noise ratio.  相似文献   

Can devolution and rural capacity trigger de-urbanization? Case studies in Kenya and Malaysia respectively     

Andrew Munya  Nur Huzeima Mohd Hussain  Mugwima B. Njuguna 《GeoJournal》2015,80(3):427-443

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Stable isotope dynamics of groundwater interactions with Ganges river     

Prerona Das  Abhijit Mukherjee  Syed Aaquib Hussain  Md. Shahid Jamal  Kousik Das  Ashok Shaw  Mrinal K. Layek  Probal Sengupta 《水文研究》2021,35(1):e14002

Groundwater depletion has been an emerging crisis in recent years, especially in highly urbanized areas as a result of unregulated exploitation, thus leaving behind an insufficient volume of usable freshwater. Presently Ganges river basin, the sixth largest prolific fluvial system and sustaining a huge population in South Asia, is witnessed to face (i) aquifer vulnerability through surface waterborne pollutant and (ii) groundwater stress due to summer drying of river as a result of indiscriminate groundwater abstraction. The present study focuses on a detailed sub-hourly to seasonally varying interaction study and flux quantification between river Ganges and groundwater in the Indian subcontinent which is one of the first documentations done on a drying perennial river system that feeds an enormous population. Contributing parameters to the total discharge of a river at its middle course on both temporal and spatial scale is estimated through three-component hydrograph separation and end-member mixing analysis using high-resolution water isotope (δ¹⁸O and δ²H) and electrical conductivity data. Results from this model report groundwater discharge in river to be the highest in pre-monsoon, that is, 30%, whereas, during post-monsoon the contribution lowers to 25%; on the contrary, during peak monsoon, the flow direction reverses thus recharging the groundwater which is also justified using annual piezometric hydrographs of both river water and groundwater. River water-groundwater interaction also shows quantitative variability depending on river morphometry. The current study also provides insight on aquifer vulnerability as a result of pollutant mixing through interaction and plausible attempts towards groundwater management. The present study is one of the first in South Asian countries that provides temporally and spatially variable detailed quantification of baseflow and estimates contributing parameters to the river for a drying mega fluvial system.  相似文献   

Long-term variability and changes of the precipitation regime in Pakistan   总被引：2，自引：0，他引：2  

Mian Sabir Hussain  Seungho Lee 《Asia-Pacific Journal of Atmospheric Sciences》2014,50(3):271-282

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Simulation of vortex-induced vibrations of a cylinder using ANSYS CFX   总被引：1，自引：0，他引：1  

Abu Bakar Izhar  Arshad Hussain Qureshi  Shahab Khushnood 《中国海洋工程》2014,28(4):541-556

In this paper, vortex-induced vibrations of a cylinder are simulated by use of ANSYS CFX simulation code. The cylinder is treated as a rigid body and transverse displacements are obtained by use of a one degree of freedom spring damper system. 2-D as well as 3-D analysis is performed using air as the fluid. Reynolds number is varied from 40 to 16000 approx., covering the laminar and turbulent regimes of flow. The experimental results of （Khalak and Williamson, 1997） and other researchers are used for validation purposes. The results obtained are comparable.  相似文献   

Building population mapping with aerial imagery and GIS data     

Serkan Ural  Ejaz Hussain  Jie Shan 《International Journal of Applied Earth Observation and Geoinformation》2011

Geospatial distribution of population at a scale of individual buildings is needed for analysis of people's interaction with their local socio-economic and physical environments. High resolution aerial images are capable of capturing urban complexities and considered as a potential source for mapping urban features at this fine scale. This paper studies population mapping for individual buildings by using aerial imagery and other geographic data. Building footprints and heights are first determined from aerial images, digital terrain and surface models. City zoning maps allow the classification of the buildings as residential and non-residential. The use of additional ancillary geographic data further filters residential utility buildings out of the residential area and identifies houses and apartments. In the final step, census block population, which is publicly available from the U.S. Census, is disaggregated and mapped to individual residential buildings. This paper proposes a modified building population mapping model that takes into account the effects of different types of residential buildings. Detailed steps are described that lead to the identification of residential buildings from imagery and other GIS data layers. Estimated building populations are evaluated per census block with reference to the known census records. This paper presents and evaluates the results of building population mapping in areas of West Lafayette, Lafayette, and Wea Township, all in the state of Indiana, USA.  相似文献