Detecting groundwater contamination of a river in Georgia, USA using baseflow sampling     

James S. Reichard  Chandra M. Brown 《Hydrogeology Journal》2009,17(3):735-747

Algal blooms and fish kills were reported on a river in coastal Georgia (USA) downstream of a poultry-processing plant, prompting officials to conclude the problems resulted from overland flow associated with over-application of wastewater at the plant’s land application system (LAS). An investigation was undertaken to test the hypothesis that contaminated groundwater was also playing a significant role. Weekly samples were collected over a 12-month period along an 18 km reach of the river and key tributaries. Results showed elevated nitrogen concentrations in tributaries draining the plant and a tenfold increase in nitrate in the river between the tributary inputs. Because ammonia concentrations were low in this reach, it was concluded that nitrate was entering via groundwater discharge. Data from detailed river sampling and direct groundwater samples from springs and boreholes were used to isolate the entry point of the contaminant plume. Analysis showed two separate plumes, one associated with the plant’s unlined wastewater lagoon and another with its LAS spray fields. The continuous discharge of contaminated groundwater during summer low-flow conditions was found to have a more profound impact on river-water quality than periodic inputs by overland flow and tributary runoff.  相似文献   

Abnormally large magnetospheric electric field on 9?November?2004 and its effect on equatorial ionosphere around the world     

R G Rastogi  H Chandra  Louis Condori  M A Abdu  B Reinisch  R T Tsunoda  D S V V D Prasad  T K Pant  T Maruyama 《Journal of Earth System Science》2012,121(5):1145-1161

  相似文献   

Evaluating the Long-term Urban Expansion of Ranchi Urban Agglomeration,India Using Geospatial Technology     

Amit Kumar  Arvind Chandra Pandey  Najmul Hoda  A. T. Jeyaseelan 《Journal of the Indian Society of Remote Sensing》2011,39(2):213-224

The present study analyzes the built-up expansion of Ranchi urban agglomeration over a period of about 8 decades from 1927–2005. Satellite images and topographical maps were used to evaluate land use dynamics during these periods. Built-up growth of 473.7% during 1927–2005 was primarily at the expense of agricultural land along with reduction of natural water bodies reflects negative impacts of built-up expansion, which increased many folds in recent decades. The built-up growth is also analyzed with reference to population growth, land consumption rate and land transformation. The land loss due to increasing built-up growth of Ranchi were compared with other capital regions and cities along with population increase to provide insight into the possible scenario of built-up expansion in Ranchi urban area.  相似文献   

Statistical analysis of annual maximum rainfall in North-East India: an application of LH-moments   总被引：1，自引：1，他引：0  

Surobhi Deka  Munindra Borah  Sarat Chandra Kakaty 《Theoretical and Applied Climatology》2011,104(1-2):111-122

An attempt has been made to determine the best fitting distribution to describe the annual series of maximum daily rainfall data for the period 1966 to 2007 of nine distantly located stations in North East India. The LH-moments of order zero (L) to order four (L₄) are used to estimate the parameters of three extreme value distributions viz. generalized extreme value distribution (GEV), generalized logistic distribution (GLD), and generalized Pareto distribution (GPD). The performances of the distributions are assessed by evaluating the relative bias (RBIAS) and relative root mean square error (RRMSE) of quantile estimates through Monte Carlo simulations. Then, the boxplot is used to show the location of the median and the associated dispersion of the data. Finally, it can be revealed from the results of boxplots that zero level of LH-moments of the generalized Pareto distribution would be appropriate to the majority of the stations for describing the annual maximum rainfall series in North East India.  相似文献   

Equatorial electrojet in the south Atlantic anomaly region     

R G Rastogi  H Chandra  N B Trivedi  V Doumbia 《Journal of Earth System Science》2011,120(2):301-310

Features of the equatorial electrojet are studied at Sao Luiz (2.6°S, 44.2°W, inclination −0.25°) in eastern Brazil and Sikasso (11.3°N, 5.7°W, inclination 0.1°) in the western African sector. The stations are situated on either side of the lowest magnetic field intensity in the region of rapid changes in the declination. The daily variations of ΔX at the two stations are almost similar with the peak around noon with maximum values during equinoxes and minimum values during J-solstices. Daily variations of ΔY differ with the maximum deviation of about −35 nT around noon at Sao Luiz and much smaller value of about −10 nT around 14 h LT for Sikasso. The direction of the H vector varies from 15°W of north at 08 h to more than 30°W of north at 17 h for Sao Luiz and from 14°E of north to 25°W of north at 18 h for Sikasso. The plot of the deviations in ΔX and ΔY at different hours for the two stations shows the points along narrow ellipses with major axis aligned along 22°W of north for Sao Luiz and along 3°W of north for Sikasso as compared to declination of 20°W for Sao Luiz and 6°W for Sikasso. The deviations in ΔX at the two stations are fairly well correlated.  相似文献   

Small Fe bearing ring molecules of possible astrophysical interest: molecular properties and rotational spectra     

C. Chang  A. B. C. Patzer  W. H. Kegel  S. Chandra 《Astrophysics and Space Science》2013,347(2):315-325

A number of small, cyclic molecules containing several carbon atoms in their ring structure has been identified in different astrophysical environments. It is the aim of this work to study important molecular properties of such heterocyclic species bearing an iron atom, which is one of the most abundant cosmic elements. Quantum theoretical calculations based on a density functional approach have been employed to investigate physical properties of six small cyclic carbon and hydrocarbon molecules containing iron as a hetero atom, viz. FeC₂H _n and FeC₃H _n (n=0,2,4). The full geometry optimisation at the chosen level of electronic structure theory (B3LYP/6-31G(d)) including vibrational anharmonicities and non-rigidity, has furnished values for the rotational constants of these species to an expected accuracy of about one per cent. We present structural, electronic, vibrational, and rotational molecular properties including line frequencies, line strengths, and transition probabilities. These results may be helpful for identifying these molecules in future laboratory experiments in view of tentative astronomical observations.  相似文献   

Landslide risk analysis between Giri and Tons Rivers in Himachal Himalaya (India)     

Piyoosh Rautela  Ramesh Chandra Lakhera 《International Journal of Applied Earth Observation and Geoinformation》2000,2(3-4)

The area around Sataun in the Sirmur district of Himachal Pradesh, India (falling between the rivers Giri and Tons; both tributaries of the Yamuna River) was studied for landslide vulnerability on behalf of the inhabitants. The study was made using extensive remote sensing data (satellite and airborne). It is well supported by field evidence, demographic and infrastructural details and aided by Geographic Information System (GIS) based techniques. Field observations testify that slope, aspect, geology, tectonic planes, drainage, and land use all influence landslides in the region. These parameters were taken into consideration using the statistical approach of landslide hazard zonation. Using the census data of 1991, vulnerability of the populace to the landslide hazard was accessed. As most of the infrastructure in the region is concentrated around population centres, population data alone was used for vulnerability studies.  相似文献   

Comments on the heating of solar active regions by magnetic energy dissipation     

Suresh Chandra 《Astrophysics and Space Science》1986,123(2):403-404

The method of Kumar and Narain (1985) to calculate the twisting velocity of magnetic field appears to be erroneous. Hence, their conclusion about Tucker's proposal for the heating of active regions by magnetic energy dissipation may not be correct.  相似文献   

Trapezoidal footings on non-linear subgrades     

S. Chandra  M. R. Madhav  N. G. R. Iyengar 《国际地质力学数值与分析法杂志》1984,8(6):519-529

The pressure versus settlement response is highly non-linear for soils, in general. In the present study, a cubic equation of the type p = K₁w ? K₂w³ is suggested to incorporate the non-linear behaviour. A trapezoidal footing with constant depth resting on a subgrade having non-linear response is analysed. The resulting fourth order non-linear differential equation with variable coefficients is solved by using the Galerkin technique and beam characteristic functions are employed to obtain faster convergence. The results are presented in the form of non-dimensional charts for valid ranges of footings and soil parameters.  相似文献   

Solar coronal loop     

Suresh Chandra 《Astrophysics and Space Science》1985,113(1):193-194

The conclusions drawn by Narain (1983) appear to be in error.  相似文献