Appraisal of highly fluoride zones in groundwater of Kurmapalli watershed,Nalgonda district,Andhra Pradesh (India)

Fluoride (F) contamination study had been carried out to see its allocation in Kurmapalli watershed, Nalgonda district, Andhra Pradesh, India. The study area is located about 60 km SE of Hyderabad city. The groundwater is the main source of water for their living. The groundwater in villages and its surrounding are affected by fluoride contamination and consequently the majority of the people living in these villages has health hazards and is facing fluorosis. The purpose of this study is to identify the wells with high F, raise awareness in people, study the water chemistry, and also find out the source of F in groundwater. A total of 32 groundwater samples were collected from different wells in both shallow aquifers and deeper fractures zones during October 2004. The chemical analysis of groundwater has been done. Fluoride values vary from 0.7 to 19.0 mg/l. It is noted that the maximum value (19.0 mg/l) is one of the highest values found in groundwater in India and 78% of the total samples show F concentrations that exceeds the permissible limit value (1.5 mg/l). The highest value of F is found at Madanapur bore well which is located at central part of the watershed. The F value of this bore well was monitored from October 2004 to October 2006. During this period the F concentration varies from 17.8 to 21.0 mg/l with mean 19.3 mg/l. There is no correlation of F with chemical parameters except calcium. The Ca has shown inverse proportional with F. Water–rock interaction studies were also carried out to understand the behavior of F in groundwater at prominent F affected areas. Rock samples were collected and analyzed, and found their enrichment of F. The anthropogenic possibility of F is almost negligible. The rocks of this area are enriched in F from 460 to 1,706 mg/kg. It is indicated that the rock–water interaction is the main source of F in groundwater. The highest values of F are found in middle part of the region and are related to the occurrence of fluoride rich rocks and their chemical kinetic behavior with groundwater.     

Modeling of the Removal of Arsenic Species from Simulated Groundwater Containing As,Fe, and Mn: A Neural Network Based Approach

The present paper deals with the modeling of the removal of total arsenic As(T), trivalent arsenic As(III), and pentavalent arsenic As(V) from synthetic solutions containing total arsenic (0.167–2.0 mg/L), Fe (0.9–2.7 mg/L), and Mn (0.2–0.6 mg/L) in a batch reactor using Fe impregnated granular activated charcoal (GAC‐Fe). Mass ratio of As(III) and As(V) in the solution was 1:1. Multi‐layer neural network (MLNN) has been used and full factorial design technique has been applied for the selection of input data set. The developed models are able to predict the adsorption of arsenic species with an error limit of ?0.3 to +1.7%. Combination of MLNN with design of experiment has been able to generalize the MLNN with less number of experimental points.     

Gravitational wave emission from a companion black hole in the presence of an accretion disc around a super-massive Kerr black hole

Gravitational wave signal characteristics from a binary black hole system in which the companion moves through the accretion disc of the primary are studied. We chose the primary to be a super-massive  ( M = 10⁸ M_⊙)  Kerr black hole and the companion to be a massive black hole  ( M = 10⁵ M_⊙)  to clearly demonstrate the effects. We show that the drag exerted on the companion by the disc is sufficient to reduce the coalescence time of the binary. The drag is primarily due to the fact that the accretion disc on a black hole deviates from a Keplerian disc and becomes sub-Keplerian due to inner boundary condition on the black hole horizon. We consider two types of accretion rates on to the companion. The companion is deeply immersed inside the disc and it can accrete at the Bondi rate which depends on the instantaneous density of the disc. However, an accretion disc can also form around the smaller black hole and it can accrete at its Eddington rate. Thus, this case is also studied and the results are compared. We find that the effect of the disc will be significant in reducing the coalescence time and one needs to incorporate this while interpreting gravitational wave signals emitted from such a binary system.     

Effects of vertical irregularity and thickness of unreinforced masonry infill on the robustness of RC framed buildings

Presence of irregularities in reinforced concrete (RC) buildings increases seismic vulnerability. During severe seismic shaking, such buildings may suffer disproportionate damage or even collapse that can be minimized by increasing robustness. Robustness is a desirable property of structural systems that can mitigate susceptible buildings to disproportionate collapse. In this paper, the effects of vertical irregularity and thickness of unreinforced masonry infill on the robustness of a six‐story three‐bay RC frame are quantified. Nonlinear static analysis of the frame is performed, and parametric study is undertaken by considering two parameters: absence of masonry infill at different floors (i.e., vertical irregularities) and infill thickness. Robustness has been quantified in terms of stiffness, base shear, ductility, and energy dissipation capacity of the frame. It was observed that the infill thickness and vertical irregularity have significant influence on the response of RC frame. The response surface method is used to develop a predictive equation for robustness as a function of the two parameters. The predictive equation is validated further using 12 randomly selected computer simulations. Copyright © 2013 John Wiley & Sons, Ltd.     

Identification of water-bearing fractures in hard rock terrain by electrical conductivity logs, India

For the delineation of water-bearing fractures in hard rock areas, a new hydro-chemical technique has been developed which is based on electrical conductivity (EC) logs. The EC logs were carried out in experimental shallow bore wells (≈50 m) in three different parts of India. A sharp variation in EC was observed near water-bearing fractures in hard rock areas. To access applications of this technique, different locations in India were selected and experimental bore wells (≈50 m) were drilled. These were:

A Study Of Global Monopole In Einstein–Cartan Theory

The gravitational field of a global monopole in the context of Einstein–Cartan theory is investigated. A comparison is made with the corresponding results predicted by general relativity. PACS Nos: 98.80cq; 04.20 jb; 04.50     

Quantitative Separation of As(III) and As(V) from a Synthetic Water Solution Using Ion Exchange Columns in the Presence of Fe and Mn Ions

The quantitative separation of As(III) from a water sample containing As(III) and As(V) in the presence of Fe and Mn in an ion exchange resin (AG1 X8) column for the speciation of arsenic is described. Individual and combined effects of Fe and Mn on the separation of As(III) from the solution have been studied separately. In absence of Fe and Mn, the ratio between the As(T) concentration in the eluent and the As(III) concentration in the original sample has been found to be 0.9717 under optimum process conditions. The presence of Fe(II) in the water sample increased the As(T) concentration in the eluent whereas Mn(II) decreased it. Combined effects of Fe and Mn on the percentage increment in the eluent arsenic concentration have been expressed by additive and interactive models. The interactive model has been developed by a statistical software with a 95 % confidence level. In most of the cases the error on the determination of the As(III) concentration had a minimum when using the interactive model.     

Uncertainty of soil erosion modelling using open source high resolution and aggregated DEMs

Digital Elevation Model (DEM) is one of the important parameters for soil erosion assessment. Notable uncertainties are observed in this study while using three high resolution open source DEMs. The Revised Universal Soil Loss Equation (RUSLE) model has been applied to analysis the assessment of soil erosion uncertainty using open source DEMs (SRTM, ASTER and CARTOSAT) and their increasing grid space (pixel size) from the actual. The study area is a part of the Narmada river basin in Madhya Pradesh state, which is located in the central part of India and the area covered 20,558 km². The actual resolution of DEMs is 30 m and their increasing grid spaces are taken as 90, 150, 210, 270 and 330 m for this study. Vertical accuracy of DEMs has been assessed using actual heights of the sample points that have been taken considering planimetric survey based map (toposheet). Elevations of DEMs are converted to the same vertical datum from WGS 84 to MSL (Mean Sea Level), before the accuracy assessment and modelling. Results indicate that the accuracy of the SRTM DEM with the RMSE of 13.31, 14.51, and 18.19 m in 30, 150 and 330 m resolution respectively, is better than the ASTER and the CARTOSAT DEMs. When the grid space of the DEMs increases, the accuracy of the elevation and calculated soil erosion decreases. This study presents a potential uncertainty introduced by open source high resolution DEMs in the accuracy of the soil erosion assessment models. The research provides an analysis of errors in selecting DEMs using the original and increased grid space for soil erosion modelling.