Geochemical characterization of adsorbed light gaseous alkanes in near surface soils of the eastern Ganga basin for hydrocarbon prospecting

This study aims to assess the hydrocarbon potential of Ganga basin utilizing the near surface geochemical prospecting techniques. It is based on the concept that the light gaseous hydrocarbons from the oil and gas reservoirs reach the surface through micro seepage, gets adsorbed to soil matrix and leave their signatures in soils and sediments, which can be quantified. The study showed an increased occurrence of methane (C₁), ethane (C₂) and propane (C₃) in the soil samples. The concentrations of light gaseous hydrocarbons determined by Gas Chromatograph ranged (in ppb) as follows, C₁: 0–519, C₂: 0–7 and C₃: 0–2. The carbon isotopic (VPDB) values of methane varied between ?52.2 to ?27.1‰, indicating thermogenic origin of the desorbed hydrocarbons. High concentrations of hydrocarbon were found to be characteristic of the Muzaffarpur region and the Gandak depression in the basin, signifying the migration of light hydrocarbon gases from subsurface to the surface and the area’s potential for hydrocarbon resources.     

Bianchi type-II, VIII & IX perfect fluid magnetized cosmological models in Brans-Dicke theory of gravitation

Spatially homogeneous Bianchi type-II, VIII & IX charged perfect fluid cosmological models in Brans-Dicke theory of gravitation are obtained and presented. Various physical and geometrical features of the models are also discussed.     

Optimization of Minimal Salt Medium for Efficient Phenanthrene Biodegradation by Mycoplana sp. MVMB2 Isolated from Petroleum Contaminated Soil Using Factorial Design Experiments

This study presents the degradation of phenanthrene by Mycoplana sp. MVMB2 isolated from petroleum contaminated soil and the media optimization by factorial design experiments. The Plackett–Burman design was used to evaluate the effects of eight variables (potassium dihydrogen phosphate, disodium hydrogen phosphate, magnesium sulfate, calcium chloride, ferrous sulfate, glucose, inoculum concentration, and phenanthrene concentration) on phenanthrene degradation. Based on the results, the critical medium components having significant influence on the degradation were found to be disodium hydrogen phosphate, magnesium sulfate, ferrous sulfate, and phenanthrene. Furthermore, these four variables were used as central composite design parameters. The optimum minimal salt medium composition obtained by conventional and factorial design experiments for the degradation of phenanthrene by Mycoplana sp. MVMB2 at pH 6.5 and 30°C were found to be, potassium 2.5 g/L dihydrogen phosphate, 0.3505 g/L disodium hydrogen phosphate, 0.5501 g/L magnesium sulfate, 0.02 g/L calcium chloride, 0.0261 g/L ferrous sulfate, 0.6756 g/L phenanthrene, 0.5 g/L glucose, 0.5 g/L ammonium sulfate, and inoculum 5% v/v. The phenanthrene degradation was confirmed by analyzing the metabolites formed.     

Error in digital network and basin area delineation using d8 method: A case study in a sub-basin of the Ganga

Digital elevation model (DEM) is one of the input data derived from different satellite sensors for hydrologic and hydraulic modelings. Two prime questions could be answered before using these DEMs. First, the acceptability of datasets for our use and second appropriate resolution of the dataset. Three widely used DEMs SRTM 30m, ASTER 30m and SRTM 90m are analyzed to evaluate their suitability to delineate river network and basin boundary area. The hydrology tool of spatial analyst extension inbuilt in ArcGIS 10.2 (which uses the D8 method for calculation of flow direction) has been used for the delineation of both river networks and basin boundary. The assessment of river network alignment and boundary delineation is carried out in the seven sub-catchments of Gandak river basin having different morphological characteristics. The automatically delineated boundary area for all the three DEMs reflects a significant difference when compared with the digitized basin area from the Ganga flood control commission (GFCC) map. The maximum boundary area delineation error is 39137.20 km₂ forASTER 30m, and minimum delineation error of 13239.28 km₂ for SRTM 90m. In the stream network, delineation accuracy is good for SRTM 90m while, except Gandak trunk, ASTER 30m DEM shows better delineation accuracy indicated by mean absolute error (MAE) and standard deviation (SD).     

Removal of NO3– from Drinking Water by Electrocoagulation – An Alternate Approach

The present study provides an electrocoagulation method, for the removal of NO₃^– from drinking water using magnesium as the anode and cathode. The experiments are carried out as a function of pH, temperature, and current density. The results show that the maximum removal efficiency of 95.8% was achieved at a current density of 0.25 A/dm², at a pH of 7.0. The adsorption of NO₃^– preferably fitting the Langmuir adsorption isotherm suggests monolayer coverage of the adsorbed molecules. The adsorption process follows a second‐order kinetics model. Thermodynamic studies show that the adsorption was exothermic and spontaneous in nature.     

Bianchi type-V anisotropic cosmological models in certain theories of gravitation with perfect fluid distribution

Exact Bianchi type-V cosmological models are presented in Einstein’s theory of gravitation with cosmological constant Λ in case of perfect fluid distribution. Also obtained Bianchi type-V cosmological models in a scalar-tensor theory of gravitation proposed by Saez and Ballester (1986) in case of perfect fluid distribution using and without using negative constant deceleration parameter. Some physical and geometrical properties of the models are also discussed.     

Exact Bianchi type II, VIII and IX string cosmological models in General Relativity and self-creation theory of gravitation

Exact Bianchi type II, VIII and IX String cosmological models are obtained in Einstein’s theory of gravitation and Barber’s (1982) second self-creation theory of gravitation. Some physical and geometrical properties of the models are also discussed.     

Equilibrium studies on removal of lead (II) ions from aqueous solution by adsorption using modified red mud

In the present experimental study, solid waste was used as an adsorbent and the effectiveness of the adsorbent was increased by novel treatment methods. Red mud, acid-treated activated red mud and iron oxide-coated acid-treated activated red mud were used for the removal of lead (II). The structural and functional groups were identified to confirm the removal of lead (II) by powder X-ray diffraction and Fourier transform infrared spectroscopy analyses. The enhancement of surface area was confirmed by Brunauer–Emmett–Teller analysis. Batch adsorption experiment was also conducted, and various parameters such as the effect of adsorbent dosage, pH, contact time and initial ion concentration were analyzed and reported. Adsorption equilibrium data were investigated using Langmuir, Freundlich and Dubinin–Radushkevich isotherm models with three parameters, and the rate of reaction was examined through kinetic models. The results indicate that in particular a novel modified form of red mud, namely iron oxide-coated acid-treated activated red mud was well fitted in lead (II) removal compared with reported adsorbents. The Langmuir isotherm shows that the maximum adsorption of adsorbate per gram was greater than other adsorbents (27.02 mg/g). In Freundlich isotherm, the Freundlich constant n values lie between 1 and 10 indicate the favorable adsorption. The calculated n values for normal red mud, acid-treated activated red mud and iron oxide-coated acid-treated activated red mud were found to be 1.9, 2.1 and 2.0 respectively. The correlation coefficient value was higher and the rate of reaction follows the pseudo-second-order kinetic model.     

Geochemistry of the mafic dykes in the Prakasam Alkaline Province of Eastern Ghats Belt, India: Implications for the genesis of continental rift-zone magmatism

Mesoproterozoic rift-zone magmatism in the Prakasam Alkaline Province of Eastern Ghats Belt, India is represented by three geochemically distinct primary mafic magmas and their plutonic differentiates. The three mafic magmas correspond to the alkali basaltic dykes, gabbroic dykes and lamprophyric dykes. The dyke activity is synchronous with the host plutons and belongs to the 1350–1250 Ma period Mesoproterozoic magmatism. Geochemical signatures suggest that the alkali basaltic dykes have a source in the thermal boundary layer, which has a history of prior melt extraction followed by enrichment. Both the gabbroic and lamprophyric dykes are derived from lithospheric sources and their geochemical variation can be explained by “vein-plus-wall-rock melting model”. Vein/wall-rock ratio is low for the sources of gabbroic dykes, whereas it is high for the lamprophyric dykes. Geochemistry of the gabbro dykes further indicates preservation of previous arc-signals by the lithosphere beneath the Prakasam Alkaline Province during the Mesoproterozoic. Geochemical signatures of lamproite, which could be a cratonic expression of the rift-triggered magmatism in the Prakasam Province, suggest a general increase in the metasomatic imprint with increasing lithosphere thickness from cratonic margin towards interior. It is found that geochemistry of continental rift-zone magmatism of the Prakasam rift is remarkably similar to that of the Gardar rift of South Greenland. It appears that the geodynamic conditions under which melting occurred in the Prakasam Alkaline Province are similar to that of a propagating rift with variable contributions from the convective mantle and subcontinental lithosphere mantle to the rift-zone magmas. The present study illustrates how fertility and chemical heterogeneity of the lithosphere play significant roles in the creation of enormous geochemical diversity characteristic of continental rift-zone magmatism.