Multigroup discrimination of river, beach, and dune sands using axial-ratio sample statistics of quartz grains

Optimal discrimination among several groups can be achieved by simultaneous diagonalization of pooled within-group, W, and among-group, A, sums of squares and cross-product matrices formed by utilizing axial-ratio sample statistics of quartz grains belonging to different sieve grades. This method maximizes the ratio of among-group cross products to within-group cross product quadratic forms (V'AV/V'WV)and simultaneously yields discriminant scores whose correlation coefficients are zero for group means as well as for within each group. This procedure enables a simple Euclidean distance measure for partitioning the discriminant space for assignment. Although W^–1 and Amatrices are symmetric, the W^–1 Amatrix needed for multigroup discrimination is asymmetric and hence the eigenstructure of W^–1 Ais obtained by simultaneous diagonalization of Wand Amatrices. The first four sample statistics (mean, standard deviation, skewness, kurtosis) of normalized axial-ratios are required for discrimination, although the mean and standard deviation are the most important discriminators.     

Nonplanar ion acoustic solitary waves with superthermal electrons and positrons

The properties of cylindrical and spherical ion acoustic solitary waves (IASWs) are investigated in a three-component unmagnetized, collisionless plasma consisting of warm ion fluid and superthermally distributed electrons and positrons in a nonplanar cylindrical or spherical geometry. Using the reductive perturbation technique, the nonplanar cylindrical and spherical Korteweg-de Vries (KdV) equations are derived. The effects of spectral index of electron and positron, and other plasma parameters are studied. It is found that both negative as well as positive solitary potential structures are formed in nonplanar geometries. The numerical solution shows that amplitude of the soliton is large in spherical geometry in comparison with cylindrical geometry. Numerical results indicate that the amplitude of the soliton is large in spherical geometry in comparison with cylindrical geometry.     

String fluid cosmological models in general relativity

LRS Bianchi type-I string cosmological models are studied in the frame work of general relativity when the source for the energy momentum tensor is a bulk viscous fluid containing one dimensional strings embedded in electromagnetic field. A barotropic equation of state for the pressure and density is assumed to get determinate solutions of the field equations. The bulk viscosity is assumed to be inversely proportional to the scalar expansion. The physical and kinematical properties of the models are discussed. The effect of viscosity and electromagnetic field on the physical and kinematical properties is also investigated.     

String cloud cosmologies for Bianchi type-III models with electromagnetic field

The Saez-Ballester field equations for spatially homogeneous and anisotropic Bianchi type-III cosmological models have been solved for pure geometric cosmic string cloud pervading the universe either in the absence or in presence of electromagnetic field. It has been established here that the model does not survive for geometric cosmic string cloud pervading the universe when there is no electromagnetic field. But in presence of electromagnetic field the model can have plausible solutions fostering the idea that strings forming the surface of the world sheet have to co-exist with electromagnetic field.     

Geochemical appraisal of mine discharge and tailing at Malanjkhand copper mine,India

Geophysical investigation using Vertical Electrical Sounding (VES), Electrical Resistivity Tomography (ERT) and Seismic Refraction at a proposed conference center site along Ajibode-Labani road, Ibadan, southwestern Nigeria has been carried out. The investigation aims at characterizing and delineating the subsurface strata to understand the weathered profile at the site. Understanding the weathered profile is essential in determining the suitability of the site for engineering construction of the future conference center. A total of 25 VES and 10 ERT profiles were acquired in a systematic grid pattern using both Schlumberger andWenner configurations with Allied omega terrameter. TheVES data were processed and analyzed using WinResist and the ERT data were inverted using RES2DINV. The data were combined to form a 3-D data set of the site and RES3DINV was used to produce the depth slices. Seismic refraction data were also acquired with an ABEM seismograph and processed using SeisImager and Fajseis software. Seismic data were used in understanding the velocity distribution and thickness. The results of VES, ERT and seismic refraction show good correlation. Four sub-surface layers were delineated: top layer of reworked sand, clayey sand/ lateritic hard pan, clay/ sandy clay and fracture/ fresh basement. The 3-D model permits a pictorial view of the sub-surface in relation to materials that overlie the basement. The thickness of unconsolidated materials to bedrock varies from 2.7 m to 12.2 m which revealed inhomogeneity in weathering under the shallow sub-surface. It is found that the integrated geophysical tool is well suited to characterize and delineate sub-surface structure (weathered profile) for engineering site characterization.     

Multivariate statistical approach for assessment of subsidence in Jharia coalfields,India

Indian coalfields, one of the major coal producers, are facing serious problem of subsidence now-a-days. This paper attempts to investigate various factors and their influence on magnitude and extent of subsidence. The study was conducted in the Jharia coalfields, India where extraction of thick seams at shallow depths has damaged the ground surface in the form of subsidence. For precise pre-estimation of subsidence, it is therefore necessary to know the contribution of each factor to the occurrence of subsidence. In order to achieve the objectives of this study, several multivariate statistical techniques such as factor analysis (FA), principal component analysis (PCA) and cluster analysis (CA) have been used. Two factors were extracted using FA. Factor 1 and factor 2 account for 42.327% and 24.661% of the variability respectively. Factor 1 represents “natural factor” whereas factor 2 represents “subsidence coefficient”. Spatial variations in regarding susceptibility to the subsidence were determined from hierarchical CA using the linkage distance. Further, the findings of this study would be helpful for prediction of magnitude of subsidence empirically.     

Rayleigh waves in liquid layer resting over an initially stressed orthotropic half-space under self-weight

The study of surface waves (Rayleigh wave) finds their virtuous applications in a numerous geological and geophysical fields including water, oil, gas, and other subsurface geological probing and exploration. The present paper efforts to investigate the influence of initial stress, Earth magnetism, and gravity on propagation of Rayleigh waves. Considered model is consist of a liquid layer lying over a magnetoelastic orthotropic half-space under self-weight and initial stress. Method of separation of variable is used to solve the equation of motion. Solutions of governing equations are obtained in terms of displacement. Frequency relation for Rayleigh wave has been obtained and matched with classical Rayleigh wave equation. In addition to classical case, some existing results have been deduced as particular case of the present study. Obtained results have been shown through numerical illustrations. It is found that the considered parameters (initial stress, Earth magnetism, and gravity) have prominent effect on phase velocity of Rayleigh wave. Graphical representations have been made to exhibit the velocity profile of Rayleigh waves for different cases with the help of MATHEMATICA. The present study may be useful for seismologists and engineers who are concern with applications of wave propagation in magnetoelastic orthotropic medium.     

Emplacement kinematics of nepheline syenites from the Terrane Boundary Shear Zone of the Eastern Ghats Mobile Belt,west of Khariar,NW Orissa: Evidence from meso- and microstructures

Nepheline syenite plutons emplaced within the Terrane Boundary Shear Zone of the Eastern Ghats Mobile Belt west of Khariar in northwestern Orissa are marked by a well-developed magmatic fabric including magmatic foliation, mineral lineations, folds and S-C fabrics. The minerals in the plutons, namely microcline, orthoclase, albite, nepheline, hornblende, biotite and aegirine show, by and large, well-developed crystal faces and lack undulose extinction and dynamic recrystallization, suggesting a magmatic origin. The magmatic fabric of the plutons is concordant with a solid-state strain fabric of the surrounding mylonites that developed due to noncoaxial strain along the Terrane Boundary Shear Zone during thrusting of the Eastern Ghats Mobile Belt over the Bastar Craton. However, a small fraction of the minerals, more commonly from the periphery of the plutons, is overprinted by a solid state strain fabric similar to that of the host rock. This fabric is manifested by discrete shear fractures, along which the feldspars are deformed into ribbons, have undergone dynamic recrystallization and show undulose extinction and myrmekitic growth. The shear fractures and the magmatic foliations are mutually parallel to the C-fabric of the host mylonites. Coexistence of concordant solid state strain fabric and magmatic fabric has been interpreted as a transitional feature from magmatic state to subsolidus deformation of the plutons, while the nepheline syenite magma was solidifying from a crystal-melt mush state under a noncoaxial strain. This suggests the emplacement of the plutons synkinematic to thrusting along the Terrane Boundary Shear Zone. The isotopic data by earlier workers suggest emplacement of nepheline syenite at 1500 +3/−4Ma, lending support for thrusting of the mobile belt over the craton around that time.     

Classification of coal seams with respect to their spontaneous heating susceptibility—a neural network approach

The paper presents the application of adaptive resonance theory of artificial neural networks (ANN) for classification of coal seams with respect to their proneness to spontaneous heating. In order to apply this technique, 31 coal samples have been collected from different Indian coalfields covering both fiery and non-fiery coal seams of varying ranks spreading over 8 different mining companies. The intrinsic properties of these samples have been determined by carrying out proximate, ultimate and petrographic analyses. The susceptibility indices of these samples have been studied by five different methods, viz. crossing point temperature, differential thermal analysis, critical air blast analysis, wet oxidation potential difference analysis and differential scanning calorimetric studies. Exhaustive correlation studies between susceptibility indices and the intrinsic properties have been carried out for identifying the appropriate spontaneous heating susceptibility indices and intrinsic properties to be used for classification of coal seams. The identified parameters are used as inputs and adaptive resonance theory of ANN has been applied to classify the coal seams into four different categories. This classification system will help the planners and practising mining engineers to take ameliorative measures in advance to prevent the occurrence of fire in mines.