The loghyperbolic: An alternative to the lognormal for modeling oil field size distribution

The lognormal distribution is widely used to represent the distribution of deposit or reserve size of oil and gas fields. The purpose of this paper has been to investigate the potential usefulness of the loghyperbolic distribution as an alternative to the lognormal distribution. This hypothesis is tested using a set of data from the Denver basin. The results indicate that the loghyperbolic distribution shows a better fit to the empirical data than the lognormal distribution.     

Photo-coulomb neutrino process

The photo-coulomb neutrino process has been considered in the electro-weak theory and the influence of this process to the evolution of stars has been outlined. The scattering cross-section of this process is calculated in both low and high energy limit. The neutrino mass has been taken into account in this calculation. In the low-energy limit the neutrino luminosity is computed in the temperature range 10⁸–10⁹ K and is also compared to the previous result obtained according to the current-current coupling theory. The process may be significant for the evolution of stars in the later phases.     

Toxic Trace Metals in the Surface Water Sources of Jia–Bharali river basin,North Brahmaputra Plain,India—A Hydrochemical Elucidation

Water Resources - Surface water samples from thirty five sources in the Jia Bharali river basin in north Brahmaputra plain, North East India were analyzed for ten toxic trace elements namely As,...     

On the understanding of the observed flat or slowly rising rotation curves in large disk galaxies

Recent observations of the rotation curves of large disk galaxies of all Hubble-types have shown that they possess flat or slowly rising rotation curves up to large distances from the centre. It has been suggested here that such rotation curves are understood under normal fluid dynamical considerations provided that viscous (and/or magnetic) transfer of mass and angular momentum from inner to outer regions of these galaxies is efficient. Flow of gas from halo to the disk in regions close to the axis of rotation is also suggested. The existence of rising rotation curves in some galaxies with varying gradients and flat rotation curves in others suggest that probably these galaxies are not coeval. The formers are probably of more recent origin.     

SH waves in a semi-infinite elastic space due to torsional disturbance

Summary The paper concerns the finding of displacement in a semi-infinite elastic space due to torsional disturbance produced by an expanding source. A formal solution has been derived by the integral transform technique and the modified Cagniard method in two different cases, viz. velocity of expansion is less than or greater than the velocity of shear waves in the medium.     

Geometry of isograds in metamorphic terrains

A simple mathematical relation among the dip of isograd surface (θ), dip of isotherm surface (α), temperature gradient (T_g), pressure gradient (P_g) and δT/gdP of reaction is given by:

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P_g is taken to be constant at 0.3 kb/km. Four major theoretical models for shapes and orientations of isograds are formulated on the basis of the parameters α, T_g and δT/δP. This offers a rational basis for studying the geometry of isograds, normal/reverse metamorphism and determination of temperature gradient. Two examples have been studied in the light of these models; in one case the domed shape of the isograd is best explained by a downwardly directed T_g; in the other case, reverse metamorphism is best explained as the result of a horizontal T_g of 18°C/km.     

Derivation of antiproton-proton flux ratio from the closed galaxy model

The antiproton-proton flux ratio has been estimated from the closed galaxy model of Peters and Westergaard by using the latest primary nucleon spectrum and inclusive reaction accelerator results. The derived flux ratio is about three times higher than those expected from the leaky box model. The results have been compared with the previous estimates by different authors.     

Validation of ERS-1 and High-Resolution Satellite Gravity with in-situ Shipborne Gravity over the Indian Offshore Regions: Accuracies and Implications to Subsurface Modeling

Geoid and gravity anomalies derived from satellite altimetry are gradually gaining importance in marine geoscientific investigations. Keeping this in mind, we have validated ERS-1 (168 day repeat) altimeter data and very high-resolution free-air gravity data sets generated from Seasat, Geosat GM, ERS-1 and TOPEX/POSEIDON altimeters data with in-situ shipborne gravity data of both the Bay of Bengal and the Arabian Sea regions for the purpose of determining the consistencies and deviations. The RMS errors between high resolution satellite and ship gravity data vary from 2.7 to 6.0 mGal, while with ERS-1 data base the errors are as high as 16.5 mGal. We also have generated high resolution satellite gravity maps of different regions over the Indian offshore, which eventually have become much more accurate in extracting finer geological structures like 85° E Ridge, Swatch of no ground, Bombay High in comparison with ERS-1satellite-derived gravity maps. Results from the signal processing related studies over two specific profiles in the eastern and western offshore also clearly show the advantage of high resolution satellite gravity compared to the ERS-1 derived gravity with reference to ship gravity data.