Cosmic expansion driven by real scalar field for different forms of potential

We discuss the expansion of the universe in the FRLW model assuming that the source of dark energy is either tachyonic scalar field or quintessence. The tachyonic scalar field with exponential and power-law potential (function of homogeneous scalar field ?) both gives exponential expansion of the universe. It is found that this behaviour is not distinguishable from the quintessence with respect to these potentials.     

DEM Generation for Lunar Surface using Chandrayaan-1 TMC Triplet Data

Digital Elevation Model (DEM) is an important prerequisite for understanding the lunar surface. However, making accurate DEM is a very challenging task due to (a) lack of support of projection parameters in COTS packages (eg. PCI Geomatica), which are to be used in generation of Lunar DEM and (b) unavailability of Ground Control Points (GCPs). In the present study, DEM generation of lunar surface was attempted without GCPs using Rational Function (RF) model from Chandrayaan-1 TMC triplet images. In the study, a good correlation (of almost same order) is observed between Nadir-Fore (NF), Nadir - Aft (NA), Fore - Aft (FA) and Fore - Nadir - Aft (FNA) image pairs. The results suggest that DEM for lunar surface can be created without GCPs using RF model.     

Propagation of Rayleigh waves on visco-elastic cylindrical surfaces placed in a magnetic field

Summary This paper studies axial Rayleigh waves in visco-elastic cylinder surrounded by vacuum and for body of same material with a cylindrical cavity. Magneto-elastic equations of motion for wave propagation in the radial and axial direction have been solved to obtain frequency equations.     

A Laboratory Study to Assess Separate and In-combination Effects of Zinc,Chromium and Nickel to the Fish Mystus vittatus

The present investigation is designed to work out the isolated and in-combination effects of Zn²⁺, Cr⁶⁺ and Ni²⁺ to a fish Mystus vittatus. From all the 12 combinations, 6 are antagonistic and 6 are synergistic. The combination Cr/Ni is highly synergistic while combination (Cr + Ni)/Zn is highly antagonistic in nature. The possible mechanisms responsible for antagonistic and synergistic combinations have been discussed and indicated as the occupation of critical receptor sites by less toxic metal (antagonism) or intrinsic affinity of the individual metal for the critical site or relative concentration and distribution of the metals within the target organ site (synergism). The results drawn can be indicated in terms of the effective concentration required to reach a particular level for a particular biological end point and can be expressed as follows.     

A self-similar flow of self-gravitating gas behind a spherical shock wave in magnetogasdynamics

This paper considers a spherical shock, in a conducting gas, of self-gravitating gas propagating in a non-uniform atmosphere at rest. Similarity principle has been used to reduce the equations governing the flow to ordinary differential equations under the assumption that the density varies as an inverse-power of distance from the point or explosion. The total energy of the wave is variable.Supported by CSIR, New Delhi under grant No. 7/57/287/81/EMR-I.     

A statistical significance of differences in classification accuracy of crop types using different classification algorithms

Crop classification is needed to understand the physiological and climatic requirement of different crops. Kernel-based support vector machines, maximum likelihood and normalised difference vegetation index classification schemes are attempted to evaluate their performances towards crop classification. The linear imaging self-scanning (LISS-IV) multi-spectral sensor data was evaluated for the classification of crop types such as barley, wheat, lentil, mustard, pigeon pea, linseed, corn, pea, sugarcane and other crops and non-crop such as water, sand, built up, fallow land, sparse vegetation and dense vegetation. To determine the spectral separability among crop types, the M-statistic and Jeffries–Matusita (J–M) distance methods have been utilised. The results were statistically analysed and compared using Z-test and χ²-test. Statistical analysis showed that the accuracy results using SVMs with polynomial of degrees 5 and 6 were not significantly different and found better than the other classification algorithms.     

3D instability analysis of an underground geological repository—an Indian case study

Conceptual geological repositories are generally used for disposing spent nuclear wastes containing both high and low level of nuclear radiation and heat. Due to its long-lasting effect, it is imperative to analyze its long-term effect on the surrounding rock. Before analyzing radiation and thermal effect, it is important to have structurally stable cavern because designing an opening in rock is a more difficult problem than designing the structure made of steel. Underground rocks are under stress because of the weight of the overlying rock, and in addition, an underground opening will produce a stress concentration and stress relaxation in the surrounding rock. If the induced stress in the surrounding rock exceeds its strength, the opening will fail either by fracturing or by deforming more than the tolerable limit. In this paper, the stability of four different shapes of excavation has been examined for conceptual geological repositories in Indian context. This has been done using equivalent continuum numerical model which has been incorporated in the commercial finite difference code-FLAC-3D. Effects of opening shapes on stress distribution, subsidence of crown and side wall, and their stability have been analyzed and discussed. The validation of FLAC^3D software for its applicability in conceptual underground geological repositories has been done with a published literature.     

Studies on the Pollution of the Kalinadi by Industrial Wastes near Mansurpur Part 2: Biological Index of Pollution and Biological Characteristics of the River

From the biological data presented here it is difficult to define any species of fish as an indicator of pollution in the strict sense. Nevertheless, the following generalizations are possible.

• - Species as Wallago attu, Clarias batrachus, Heteropneustes fossilis, Ophiocephalus striatus and Oph. punctatus occur in good number in the polluted stretch and seem to be tolerant species.
• - The species as Esomus danrica, Labeo rohita, Labeo gonius, L. bata, Catla catla, Cirrhina mrigala, Barbus chagunio, Barbus spec., Notopterus notopterus and Mugil corsula are most sensitive and disappear first in the polluted stretch.
• - The species as Barilius bola, B. bendelisis, Nemacheilus latius, Notopterus chitala, Collichrous bimaculatus, and Nandus nandus are moderately sensitive.
• - It appears that the main damage is caused to carp and feather-back fishes. The whole stretch of heavy pollution is almost devoid of carp and featherback.

The following important conclusions can be drawn from the distribution of plankton and bottom organisms:

• - The higher number of protozoans, chironomids, maggots and the decrease in the number of mollusca can be considered as the indicator of pollution, because of their abundance in polluted zones.
• - Chlorella, Lyngbya, Gyrosigma and Euglena (algae), Viviparius (mollusc) and Bosmina (crustacea) are very sensitive to pollution.
• - Oscillatoria, Pandorina, Anabaena, Nitzschia, Closterium (algae), Branchionus, Rotatoria (rotifers) and Naidium (annelid) are moderately sensitive.
• - Synedra, Spirogyra, Desmidium, Rivularia, Navicula, Fragillaria Phacus, Arcella and Vorticella are fairly tolerant forms.
• The stretch studied has been subdivided into five zones with characteristic features:
• - The Oligosaprobic Zone - characterized by a sufficient oxygen saturation, low B. O. D. and C. O. D., with a good fauna and flora.
• - The Polysaprobic Zone - with low oxygen saturation, high B. O. D. and C. O. D. and hydrogen sulphides with a restricted fauna and flora.
• - The α-Mesosaprobic zone - with moderate oxygen saturation, moderate B. O. D. and C. O. D. traces of hydrogen sulphide with the improvement of the fauna and flora.
• - The β-Mesosaprobic Zone - with fair oxygen saturation, low B. O. D. and C. O. D., with the reappearence of fauna and flora.
• - The Oligosaprobic Zone - similar to the zone of low pollution in all characteristics.