Radio and near-infrared observations of the steep spectrum Galactic plane radio source WKB 0314+57.8

Radio and near-infared observations towards the steep spectrum Galactic plane radio source WKB 0314+57.8 are presented, in order to clarify the nature of this source. The radio observations include archival and survey data, together with new Giant Metrewave Radio Telescope observations at 617 MHz. The near-infrared observations are in the J and K bands, from the Gemini instrument on the Shane 3-m telescope. The radio observations show that WKB 0314+57.8 is extended, with an very steep spectrum (with flux density proportional to frequency to -2.5 power between 40 MHz and 1.5 GHz). The colour--magnitude diagram constructed from near-infrared observations of the field suggests the presence of a z approx 0.08 galaxy cluster behind the Galactic plane, reddened by about 6 magnitudes of visual extinction. Although the steep spectrum source has no obvious identification, two other radio sources in the field covered by the near-infrared observations have tentative identifications with galaxies. These observations indicate that WKB 0314+57.8 is a relic source in a cluster of galaxies, not a pulsar.Comment: 6 pages, to appear in MNRAS, typos correcte

Recovery of Vanadium Pentoxide from Vanadium Bearing Titaniferrous Magnetites Projected Pilot Plant Studies

The treatment of vanadium bearing ores for the recovery of vanadium pentoxide is not new to India. A plant capable of producing 250 lbs. of vanadium pentoxide per day was set up at Jamshedpur during World War II by the Tata Iron & Steel Co. Ltd., but as the demand of ferro-vanadium decreased considerably after the war, the plant had to be shut down. A company was also set up for the extraction of vanadium at Rairangpur during World War II and it is reported that the plant went-into production in September, 1945 and stopped work in April 1946 and has since been lying idle.Various reasons, viz., high cost of production, lack of demand etc. have been assigned for closing down the plant. With the country's industrial development and the establishment of'"the alloy and tool steel industry, as envisaged in the 3rd Five Year Plan, it is anticipated that the demand of ferro-vanadium will increase consid-erably

The late time radio emission from SN 1993J at meter wavelengths

We present the investigations of SN 1993J using low frequency observations with the Giant Meterwave Radio Telescope. We analyze the light curves of SN 1993J at 1420, 610, 325 and 243 MHz during $7.5-10$ years since explosion.The supernova has become optically thin early on in the 1420 MHz and 610 MHz bands while it has only recently entered the optically thin phase in the 325 MHz band. The radio light curve in the 235 MHz band is more or less flat. This indicates that the supernova is undergoing a transition from an optically thick to optically thin limit in this frequency band. In addition, we analyze the SN radio spectra at five epochs on day 3000, 3200, 3266, 3460 and 3730 since explosion. Day 3200 spectrum shows a synchrotron cooling break. SN 1993J is the only young supernova for which the magnetic field and the size of the radio emitting region are determined through unrelated methods. Thus the mechanism that controls the evolution of the radio spectra can be identified. We suggest that at all epochs, the synchrotron self absorption mechanism is primarily responsible for the turn-over in the spectra. Light curve models based on free free absorption in homogeneous or inhomogeneous media at high frequencies overpredict the flux densities at low frequencies. The discrepancy is increasingly larger at lower and lower frequencies. We suggest that an extra opacity, sensitively dependent on frequency, is likely to account for the difference at lower frequencies. The evolution of the magnetic field (determined from synchrotron self absorption turn-over) is roughly consistent with $B \propto t^{-1}$. Radio spectral index in the optically thin part evolves from $\alpha \sim 0.8-1.0$ at few tens of days to $\sim 0.6$ in about 10 years.Comment: 37 pages, 9 figures in LaTex; scheduled for ApJ 10 September 2004, v612 issue; send comments to: [email protected]

Impact of Mass Bathing and Religious Activities on Water Quality Index of Prominent Water Bodies: A Multilocation Study in Haryana, India

The present study was designed to assess the impact of mass bathing and religious activities on water quality index (WQI) of prominent water bodies (eight) in Haryana, India. Water quality characteristics revealed significant increase in the values of nitrate, biochemical oxygen demand (BOD), turbidity, total dissolved solids (TDS), conductivity, total hardness, total alkalinity, and MPN count after the religious activities. The computed WQI at all the eight selected sites varied from 47.55 to 211.42. The results revealed that there was a significant increase in the value of WQI after mass bathing or any other ritual performed. Out of eight water bodies studied three (sites 3, 4, and 5) were found under good water quality status; four sites (1, 2, 6, and 7) depicted medium water quality but site 8 was found under poor water quality after the religious activities. The good water quality status of water bodies was correlated with larger size of the water bodies and less number of pilgrims; however, the poor WQI values may be attributed to smaller size of the water body and heavy load of pilgrims on such sites. Therefore, water of these religious water bodies needed to be regularly changed after mass bathing to protect the aquatic component from different contaminations

Economic utilization, recovery and substitution of some strategic non-ferrous metals

With the increased tempo of industrial expansion and the ever rising consumption of common nonferrous metals like copper, lead, zinc, tin, deficient in India, their conservation, substitution, reclamation from waste pro-ducts and substandard raw materials are of paramount importance for India, not only to tide over the present crisis but also in the larger interest of economic growth and self-sufficiency. Self-sufficiency can be attained by developing processes for the utilization of low grade and other complex ores, recovery of metals from waste products like slags, ashes, drosses and above all by the conservation of non-ferrous metals not avail-able in the country by their judicious use and subst-itution

Tropospheric Scatter Propagation Measurements Beyond the Horizon in Arid Zone-A Note

Tropospheric scatter study beyond the horizon radio link presently necessitates tests to establish the median path loss and to determine the magnitude and duration of the path loss variations. The average basic transmission loss of the scattered component, Lbs can be found if K (ratio of r.m.s. value of scattered and constant component) and the resultant basic transmission loss Lbm are known. This paper also deals with the diurnal and seasonal behaviour of signal strength, based on the ana!ysis of about ten months recording on a C band Troposcatter Link between Pilani and Delhi

Energy-Conserving Lattice Boltzmann Thermal Model in Two Dimensions

A discrete velocity model is presented for lattice Boltzmann thermal fluid dynamics. This model is implemented and tested in two dimensions with a finite difference scheme. Comparison with analytical solutions shows an excellent agreement even for wide temperature differences. An alternative approximate approach is then presented for traditional lattice transport schemes