Mineral Characterisation of some Indian Phosphatic depo-sits and its influence on their processing problems

Phosphatic mineral deposits are extensively used in the manufacture of fertilisers which are so essential for agriculture and also in chemical and other industries. Phosphorus is widely dispersed in the earth's crust but it is most economically concentrated in the form of few mine-rals of which apatite and collophane are of commercial importance. The presence of these minerals are quite appreciable in many magnetite-quartzites, quartz-chlorite schists, rock phosphatic limestones. The naturel sources of phosphorus are phsophatic nodules and guano

Potentials and Availability of Mineral Raw Materials for Ferro Alloy Production in India

With an ever increasing tempo for more and more iron and steel production, the demand for ferro alloys has increased considerably, which ultimately depend on the mineral raw materials position. With this in view an appraisal has been made in this paper on the potentials and availability of some of the mineral raw materials for ferro-alloy industry. The different raw materials with their specifications, occurences, distribution, grades, reserves, production, consumption, exports and imports etc. have been discussed

The Vissannapeta eucrite

A wholly encrusted single stone that fell in Vissannapeta, Andhra Pradesh, India has been identified as a cumulate eucrite based on its primary texture and mineral composition: anorthite (An92.4-94.6), orthopyroxene (En49.1-51.8Fs44.2-49.7Wo1.2-4.0), and clinopyroxene (En38.8-46.8Fs14.8-33.6Wo19.6-46.4). The stone is pyramidal in shape, and the crust shows rib-like flow features indicating that it had an oriented passage through the atmosphere towards the terminal stage of its flight. Conditions of its fall, mineralogical characteristics, and results of measurements of cosmogenic radioactivity (26Al, 22Na, and 54Mn) and track density are described. Aluminum-26 and 22Na in Vissannapeta are ∼ 75% of the expected values and also lower by a similar factor compared to the activities measured in Piplia Kalan, another eucrite, which fell ∼ 18 months before Vissannapeta. Because higher activity of 22Na and 54Mn would be expected from solar cycle modulation of galactic cosmic rays, these results, as well as the track density gradient, indicate that Vissannapeta was a small body (≤ 120 kg) in the interplanetary space wherein the nuclear cascade due to galactic cosmic rays did not develop fully. Tracks, surface morphology, and crustal features indicate at least two fragmentation events in the atmosphere

Single step process for the synthesis of carbon nanotubes and metal/alloy-filled multiwalled carbon nanotubes

A single-step approach for the synthesis of multi-walled nanotubes (MWNT) filled with nanowires of Ni/ternary Zr based hydrogen storage alloy has been illustrated. We also demonstrate the generation of CO-free hydrogen by methane decomposition over alloy hydride catalyst. The present work also highlights the formation of single-walled nanotubes (SWNT) and MWNTs at varying process conditions. These carbon nanostructures have been characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), high resolution TEM (HRTEM), Energy dispersive X-ray analysis (EDX) and Raman spectroscopy. This new approach overcomes the existing multi-step process limitation, with possible impact on the development of future fuel cell, nano-battery and hydrogen sensor technologies

Some studies on the ionospheric absorption at Waltair

The results of absorption measurements made on frequencies 2·0 Mc/s, 2·5 Mc/s and 3·0 Mc/s at Waltair (Geog. Lat. 17°43'N, Long. 83°18'E, Geomag. Lat. 7·4°N) during the period January 1963 to February 1965 are presented. The main aspects studied are (i) diurnal variation of absorption, (ii) the relative contributions of D- and E-region absorptions, (iii) sunspot variation of absorption and (iv) effect of magnetic activity on absorption. The value of cos Χ index n for the diurnal variation of absorption on 2·0 Mc/s is found be 0·8. The relative contributions of D- and E-regions to 2·0 Mc/s absorption are estimated and it is found that the D-region contribution consists of two parts, one depending on the solar zenith angle and the other independent of it. The results of correlation between the absorption and magnetic activity are presented and it is found that the effect of magnetic activity is more at higher levels of the absorbing stratum when compared to that at lower levels

HF Doppler Observations during the Total Solar Eclipse of 16 February 1980

230-233HF Doppler observations were made at Waltair on 10 MHz ATA standard time and frequency CW signal from New Delhi during the total solar eclipse of 16 Feb. 1980 across South India. The Doppler record showed characteristic frequency variations particularly observable on an eclipse day, which throw some light on reflection height changes in the ionosphere during an eclipse. The record also exhibits a quasi-periodic structure of 6-min period which would not be present normally for this time of the day. This feature could be an eclipse generated phenomenon

Simultaneous Study of Sea Breeze with Two Monostatic Acoustic Sounders

136-142Sea breeze at Visakhapatnamis influenced by the unique combination of topographic meteorological and oceanographic features To characterize the main features of sea breeze as it penetrates inland, two monostatic acoustic sounders have been operated simultaneousliy in May 1983 one at the University site about 1 km away from the coastline and other at the airport meteorological observatory about 11 km west inland. From the sounder records of the two sites and the supporting meteorological data it has been observed that the sea breeze at the two locations differs considerably in respect of its onset, duration, depth and thermal turbulence distribution. This marked variability is attributed to the peculiar orography of the locale

Seasonal Variation of Coastal Meteorological Phenomena as Revealed by Acoustic Sounder

57-60A climatology of the boundary layer of the atmosphere at Visakhapatnam is compiled using the acoustic sounder data collected for a period of 3 yr from May 1980 to April 1983. The meteorological phenomena as inferred from the facsimile records are classified into 13 categories and then analyzed for percentage period of occurrence of each category in each month. It is found that the complex meteorological processes in coastal zones have a significant seasonal dependence

Acoustic Sounder Study of Sea Breeze in Southwest Monsoon Season

199-204Acoustic sounder echo patterns obtained at Visakhapatnam during periods of sea breeze in the month of July 1980 (monsoon month) are presented and discussed in the light of the prevailing weather conditions and surface meteorological data obtained from the antenna site. Sea breeze occurrence in July is occasional. unlike daily occurrence in summer, because of the dominant gradient flow from west to east due to the prevailing southwest monsoon. A large increase in the intensity and height of backscattered echoes was observed at the onset of sea breeze indicating the thermally inhomogeneous and turbulent nature of the air just behind the moving sea breeze front. The increase in the depth of the sea breeze as shown by the acoustic records was mirrored in hygrograrns