Study on System Design and Integration of Variable Buoyancy Systems for Underwater Operation

This paper presents the design and analysis of the ‘Variable Buoyancy System (VBS)’ for depth control which is an essential operation for all underwater vehicles. We use the ‘Water Hydraulic Variable Buoyancy System (WHVBS)’ method to control the buoyancy and discuss details of the system design architecture of various components of VBS. The buoyancy capacity of the developed VBS is five kilograms and the performance of the VBS in standalone mode is analysed using numerical simulation. Presented VBS is operable to control the buoyancy up to sixty meters of depth and it can be directly installed to medium size UVs. Simulation results show that the developed VBS can reduce the energy consumption significantly and higher in each cycle (i.e. descending and ascending) of the same VBS in standalone mode being operated with either propeller or thruster for sixty meters depth of operation. Our results conclude and demonstrate that the designed VBS is effective in changing the buoyancy and controlling the heave velocity efficiently and this serves the purpose of higher endurance and better performances desired in rescue/attack operations related to the UVs both in civilian and defense domains

Pilot Scale Processing of Red Flesh Guava RTS Beverage

Pilot scale studies on production of ready-to-serve (RTS) beverage from red flesh guava were done using 100 kg of the fruit. Pulp yield was more (73.68 %) in lye peeling than in hand peeling (58.68 %). RTS beverage was prepared by mixing fruit pulp with syrup to an optimum level of acidity and sugar, as standardized on a laboratory scale. Blending RTS beverage by using colloidal mill improved the colour, consistency and overall quality. From 100 kg of red flesh guava, 247 litres of RTS beverage could be obtained. The cost:benefit ratio and value addition from this process were worked out at 1.79 and Rs. 5.45/kg of fruit, respectively

Evolution of Currents of Opposite Signs in the Flare Productive Solar Active Region NOAA 10930

Analysis of a time series of high spatial resolution vector magnetograms of the active region NOAA 10930 available from SOT/SP on-board Hinode revealed that there is a mixture of upward and downward currents in the two foot-points of an emerging flux-rope. The flux emergence rate is almost the same in both the polarities. We observe that along with an increase in magnetic flux, the net current in each polarity increases initially for about three days after which it decreases. This net current is characterized by having exactly opposite signs in each polarities while its magnitude remains almost the same most of the time. The decrease of net current in both the polarities is due to the increase of current having a sign opposite to that of the net current. The dominant current, with same sign as the net current, is seen to increase first and then decreases during the major X-class flares. Evolution of non-dominant current appears to be a necessary condition for a flare initiation. The above observations can have a plausible explanation in terms of the superposition of two different force-free states resulting in non-zero Lorentz force in the corona. This Lorentz force then push the coronal plasma and might facilitate the magnetic reconnection required for flares. Also, the evolution of the net current is found to follow the evolution of magnetic shear at the polarity inversion line.Comment: 24 pages, 6 figures, Submitted to Astrophysical Journa

Many-body approach to low-lying collective excitations in a BEC approaching collapse

An approximate many-body theory incorporating two-body correlations has been employed to calculate low-lying collective multipole frequencies in a Bose-Einstein condensate containing $A$ bosons, for different values of the interaction parameter $\lambda=\frac{Aa_{s}}{a_{ho}}$. Significant difference from the variational estimate of the Gross-Pitaevskii equation has been found near the collapse region. This is attributed to two-body correlations and finite range attraction of the realistic interatomic interaction. A large deviation from the hydrodynamic model is also seen for the second monopole breathing mode and the quadrupole mode for large positive $\lambda$.Comment: 8 pages, 2 figure

Problems & Prospects of Ferromanganese industry in India

This paper deals with the trend of production and export of ferro-manganese in the country with reference to steel production. The various problems encountered by this indu-stry, such as deterioration in the quality of raw mater-ials, their price rise, shortage of power with its high tariff and non-utilisation of installed capacity have been discussed in detail. Attention has also been drawn to some of the commercial points related to rise in excise duty, railway freight, decline in sales and export. The prospect of Fe-Mn industry vis-a-vis the increase in output of steel in the country and improvement in the global trend has been dealt with