Angular Resolution of an EAS Array for Gamma Ray Astronomy at Energies Greater Than 5 x 10 (13) Ev

A 24 detector extensive air shower array is being operated at Ootacamund (2300 m altitude, 11.4 deg N latitude) in southern India for a study of arrival directions of showers of energies greater than 5 x 10 to the 13th power eV. Various configurations of the array of detectors have been used to estimate the accuracy in determination of arrival angle of showers with such an array. These studies show that it is possible to achieve an angular resolution of better than 2 deg with the Ooty array for search for point sources of Cosmic gamma rays at energies above 5 x 10 to the 13th power eV

Estimation of small ion concentration near the Earth's surface

Atmospheric ions produced by radon gas exhalation from the Earth's surface can play a vital role in the electrification of atmosphere, especially during nights when the gases are trapped in a stable layer close to the surface. The measurements of concentration of radon and its progeny, air conductivity and aerosol size distribution made at Pune, India, have been analyzed. The concentrations of radon and its progeny show maxima during night and early morning hours, between 0500 and 0700. IST when atmosphere is more stable and mixing is low and start decreasing after sunrise and attain minima during 1000-1800. h when air is unstable. The diurnal variation of the ionization rate, calculated using the concentrations of radon and its progeny, follows the variations of concentrations of radon and its progeny. The ion-aerosol balance equations are solved to study the effect of aerosols on small ion concentration in the lower atmosphere. It has been found that during daytime when aerosol concentration is high, 20-30 reduction in small ion concentration can occur due to aerosols. The small ion concentration estimated using measured air conductivity is compared with small ion concentration estimated by solving ion-aerosol balance equations and both are found to be in good agreement with each other. © 2011 Elsevier Ltd

THERMAL DEGRADATION AND XRD STUDIES OF VEGETABLE OIL BASED NOVOLAC SCAFFOLDS FOR THE FORMULATION OF RESINS

Biomaterials, chemicals and energy from renewable resources have been the object of considerable interest in recent years. Vegetable oils are one of the cheapest and most abundant biological sources available in large quantities and their use as starting materials has numerous advantages such as low toxicity, inherent biodegradability and high purity. They are considered to be one of the most important classes of renewable resources for the production of bio-based thermosets. As a substitute to the use of conventional reinforcing synthetic resins, biobased resins were synthesized from cardanol, renewable and low cost industrial grade oil obtained by vacuum distillation of Cashew Nut Shell Liquid (CNSL), an abundant agricultural byproduct of cashew industry. On the other hand to further expand the field of application, cardanol-based novolac scaffolds, used in the formulation of thermosetting resins by blending with a conventional epoxy resin, especially designed to be compatible with conventional bisphenol- A epoxy resins. In the present study resins have been synthesized by condensing diazotized p-anisidine cardanol dye with urea, resorcinol and furfural as condensing agent.. The resins have been characterised by FT-IR, 1H-NMR and XRD studies. Thermal behavior of the resins has been studied by Thermogravimetric Analysis (TGA) and Differential thermal analysis (DTA). The DTA, SEM and XRD data indicated the percentage of crystallinity associated with the thermal stability of the resins

CFD investigation of the cold hydrodynamics of a laboratory scale CFB furnace

This investigation presents a computational and experimental study of the flow characteristics of a laboratory scale CFB cold model riser. i) The first part of the work deals with 2D, CFD validation of a literature based CFB riser of circular cross section of 1m height. Simulation results showed good agreement with experimental literature data for radial profiles of volume fraction and particle velocity. ii) The second part is a work on simulation and experimental verification of a CFB riser flow characteristics of a CFB riser of rectangular cross section (400mm x 550mm x2000mm). An experimental run on the test rig was conducted for sand of 300 micron size at a fluidization velocity of 4 m/s and the fluidization behavior was captured on a high speed camera. For simulation, 3D, transient, Euler-ian approach combined with the Kinetic theory of Granular flow and Gidaspow drag model was used to describe the gas–particle behavior. A frame by frame visual comparison of instantaneous volume fraction distribution was made between camera images and 3D simulated profiles. A further graphical comparison between experimental literature data and simulated 3D profiles of volume fraction and particle velocity profiles yielded fairly good results. It was observed that, in spite of non inclusion of turbulence factor in the current 3D simulation, no significant influence was observed in the result

Preliminary Screening of Antibacterial Compounds from Palar River Basin Flora

Considering the significance of phytochemicals as antimicrobial agents, attempt was made in the present study, to categorize several rare plant species present in and around Palar river basin and to assess their antimicrobial activity. The densities of the green cover of the Palar river basin flora were assessed by the Google Earth software. Totally 28 plants were identified and classified into 17 families according to binomial classification system. Plant extracts were prepared from leaves of all collected plants by using methanol and chloroform. Thus, the crude methanol and chloroform extracts of 28 plant species were subjected to preliminary screening against 6 strains of human bacterial pathogen using the dick diffusion method at 500 µg/disc concentrations. The results indicated that 21 different plant species exhibited activity against one or more of the bacteria while four species, viz., Ammania baccifera, Plectranthus sp., Vitex trifolia and Vitex negundo showed activity against all test organisms. The plants containing bioactive metabolites demonstrated stronger anti-microbial properties stressing the need for further investigations using fractionated extracts and purified chemical components

Sea ranching of prawn

Sea ranching of praw

Mariculture in India: an overview

The world is projected to require a 50% increase in food production by 2050 to sustain an anticipated global population of 9.7 billion (FAO, 2017). Accomplishing this task poses considerable challenges, given the existing scarcity of land and freshwater resources, coupled with the looming threats of climate change and geopolitical impacts. In the global landscape, aquaculture has established itself as the fastest-growing sector in food production, boasting an annual growth rate exceeding 6% over the last two decades. Within aquaculture, mariculture stands out as the most rapidly expanding subsector, holding immense growth potential. The year 2020 witnessed mariculture contributing a substantial 33.0 million tonnes of food fish, constituting approximately 27% of the global food fish aquaculture production. The overall mariculture production, inclusive of seaweeds, reached an impressive 68.1 million tonnes, representing a significant 55.6% of the total world aquaculture production during the same year. India, with its burgeoning demand for seafood, is positioned to harness the considerable potential of mariculture, recognizing that reliance on the capture fisheries sector alone cannot meet this growing demand. The National Policy on Marine Fisheries (NPMF, 2017) underscores the pivotal role of mariculture in enhancing fish production from coastal waters. The government, in alignment with this policy, is committed to addressing the institutional and commercial requirements of the emerging mariculture sector. This commitment encompasses the formulation of leasing rights policies, spatial planning, provision of technological inputs such as husbandry, seed, feed, and health management, as well as addressing environmental and social impacts. Moreover, there is a concerted effort towards capacity building for local fishers and entrepreneurs to actively participate in mariculture