323 research outputs found

    Introduction to geostatistics

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    Geographical Information System (GIS) is a technological tool used to describe and characterize spatially referenced geographical information for the purpose of visualizing, querying and analyzing. The tool enables capturing, storing, analyzing, sharing, displaying and modelling of spatial data maintained with in single database. Making decision based on geography is basics to human thinking and spatial analysis using GIS enable people to combine information from many independent sources and derive entirely new layers of information that are more accurate and reliable in decision making. Spatial analysis involves study of phenomenon that varies with time and space

    Design and analysis of contour bell nozzle and comparison with dual bell nozzle

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    The performance and the thrust delivery of the engine such as nozzles are in renovation for the greater performance. Modern combustion expansion system like in rocket nozzles will be updated with respect to the application. Bell and Dual bell nozzle is the One of such development. Four different types of Bell nozzle one duel bell nozzle is selected and studied using computational fluid dynamics (CFD) in the present paper. The project mainly focuses on design and analysis of contoured convergent divergent bell nozzle. For the simulation, consider  a 2D , parabolic contoured thrust optimized axisymmetric nozzle. The priority is  given to design a bell nozzle with negligible shock wave. The temperature effects are not taken into this study, the flow is purely cold flow (303K). A full length Bell nozzle created using Gambit software. The meshing and analysis of the Bell model were done using FLUENT software. Air is taken as working medium for the nozzle and also for the ambience. Only one half of the nozzle is simulated due to symmetry reasons, and symmetry boundary conditions are used at the corresponding planes. The nozzle walls were set as adiabatic and assumed to be hydraulically smooth. A control volume was constructed around the nozzle to take the interaction with the ambience. The behavior of flow along the bell nozzle is thus obtained

    Scale worm recorded from Lakshadweep

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    During an underwater survey in lagoon of Chetlat island Lakshdweep in 2015 a cryptic, commensalistic scale worm association on the sea cucumber Stichopus chloronotus was observed. This scale worm was identified as Gastrolepidia clavigera Schmarda, 1861 which come under polychaetes (Family:Polynoidae). These are known to inhabit the surface of holothurians in its anterior or posterior ends, and if disturbed crawl into the mouth or cloaca of the sea cucumber. The colour of the scale worm mimics the colour of the host which makes it difficult to be detected. Studies have found that this scale worm species feed on the tissue of the sea cucumber and are resistant to the toxin holothurin which is commonly released by sea cucumbers against predators

    ‘Pakshi Pitti’: a robust haven for pelagic birds in the Indian Ocean

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    India, a land of distinct climatic and geographic zones, supports a remarkable diversity of avian fauna within both its mainland and its seas. There are over 1200 species of birds recorded in India, with the majority occurring in the mainland (Praveen et al., 2016). Surrounded by extensive marine zones on its three sides, territorial waters and marginal seas around India form seamless habitats for a significant number of marine avian species. Seventy species of marine birds are observed in the region (BirdLife International 2015). These include predominantly open oceanic species like frigate birds, tropicbirds, shearwaters and petrels which are winter visitors or vagrants, but birds like gulls and terns are more commonly found along the coastal waters of India

    Species distribution modelling of seaweeds in Indian Seas

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    Seaweeds, the green pastures of the ocean, hold immense potential for India’s coastal communities and its burgeoning blue economy. These marine macroalgae are not just ecological keystones, responsible for oxygen production and forming the base of marine food webs, but also a multi-billion-dollar industry offering a cornucopia of products, from food supplements to hydrocolloids. With projections for exponential growth in the coming decades, harnessing the potential of seaweeds requires precise and sustainable approaches. While India stands strong as a seaweed cultivating nation, identifying suitable regions for this marine bounty remains a complex puzzle. The vast and diverse coastline demands advanced tools to unlock hidden opportunities. The realm of species distribution modelling (SDM) aids in identifying the suitable habitats along our coast. This book chapter offers a comprehensive exploration of how SDM can illuminate the path for a thriving seaweed industry in India. Through a real-world case study of an SDM exercise, we paint a vivid picture of how this technology can translate knowledge into action

    Rough triggerfish, Canthidermis maculata from Gujarat coast

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    A specimen of the Rough triggerfish, Canthidermis maculata (Bloch, 1786) was landed by a multiday trawler on 25th November 2015 at Mangrol Fisheries Harbour, Gujarat. The specimen was brownish grey in colour with characteristic white spots all over the body including the head. It measured 309 mm and 256 mm in Total length and Standard length respectively with a weight of 580 g (Fig. 1). The fish is usually found in areas having sandy, muddy or rocky bottoms at a depth range of 50-100 m and is reported from the Western Indian Ocean

    Plankton Productivity in Lagoons of Agatti and Bangaram Atolls of Lakshadweep Archipelago, India

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    Phytoplankters and zooplankters function as important links in the food chain and form the food of a large number of organisms in the aquatic ecosystem. As plankters play an important role in the health of an aquatic ecosystem, the study on these resources in the productive aquatic ecosystems of Lakshadweep is significant. Earlier studies carried out earlier from Agatti and Bangaram are by Pratap et al. (1977), Achuthankutty et al. (1989) and Casanova & Nair (1999). No recent reports are available on plankters from Agatti and Bangaram. Hence, an attempt is made to study the qualitative and quantitative abundance of phytoplankters and zooplankters in the selected lagoons of Lakshadweep
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