309 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

    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

    GIS based mapping of zoanthids along Saurashtra coast, Gujarat, India

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    Zooxanthellate zoanthids (or. Zoantharia) are the third largest order of Hexacorallia and are an integral part of the coral reef ecosystem. Worldwide coral reefs will continue to suffer under the synergistic effect of anthropogenic agent and climate change, thereby shifting towards more adaptive and resilient species. Zoanthids are looked upon as adaptive species under the current dynamics of climate change. Zoanthids are also studied for their biochemical properties like extraction of zoanthamine, Oxytoxic agent, Green Fluorensce Proteins (GFP). Hence understanding the ecology and spatial distribution patterns of zoanthids is important in formulating conservational and management policies pertaining to marine ecosystems. The present study encompasses the spatial distribution pattern of zoanthids along the Saurashtra coast of Gujarat, India. Nineteen stations have been selected from Okha to Bhavnagar and spatial distribution patterns of eight zoanthid species have been studied using modified belt transact method, GIS and IDW interpolation technique. The results indicated Palythoa mutuki as the most common and abundant species along the Saurashtra coast of Gujarat followed by Zoanthus sansibaricus and Palythoa tuberculosa. While species such as Zoanthus gigantus and Palythoa heliodiscus, been the rarest species along this coast. The study is first of its kind and attempt has been made to incorporate the modern tools which overcome the constraints of spatial variation in the distribution over traditional methods of biodiversity studies. The study also forms baseline study to monitor zoanthid progression in the future and developing georeferenced database along the Saurashtra coast of India for long term permanent transect monitoring and policy framework development
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