OALib Journal期刊

ISSN: 2333-9721




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匹配条件: “Sanjoy Sutradhar” ,找到相关结果约181条。
Herpetofaunal assemblage with special emphasis on community structure and spatiality in amphibians of Cauvery delta region, Tamil Nadu
Anukul Nath,Sanjoy Sutradhar,A. Kalai Mani,Vishnu Vijyan
Asian Journal of Conservation Biology , 2012,
Abstract: We studied the amphibian community structure, spatial overlap and herpetofaunal assemblage at Mannampandal, Tamil Nadu during October, 2010 to January, 2011. The survey methods involved careful visual estimation of amphibians in all the possible microhabitats present in the study area. Five different microhabitat categories were selected, viz., leaf litters, temporary water pools, tree holes, shrubs & grasses (ground vegetation), pathways, open floor & outer edges of buildings. We identified 26 species of reptiles and 14 species of amphibians. There was a significant difference found among the amphibian species occupying in different microhabitats. Species diversity was calculated, Shanon-Wiener H'= 1.55. The high niche overlap was found between Duttaphrynus scaber and Uperodon systoma followed by Fejervarya sp. and Sphaerotheca breviceps. The present study on amphibian community is just a representation to show the microhabitat occupancy and adjustment by the amphibians in human settlements and competition among them as, spatial resource partitioning.
Analysis of Density of Sintered Iron Powder Component Using the Response Surface Method  [PDF]
Prasanta Kumar Bardhan, Suprs Patra, Goutam Sutradhar
Materials Sciences and Applications (MSA) , 2010, DOI: 10.4236/msa.2010.13024
Abstract: The continued growth of ferrous powder metallurgy in automobile and others engineering application is largely de-pendent on the development of higher density materials and improved mechanical properties. Since density is a predominant factor in the performance of powder metallurgy components, it has been primarily considered for the present investigation. An experimental investigation have been undertaken in order to understand the variation of density with respect to the variation of process parameters viz., compaction load, sinter temperature and sintering time. The relation among the various process parameters with density has been observed. A mathematical model has been developed using second order response surface model (RSM) with central composite design (CCD) considering the above mentioned process parameters. The developed mathematical model would help in predicting the variation in density with the change in the level of different parameters influencing the density variation. This model also can be useful for setting of optimum value of the parameters for achieving the target density.
FEM Simulation and Experimental Validation of Cold Forging Behavior of LM6 Base Metal Matrix Composites  [PDF]
Hillol Joardar, Goutam Sutradhar, Nitai Sundar Das
Journal of Minerals and Materials Characterization and Engineering (JMMCE) , 2012, DOI: 10.4236/jmmce.2012.1110100
Abstract: The present paper examines the deformation behavior of solid cylinders of an aluminium alloy metal matrix composite (MMC) undergoing axial compression in a Universal Testing Machine under dry condition. The composite was pre- pared by the stir casting method from LM6 aluminium alloy using silicon carbide particles (SiC) as reinforcing agent. The effect of weight percentage of silicon carbide on microstructure, hardness and upsetting load is studied. The friction factor at die metal interface is evaluated by ring compression tests and its effect on non-uniform deformation is investi- gated. The experimental results are finally compared with those obtained by FEM simulation.
Wear Behaviour of Al-SiCp Metal Matrix Composites and Optimization Using Taguchi Method and Grey Relational Analysis  [PDF]
Shouvik Ghosh, Prasanta Sahoo, Goutam Sutradhar
Journal of Minerals and Materials Characterization and Engineering (JMMCE) , 2012, DOI: 10.4236/jmmce.2012.1111115
Abstract: Aluminium metal matrix composite is a relatively new material that has proved its position in automobile, aerospace and other engineering design applications due to its wear resistance and substantial hardness. Need for improved tribological performance has led to the design and selection of newer variants of the composite. The present investigation deals with the study of wear behaviour of Al-SiCp metal matrix composite for varying reinforcement content, applied load, sliding speed and time. Aluminium metal matrix composites reinforced with SiC particles are prepared by liquid metallurgy route using LM6 aluminium alloy and silicon carbide particles (size ~ 37 μm) by varying the weight fraction of SiC in the range of 5% - 10%. The material is synthesized by stir casting process in an electric melting furnace. The materials are then subjected to wear testing in a multitribotester using block on roller configuration. A plan of experiments based on L27 Taguchi orthogonal array is used to acquire the wear data in a controlled way. An analysis of variance is employed to investigate the influence of four controlling parameters, viz., SiC content, normal load, sliding speed and sliding time on dry sliding wear of the composites. It is observed that SiC content, sliding speed and normal load significantly affect the dry sliding wear. The optimal combination of the four controlling parameters is also obtained for minimum wear. The microstructure study of worn surfaces indicates nature of wear to be mostly abrasive.
Machinability of LM6/SiCp metal matrix composites with tungsten carbide cutting tool inserts
Rabindra Behera,G. Sutradhar
Journal of Engineering and Applied Sciences , 2012,
Abstract: This paper explains the influence of machining parameters such as cutting forces and surface roughness on the machinability of LM6/ SiCp metal matrix composites at different weight fraction of SiCp. Machining tests were carried out at different cutting speed (i.e., 30, 68 and103 m/min) and different depth of cuts (i.e., 0.5, 1.0 and 1.5mm) at constant feed rate i.e., 0.05 mm/rev to study the machinability of as cast composites. It was observed that the depth of cut and the cutting speed at constant feed rate affects the surface roughness and the cutting forces during dry turning operation of cast MMCs. It was also observed that higher weight percentage of SiCp reinforcement imparts a higher surface roughness and needs high cutting forces. This experimental analysis and test results on the machinability of Al/SiC-MMC will provide essential guidelines to the manufacturers.
Struggling to a monumental triumph: re-assessing the final phases of the smallpox eradication program in India, 1960-1980
Bhattacharya, Sanjoy;
História, Ciências, Saúde-Manguinhos , 2007, DOI: 10.1590/S0104-59702007000400002
Abstract: the global smallpox program is generally presented as the brainchild of a handful of actors from the who headquarters in geneva and at the agency's regional offices. this article attempts to present a more complex description of the drive to eradicate smallpox. based on the example of india, a major focus of the campaign, it is argued that historians and public health officials should recognize the varying roles played by a much wider range of participants. highlighting the significance of both indian and international field officials, the author shows how bureaucrats and politicians at different levels of administration and society managed to strengthen-yet sometimes weaken-important program components. centrally dictated strategies developed at who offices in geneva and new delhi, often in association with indian federal authorities, were reinterpreted by many actors and sometimes changed beyond recognition.
Contribui??es multifacetadas: trabalhadores da saúde e a erradica??o da varíola na índia
Ciência & Saúde Coletiva , 2008, DOI: 10.1590/S1413-81232008000300017
Abstract: smallpox eradication in south asia was a result of the efforts of many grades of health-workers. working from within the confines of international organisations and government structures, the role of the field officials, who were of various nationalities and also drawn from the cities and rural enclaves of the countries in these regions, was crucial to the development and deployment of policies. however, the role of these personnel is often downplayed in official histories and academic histories, which highlight instead the roles played by a handful of senior officials within the world health organization and the federal governments in the sub-continent. this article attempts to provide a more rounded assessment of the complex situation in the field. in this regard, an effort is made to underline the great usefulness of the operational flexibility displayed by field officers, wherein lessons learnt in the field were made an integral part of deploying local campaigns; careful engagement with the communities being targeted, as well as the employment of short term workers from amongst them, was an important feature of this work.
Physics Education Research: Or it's so hard to find good help these days
Sanjoy Mahajan
Physics , 2004,
Abstract: Physics education research (PER) aims to improve how students solve problems. But whose problems are we teaching students to solve? Physics has grown up as a child of war, and PER stems from the cognitive revolution in psychology, which arose from military needs and funding. Physics, PER, and state power are allies. By improving physics teaching, we arm the state against ourselves and move farther from a peaceful and humane world.
Observations on teaching first-year physics
Sanjoy Mahajan
Physics , 2005,
Abstract: Highly successful students, as measured by grades and by scores on the Force Concept Inventory, still struggle with fundamental concepts in mathematics and physics. These difficulties, which turn physics into parrot learning and include confusing velocity and acceleration or being unable to reason with graphs, are revealed by problems requiring estimation and conceptual reasoning. I discuss these problems, the difficulties that they reveal, and suggest possible remedies.
Estimating gas mileage: An example of order-of-magnitude physics
Sanjoy Mahajan
Physics , 2005,
Abstract: I discuss how to estimate the gas mileage of a car. This discussion, which covers air resistance and Reynolds numbers, describes one way to introduce dimensional analysis and order-of-magnitude physics into introductory physics (if only the syllabus would allow it). It is part teacher's guide and part textbook chapter -- I hope not the worst parts of each.

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