2,741 research outputs found

    Some design and operational aspects of continous weld mill furnace

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    The steel tube Industry in India had its beginning only as recently as recently as 1954. Today the lincensed capacity of steel tubes in the organized sectors of the country Is approximately 2 million tonnes

    Coefficient of Drag and Trajectory Simulation of 130 mm Supersonic Artillery Shell with Recovery Plug or Fuze

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    In the present study, the drag variation and trajectory elements estimation of a supersonic projectile having two different nose shapes are made numerically. The study aims at finding the coefficient of drag and shock wave pattern for 130 mm artillery shell fitted with recovery plug or with fuze, when travelling at zero angle of attack in a supersonic flow of air. The coefficient of drag (CD) obtained from the simulation is used as an input parameter for estimation of trajectory elements. The numerical results, i.e., the coefficient of drag at different Mach numbers and trajectory elements are validated with the data recorded by tracking radar from an experimental firing. Based on numerical results and data recorded in experimental firing, the coefficient of drag in the case of the shell with recovery plug is 2.7 times more than for the shell with fuze. The shock wave in the case of the shell with recovery plug is detached bow shock wave, whereas in the case of a shell with fuze, the shock is attached. The results indicate that the coefficient of drag increases with detached shock wave and an increase in the radius of the shell nose. Good agreements were observed between numerical results and experimental observations.Defence Science Journal, Vol. 64, No. 6, November 2014, pp.502-508, DOI:http://dx.doi.org/10.14429/dsj.64.811

    Market Efficiency of Hessian Cloth and Sacking Bags’ Transferable Specific Delivery Contract transactions in a Regional Commodity Exchange in West Bengal, India

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    The price stabilization function of the commodity futures market is conditioned upon the efficiency of the market. An attempt has been made in this paper to test the efficiency of the hessian cloth and sacking bags’ contracts transactions in the East India Jute and Hessian Commodity Exchange - the oldest commodity-specific regional exchange in India - so as to gauge its contribution in the economically significant roles of price stabilization and price discovery in the underlying commodity spot market. Empirical results, based on the Johansen cointegration test, suggested that most of the hessian and sacking bags’ contracts were inefficient in the long run. In the short run, the sacking bags’ forward market exhibited short-run inefficiencies and pricing biases. However, large positive deviations from the co-integrating relation between the forward and spot prices of hessian cloth contracts were significantly corrected in the following period in the forward market. Therefore, the paper concludes, hessian forward contracts are relatively more efficient as compared to sacking bags’ contracts.Keywords: Market efficiency, East India Jute and Hessian Commodity Exchange, Hessian, Sacking, Cointegration test, Vector Error Correction.JEL classification: C58, G13, G14, P22

    Recurrence network analysis in a model tripartite quantum system

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    In a novel approach to quantum dynamics, we apply the tools of recurrence network analysis to the dynamics of the quantum mechanical expectation values of observables. We construct and analyse ϵ\epsilon-recurrence networks from the time-series data of the mean photon number in a model tripartite quantum system governed by a nonlinear Hamiltonian. The role played by the intensity-dependent field-atom coupling in the dynamics is investigated. Interesting features emerge as a function of a parameter characterising this intensity-dependent coupling in both the short-time and the long-time dynamics. In particular, we examine the manner in which standard measures of network theory such as the average path length, the link density and the clustering coefficient depend on this parameter.Comment: Comments are welcome (7 pages, 6 figures
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